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Objective: Acute biliary cholecystitis (ABC) is a significant cause of abdominal pain in emergency department. In this study, we investigated the role of immature granulocytes (Ig) as markers of inflammatory response in distinguishing between biliary colic and ABC. Materials and Methods: This retrospective study included 150 patients who presented with abdominal pain and were found to have or were diagnosed with gallstones. Patients were divided into biliary colic and ABC groups. Laboratory values of the patients, such as age, white blood cell count (WBC), hemoglobin, platelet, mean platelet volume, red cell distribution width, neutrophil (Neu), lymphocyte, Ig%, Ig number, and C-reactive protein (CRP) were recorded in the study form. Receiver operating characteristic and regression analysis were performed for the diagnosis of ABC. Results: We found that the WBC, Neu, and Ig counts were statistically significantly higher in patients with ABC than in those with biliary colic. However, in the regression analysis, only the Murphy's sign and CRP value were found to be significant in the diagnosis of ABC [p<0.001, odds ratio (OR): 0.119 [95% confidence interval (CI): 0.053-0.268], p=0.002, OR: 1.007 (95% CI: 1.002-1.011), respectively]. Conclusion: Although the Ig number was statistically significant in distinguishing between ABC and biliary colic, we believe that the CRP value and Murphy's sign are superior parameters. [ABSTRACT FROM AUTHOR]

The origins and evolution of the eosinophilic leukocyte have received only scattered attention since Paul Ehrlich first named this granulocyte. Studies suggest that myeloperoxidase, expressed by granulocytes, and eosinophil peroxidase diverged some 60 to 70 million years ago, but invertebrate to vertebrate evolution of the eosinophil lineage is unknown. Vertebrate eosinophils have been characterized extensively in representative species at light microscopic, ultrastructural, genetic, and biochemical levels. Understanding of eosinophil function continues to expand and includes to date regulation of "Local Immunity And/Or Remodeling/Repair" (the so-called LIAR hypothesis), modulation of innate and adaptive immune responses, maintenance of tissue and metabolic homeostasis, and, under pathologic conditions, inducers of tissue damage, repair, remodeling, and fibrosis. This contrasts with their classically considered primary roles in host defense against parasites and other pathogens, as well as involvement in T-helper 2 inflammatory and immune responses. The eosinophils' early appearance during evolution and continued retention within the innate immune system across taxa illustrate their importance during evolutionary biology. However, successful pregnancies in eosinophil-depleted humans/primates treated with biologics, host immune responses to parasites in eosinophil-deficient mice, and the absence of significant developmental or functional abnormalities in eosinophil-deficient mouse strains under laboratory conditions raise questions of the continuing selective advantages of the eosinophil lineage in mammals and humans. The objectives of this review are to provide an overview on evolutionary origins of eosinophils across the animal kingdom, discuss some of their main functions in the context of potential evolutionary relevance, and highlight the need for further research on eosinophil functions and functional evolution. [ABSTRACT FROM AUTHOR]

Purpose: Cerebrospinal fluid (CSF) granulocytes are associated with bacterial meningitis, but information on its diagnostic value is limited and primarily based on retrospective studies. Therefore, we assessed the diagnostic accuracy of CSF granulocytes. Methods: We analyzed CSF granulocytes (index test) from all consecutive patients in two prospective cohort studies in the Netherlands. Both studies included patients ≥ 16 years, suspected of a central nervous system (CNS) infection, who underwent a diagnostic lumbar puncture. All episodes with elevated CSF leukocytes (≥ 5 cells per mm3) were selected and categorized by clinical diagnosis (reference standard). Results: Of 1261 episodes, 625 (50%) had elevated CSF leukocytes and 541 (87%) were included. 117 of 541 (22%) were diagnosed with bacterial meningitis, 144 (27%) with viral meningoencephalitis, 49 (9%) with other CNS infections, 76 (14%) with CNS autoimmune disorders, 93 (17%) with other neurological diseases and 62 (11%) with systemic diseases. The area under the curve to discriminate bacterial meningitis from other diagnoses was 0.97 (95% confidence interval [CI] 0.95–0.98) for CSF granulocyte count and 0.93 (95% CI 0.91–0.96) for CSF granulocyte percentage. CSF granulocyte predominance occurred in all diagnostic categories. A cutoff at 50% CSF granulocytes gave a sensitivity of 94% (95% CI 90–98), specificity of 80% (95% CI 76–84), negative predictive value of 98% (95% CI 97–99) and positive predictive value of 57% (95% CI 52–62). Conclusion: CSF granulocytes have a high diagnostic accuracy for bacterial meningitis in patients suspected of a CNS infection. CSF granulocyte predominance occurred in all diagnostic categories, limiting its value in clinical practice. [ABSTRACT FROM AUTHOR]

Background: Craniotomy is a common neurosurgery used to treat intracranial pathologies. Nearly 5% of the 14 million craniotomies performed worldwide each year become infected, most often with Staphylococcus aureus (S. aureus), which forms a biofilm on the surface of the resected bone segment to establish a chronic infection that is recalcitrant to antibiotics and immune-mediated clearance. Tumor necrosis factor (TNF), a prototypical proinflammatory cytokine, has been implicated in generating protective immunity to various infections. Although TNF is elevated during S. aureus craniotomy infection, its functional importance in regulating disease pathogenesis has not been explored. Methods: A mouse model of S. aureus craniotomy infection was used to investigate the functional importance of TNF signaling using TNF, TNFR1, and TNFR2 knockout (KO) mice by quantifying bacterial burden, immune infiltrates, inflammatory mediators, and transcriptional changes by RNA-seq. Complementary experiments examined neutrophil extracellular trap formation, leukocyte apoptosis, phagocytosis, and bactericidal activity. Results: TNF transiently regulated neutrophil and granulocytic myeloid-derived suppressor cell recruitment to the brain, subcutaneous galea, and bone flap as evident by significant reductions in both cell types between days 7 to 14 post-infection coinciding with significant decreases in several chemokines, which recovered to wild type levels by day 28. Despite these defects, bacterial burdens were similar in TNF KO and WT mice. RNA-seq revealed enhanced lymphotoxin-α (Lta) expression in TNF KO granulocytes. Since both TNF and LTα signal through TNFR1 and TNFR2, KO mice for each receptor were examined to assess potential redundancy; however, neither strain had any impact on S. aureus burden. In vitro studies revealed that TNF loss selectively altered macrophage responses to S. aureus since TNF KO macrophages displayed significant reductions in phagocytosis, apoptosis, IL-6 production, and bactericidal activity in response to live S. aureus, whereas granulocytes were not affected. Conclusion: These findings implicate TNF in modulating granulocyte recruitment during acute craniotomy infection via secondary effects on chemokine production and identify macrophages as a key cellular target of TNF action. However, the lack of changes in bacterial burden in TNF KO animals suggests the involvement of additional signals that dictate S. aureus pathogenesis during craniotomy infection. [ABSTRACT FROM AUTHOR]

Derived from the myeloid lineage, granulocytes, including basophils, eosinophils, and neutrophils, along with mast cells, play important, often disparate, roles across the allergic disease spectrum. While these cells and their mediators are commonly associated with allergic inflammation, they also exhibit several functions either promoting or restricting tumor growth. In this Position Paper we discuss common granulocyte and mast cell features relating to immunomodulatory functions in allergy and in cancer. We highlight key mechanisms which may inform cancer treatment and propose pertinent areas for future research. We suggest areas where understanding the communication between granulocytes, mast cells, and the tumor microenvironment, will be crucial for identifying immune mechanisms that may be harnessed to counteract tumor development. For example, a comprehensive understanding of allergic and immune factors driving distinct neutrophil states and those mechanisms that link mast cells with immunotherapy resistance, might enable targeted manipulation of specific subpopulations, leading to precision immunotherapy in cancer. We recommend specific areas of investigation in AllergoOncology and knowledge exchange across disease contexts to uncover pertinent reciprocal functions in allergy and cancer and allow therapeutic manipulation of these powerful cell populations. These will help address the unmet needs in stratifying and managing patients with allergic diseases and cancer. [ABSTRACT FROM AUTHOR]

T-cell malignancies, including T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL), present significant challenges to treatment due to their aggressive nature and chemoresistance. Chemotherapies remain a mainstay for their management, but the aggressiveness of these cancers and their associated toxicities pose limitations. Immunepotent CRP (ICRP), a bovine dialyzable leukocyte extract, has shown promise in inducing cytotoxicity against various cancer types, including hematological cancers. In this study, we investigated the combined effect of ICRP with a panel of chemotherapies on cell line models of T-ALL and T-LBL (CEM and L5178Y-R cells, respectively) and its impact on immune system cells (peripheral blood mononuclear cells, splenic and bone marrow cells). Our findings demonstrate that combining ICRP with chemotherapies enhances cytotoxicity against tumoral T-cell lymphoblasts. ICRP + Cyclophosphamide (CTX) cytotoxicity is induced through a caspase-, reactive oxygen species (ROS)-, and calcium-dependent mechanism involving the loss of mitochondrial membrane potential, an increase in ROS production, and caspase activation. Low doses of ICRP in combination with CTX spare non-tumoral immune cells, overcome the bone marrow-induced resistance to CTX cell death, and improves the CTX antitumor effect in vivo in syngeneic Balb/c mice challenged with L5178Y-R. This led to a reduction in tumor volume and a decrease in Ki-67 proliferation marker expression and the granulocyte/lymphocyte ratio. These results set the basis for further research into the clinical application of ICRP in combination with chemotherapeutic regimens for improving outcomes in T-cell malignancies. [ABSTRACT FROM AUTHOR]

Puumala orthohantavirus-caused hemorrhagic fever with renal syndrome (PUUVHFRS) is characterized by strong neutrophil activation. Neutrophils are the most abundant immune cell type in the circulation and are specially equipped to rapidly respond to infections. They are more heterogenous than previously appreciated, with specific neutrophil subsets recently implicated in inflammation and immunosuppression. Furthermore, neutrophils can be divided based on their density to either low-density granulocytes (LDGs) or "normal density" polymorphonuclear cell (PMN) fractions. In the current study we aimed to identify and characterize the different neutrophil subsets in the circulation of PUUV-HFRS patients. PMNs exhibited an activation of antiviral pathways, while circulating LDGs were increased in frequency following acute PUUV-HFRS. Furthermore, cell surface marker expression analysis revealed that PUUV-associated LDGs are primarily immature and most likely reflect an increased neutrophil production from the bone marrow. Interestingly, both the frequency of LDGs and the presence of a "left shift" in blood associated with the extent of thrombocytopenia, one of the hallmarks of severe HFRS, suggesting that maturing neutrophils could play a role in disease pathogenesis. These results imply that elevated circulating LDGs might be a general finding in acute viral infections. However, in contrast to the COVID-19 associated LDGs described previously, the secretome of PUUV LDGs did not show significant immunosuppressive ability, which suggests inherent biological differences in the LDG responses that can be dependent on the causative virus or differing infection kinetics. [ABSTRACT FROM AUTHOR]

Background Study Design/Methods Results Discussion Granulocyte transfusions for patients with prolonged neutropenia and severe infections has been a controversial practice. Previous studies suggest a benefit of high‐dose granulocyte transfusions (≥0.6 × 109/kg), although, until recently, the consistent production of high‐dose units has been challenging. Here, we present our experience and results utilizing high‐dose granulocyte transfusions at a large, tertiary academic medical center for the treatment of infections in adult, neutropenic patients.A retrospective chart review (2018–2021) was conducted for all patients who received high‐dose granulocyte transfusions from donors stimulated with granulocyte colony‐stimulating factor (G‐CSF) and dexamethasone. Gathered parameters included patient demographics, clinical history, infection status, dose, clinical outcomes, pre‐ and post‐absolute neutrophil count (ANC), and transfusion times including time between granulocyte collection, administration, and posttransfusion ANC count. Gathered parameters were summarized using descriptive statistics, outcomes were assessed utilizing Kaplan–Meier curves/log‐rank/regression testing.Totally 28 adult, neutropenic patients refractory to antimicrobial agents and/or G‐CSF received a total of 173 granulocyte concentrates. Median ANC increased from 0.7 × 109/L pre‐transfusion to 1.6 × 109/L posttransfusion. The mean granulocyte yield was 77.4 × 109 resulting in an average dose per kilogram of 0.90 × 109 ± 0.30 × 109 granulocytes. Composite day 42 survival and microbial response was 42.9% (n = 12/28) without significant adverse reactions.Here, we demonstrate the successful and safe implementation of high‐dose granulocyte transfusions for neutropenic patients. Given the rapid and consistent production, distribution, and improved granulocyte quality, further investigations to determine the clinical efficacy of G‐CSF primed granulocyte transfusions is now possible. [ABSTRACT FROM AUTHOR]

Background: Hematological abnormalities in COVID-19 infection included quantitative and qualitative changes and should be further characterized. Evaluation for myelodysplastic syndromes (MDS) is usually prompted by abnormal hematologic findings and the presence of dysplastic morphologies. Viral infections are considered to be the cause of dysplastic morphologies and should be considered by morphologists. There are few reports of dysplastic abnormal morphologies in patients with COVID-19 infection. However, such correlations still have to be clarified. Materials and Methods: In the present study, we examined the granulocyte lineage morphological abnormalities in symptomatic RT-PCR-confirmed COVID patients. Peripheral blood samples were collected from 82 patients with symptomatic COVID-19. Blood smears were prepared according to the standard Wright-Giemsa staining procedure. The morphological examination was carried out by two laboratory experts. Results: Blood smear examination revealed common myelodysplastic syndrome (MDS) type abnormalities including but not limited to pseudo-pelger nuclear lobulation (4.8%), hypogranulation (7.3%), Howell-Jolly-like bodies or detached nuclear segments (6.0%) and elongated and thin nuclear filaments (6.0%). One case of abnormal immature granulocyte and ring form nucleus is also evident. Conclusion: Our results accounted for the possibility of active COVID-19 infection in all subjects with granulocyte dysplasia. These results are of practical importance for patients suspected of having myelodysplastic syndromes or disease processes associated with myeloid malignancies. [ABSTRACT FROM AUTHOR]

IBD is an uncontrolled inflammatory condition of the gastrointestinal tract, which mainly manifests in two forms: ulcerative colitis (UC) and Crohn's disease (CD). The pathogenesis of IBD appears to be associated with an abnormal response of innate and adaptive immune cells. Innate immunity cells, such as macrophages, mast cells, and granulocytes, can produce proinflammatory (e.g., TNF-α) and oxidative stress (ROS) mediators promoting intestinal damage, and their abnormal responses can induce an imbalance in adaptive immunity, leading to the production of inflammatory cytokines that increase innate immune damage, abate intestinal barrier functions, and aggravate inflammation. Considering that Ca2+ signalling plays a key role in a plethora of cellular functions, this review has the purpose of deepening the potential Ca2+ involvement in IBD pathogenesis. [ABSTRACT FROM AUTHOR]

Single-cell technologies such as flow cytometry and single-cell RNA sequencing have allowed for comprehensive characterization of the kidney cellulome. However, there is a disparity in the various protocols for preparing kidney single-cell suspensions. We aimed to address this limitation by characterizing kidney cellular heterogeneity using three previously published single-cell preparation protocols. Single-cell suspensions were prepared from male and female C57BL/6 kidneys using the following kidney tissue dissociation protocols: a scRNAseq protocol (P1), a multi-tissue digestion kit from Miltenyi Biotec (P2), and a protocol established in our laboratory (P3). Following dissociation, flow cytometry was used to identify known major cell types including leukocytes (myeloid and lymphoid), vascular cells (smooth muscle and endothelial), nephron epithelial cells (intercalating, principal, proximal, and distal tubule cells), podocytes, and fibroblasts. Of the protocols tested, P2 yielded significantly less leukocytes and type B intercalating cells compared with the other techniques. P1 and P3 produced similar yields for most cell types; however, endothelial and myeloid-derived cells were significantly enriched using P1. Significant sex differences were detected in only two cell types: granulocytes (increased in males) and smooth muscle cells (increased in females). Future single-cell studies that aim to enrich specific kidney cell types may benefit from this comparative analysis. NEW & NOTEWORTHY: This study is the first to evaluate published single-cell suspension preparation protocols and their ability to produce high-quality cellular yields from the mouse kidney. Three single-cell digestion protocols were compared and each produced significant differences in kidney cellular heterogeneity. These findings highlight the importance of the digestion protocol when using single-cell technologies. This study may help future single-cell science research by guiding researchers to choose protocols that enrich certain cell types of interest. [ABSTRACT FROM AUTHOR]

Granulocyte transfusions are indicated for patients with severe neutropenia and evidence of bacterial or fungal infection who are unresponsive to standard antimicrobial therapy. With a limited expiration time of 24 hours after collection, granulocytes are often transfused before results of infectious-disease screening tests are available, and before a transfusion service can perform a risk assessment if postdonation information is provided after the collection. The case we describe herein demonstrates a clinical scenario meeting indications for granulocyte transfusion, coupled with the clinical management undertaken after the granulocyte donor disclosed a positive result for a COVID-19 self-test taken 1 day after donation. In this case, the patient did not develop new COVID-19 symptoms and tested negative for COVID-19 after transfusion of the implicated unit. These findings add to the body of evidence in the literature that COVID-19 is not transmitted via blood transfusion. [ABSTRACT FROM AUTHOR]

Background: Aberrant expression of adipocyte enhancer‐binding protein 1 (AEBP1) has been demonstrated to be involved in the tumorigenesis and progression of numerous cancers. This study was aimed to investigate the mechanism of AEBP1 in the development of cervical cancer. Methods: The expression of AEBP1 in cervical cancer was assessed by immunohistochemistry. The function of AEBP1 on cell proliferation, migration, and invasion was determined by methyl thiazolyl tetrazolium assay, colony formation, and transwell assay. The activation of related signaling pathway was determined by western blot. The bioinformatics analysis was performed by Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Results: Higher protein expression of AEBP1 was observed in patients with cervical cancer. Overexpressed AEBP1 promoted cell proliferation, migration, and invasion abilities in cervical cancer cells. Moreover, the research manifested that AEBP1 activated the phosphorylation of STAT3. GO and KEGG analysis showed that genes positively related to AEBP1 were highly enriched in functions like epithelial cell proliferation, muscle cell migration, myoblast migration, smooth muscle tissue development, ECM–receptor interaction, transcriptional misregulation in cancer, and proteoglycans in cancer. While genes negatively related to AEBP1 were associated with immunity, including inflammatory response, external‐stimulus response, neutrophil, granulocyte, and macrophage chemotaxis. Conclusions: This study suggested that AEBP1 acts as an oncogened and might be a potential therapeutic target for the treatment of cervical cancer. [ABSTRACT FROM AUTHOR]

Abstract Background Craniotomy is a common neurosurgery used to treat intracranial pathologies. Nearly 5% of the 14 million craniotomies performed worldwide each year become infected, most often with Staphylococcus aureus (S. aureus), which forms a biofilm on the surface of the resected bone segment to establish a chronic infection that is recalcitrant to antibiotics and immune-mediated clearance. Tumor necrosis factor (TNF), a prototypical proinflammatory cytokine, has been implicated in generating protective immunity to various infections. Although TNF is elevated during S. aureus craniotomy infection, its functional importance in regulating disease pathogenesis has not been explored. Methods A mouse model of S. aureus craniotomy infection was used to investigate the functional importance of TNF signaling using TNF, TNFR1, and TNFR2 knockout (KO) mice by quantifying bacterial burden, immune infiltrates, inflammatory mediators, and transcriptional changes by RNA-seq. Complementary experiments examined neutrophil extracellular trap formation, leukocyte apoptosis, phagocytosis, and bactericidal activity. Results TNF transiently regulated neutrophil and granulocytic myeloid-derived suppressor cell recruitment to the brain, subcutaneous galea, and bone flap as evident by significant reductions in both cell types between days 7 to 14 post-infection coinciding with significant decreases in several chemokines, which recovered to wild type levels by day 28. Despite these defects, bacterial burdens were similar in TNF KO and WT mice. RNA-seq revealed enhanced lymphotoxin-α (Lta) expression in TNF KO granulocytes. Since both TNF and LTα signal through TNFR1 and TNFR2, KO mice for each receptor were examined to assess potential redundancy; however, neither strain had any impact on S. aureus burden. In vitro studies revealed that TNF loss selectively altered macrophage responses to S. aureus since TNF KO macrophages displayed significant reductions in phagocytosis, apoptosis, IL-6 production, and bactericidal activity in response to live S. aureus, whereas granulocytes were not affected. Conclusion These findings implicate TNF in modulating granulocyte recruitment during acute craniotomy infection via secondary effects on chemokine production and identify macrophages as a key cellular target of TNF action. However, the lack of changes in bacterial burden in TNF KO animals suggests the involvement of additional signals that dictate S. aureus pathogenesis during craniotomy infection.

Background: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with an unpredictable course of recurrent exacerbations alternating with more stable disease. SLE is characterized by broad immune activation and autoantibodies against double-stranded DNA and numerous proteins that exist in cells as aggregates with nucleic acids, such as Ro60, MOV10, and the L1 retrotransposon-encoded ORF1p. Results: Here we report that these 3 proteins are co-expressed and co-localized in a subset of SLE granulocytes and are concentrated in cytosolic dots that also contain DNA: RNA heteroduplexes and the DNA sensor ZBP1, but not cGAS. The DNA: RNA heteroduplexes vanished from the neutrophils when they were treated with a selective inhibitor of the L1 reverse transcriptase. We also report that ORF1p granules escape neutrophils during the extrusion of neutrophil extracellular traps (NETs) and, to a lesser degree, from neutrophils dying by pyroptosis, but not apoptosis. Conclusions: These results bring new insights into the composition of ORF1p granules in SLE neutrophils and may explain, in part, why proteins in these granules become targeted by autoantibodies in this disease. [ABSTRACT FROM AUTHOR]

Aims Methods Results Conclusion The recommended dosage of pegylated recombinant human granulocyte‐colony stimulating factor (PEG‐rhG‐CSF) for Western chemotherapy patients is 6 mg per cycle. However, for Eastern Asians, the optimal dose remains unknown.This open‐label, randomized, non‐inferiority trial (NCT05283616) enrolled Chinese female breast cancer patients receiving adjuvant chemotherapy. Participants were randomized to receive either 3 or 6 mg of PEG‐rhG‐CSF per cycle, stratified by body weight (BW; ≤60 kg vs. >60 kg). The primary endpoint was timely absolute neutrophil count (ANC) recovery before the second cycle of chemotherapy.A total of 122 patients were randomized and 116 were included for efficacy analyses. The timely ANC recovery rate in the 3 mg arm was 89.8%, compared to 93.0% in the 6 mg arm (one‐sided 95% confidence interval [CI] lower limit for difference: −11.7%), meeting the prespecified non‐inferiority margin of 15%. The rate was 93.3% with PEG‐rhG‐CSF 3 mg and 96.6% with 6 mg in patients with BW ≤ 60 kg, and 86.2% and 89.3%, respectively, in those with BW > 60 kg. Although the incidence of severe neutropenia was similar across arms, the occurrence of excessively high ANC and white blood cell counts was higher in the 6 mg arm. No grade ≥3 adverse events related to PEG‐rhG‐CSF occurred.Three milligrams of PEG‐rhG‐CSF per cycle provided non‐inferior neutrophil protection and attenuated neutrophil overshoot compared to 6 mg doses. This low‐dose regimen could be a new supportive care option for Chinese breast cancer patients receiving anthracycline‐based adjuvant chemotherapy. [ABSTRACT FROM AUTHOR]

Modern complex therapy of patients with persistent (year-round, chronic) allergic rhinitis (AR), based on the use of antihistamines and intranasal glucocorticosteroids, in many cases is not effective enough, since drug therapy acts only on individual links in the pathogenesis, without preventing the progression of the allergic disease. At the same time, the quantitative and reserve capabilities of neutrophil granulocytes are depleted, which increases the level of antigenic load in patients with AR. The aim of this study is to investigate the phagocytic activity of neutrophils in patients with AR who received basic therapy and patients who received basic therapy and a course of the drug from the macromycetes Ganoderma lucidum "Astmagan". We examined 40 patients of both sexes with AR, the duration of the disease ranged from 6 months to 2 years. Patients were divided into 2 equal groups: The 1st group consisted of patients who received basic therapy (oral Loratadine and intranasal Nasonex). The 2nd group consisted of patients who received basic therapy and a course of "Astmagan". The treatment course lasted 90 days. The control group consisted of 25 healthy individuals. After the treatment, patients in both groups showed a statistically significant positive dynamics of phagocytic system activity: in group 1, the phagocytic index (FI) increased by 30 % (p=0.001), in the second group this indicator reached the normal level. Also, in patients of group 1, the phagocytic number (PN) increased by 35 % (p=0.0001), but did not reach the normal level. According to the results of comparative evaluation, a greater efficacy of the treatment complex with the additional use of "Astmagan" was established, which is manifested in the restoration of phagocytic activity of peripheral blood neutrophils, the effect persists for 6 months after treatment. [ABSTRACT FROM AUTHOR]

Objectives: To examine the cost-effectiveness of using granulocyte colony-stimulating factor (G-CSF) for primary or secondary prophylaxis in patients with breast cancer from the perspective of Taiwan's National Health Insurance Administration. Methods: A Markov model was constructed to simulate the events that may occur during and after a high-risk chemotherapy treatment. Various G-CSF prophylaxis strategies and medications were compared in the model. Effectiveness data were derived from the literature and an analysis of the National Health Insurance Research Database (NHIRD). Cost data were obtained from a published NHIRD study, and health utility values were also obtained from the literature. Sensitivity analyses were performed to assess the uncertainty of the cost-effectiveness results. Results: In the base-case analysis, primary prophylaxis with pegfilgrastim had an incremental cost-effectiveness ratio (ICER) of NT$269,683 per quality-adjusted life year (QALY) gained compared to primary prophylaxis with lenograstim. The ICER for primary prophylaxis with lenograstim versus no G-CSF prophylaxis was NT$61,995 per QALY gained. The results were most sensitive to variations in relative risk of febrile neutropenia (FN) for pegfilgrastim versus no G-CSF prophylaxis. Furthermore, in the probabilistic sensitivity analysis, at a willingness-to-pay threshold of one times Taiwan's gross domestic product per capita, the probability of being cost-effective was 88.1% for primary prophylaxis with pegfilgrastim. Conclusions: Our study suggests that primary prophylaxis with either short- or long-acting G-CSF could be considered cost-effective for FN prevention in breast cancer patients receiving high-risk regimens. [ABSTRACT FROM AUTHOR]

The study aims to characterize the immune cell landscape in convalescent Asian seabass (Lates calcarifer) blood samples after exposure to scale-drop disease virus (SDDV). Traditional immunophenotyping approaches used in human and mouse studies are impractical for non-model organisms like the Asian seabass due to the lack of specific antibody-based reagents. To overcome this challenge, 10x Genomics single-cell RNA sequencing was employed. The analysis of blood samples revealed 24 distinct leukocyte clusters, with elevated proportions of B cells, granulocytes, and T cells in the convalescent group compared to the uninfected group. While distinguishing granulocyte and macrophage subsets was challenging, the analysis of differential gene expression in the macrophage population indicated that the upregulated genes were linked to inflammatory processes. Specific T cell clusters showed notable expressions of cd4-1, cd8a, perforin-1 and il-2rβ, suggesting the presence of CD4+ T helper (Th), CD8+ cytotoxic T (Tc) cells, immature T cells, and naive T cells. Attempts to categorize CD4+ T cells into Th subtypes lacked clear distinctions, while CD8+ T cells exhibited three clusters, predominantly Tc1 cells. Furthermore, comparisons between convalescent and uninfected groups revealed increased percentages of activated and antibody-secreting B cells in the convalescent group. This single-cell analysis provides vital insights into the immune cell dynamics in convalescent and uninfected Asian seabass, providing valuable information on potential immune responses to SDDV infection. [ABSTRACT FROM AUTHOR]

Aim: To determine whether the IG count (#) and IG percentage (%) are associated with disease activity in rheumatoid arthritis (RA). Methods: This retrospective study included 65 RA patients and 65 healthy controls. Clinical and demographic characteristics of controls and RA patients (at active period and when the patients achieved remission) were obtained from medical records. Disease activity was defined by disease activity score 28 (DAS28). Furthermore, the clinical disease activity index (CDAI), and simple disease activity index (SDAI) were calculated. For the differential diagnosis of RA patients from healthy controls, the cut‐off value was estimated by making receiver‐operator curves (ROC). Results: In active RA patients, erythrocyte sedimentation rate (ESR), C‐reactive protein (CRP), IG#, and IG% levels were significantly higher compared to the healthy controls (p <.001, for all). When the patients achieved remission, DAS28, CDAI, SDAI, ESR, CRP, IG#, and IG% values were significantly decreased (p <.001, for all). IG# and IG% were significantly positively correlated with DAS28, CDAI, SDAI, ESR, and CRP (p =.024, p =.008, p =.003, p <.001, p <.001, respectively). According to ROC curve analysis, IG% and IG# were the biomarkers to have a significant diagnostic value for RA with the area under the curve of 0.853 and 0.865 (p <.001, for all). Conclusion: The present study demonstrated that two novel inflammatory markers, IG# and IG%, can be useful for monitoring RA patients' disease activity. Furthermore, IG# and IG% can also be used as fast, inexpensive, and easily available complementary diagnostic markers to diagnose RA patients. [ABSTRACT FROM AUTHOR]

Purpose: Myelosuppressive chemotherapy-induced neutropenia (CIN) remains a major limitation of cancer treatment efficacy, necessitating very expensive supportive care. Lithium carbonate, an inexpensive drug, can increase the number of neutrophils, possibly providing an efficacious and cost-effective alternative for treating CIN. The aim of this study was to determine whether lithium therapy can attenuate chemotherapy-induced neutropenia and leukopenia in breast cancer patients. Methods: A total of 50 breast cancer patients were enrolled in this prospective, interventional, randomized, controlled, and single-blind study. The patients were divided into two groups: a control group (group 1, N = 25 patients) and a lithium-treated (treatment) group (group 2, N = 25 patients). Group 1 patients were further subclassified into a non-neutropenic control group (N = 16) and a neutropenic control (N = 9) based on the subsequent development of severe neutropenia, or not. The control group received 4 cycles of doxorubicin or epirubicin plus cyclophosphamide followed by 2 cycles of paclitaxel. The treatment group received the same regimen as the control group as well as oral lithium carbonate throughout the chemotherapy cycles. Results: The results showed that the absolute neutrophil count (ANC) was increased in the lithium-treated group, while it was markedly reduced in both the non-neutropenic and neutropenic control groups (by 55.56% and 65.42% post-4 chemotherapy cycles, and by 19.57% and 39.90% post-6 cycles, respectively). The same pattern of alterations was observed for the total white blood cell count in both the control and treatment groups. In addition, the incidence and period prevalence were greatly reduced in the lithium-treated group compared to non-neutropenic and neutropenic control groups. Conclusion: Lithium therapy ameliorated chemotherapy-induced leukopenia and neutropenia in breast cancer patients. This may provide a new strategy for cost-effective treatment of CIN, particularly in Egyptian cancer patients. [ABSTRACT FROM AUTHOR]

Objectives: Predicting the need for surgical treatment among patients with chronic rhinosinusitis (CRS) is challenging. The delta neutrophil index (DNI) has been proposed as a useful laboratory marker of immature granulocytes, which indicates infection or severe inflammation in several diseases. This study evaluated DNI as an early predictor of the need for surgery in patients with CRS. Methods: A total of 117 patients diagnosed with CRS were enrolled in this retrospective and observational study. Medical records, including symptoms data, WBC count, ESR level, LUC count, Lund-Mackay scores, and DNI, were reviewed. The receiver operating characteristic (ROC) curves were analyzed to determine the optimal cut-off values for predicting surgery. Results: Among 117 patients, 49 patients (41.9%) needed surgical intervention. The areas under the WBC, ESR, LUC, and DNI ROC curves were.571,.600,.592, and.782, respectively. The optimal cut-off value of DNI to predict surgery was.9%. The prognostic precision of DNI showed that the sensitivity was 59.2% and the specificity was 98.5%. In the analysis of risk factors, DNI levels were significantly associated with surgical intervention (odds ratio, 2.22; 95% confidence interval, 1.48-3.34; P <.01). Conclusions: The level of DNI, which reflects the severity of the disease, may be a useful predictor for determining the need for surgical intervention in patients with CRS. This is the first literature to verify the role of DNI in upper airway disease. [ABSTRACT FROM AUTHOR]

Objectives VEXAS syndrome is an adult-onset autoinflammatory disease caused by a somatic pathogenic mutation in the UBA1 (ubiquitin-like modifier activating enzyme 1) gene. Patients present with rheumatologic manifestations and cytopenias and may have an increased predisposition to myelodysplastic syndrome (MDS) and plasma cell neoplasms. Prior studies have reported on the peripheral blood and bone marrow findings in patients with VEXAS syndrome. Due to the protean clinical presentation and lack of specificity of morphologic features (eg, vacuoles in early erythroid and granulocytic precursors), an optimal screening methodology to identify these patients in a timely fashion is desirable. Methods To further evaluate and describe the salient diagnostic morphologic features in VEXAS syndrome, we carried out a comprehensive study of the largest single-institution cohort to date. Diagnostic and follow-up bone marrow biopsy specimens from 52 male patients with molecularly identified VEXAS syndrome underwent central review. Results Cytopenias were common in all cases, primarily macrocytic anemia, monocytopenia, and thrombocytopenia. Bone marrow aspirate and biopsy were often hypercellular, with an increased myeloid/erythroid ratio, granulocytic hyperplasia with left shift, erythroid left shift, and megakaryocyte hyperplasia, which exhibited a range of striking morphologic findings. Distinctly vacuolated myeloid and erythroid precursors were seen in more than 95% of cases. Conclusions Our data reveal potential novel diagnostic features, such as a high incidence of monocytopenia and distinct patterns of atypical megakaryopoiesis, that appear different from dysmegakaryopoiesis typically associated with MDS. In our experience, those findings are suggestive of VEXAS, in the appropriate clinical context. [ABSTRACT FROM AUTHOR]

Neutrophil granulocytes play a crucial role in host defense against invading pathogens and in inflammatory diseases. The aim of this study was to elucidate membrane potential dynamics during the initial phase of neutrophil activation and its relation to migration and production of reactive oxygen species (ROS). We performed ROS production measurements of neutrophils from healthy C57BL/6J mice after TNFα-priming and/or C5a stimulation. The actin cytoskeleton was visualized with fluorescence microscopy. Furthermore, we combined migration assays and measurements of membrane potential dynamics after stimulating unprimed and/or TNFα-primed neutrophils with C5a. We show that C5a has a concentration-dependent effect on ROS production and chemokinetic migration. Chemokinetic migration and chemotaxis are impaired at C5a concentrations that induce ROS production. The actin cytoskeleton of unstimulated and of ROS-producing neutrophils is not distributed in a polarized way. Inhibition of the phagocytic NADPH oxidase NOX2 with diphenyleneiodonium (DPI) leads to a polarized distribution of the actin cytoskeleton and rescues chemokinetic migration of primed and C5a-stimulated neutrophils. Moreover, C5a evokes a pronounced depolarization of the cell membrane potential by 86.6 ± 4.2 mV starting from a resting membrane potential of -74.3 ± 0.7 mV. The C5a-induced depolarization occurs almost instantaneously (within less than one minute) in contrast to the more gradually developing depolarization induced by PMA (lag time of 3—4 min). This initial depolarization is accompanied by a decrease of the migration velocity. Collectively, our results show that stimulation with C5a evokes parallel changes in membrane potential dynamics, neutrophil ROS production and motility. Notably, the amplitude of membrane potential dynamics is comparable to that of excitable cells. [ABSTRACT FROM AUTHOR]

Background: The MC‐80 (Mindray, Shenzhen, China), a newly available artificial intelligence (AI)‐based digital morphology analyzer, is the focus of this study. We aim to compare the leukocyte differential performance of the Mindray MC‐80 with that of the Sysmex DI‐60 and the gold standard, manual microscopy. Methods: A total of 100 abnormal peripheral blood (PB) smears were compared across the MC‐80, DI‐60, and manual microscopy. Sensitivity, specificity, predictive value, and efficiency were calculated according to the Clinical and Laboratory Standards Institute (CLSI) EP12‐A2 guidelines. Comparisons were made using Bland–Altman analysis and Passing‐Bablok regression analysis. Additionally, within‐run imprecision was evaluated using five samples, each with varying percentages of mature leukocytes and blasts, in accordance with CLSI EP05‐A3 guidelines. Results: The within‐run coefficient of variation (%CV) of the MC‐80 for most cell classes in the five samples was lower than that of the DI‐60. Sensitivities for the MC‐80 ranged from 98.2% for nucleated red blood cells (NRBC) to 28.6% for reactive lymphocytes. The DI‐60's sensitivities varied between 100% for basophils and reactive lymphocytes, and 11.1% for metamyelocytes. Both analyzers demonstrated high specificity, negative predictive value, and efficiency, with over 90% for most cell classes. However, the DI‐60 showed relatively lower specificity for lymphocytes (73.2%) and lower efficiency for blasts and lymphocytes (80.1% and 78.6%, respectively) compared with the MC‐80. Bland–Altman analysis indicated that the absolute mean differences (%) ranged from 0.01 to 4.57 in MC‐80 versus manual differential and 0.01 to 3.39 in DI‐60 versus manual differential. After verification by technicians, both analyzers exhibited a very high correlation (r = 0.90–1.00) with the manual differential results in neutrophils, lymphocytes, and blasts. Conclusions: The Mindray MC‐80 demonstrated good performance for leukocyte differential in PB smears, notably exhibiting higher sensitivity for blasts identification than the DI‐60. [ABSTRACT FROM AUTHOR]

This study investigates immune priming effects associated with granulocytes in crickets through a comprehensive analysis. Kaplan-Meier survival analysis reveals a significant contrast in survival rates, with the heat-killed Bacillus thuringiensis (Bt)-primed group exhibiting an impressive ~80% survival rate compared to the PBS buffer-primed group with only ~10% survival 60 hours post live Bt infection. Hemocyte analysis underscores elevated hemocyte counts, particularly in granulocytes of the killed Bt-primed group, suggesting a correlation between the heat-killed Bt priming and heightened immune activation. Microscopy techniques further explore granulocyte morphology, unveiling distinctive immune responses in the killed Bt-primed group characterized by prolonged immune activation, heightened granulocyte activity, phagocytosis, and extracellular trap formation, contributing to enhanced survival rates. In particular, after 24 hours of injecting live Bt, most granulocytes in the PBS buffer-primed group exhibited extracellular DNA trap cell death (ETosis), while in the killed Bt-primed group, the majority of granulocytes were observed to maintain highly activated extracellular traps, sustaining the immune response. Gene expression analysis supports these findings, revealing differential regulation of immune-related genes such as antibacterial humoral response, detection of bacterial lipopeptides, and cellular response to bacteria lipopeptides. Additionally, the heat-killed Bt-primed group, the heat-killed E. coli-primed group, and the PBS-primed group were re-injected with live Bt 2 and 9 days post priming. Two days later, only the PBS-primed group displayed low survival rates. After injecting live Bt 9 days later, the heat-killed E. coli-primed group surprisingly showed a similarly low survival rate, while the heat-killed Bt-primed group exhibited a high survival rate of ~60% after 60 hours, with actively moving and healthy crickets. In conclusion, this research provides valuable insights into both short-term and long-term immune priming effects in crickets, contributing to our understanding of invertebrate immunity with potential applications in public health. [ABSTRACT FROM AUTHOR]

Typical BCR::ABL1-negative myeloproliferative neoplasms (MPN) are mainly referred to as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofbrosis (PMF). Granulocytes in MPN patients are involved in their inflammation and form an important part of the pathophysiology of MPN patients. It has been shown that the immunophenotype of granulocytes in MPN patients is altered. We used flow cytometry to explore the immunophenotype of MPN patients and correlate it with clinical parameters. The results showed that PMF patients and PV patients had higher CD15+CD11b+ granulocytes than ET patients and normal controls. When grouped by gene mutation, changes in the granulocyte immunophenotype of MPN patients were independent of the JAK2V617F and CALR mutations. There was no significant heterogeneity in immunophenotype between ET patients and Pre-PMF, and between Overt-PMF and Pre-PMF patients. Granulocytes from some MPN patients showed an abnormal CD13/CD16 phenotype with a significant increase in mature granulocytes on molecular and cytomorphological grounds, and this abnormal pattern occurred significantly more frequently in PMF patients than in ET patients. CD15–CD11b– was negatively correlated with WBC and Hb and positively correlated with DIPSS score, whereas high CD10+ granulocytes were significantly and negatively associated with prognostic system IPSS and DIPSS scores in PMF patients. In conclusion, this study demonstrates the landscape of bone marrow granulocyte immunophenotypes in MPN patients. MPN patients, especially those with PMF, have a significant granulocyte developmental overmaturation phenotype. CD10+ granulocytes may be involved in the prognosis of PMF patients. [ABSTRACT FROM AUTHOR]

Probiotic feed additives have attracted considerable research interest in recent years because the effectiveness of probiotics can differ across microbial strains and the supplemented macroorganisms. The present study was conducted on 16 lambs divided equally into two groups (C—control and E—experimental). The examined lambs were aged 11 days at the beginning of the experiment and 40 days at the end of the experiment. The diet of group E lambs was supplemented with a multi-strain probiotic formulation (Lactobacillus plantarum AMT14, Lactobacillus plantarum AMT4, Lactobacillus rhamnosus AMT15, and Bifidobacterium animalis AMT30), whereas group C lambs did not receive the probiotic additive. At the beginning of the experiment (day 0) and on experimental days 15 and 30, blood was sampled from the jugular vein to determine and compare: phagocytic activity (Phagotest) and oxidative metabolism (Phagoburst) of peripheral blood granulocytes and monocytes by flow cytometry. An analysis of the phagocytic activity of granulocytes and monocytes revealed significantly higher levels of phagocytic activity (expressed as the percentage of phagocytic cells and mean fluorescence intensity) in lambs that were administered the multi-strain probiotic formulation compared with lambs in the control group. The probiotic feed additive also exerted a positive effect on the oxidative metabolism of both granulocytes and monocytes (expressed as the percentage of oxidative metabolism and mean fluorescence intensity) after stimulation with Escherichia coli bacteria and with PMA (4-phorbol-12-β-myristate-13-acetate). These findings suggest that the tested probiotic formulation may have a positive effect on the immune status of lambs. [ABSTRACT FROM AUTHOR]

The importance of eosinophilic granulocytes in cancer has been widely discussed in recent years. The current study reviews the evidence on the role of eosinophilic granulocytes in melanoma as a prognostic marker for cancer progression and the efficacy of treatment with modern immune checkpoint inhibitors. A total of 33 human clinical studies were included in the review, with heterogeneous data due to differences in patients populations, study design and inclusion of small study groups. However, 28 of the 33 studies suggested that eosinophilic granulocytes could be used as a prognostic biomarker for outcome and/or potential response to systemic treatment and/or occurrence of adverse events in melanoma patients. Nevertheless, the exact role of eosinophils remains to be elucidated. Further prospective, larger and better controlled studies are warranted to clarify the significance of eosinophilic granulocytes in patients with melanoma, in more details. [ABSTRACT FROM AUTHOR]

Monocyte-derived macrophages play a key pathogenic role in inflammatory diseases. In the case of rheumatoid arthritis (RA), the presence of specific synovial tissue-infiltrating macrophage subsets is associated with either active disease or inflammation resolution. JAK inhibitors (JAKi) are the first targeted synthetic disease-modifying antirheumatic drugs (tsDMARD) approved for treatment of RA with comparable efficacy to biologics. However, the effects of JAKi on macrophage specification and differentiation are currently unknown. We have analyzed the transcriptional and functional effects of JAKi on human peripheral blood monocyte subsets from RA patients and on the differentiation of monocyte-derived macrophages promoted by granulocyte-macrophage colony-stimulating factor (GM-CSF), a factor that drives the development and pathogenesis of RA. We now report that JAKi Upadacitinib restores the balance of peripheral blood monocyte subsets in RA patients and skewed macrophages towards the acquisition of an anti-inflammatory transcriptional and functional profile in a dose-dependent manner. Upadacitinib-treated macrophages showed a strong positive enrichment of the genes that define synovial macrophages associated to homeostasis/inflammation resolution. Specifically, Upadacitinib-treated macrophages exhibited significantly elevated expression of MAFB and MAFB-regulated genes, elevated inhibitory phosphorylation of GSK3β, and higher phagocytic activity and showed an anti-inflammatory cytokine profile upon activation by pathogenic stimuli. These outcomes were also shared by macrophages exposed to other JAKi (baricitinib, tofacitinib), but not in the presence of the TYK2 inhibitor deucravacitinib. As a whole, our results indicate that JAKi promote macrophage re-programming towards the acquisition of a more anti-inflammatory/pro-resolution profile, an effect that correlates with the ability of JAKi to enhance MAFB expression. [ABSTRACT FROM AUTHOR]

Coronary heart disease (CHD) is related to aberrant aggregation of immune cells in the plaques. This study focused on identification of abnormal T cell subtypes and inflammatory factors in CHD patients. To this end, the subtypes of T cells in peripheral blood of CHD patients (n=141) and healthy controls (n=46) were analyzed by flow cytometry. Plasma concentrations of cytokines were analyzed by multiplex assay. It was shown that the number of T helper cells producing granulocyte-macrophage CSF (GM-CSF) was higher in CHD patients in comparison with healthy controls. In addition, the fractions of Th1 and Th17 cells as well as the levels of IL-4, IL-5, IL-6, and IL-10 in CHD patients also surpassed the control values (p<0.05). However, the level of GM-CSF was insignificantly lower in CHD patients. Thus, we revealed a relationship between the number of T cells producing GM-CSF and the severity of CHD. Our results can be used to develop new potential biomarkers for CHD detection. [ABSTRACT FROM AUTHOR]

Blood count is crucial for assessing bone marrow's cell production and differentiation during infections, gaging disease severity, and monitoring therapeutic responses. The profile of blood count in chronic forms of paracoccidioidomycosis (PCM) has been insufficiently explored. To better understand the changes in hematological cells in different stages of the PCM chronic form, we evaluated the blood count, including immature blood cells in automated equipment, before and during the treatment follow-up of 62 chronic PCM patients. Predominantly male (96.8%) with an average age of 54.3 (standard deviation SD 6.9) years, participants exhibited pre-treatment conditions such as anemia (45.2%), monocytosis (38.7%), and leukocytosis (17.7%), which became less frequent after clinical cure. Anemia was more prevalent in severe cases. Notably, hemoglobin and reticulocyte hemoglobin content increased, while leukocytes, monocytes, neutrophils, immature granulocytes, and platelets decreased. Chronic PCM induced manageable hematological abnormalities, mainly in the red blood series. Monocytosis, indicating monocytes' role in PCM's immune response, was frequent. Post-treatment, especially after achieving clinical cure, significant improvements were observed in various hematological indices, including immature granulocytes and reticulocyte hemoglobin content, underscoring the impact of infection on these parameters. [ABSTRACT FROM AUTHOR]

Sporothrix schenckii is one of the etiological agents of sporotrichosis, a cutaneous and subcutaneous infection distributed worldwide. Like other medically relevant fungi, its cell wall is a molecular scaffold to display virulence factors, such as protective pigments, hydrolytic enzymes, and adhesins. Cell wall proteins with adhesive properties have been previously reported, but only a handful of them have been identified and characterized. One of them is Gp70, an abundant cell wall protein mainly found on the surface of yeast-like cells. Since the protein also has a role in the activity of 3-carboxy-cis,cis-muconate cyclase and its abundance is low in highly virulent strains, its role in the Sporothrix–host interaction remains unclear. Here, a set of GP70-silenced strains was generated, and the molecular and phenotypical characterization was performed. The results showed that mutants with high silencing levels showed a significant reduction in the adhesion to laminin and fibrinogen, enzyme activity, and defects in the cell wall composition, which included reduced mannose, rhamnose, and protein content, accompanied by an increment in β-1,3-glucans levels. The cell wall N-linked glycan content was significantly reduced. These strains induced poor TNFα and IL-6 levels when interacting with human peripheral blood mononuclear cells in a dectin-1-, TLR2-, and TLR4-dependent stimulation. The IL-1β and IL-10 levels were significantly higher and were stimulated via dectin-1. Phagocytosis and stimulation of neutrophil extracellular traps by human granulocytes were increased in highly GP70-silenced strains. Furthermore, these mutants showed virulence attenuation in the invertebrate model Galleria mellonella. Our results demonstrate that Gp70 is a versatile protein with adhesin properties, is responsible for the activity of 3-carboxy-cis,cis-muconate cyclase, and is relevant for the S. schenckii–host interaction. [ABSTRACT FROM AUTHOR]

Human granulocyte colony-stimulating factor (G-CSF) is a granulopoietic growth factor used in the treatment of neutropenia following chemotherapy, myeloablative treatment, or healthy donors preparing for allogeneic transplantation. Few hypersensitivity reactions (HRs) have been reported, and its true prevalence is unknown. We aimed to systematically characterize G-CSF-induced HRs while including a comprehensive list of adverse reactions. We reviewed articles published before January 2024 by searching in the PubMed, Embase, Cochrane Library, and Web of Science databases using a combination of the keywords listed, selected the ones needed, and extracted relevant data. The search resulted in 68 entries, 17 relevant to our study and 7 others found from manually searching bibliographic sources. A total of 40 cases of G-CSF-induced HR were described and classified as immediate (29) or delayed (11). Immediate ones were mostly caused by filgrastim (13 minimum), with at least 9 being grade 5 on the WAO anaphylaxis scale. Delayed reactions were mostly maculopapular exanthemas and allowed for the continuation of G-CSF. Reactions after first exposure frequently appeared and were present in at least 11 of the 40 cases. Only five desensitization protocols have been found concerning the topic at hand in the analyzed data. We believe this study brings to light the research interest in this topic that could benefit from further exploration, and propose regular updating to include the most recently published evidence. [ABSTRACT FROM AUTHOR]

Heart Rate (HR) is widely used for erobic exercise intensity prescriptions and/or studies of exercise training. It is often assumed that exercising at a given HR results in similar physiological response, regardless of exercise modality. This study aimed to gauge cellular immune mobilization to submaximal exercise at a given target HR on a cycle ergometer (CE) and treadmill (TM). Thirteen healthy male adults (23.2 ± 3.5 y.o) completed 4 laboratory visits. Participants performed two graded exercise tests to exhaustion on CE and TM and two 30‐min constant exercise challenges at 70% HR reserve on CE or TM in random order. Rating of Perceived Exertion (RPE) was recorded every 5 min, and blood was drawn before and after exercise to measure leukocytes subpopulation levels, lactate, and IL‐6. HR was successfully "clamped" during the exercise in CE and TM (CE 156.7 ± 1.1; TM 159.3 ± 1.6 bpm). Cycling was perceived as more strenuous than running and was accompanied by a greater increase in lactate post‐exercise (p < 0.0001; 6.2 ± 0.3 vs. 2.9 ± 0.3 mmol/L). IL‐6 and leukocytes subpopulations were significantly elevated post‐exercise (p < 0.003) with no difference between exercise modalities (monocytes; CE 57.6% TM 61.2%, granulocytes; CE 41.37%, TM 50.1%, lymphocytes; CE 91.03%, TM 78.8%). The findings revealed that HR is not sufficient in and of itself to fully assess the metabolic stress associated with a given exercise modality. However, despite different metabolic and subjective stress, the IL‐6 and leukocyte counts relative changes were similar in the two modalities. Highlights: These findings provide valuable insights into the leukocytes and lactate responses to cycling and running at the same target heart rate. The study further elaborates on the shared patterns and distinctions in physiological and metabolic responses and their implications for designing targeted training programs.At the same target heart rate, running resulted in significantly lower lactate levels and subjective rate of perceived exertion (RPE) while yielding higher VO2 levels compared to cycling.Leukocytes and IL‐6 increases post‐exercise were not different between running and cycling, indicating that they did not reflect the distinct metabolic and subjective perceived loads associated with cycling and running.Since heart rate in and of itself is not sufficient to fully characterize the metabolic stress induced by a specific exercise modality, it is important to consider the modality of exercise when prescribing training programs for improving cardiovascular fitness or achieving target energy expenditure through heart rate monitoring. [ABSTRACT FROM AUTHOR]

No reports on granulocyte colony-stimulating factor-producing lung cancer associated with antiphospholipid antibody syndrome. A 73-year-old man was referred to our department to undergo surgery for lung cancer in the right upper lobe. His examination results suggested that his condition was caused by an elevated white blood cell count and an increased inflammatory response due to granulocyte colony-stimulating factor production. The presence of antiphospholipid antibody syndrome was suspected, and the decrease in coagulation factors was considered to be inhibited by the lupus anticoagulant. Perioperatively, the patient was treated with heparin and steroids, and a thoracoscopically assisted right upper lobectomy was performed. Postoperatively, histopathological examination revealed pleomorphic carcinoma, and the patient tested negative for anticardiolipin IgG antibodies. In lung cancer patients with elevated white blood cell counts, fever, and an inflammatory response, granulocyte colony-stimulating factor-producing lung cancer is an important differential diagnosis. Additionally, when coagulation abnormalities are observed preoperatively, a thorough examination is necessary to prepare for perioperative management. [ABSTRACT FROM AUTHOR]

Only one report on the successful use of filgrastim (granulocyte colony-stimulating factor) in cats for severe neutropenia following azathioprine toxicity exists. Here, we report on a case in which a cat was prescribed methimazole but the medication was filled incorrectly with azathioprine tablets and the prescription label indicated a methimazole dosing regimen that was administered for three days before recognition of the error. On presentation, the cat's physical examinations were consistent with previous examinations before ingestion of azathioprine. A complete blood cell count revealed neutropenia and leukopenia. The cat later developed hyporexia, dehydration, and vomiting. Treatment included antinausea and appetite stimulant medications, filgrastim, and antibiotics. Filgrastim given as subcutaneous injections over the course of treatment increased neutrophil cell counts after suppression. The cat made a full recovery after responding to the treatment protocol. Based on the perceived response to filgrastim in this single feline case report, its use can be considered for the treatment of azathioprine-induced neutropenia in cats. [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to improve the clinical cognition of leukemia-like reaction caused by voriconazole and granulocyte colony-stimulating factor and to avoid misdiagnosis or delayed diagnosis. Methods: A case of drug analysis of Voriconazole combined with granulocyte colony stimulating factor was retrospectively analyzed and related literature was reviewed. Results: Blood routine of the patient on July 29: WBC 13.48 x 109/L, neutrophil 85.3%, lymphocyte 13.4%, hemoglobin 111 g/L, platelet 285 x 109/L. Vancomycin was given to prevent intracranial infection. Lumbar puncture was performed on July 30, cerebrospinal fluid was sent for routine and biochemical examination, leukocytes were 0.15 x 109/L, monocytes 45%, polynuclear cells 55%, protein 1.172 g/L, Acinetobacter baumannii and Candida clorbicus were detected in sputum culture, vancomycin and meropenem static sites were given to prevent intracranial secondary infection. Fungi were detected in urine culture, and voriconazole was given to prevent fungal infection. Blood routine: White blood cell 0.61 x 109/L, neutrophil 23%, lymphocyte 73.8%, red blood cell 2.65 x 1012/L, hemoglobin 77 g/L, platelet 17 x 109/L, bone marrow was extracted after medication. Bone marrow images show poor myelodysplasia, with granulocytes dominated by proto-early cells. Subsequent flow cytometry, chromosomal karyotype, and fusion gene analysis were performed to exclude the possibility of leukemia. Flow cytometry showed that the proportion of myeloid primordial cells was not high, the granulocytes were mainly at the early and young stage, no abnormal phenotype was observed in erythrocytes, monocytes and NK cells, no obvious mature B lymphocytes were observed, and the ratio of CD4+/CD8+ was decreased. Karyotype results showed that there was no mitotic phase. The results of fusion gene analysis showed that the fusion gene was negative or lower than the detection sensitivity. Voliconazole was stopped first, and granulocyte colony stimulating factor was stopped 3 days later. Two weeks later, blood and bone marrow images basically recovered, white blood cell 7.88 x 109/L, neutrophil 46.3%, lymphocyte 48.2%, hemoglobin 126 g/L, platelet 142 x 109/L, bone marrow hyperplasia active. The proportion of three series is roughly normal. Conclusions: The reason for the occurrence of leukemia-like reaction in this patient was considered to be related to voriconazole and granulocyte colony stimulating factor, cessation of voriconazole and granulocyte colony stimulating factor, and recovery of blood and bone marrow images. In the clinical use of voriconazole and granulocyte colony stimulating factor, close attention should be paid to the drug interaction and individualized medication should be carried out to ensure the safety of medication. [ABSTRACT FROM AUTHOR]

African trypanosomes replicate within infected mammals where they are exposed to the complement system. This system centres around complement C3, which is present in a soluble form in serum but becomes covalently deposited onto the surfaces of pathogens after proteolytic cleavage to C3b. Membrane-associated C3b triggers different complement-mediated effectors which promote pathogen clearance. To counter complement-mediated clearance, African trypanosomes have a cell surface receptor, ISG65, which binds to C3b and which decreases the rate of trypanosome clearance in an infection model. However, the mechanism by which ISG65 reduces C3b function has not been determined. We reveal through cryogenic electron microscopy that ISG65 has two distinct binding sites for C3b, only one of which is available in C3 and C3d. We show that ISG65 does not block the formation of C3b or the function of the C3 convertase which catalyses the surface deposition of C3b. However, we show that ISG65 forms a specific conjugate with C3b, perhaps acting as a decoy. ISG65 also occludes the binding sites for complement receptors 2 and 3, which may disrupt recruitment of immune cells, including B cells, phagocytes, and granulocytes. This suggests that ISG65 protects trypanosomes by combining multiple approaches to dampen the complement cascade. [ABSTRACT FROM AUTHOR]

Although anti-citrullinated protein autoantibodies (ACPAs) are a hallmark serological feature of rheumatoid arthritis (RA), the mechanisms and cellular sources behind the generation of the RA citrullinome remain incompletely defined. Peptidylarginine deiminase IV (PAD4), one of the key enzymatic drivers of citrullination in the RA joint, is expressed by granulocytes and monocytes; however, the subcellular localization and contribution of monocyte-derived PAD4 to the generation of citrullinated autoantigens remain underexplored. In this study, we demonstrate that PAD4 displays a widespread cellular distribution in monocytes, including expression on the cell surface. Surface PAD4 was enzymatically active and capable of citrullinating extracellular fibrinogen and endogenous surface proteins in a calcium dose-dependent manner. Fibrinogen citrullinated by monocyte-surface PAD4 could be specifically recognized over native fibrinogen by a panel of eight human monoclonal ACPAs. Several unique PAD4 substrates were identified on the monocyte surface via mass spectrometry, with citrullination of the CD11b and CD18 components of the Mac-1 integrin complex being the most abundant. Citrullinated Mac-1 was found to be a target of ACPAs in 25% of RA patients, and Mac-1 ACPAs were significantly associated with HLA-DRB1 shared epitope alleles, higher C-reactive protein and IL-6 levels, and more erosive joint damage. Our findings implicate the monocyte cell surface as a unique and consequential site of extracellular and cell surface autoantigen generation in RA. [ABSTRACT FROM AUTHOR]

Although the compatibility of Astragali Radix (AR) and Angelicae Sinensis Radix (ASR) has favorable effect on promoting hematopoiesis in traditional Chinese medicine (TCM), the main active components and pharmacological mechanism are unknown. We investigated the five active components and its mechanisms in vitro and in vivo. Five active components of Astragalus glycosides (AST), Formononetin (FRM), Ferulic acid (FRA), Calycosin (CAL), and Calycosin-7-glucoside (CLG), which could be absorbed in intestinal tract, were detected in this study. The peripheral blood, hematopoietic growth factors (HGFs), and hematopoietic progenitor cells (HPCs) colony were observed to evaluate the effect of these five active components promoting hematopoiesis. Furthermore, hematopoietic stem cell (HSC) proliferation, aging, cycle, and related proteins were detected to explore the mechanism of these five components promoting HSC proliferation. i) The in vivo experiments showed that the combination of the five active components could remarkably increase the number of RBCs, WBCs, PLTs, and content of Hb in peripheral blood and the area of bone marrow hematopoietic tissue, as well as thrombopoietin (TPO), erythropoietin (EPO), granulocyte-macrophage colony stimulating factor (GM-CSF), and colony of CFU-GM, CFU-MK, CFU-E, and BFU-E in serum. Each of these five components promoted the recovery of RBCs and Hb, and increased TPO, CFU-MK, and CFU-E. All components except for AST increased the CFU-GM. FRA increased the number of WBCs, the area of bone marrow hematopoietic tissue, and BFU-E. FRA and AST promoted PLT recovery. FRA and CAL improved the content of GM-CSF. FRA, CAL, and CLG improved the content of EPO. ii) The in vitro experiments showed that FRA, FRM, and AST significantly promoted cell proliferation, reduced the positive rate and G0/G1 cells, and increased G2/M + S cells and the expression of cyclin D1 and CDK4 proteins in aging HSCs. Furthermore, the combination of five components had the best effect. Taken together, the five active components of AST, FRM, FRA, CAL, and CLG were the main pharmacodynamic substances of the AR-ASR compatibility, which promoted hematopoiesis. The combination of them had a synergistic effect. The mechanism of promoting hematopoiesis may be relevant to regulating cyclin-related proteins, promoting cell cycle transformation, and promoting HSC proliferation. [ABSTRACT FROM AUTHOR]

Background: Paraneoplastic ischemic stroke has a poor prognosis. We have recently reported an algorithm based on the number of ischemic territories, C-reactive protein (CRP), lactate dehydrogenase (LDH), and granulocytosis to predict the underlying active cancer in a case-control setting. However, co-occurrence of cancer and stroke might also be merely incidental. Objective: To detect cancer-associated ischemic stroke in a large, unselected cohort of consecutive stroke patients by detailed analysis of ischemic stroke associated with specific cancer subtypes and comparison to patients with bacterial endocarditis. Methods: Retrospective single-center cohort study of consecutive 1612 ischemic strokes with magnetic resonance imaging, CRP, LDH, and relative granulocytosis data was performed, including identification of active cancers, history of now inactive cancers, and the diagnosis of endocarditis. The previously developed algorithm to detect paraneoplastic cancer was applied. Tumor types associated with paraneoplastic stroke were used to optimize the diagnostic algorithm. Results: Ischemic strokes associated with active cancer, but also endocarditis, were associated with more ischemic territories as well as higher CRP and LDH levels. Our previous algorithm identified active cancer-associated strokes with a specificity of 83% and sensitivity of 52%. Ischemic strokes associated with lung, pancreatic, and colorectal (LPC) cancers but not with breast and prostate cancers showed more frequent and prominent characteristics of paraneoplastic stroke. A multiple logistic regression model optimized to identify LPC cancers detected active cancer with a sensitivity of 77.8% and specificity of 81.4%. The positive predictive value (PPV) for all active cancers was 13.1%. Conclusion: Standard clinical examinations can be employed to identify suspect paraneoplastic stroke with an adequate sensitivity, specificity, and PPV when it is considered that the association of ischemic stroke with breast and prostate cancers in the stroke-prone elderly population might be largely incidental. [ABSTRACT FROM AUTHOR]

Introduction: Flow cytometry‐based paroxysmal nocturnal hemoglobinuria (PNH) testing involves utilization of monoclonal antibodies against GPI‐linked proteins and FLAER. The ability of FLAER to bind to a wide variety of GPI‐linked structures and to be utilized across different leukocyte subsets is remarkable. We hypothesize that FLAER as a standalone reagent may be equally effective for detecting PNH clones. The present study intends to compare the results of a FLAER alone‐based strategy to the recommended FLAER+GPI‐linked protein‐based approach for applicability in clinical settings. Methods: EDTA‐anticoagulated blood samples from patients for PNH workup were tested for PNH by multiparametric flow cytometry. A conventional panel comprising gating markers (CD45 for WBC, CD15 for granulocytes, and CD64 for monocytes) and a combination of FLAER and GPI‐linked markers, such as CD24 and CD14, henceforth referred to as the "routine panel," was employed. Second, a "FLAER‐only panel" comprising the gating markers and FLAER alone (excluding the GPI‐linked markers CD24 and CD14) was set up. The samples were processed using the lyse‐wash‐stain‐wash technique, and events were acquired on BC Navios Ex flow cytometer (Beckman Coulter, Inc., USA) and analyzed on Kaluza Software 2.1. The presence of a PNH clone was reported at a value of ≥0.01%. Results: A total of 209 patients were tested. Both panels found a PNH clone in 20.1% of patients (n = 42/209) with a 100% concordance rate. The PNH clone range for granulocytes was 0.01%–89.68%, and for monocyte was 0.04%–96.09% in the routine panel. The range in the FLAER‐only panel for granulocytes was 0.01%–89.61%, and for monocytes, it was 0.01%–96.05%. Pearson correlation statistics revealed a significant correlation between the size of the PNH clone of granulocytes and monocytes among the two panels tested (granulocytes r = 0.9999, p < 0.0001, 95% CI = 0.9999 to 1.000; monocytes r = 0.9974, p < 0.0001, 95% CI = 0.9966–0.9980). Conclusion: Based on our results, FLAER as a standalone marker is specific and sensitive for identifying PNH clones in granulocytes and monocytes, even for high‐sensitivity PNH assay. The proposed "FLAER‐only panel" panel is efficient and cost‐effective for highly sensitive PNH testing in two different cell lineages, especially in resource‐limited clinical settings. [ABSTRACT FROM AUTHOR]

Introduction: Immature granulocyte percentage (IG%) is an important biomarker for infection control. We observed spurious cases where the IG% was dramatically underestimated on the automated Sysmex XN‐series hehmatology analyzer compared with manual differential. These cases were associated with high values of "Neutrophil Reactivity Intensity" (NEUT‐RI), which should reflect the metabolic activity of the neutrophils. Methods: We conducted a three‐stage study to evaluate whether NEUT‐RI could be utilized to screen for misclassified IG% results defined as the manual differential estimating a 10 percentage points higher IG% compared with the automated Sysmex differential. First, 124 patient samples were selected for 800‐cell manual smear analysis based on their NEUT‐RI values and compared with the automatic Sysmex IG% results. Next, 11 098 routine 110‐cell manual smear analyses were compared with the corresponding Sysmex IG% results. Finally, during a 19‐day period 160 additional patient samples underwent smear based on NEUT‐RI values ≥56 fluorescence intensity (FI) to screen for misclassified results beyond our current smear practice. Results: NEUT‐RI ≥56 predicted IG% misclassification with 91% sensitivity and 88% specificity, but primarily when the internal Sysmex flag "Abnormal WBC Scattergram" was present. 90.1% of misclassified results were identified by this flag. Beyond our existing smear rules including this flag, NEUT‐RI ≥56 FI had a positive predictive value below 1%. Conclusion: Both NEUT‐RI and the internal Sysmex flag "Abnormal WBC Scattergram" work well to identify cases of IG% misclassification. However, in our setting NEUT‐RI ≥56 FI had no meaningful additional predictive capacity to identify misclassifications beyond our current smear rules. [ABSTRACT FROM AUTHOR]

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Rationale: Inhaled granulocyte–macrophage colony-stimulating factor (GM-CSF) has been proposed as a potential immunomodulatory treatment for nontuberculous mycobacterial (NTM) infection. Objectives: This open-label, noncomparative pilot trial investigated the efficacy and safety of inhaled GM-CSF (molgramostim nebulizer solution) in patients with predominantly treatment-refractory pulmonary NTM infection (Mycobacterium avium complex [MAC] and M. abscessus [MABS]), either in combination with ongoing guideline-based therapy (GBT) or as monotherapy in patients who had stopped GBT because of lack of efficacy or intolerability. Methods: Thirty-two adult patients with refractory NTM infection (MAC, n = 24; MABS, n = 8) were recruited into two cohorts: those with (n = 16) and without (n = 16) ongoing GBT. Nebulized molgramostim 300 μg/d was administered over 48 weeks. Sputum cultures and smears and clinical assessments (6-min-walk distance, symptom scores, Quality of Life–Bronchiectasis Questionnaire score, and body weight) were collected every 4 weeks during treatment and 12 weeks after the end of treatment. The primary endpoint was sputum culture conversion, defined as three consecutive monthly negative cultures during the treatment period. Results: Eight patients (25%) achieved culture conversion on treatment (seven [29.2%] patients with MAC infection, one [12.5%] patient with MABS infection); in four patients, this was durable after the end of treatment. Of the 24 patients with MAC infection, an additional 4 patients had a partial response, converting from smear positive at baseline to smear negative at the end of treatment, and time to positivity in liquid culture media increased. Two of these patients sustained negative cultures from the end of treatment. Other clinical endpoints were unchanged. Serious adverse events were mainly pulmonary exacerbations or worsening NTM infection. Three deaths, not treatment related, were reported. Conclusions: In this population of patients with severe NTM disease, molgramostim was safe and well tolerated. Sputum culture conversion rates for patients with MAC infection (29.2%) were greater than reported for similar refractory MAC cohorts managed with GBT alone. Less benefit was seen for MABS infection. No serious safety concerns were identified. Further evaluation in a larger cohort is warranted. Clinical trial registered with www.clinicaltrials.gov (NCT 03421743). [ABSTRACT FROM AUTHOR]

The lepirudin-based human whole blood model is a well-established ex vivo system to characterize inflammatory responses. However, the contribution of individual cell populations to cytokine release has not been investigated. Thus, we modified the model by selectively removing leukocyte subpopulations to elucidate their contribution to the inflammatory response. Lepirudin-anticoagulated whole blood was depleted from monocytes or granulocytes using StraightFrom Whole Blood MicroBeads. Reconstituted blood was incubated with Escherichia coli (108/mL) for 2 hours at 37 °C. CD11b, CD62P, and CD63 were detected by flow cytometry. Complement (C3bc, sC5b-9) and platelet activation (platelet factor 4, NAP-2) were measured by enzyme-linked immunosorbent assay. Cytokines were quantified by multiplex assay. A significant (P < 0.05) specific depletion of the monocyte (mean = 86%; 95% confidence interval = 71%–92%) and granulocyte (mean = 97%; 95% confidence interval = 96%–98%) population was obtained. Background activation induced by the depletion protocol was negligible for complement (C3bc and sC5b-9), leukocytes (CD11b), and platelets (NAP-2). Upon Escherichia coli incubation, release of 10 of the 24 cytokines was solely dependent on monocytes (interleukin [IL]-1β, IL-2, IL-4, IL-5, IL-17A, interferon-γ, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, macrophage inflammatory protein-1α, and fibroblast growth factor–basic), whereas 8 were dependent on both monocytes and granulocytes (IL-1ra, IL-6, IL-8, IL-9, IL-10, macrophage inflammatory protein-1β, tumor necrosis factor, and eotaxin). Six cytokines were not monocyte or granulocyte dependent, of which platelet-derived growth factor and RANTES were mainly platelet dependent. We document an effective model for selective depletion of leukocyte subpopulations from whole blood, without causing background activation, allowing in-depth cellular characterization. The results are in accordance with monocytes playing a major role in cytokine release and expand our knowledge of the significant role of granulocytes in the response to E. coli. By selective removal of leukocyte subtypes from human blood, we were able to use a holistic approach to identify cells responsible for the cytokine release induced by Escherichia coli incubated in the whole blood model. [ABSTRACT FROM AUTHOR]

The goal was to improve the clinical cognition of nonaccelerating myelodysplastic/myeloproliferative neoplasms-unclassifiable (MDS/MPN-U) and avoid misdiagnosis or delayed diagnosis. Methods: The clinical manifestations, laboratory indicators, histopathology, and therapeutic effects of a patient with nonaccelerating MDS/MPN-U were analyzed and the relevant literature was reviewed. Results: Blood routine: white blood cell 98.48 x 109 /L, red blood cell 3.20 x 1012/L, basophils 0.42 x 109 /L, eosinophils 1.31 x 109 /L, hemoglobin 112 g/L, and platelet 113 x 109 /L. Blood smears showed granulocytosis and cells at various stages, polylobular granulocytes also can be seen. Bone marrow images show granulocytosis and dysplastic neutrophils, such as binuclear granulocyte, cyclic nuclear granulocyte, nuclear punch, cytoplasm vacuoles, polylobular granulocytes and so on. Bone marrow biopsy: Bone marrow proliferation tumor, combined with cell morphology and molecular biochemistry is recommended. Gene test showed Jak-2 positive, BCR/ABL and MPL negative. Chromosome examination indicated the presence of 46, XY, add (2)(p25), del (12) (p11.2p13)[16]/46, XY. Conclusions: MDS/MPN-U with granulocytosis and dysplastic neutrophils is rare, mostly in the elderly, and the diagnosis should be made except for other myeloid tumors. Currently, there is no uniform treatment guideline or expert consensus. The treatment options are limited and need to be further confirmed by more studies. MDS/ MPN-U with granulocytosis and dysplastic neutrophils has adverse prognostic factors such as advanced age, increase of bone marrow original cells and related gene mutations. Whether the adverse prognosis is related to specific gene mutations and cytogenetic variation remains to be clarified by more research data. [ABSTRACT FROM AUTHOR]

Antigen-presentation via major histocompatibility complex (MHC) to T cells is the key event to initiate adaptive immune responses. In teleosts, as in mammals, the main types of professional antigen-presenting cells (APCs) are dendritic cells (DCs), monocytes/macrophages, and B cells. In the current study, flow cytometry, immunostaining and qPCR have been used to show that neutrophils in the teleost fish Atlantic salmon (Salmo salar L.) have antigen-presenting properties. The neutrophils were positive for MHC class II, CD83 and CD80/86, and upon in vitro bacterial exposure, gene expression analysis of purified neutrophils showed that IL-12p40, which is essential for proliferation of naïve T cells, was highly upregulated at both 6 and 24 h post bacterial exposure. Based on presence of MHC class II and upregulation of molecules involved in antigen presentation and T cell activation, we suggest that neutrophils in Atlantic salmon have potential to function as professional APCs. This work makes an important basis for further exploring the potential of using neutrophils to develop new, targeted immunoprophylactic measures.