Search

Determining an individual's humoral immune reactivity to a pathogen, autoantigen, or environmental agent is traditionally accomplished through the assessment of specific antibody levels in blood. However, in many instances, titers of specific antibodies decline over time and thus do not faithfully reveal prior antigen exposure or establishment of immunological memory. To estimate an individual's humoral immune competence, it is therefore necessary to assess functional B cell memory. Here, we describe novel B cell ELISPOT and FluoroSpot assays (collectively referred to as ImmunoSpot) that can be rapidly developed and validated to characterize the memory B cell (Bmem) repertoire specific for any desired antigen ex vivo and at single-cell resolution. Moreover, multiplexed variants of the B cell FluoroSpot assay enable high-throughput testing of antigen-specific B cells secreting distinct antibody classes and/or IgG subclasses, with minimal cell material requirements. B cell ImmunoSpot assays also enable measurement of affinity distributions within the antigen-specific Bmem compartment and permit cross-reactivity measurements that can provide insights into Bmem established against future pathogen variants. Collectively, the ImmunoSpot® system presented here is highly reproducible, and can be readily validated for regulated tests. The newly gained ability to monitor the antigen-specific Bmem compartment should catalyze a more comprehensive understanding of humoral immunity in health and disease. [ABSTRACT FROM AUTHOR]

Enterobacteriaceae pathogens such as Escherichia coli, Salmonella sp., Shigella sp., Proteus sp., and Klebsiella pneumoniae cause a wide range of gastrointestinal and other mucosal infections. These bacteria acquire antibiotic resistance very quickly and evolve into multi-drug resistant strains thereby making the treatment very difficult. The outer membrane proteins (OMPs) in Enterobacteriaceae are potential vaccine candidates owing for their high immunogenicity and amino acid conservation. The OmpA is one such protein which need to be investigated for the development of a potential subunit vaccine against multiple infections casued by the pathogens of Enterobacteriaceae. To investigate this, we expressed and purified the highly conserved OmpA of S. typhimurium and studied the antibody mediated cross reactivity with the other Enterobacteriaceae pathogens. This was validated through dot ELISA performed with the hyperimmune sera raised against rOmpA of S. typhimurium. We further analyzed the sequence of OmpA protein and clearly understood that the B-cell epitopes in the protein are highly conserved are responsible for cross reactivity among the Enterobacteriaceae pathogens. This work led to findings that provide strong evidence for the application of OmpA in broad-spectrum subunit vaccine against enteric infections.

We present the case of a patient with antecedent of tree nuts allergy who developed an anaphylactic reaction after ingesting a piece chocolate. An allergy study detected sensitization to cocoa in skin tests as well as cross‐reactivity with tree nuts in the SDS‐PAGE immunoblotting‐inhibition. [ABSTRACT FROM AUTHOR]

Enterobacteriaceae pathogens such as Escherichia coli, Salmonella sp., Shigella sp., Proteus sp., and Klebsiella pneumoniae cause a wide range of gastrointestinal and other mucosal infections. These bacteria acquire antibiotic resistance very quickly and evolve into multi-drug resistant strains thereby making the treatment very difficult. The outer membrane proteins (OMPs) in Enterobacteriaceae are potential vaccine candidates owing for their high immunogenicity and amino acid conservation. The OmpA is one such protein which need to be investigated for the development of a potential subunit vaccine against multiple infections casued by the pathogens of Enterobacteriaceae. To investigate this, we expressed and purified the highly conserved OmpA of S. typhimurium and studied the antibody mediated cross reactivity with the other Enterobacteriaceae pathogens. This was validated through dot ELISA performed with the hyperimmune sera raised against rOmpA of S. typhimurium. We further analyzed the sequence of OmpA protein and clearly understood that the B-cell epitopes in the protein are highly conserved are responsible for cross reactivity among the Enterobacteriaceae pathogens. This work led to findings that provide strong evidence for the application of OmpA in broad-spectrum subunit vaccine against enteric infections. [ABSTRACT FROM AUTHOR]

Dermatitis herpetiformis (DH) is an inflammatory skin disorder often considered as an extra intestinal manifestation of celiac disease (CeD). Hallmarks of CeD and DH are auto‐antibodies to transglutaminase 2 (TG2) and transglutaminase 3 (TG3), respectively. DH patients have auto‐antibodies reactive with both transglutaminase enzymes. Here it is reported that in DH both gut plasma cells and serum auto‐antibodies are specific for either TG2 or TG3 with no TG2–TG3 cross reactivity. By generating monoclonal antibodies from TG3‐specific duodenal plasma cells of DH patients, three conformational epitope groups are defined. Both TG2‐specific and TG3‐specific gut plasma cells have few immunoglobulin (Ig) mutations, and the two transglutaminase‐reactive populations show distinct selection of certain heavy and light chain V‐genes. Mass spectrometry analysis of TG3‐specific serum IgA corroborates preferential usage of IGHV2‐5 in combination with IGKV4‐1. Collectively, these results demonstrate parallel induction of anti‐TG2 and anti‐TG3 auto‐antibody responses involving separate B‐cell populations in DH patients. [ABSTRACT FROM AUTHOR]

Pasteurella multocida , an encapsulated gram-negative bacterium, is a significant veterinary pathogen. The P. multocida is classified into 5 serogroups (A, B, D, E, and F) based on the bacterial capsular polysaccharide (CPS), which is important for virulence. Serogroups B and E are the primary causative agents of bovine hemorrhagic septicemia that is associated with significant yearly losses of livestock worldwide, primarily in low- and middle-income countries. The P. multocida disease is currently managed by whole-cell vaccination, albeit with limited efficacy. CPS is an attractive antigen target for an improved vaccine: CPS-based vaccines have proven highly effective against human bacterial diseases and could provide longer-term protection against P. multocida. The recently elucidated CPS repeat units of serogroups B and E both comprise a N-acetyl-β-D-mannosaminuronic acid/N-acetyl-β-D-glucosamine disaccharide backbone with β-D-fructofuranose (Fru f) side chain, but differ in their glycosidic linkages, and a glycine (Gly) side chain in serogroup B. Interestingly, the Haemophilus influenzae types e and d CPS have the same backbone residues. Here, comparative modeling of P. multocida serogroups B and E and H. influenzae types e and d CPS identifies a significant impact of small structural differences on both the chain conformation and the exposed potential antibody-binding epitopes (Ep). Further, Fru f and/or Gly side chains shield the immunogenic amino-sugar CPS backbone—a possible common strategy for immune evasion in both P. multocida and H. influenzae. As the lack of common epitopes suggests limited potential for cross-reactivity, a bivalent CPS-based vaccine may be necessary to provide adequate protection against P. multocida types B and E. [ABSTRACT FROM AUTHOR]

Rheumatic heart disease (RHD) remains a significant cardiovascular burden in the world even though it is no longer common in affluent countries. Centuries of history surrounding this disease provide us with a thorough understanding of its pathophysiology. Infections in the throat, skin, or mucosa are the gateway for Group A Streptococcus (GAS) to penetrate our immune system. A significant inflammatory response to the heart is caused by an immunologic cascade triggered by GAS antigen cross-reactivity. This exaggerated immune response is primarily responsible for cardiac dysfunction. Recurrent inflammatory processes damage all layers of the heart, including the endocardium, myocardium, and pericardium. A vicious immunological cycle involving inflammatory mediators, angiotensin II, and TGF-β promotes extracellular matrix remodeling, resulting in myocardial fibrosis. Myocardial fibrosis appears to be a prevalent occurrence in patients with RHD. The presence of myocardial fibrosis, which causes left ventricular dysfunction in RHD, might be utilized to determine options for treatment and might also be used to predict the outcome of interventions in patients with RHD. This emerging concept of myocardial fibrosis needs to be explored comprehensively in order to be optimally utilized in the treatment of RHD.

Background: Viral or bacterial infections can trigger auto-immune inflammatory reactions and conditions in children. Self-reactivity arises due to similarities in molecular structures between pathogenic microorganisms and regular body structures with consequent immune-cross reactions. Reactivation of latent Varicella Zoster Virus (VZV) infections can cause neurological sequalae, including cerebellitis, post-herpetic neuralgias, meningo/encephalitis, vasculopathy and myelopathy. We propose a syndrome caused by auto-immune reactivity triggered by molecular mimicry between VZV and the brain, culminating in a post-infectious psychiatric syndrome with childhood VZV infections. Case presentation: Two individuals, a 6-year-old male and 10-year-old female developed a neuro-psychiatric syndrome 3–6 weeks following a confirmed VZV infection with intrathecal oligoclonal bands. The 6-year-old male presented with a myasthenic syndrome, behavior deterioration and regression in school, he was poorly responsive to IVIG and risperidone, however had a pronounced response to steroid treatment. The 10-year-old female presented with marked insomnia, agitation, and behavioral regression as well as mild bradykinesia. A trial of neuroleptics and sedatives resulted in a mild unsustained reduction in psychomotor agitation and IVIG was also unsuccessful, however the patient was very responsive to steroid therapy. Conclusion: Psychiatric syndromes with evidence of intrathecal inflammation temporally related to VZV infections that are responsive to immune modulation have not been described before. Here we report two cases demonstrating neuro-psychiatric symptoms following VZV infection, with evidence of persistent CNS inflammation following the resolution of infection, and response to immune modulation.

The therapeutic targeting of the immune system, for example in vaccinology and cancer treatment, is a challenging task and the subject of active research. Several in silico tools used for predicting immunogenicity are based on the analysis of peptide sequences binding to the Major Histocompatibility Complex (pMHC). However, few of these bioinformatics tools take into account the pMHC threedimensional structure. Here, we describe a new bioinformatics tool, MatchTope, developed for predicting peptide similarity, which can trigger cross-reactivity events, by computing and analyzing the electrostatic potentials of pMHC complexes. We validated MatchTope by using previously published data from in vitro assays. We thereby demonstrate the strength of MatchTope for similarity prediction between targets derived from several pathogens as well as for indicating possible cross responses between self and tumor peptides. Our results suggest that MatchTope can enhance and speed up future studies in the fields of vaccinology and cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Light Chain (AL) Amyloidosis is a plasma cell dyscrasia producing amyloidogenic light chains (LC) that misfold and form amyloid deposits that cause damage in vital organs, primarily the heart and kidneys. Urinary extracellular vesicles (uEVs) are nanoparticles produced by renal epithelial cells throughout the nephron. We previously showed that uEVs from active renal AL amyloidosis patients contain LC oligomers that are large (>250kDa), resistant to heat and chemical denaturation, but of low abundance. Renal dysfunction in AL amyloidosis results in high urine protein, compounding technical challenges to use uEVs as analytical tools. In this study, we assess the use of uEVs as analytical diagnostic tools for response and disease progression in AL amyloidosis. Our results suggest that uEV protein concentration, urine volume, and particle concentrations are not directly correlated. Multiple strategies for overcoming non-specific antibody binding in uEV samples were validated in our study. We demonstrated that the sensitivity for pre-clinical testing is improved with a urine sample requirement algorithm that we developed. The findings of our study will provide a pathway toward development of critically needed tools for patientmanagement. Sensitive detection of LC oligomers from a non-invasive urine sample rather than an invasive renal biopsy will reduce patient burden and healthcare costs. The ability to detect LC oligomers in patients with renal progression, despite positive hematologic response; will allow clinicians to confidently treat, but not overtreat, patients at risk of ongoing significant renal injury. [ABSTRACT FROM AUTHOR]

Mycoplasma gallisepticum (MG) is responsible for serious economic losses in poultry industry in Pakistan. The present study was designed to evaluate the molecular and immunological cross reactivity among MG isolates recovered from broiler birds. For this purpose a total of four hundred and thirty-four (n=434) specimen samples were taken from suspected broilers as well as environmental samples of forty commercial poultry (broiler) farms from DIK, Tank, Peshawar, Abbottabad and Mansehra districts of Khyber Pakhtunkhwa. These samples were inoculated and serially passage into Modified Frey's broth. One hundred and nine (25.1%) samples showed turbidity and were further processed through biochemical tests (Catalase production, Tetrazolium reduction, Phosphatase production, Film and spot Assay and Glucose fermentation). Typical fried egg colonies on Frey's agar were purified. Biochemical tests indicated Mycoplasma species as 2.5% of total specimen samples. The PCR results confirmed (185 bp) three MG isolates (MG-I, MG-II and MG-III) with 0.7% prevalence in total specimen samples. All three antigens (Formalin inactivated and Montanide adjuvanted) were subcutaneously inoculated @ 0.5 ml into rabbits and booster on 7 days post first inoculation. Sera samples collected after 14 days post booster shot, were processed for antibody titration using Haemagglutination inhibition (HI) test with homologous and heterologous antigens. The immunological cross reactivity indicated all three MG isolates as distinctly separate from each other. The immunological cross reactivity was existing with 66 to 87.18% among all three isolates. The results showed high homologous GMT titers as compared to heterologous for each MG isolate. [ABSTRACT FROM AUTHOR]

Cases that experienced COVID-19 postvaccination-related thrombosis have been reported after the first dose of ChAdOx1 nCov-19 (Vaxzevria, AstraZeneca) or Ad26.COV2.S (Johnson & Johnson/Janssen) vaccine. These rare thrombotic events were observed within the expected vaccine-induced seroconversion period and could be attributed to platelet-activating (auto)antibodies against platelet factor 4 (PF4). Newly, vaccine-induced, cross-reactive anti-PF4 antibodies could explain this observation. An in-silico analysis using the Basic Local Alignment Search Tool was used to identify sequence similarity between PF4 and antigens contained in or encoded by ChAdOx1 nCov-19 or Ad26.COV2.S vaccines. Only one sequence within the signaling peptide of the SARS-CoV-2 spike protein exhibited a high percent identity (85.71%) with PF4. This sequence overlaps with a proven immunogenic peptide recognized from convalescent COVID-19 sera and could be responsible for the formation of platelet-activating immunocomplexes in susceptible patients. Manipulation of the immunogenicity of this particular sequence within the encoded SARS-CoV-2 spike protein signaling peptide may eliminate this iatrogenic severe adverse effect.

The therapeutic targeting of the immune system, for example in vaccinology and cancer treatment, is a challenging task and the subject of active research. Several in silico tools used for predicting immunogenicity are based on the analysis of peptide sequences binding to the Major Histocompatibility Complex (pMHC). However, few of these bioinformatics tools take into account the pMHC three-dimensional structure. Here, we describe a new bioinformatics tool, MatchTope, developed for predicting peptide similarity, which can trigger cross-reactivity events, by computing and analyzing the electrostatic potentials of pMHC complexes. We validated MatchTope by using previously published data from in vitro assays. We thereby demonstrate the strength of MatchTope for similarity prediction between targets derived from several pathogens as well as for indicating possible cross responses between self and tumor peptides. Our results suggest that MatchTope can enhance and speed up future studies in the fields of vaccinology and cancer immunotherapy.

Abstract Background It is essential to detect carriers of carbapenemase-producing Enterobacterales in order to implement infection control measures. The objectives of this study was to evaluate the NG-Test® CARBA 5 (CARBA 5) assay for detection of five carbapenemases and to assess the cross reactivity of other OXA-type carbapenemases with the OXA-48-like specific antibodies. Methods A total of 197 Enterobacterales isolates were tested. To evaluate the cross reactivity, 73 carbapenem-resistant A. baumannii, harboring OXA-type variants, were tested. Polymerase chain reaction (PCR) served as gold standard for carbapenemase identification. Results Excellent agreement was found between PCR and CARBA 5, for all but one isolate. The single false positive result (a bla SME positive S. marcescens isolate) was incorrectly positive for bla OXA-48 by CARBA 5. No cross reactivity was observed. The sensitivity and specificity were 100.0% and 98.0%, respectively. Conclusions The CARBA 5 assay is highly sensitive and specific and is recommended as a tool for the detection of the main carbapenemases of interest in clinical microbiology laboratories.

Porcine deltacoronavirus (PDCoV), belonging to family Coronaviridae and genus Deltacoronavirus, is a major enteric pathogen in swine. Accurate PDCoV diagnosis relying on laboratory testing and antibody detection is an important approach. This study evaluated the potential of the receptor-binding subunit of the PDCoV spike protein (S1), generated using a mammalian expression system, for specific antibody detection via indirect enzyme-linked immunosorbent assay (ELISA). Serum samples were collected at day post-inoculation (DPI) −7 to 42, from pigs (n = 83) experimentally inoculated with different porcine coronaviruses (PorCoV). The diagnostic sensitivity of the PDCoV S1-based ELISA was evaluated using serum samples (n = 72) from PDCoV-inoculated animals. The diagnostic specificity and potential cross-reactivity of the assay was evaluated on PorCoV-negative samples (n = 345) and samples collected from pigs experimentally inoculated with other PorCoVs (n = 472). The overall diagnostic performance, time of detection, and detection rate over time varied across different S/P cut-offs, estimated by Receiver Operating Characteristic (ROC) curve analysis. The higher detection rate in the PDCoV group was observed after DPI 21. An S/P cut-off of 0.25 provided 100% specificity with no serological cross-reactivity against other PorCoV. These results support the use of S1 protein-based ELISA for accurate detection of PDCoV infections, transference of maternal antibodies, or active surveillance. [ABSTRACT FROM AUTHOR]

Abstract Background Detection of Dirofilaria immitis, or heartworm, through antigen in sera is the primary means of diagnosing infections in dogs. In recent years, the practice of heat-treating serum prior to antigen testing has demonstrated improved detection of heartworm infection. While the practice of heat-treating serum has resulted in earlier detection and improved sensitivity for heartworm infections, it has been suggested that heat treatment may cause cross reactivity with A. reconditum and intestinal helminth infections of dogs. No studies have assessed the potential cross-reactivity of these parasites with heartworm tests before and after heat treatment using blood products and an appropriate gold standard reference. Methods Canine sera (n=163) was used to evaluate a heartworm antigen-ELISA (DiroCHEK®) and potential cross-reactivity with common parasitic infections. The heartworm status and additional parasite infections were confirmed by necropsy and adult helminth species verified morphologically or by PCR, and feces evaluated by centrifugal fecal flotation. Results Intestinal parasites were confirmed in 140 of the dogs by necropsy, and 130 by fecal flotation. Acanthocheilonema reconditum microfilariae were confirmed in 22 dogs. Prevalence of heartworm infection confirmed by necropsy was 35.6% (58/163). In the 105 dogs without heartworms, specificity remained unchanged at 100% both before and after heat treatment despite confirmed infections with A. reconditum, Ancylostoma caninum, Ancylostoma brasiliense, Trichuris vulpis, Toxocara canis, Dipylidium caninum, Spirometra mansonoides, Macracanthorynchus ingens, Cystoisospora sp., Giardia sp., and Sarcocystis sp. Conclusions These findings suggest that the use of heat treatment improves sensitivity of heartworm tests and is unlikely to cause false positive antigen results due to Acanthocheilonema reconditum, intestinal helminths, and protozoal parasites in dogs. Graphic abstract

Because of limited data on dengue virus in Burkina Faso, we conducted 4 consecutive age-stratified longitudinal serologic surveys, ≈6 months apart, among persons 1–55 years of age, during June 2015–March 2017, which included a 2016 outbreak. The seroconversion rate before the serosurvey enrollment was estimated by binomial regression, taking age as the duration of exposure, and assuming constant force of infection (FOI) over age and calendar time. We calculated FOI between consecutive surveys and rate ratios for potentially associated characteristics based on seroconversion using the duration of intervals. Among 2,897 persons at enrollment, 66.3% were IgG-positive, and estimated annual FOI was 5.95%. Of 1,269 enrollees participating in all 4 serosurveys, 438 were IgG-negative at enrollment. The annualized FOI ranged from 10% to 20% (during the 2016 outbreak). Overall, we observed high FOI for dengue. These results could support decision-making about control and preventive measures for dengue.

Nous rapportons un cas d'anaphylaxie sévère au pitaya (fruit du dragon) chez un enfant de 10 ans, allergique connu au pignon de pin et à la noix de cajou. L'étude de son sérum par immunoblot et immunoblot-inhibition, révélant une réactivité IgE contre des protéines du pitaya de 50 et 23 kDa ayant une forte homologie avec la légumine Ana o 2 de la noix de cajou, et de 11 kDa ayant une forte homologie avec la LTP Pru p 3, confirme l'allergie croisée entre ces trois aliments, de familles botaniques pourtant différentes. Le risque allergénique du pitaya est donc désormais à prendre en compte chez les patients allergiques au pignon de pin, allergène émergent, et chez ceux, de plus en plus nombreux, qui sont allergiques à la noix de cajou et autres anacardiacées. We report a case of severe anaphylaxis to pitaya (Dragon fruit) in a 10-year-old child, with a history of anaphylaxis to pine nut and cashew nut. Performing immunoblot and immunoblot inhibition test, we showed IgE reactivity of the patient's serum towards pitaya proteins of 50, 23 and 11 kDa molecular weight. The high homology between the proteins of 50 and 23 kDa and the cashew nut legumin Ana o 2, and between the 11 kDa protein and the LTP Pru p 3, confirms cross-reactivity of these three food allergens, though they belong to different botanical families. Allergenic risk of pitaya is now to consider in patients allergic to pine nut, an emergent allergen, and in the more and more frequent allergic patients to cashew nut and other anacardiaceous species. [ABSTRACT FROM AUTHOR]

Les manifestations d'hypersensibilité alimentaire immédiate aux champignons sont rares mais potentiellement graves. Nous rapportons le cas d'un patient atopique de 23 ans présentant un syndrome oral associé à un tableau digestif haut (nausées, vomissements) provoqué par la consommation de champignons de Paris cuisinés. Il n'a pas d'autre antécédent d'allergie alimentaire. Le prick-test réalisé avec un échantillon de champignon cuit (sans huile ni assaisonnement) est fortement positif, avec apparition d'une papule pseudopodique mesurée à 1,5 cm de grand axe après 15 min (témoin : 7 mm). Les allergènes en cause sont mal caractérisés, peut-être modifiés par la cuisson, par révélation d'épitopes cachés après dénaturation par la cuisson de la structure conformationelle protéique. Une allergénicité croisée avec Alternaria Alternata semble possible au vu de la forte sensibilisation de notre patient à l'allergène majeur de cette moisissure. La prise en charge repose sur l'éviction de tous les champignons comestibles, à l'exception des cas où la tolérance à une espèce différente est avérée. Le port d'une trousse d'urgence reste la règle. Son contenu est à adapter aux caractéristiques cliniques de la réaction. Immediate food hypersensitivity to mushrooms is rare but potentially serious. We report the case of a 23-year-old atopic patient presenting an oral syndrome and high digestive symptoms (nausea, vomiting) when consuming cooked button mushrooms. He has no other history of food allergy. The cooked mushroom prick-test is strongly positive, with the appearance of a pseudopodic papule measured at 1.5 cm from the main axis. The allergens in question are poorly characterized and may be modified by cooking, with the revelation of hidden epitopes after the conformational protein denaturation linked to heat. Cross-reactivity with Alternaria Alternata seems possible in view of the strong sensitization of our patient to the major allergens of this mold. Management is based on the eviction of all edible mushrooms, except in cases where tolerance to another species is proven. Wearing an emergency kit remains the rule. Its content should be adapted to the clinical characteristics of the reaction. [ABSTRACT FROM AUTHOR]

• IgG anti-SARS-CoV-2 Omicron spike glycoprotein antibodies were detected in 100% of health care workers, a real world population attending general practice for vaccination and haemodialysis patients 4 weeks after a third SARS-CoV-2 vaccine dose (Pfizer-BioNtech 162b2). • Against both Delta and Omicron variants, antibody levels were higher in the cohort who had previously received two doses of Astrazeneca ChAdOx1 nCoV-19 vaccine than two doses of Pfizer-Biontech 162b2. • Prior to this third vaccine dose and 6 months post second vaccine dose, there was evidence of significant waning of antibody reactivity against Delta and Omicron variants of concern, particularly in individuals initially receiving two doses of Astrazeneca ChAdOx1 nCoV-19. [ABSTRACT FROM AUTHOR]

Abstract Background Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott’s test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides). Results A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott’s tests one month after the last treatment. Conclusions We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides.

One of the challenges for control and prevention of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection is the early diagnostic at the point of care. Several tests based on qualitative antigen detection have been developed; one of these is Elecsys SARS‐CoV‐2 Antigen immunoassay (Roche Diagnostics). In total, 523 nasopharyngeal swabs were randomly selected with the aims to evaluate sensitivity, specificity, cross‐reactivity, positive and negative predictive value (PPV, NPV), and agreement of Elecsys SARS‐CoV‐2 Antigen immunoassay using reverse transcription‐polymerase chain reaction (RT‐PCR) STAT‐NAT® coronavirus disease‐2019 as reference test. Cross‐reactivity was estimated using samples positive by RT‐PCR to other respiratory viruses (influenza virus, parainfluenza virus, rhinovirus, coronavirus OC43, and HKU1). The overall sensitivity of Elecsys SARS‐CoV‐2 Antigen was 89.72% (288/321); specificity was 90.59% (183/202); and cross‐reactivity to other respiratory viruses were not detected. Elecsys SARS‐CoV‐2 Antigen immunoassay showed a high sensitivity in samples with cycle threshold value <30, which ranged from 92.81% to 95.40%, independently of symptoms. PPV and NPV were 93.81% and 84.72%, respectively. The κ coefficient was 0.79 (95% confidence interval: 0.73–0.84), showing substantial agreement between both tests. The results suggest Elecsys SARS‐CoV‐2 Antigen immunoassay could be used as an alternative to RT‐PCR testing, or in complement with it, to identify infectious individuals and reduce SARS‐CoV‐2 transmission. Highlights: Elecsys SARS‐CoV‐2 Antigen assay can be used as an alternative tool or in complement with RT‐PCR to reduce SARS‐CoV‐2 transmission.Our results indicate that Elecsys SARS‐CoV‐2 Antigen assay detects SARS‐CoV‐2 infected persons independently of viral load.Elecsys SARS‐CoV‐2 Antigen assay has good performance characteristics to be used for SARS‐CoV‐2 infection tracing. [ABSTRACT FROM AUTHOR]

Background: Detection of Dirofilaria immitis, or heartworm, through antigen in sera is the primary means of diagnosing infections in dogs. In recent years, the practice of heat-treating serum prior to antigen testing has demonstrated improved detection of heartworm infection. While the practice of heat-treating serum has resulted in earlier detection and improved sensitivity for heartworm infections, it has been suggested that heat treatment may cause cross reactivity with A. reconditum and intestinal helminth infections of dogs. No studies have assessed the potential cross-reactivity of these parasites with heartworm tests before and after heat treatment using blood products and an appropriate gold standard reference. Methods: Canine sera (n=163) was used to evaluate a heartworm antigen-ELISA (DiroCHEK®) and potential cross-reactivity with common parasitic infections. The heartworm status and additional parasite infections were confirmed by necropsy and adult helminth species verified morphologically or by PCR, and feces evaluated by centrifugal fecal flotation. Results: Intestinal parasites were confirmed in 140 of the dogs by necropsy, and 130 by fecal flotation. Acanthocheilonema reconditum microfilariae were confirmed in 22 dogs. Prevalence of heartworm infection confirmed by necropsy was 35.6% (58/163). In the 105 dogs without heartworms, specificity remained unchanged at 100% both before and after heat treatment despite confirmed infections with A. reconditum, Ancylostoma caninum, Ancylostoma brasiliense, Trichuris vulpis, Toxocara canis, Dipylidium caninum, Spirometra mansonoides, Macracanthorynchus ingens, Cystoisospora sp., Giardia sp., and Sarcocystis sp. Conclusions: These findings suggest that the use of heat treatment improves sensitivity of heartworm tests and is unlikely to cause false positive antigen results due to Acanthocheilonema reconditum, intestinal helminths, and protozoal parasites in dogs. [ABSTRACT FROM AUTHOR]

Whether endogenous neurogenesis occurs in the adult cortex remains controversial. An increasing number of reports suggest that doublecortin (DCX)-positive neurogenesis persists in the adult primate cortex, attracting enormous attention worldwide. In this study, different DCX antibodies were used together with NeuN antibodies in immunohistochemistry and western blot assays using adjacent cortical sections from adult monkeys. Antibody adsorption, antigen binding, primary antibody omission and antibody-free experiments were used to assess specificity of the signals. We found either strong fluorescent signals, medium-weak intensity signals in some cells, weak signals in a few perikarya or near complete lack of labeling in adjacent cortical sections incubated with the various DCX antibodies. The putative DCX-positive cells in the cortex were also positive for NeuN, a specific marker of mature neurons. However, further experiments showed that most of these signals were either the result of antibody cross reactivity, the non-specificity of secondary antibodies or tissue autofluorescence. No confirmed DCX-positive cells were detected in the adult macaque cortex by immunofluorescence. Our findings show that DCX-positive neurogenesis does not occur in the cerebral cortex of adult primates, and that false-positive signals (artefacts) are caused by antibody cross reactivity and autofluorescence. The experimental protocols were approved by the Institutional Animal Care and Use Committee of the Institute of Neuroscience, Beijing, China (approval No. IACUC-AMMS-2014-501).

Abstract Objectives The human specific commercially available STRs system are often not tested in non human primates for their cross applicability. The aim of this study is to test Cross-species validation of two commercially available human specific STR kits i.e. SureID® 21G and SureID® 23comp (Health Gene Technologies) for their positive application in Chimpanzee (Pan troglodytes). Result In SureID® 21G, 19 loci amplified and while 20 loci amplified in SureID® 23comp. All the amplified loci in both STR kits were found polymorphic and the locus Amelogenin showed differential banding patterns between male and female revealing their known gender. The present study validates the applicability of these human specific STR kits in Chimpanzee that can be used in forensics analysis, paternity testing and population genetic studies.

There are more than 3,000 mosquito species. Aedes aegypti, Ae. communis, and C. quinquefasciatus are, among others, three of the most important mosquito allergen sources in the tropics, western, and industrialized countries. Several individuals are sensitized to mosquito allergens, but the epidemiological data indicates that the frequency of sensitization markedly differs depending on the geographical region. Additionally, the geographical localization of mosquito species has been affected by global warming and some mosquito species have invaded areas where they were not previously found, at the same time as other species have been displaced. This phenomenon has repercussions in the pathogenesis and the accuracy of the diagnosis of mosquito allergy. Allergic individuals are sensitized to mosquito allergens from two origins: saliva and body allergens. Exposure to saliva allergens occurs during mosquito bite and induces cutaneous allergic reactions. Experimental and clinical data suggest that body allergens mediate different manifestations of allergic reactions such as asthma and rhinitis. The most studied mosquito species is Ae. aegypti, from which four and five allergens of the saliva and body, respectively, have been reported. Many characterized allergens are homologs to arthropod-derived allergens, which cause strong cross-reactivity at the humoral and cellular level. The generalized use of whole body Ae. communis or C. quinquefasciatus extracts complicates the diagnosis of mosquito allergy because they have low concentration of saliva allergens and may result in poor diagnosis of the affected population when other species are the primary sensitizer. This review article discusses the current knowledge about mosquito allergy, allergens, cross-reactivity, and proposals of component resolved approaches based on mixtures of purified recombinant allergens to replace saliva-based or whole-body extracts, in order to perform an accurate diagnosis of allergy induced by mosquito allergen exposure.

Background: It is essential to detect carriers of carbapenemase-producing Enterobacterales in order to implement infection control measures. The objectives of this study was to evaluate the NG-Test® CARBA 5 (CARBA 5) assay for detection of five carbapenemases and to assess the cross reactivity of other OXA-type carbapenemases with the OXA-48-like specific antibodies. Methods: A total of 197 Enterobacterales isolates were tested. To evaluate the cross reactivity, 73 carbapenem-resistant A. baumannii, harboring OXA-type variants, were tested. Polymerase chain reaction (PCR) served as gold standard for carbapenemase identification. Results: Excellent agreement was found between PCR and CARBA 5, for all but one isolate. The single false positive result (a blaSME positive S. marcescens isolate) was incorrectly positive for blaOXA-48 by CARBA 5. No cross reactivity was observed. The sensitivity and specificity were 100.0% and 98.0%, respectively. Conclusions: The CARBA 5 assay is highly sensitive and specific and is recommended as a tool for the detection of the main carbapenemases of interest in clinical microbiology laboratories. [ABSTRACT FROM AUTHOR]

The reason why only few coeliac patients develop the cutaneous manifestation of the disease, named dermatitis herpetiformis (DH), is still unknown. Epidermal transglutaminase (TG3) has been described as the main autoantigen of humoral immunity in DH but the mechanisms leading to this autoimmune response remain obscure. Here we characterized T cells from skin, gut and peripheral blood of DH and coeliac disease (CD) patients, evaluated the impact of the gluten-free diet on circulating T lymphocytes’ phenotype and investigated antigen specific T cell response toward epidermal and tissue transglutaminase (TG2). DH patients showed an increased frequency of skin-derived T cells producing TNFα when compared to CD patients. Moreover, circulating T cells producing TNFα and IL-17A positively correlated with clinical score of skin disease activity and decreased after gluten-free diet. Finally, TG2 and TG3-specific T cells resulted more reactive to antigens stimulation in DH patients and showed cross reactivity toward the two autoantigens in both the group of patients. Our data suggest a role of TNFα and IL-17A producing cells in the development of DH and, for the first time, show the existence of a crossed T cell response toward the two transglutaminases isoforms, thus suggesting new insights on T cells role in skin damage.

Porcine deltacoronavirus (PDCoV), belonging to family Coronaviridae and genus Deltacoronavirus, is a major enteric pathogen in swine. Accurate PDCoV diagnosis relying on laboratory testing and antibody detection is an important approach. This study evaluated the potential of the receptor-binding subunit of the PDCoV spike protein (S1), generated using a mammalian expression system, for specific antibody detection via indirect enzyme-linked immunosorbent assay (ELISA). Serum samples were collected at day post-inoculation (DPI) −7 to 42, from pigs (n = 83) experimentally inoculated with different porcine coronaviruses (PorCoV). The diagnostic sensitivity of the PDCoV S1-based ELISA was evaluated using serum samples (n = 72) from PDCoV-inoculated animals. The diagnostic specificity and potential cross-reactivity of the assay was evaluated on PorCoV-negative samples (n = 345) and samples collected from pigs experimentally inoculated with other PorCoVs (n = 472). The overall diagnostic performance, time of detection, and detection rate over time varied across different S/P cut-offs, estimated by Receiver Operating Characteristic (ROC) curve analysis. The higher detection rate in the PDCoV group was observed after DPI 21. An S/P cut-off of 0.25 provided 100% specificity with no serological cross-reactivity against other PorCoV. These results support the use of S1 protein-based ELISA for accurate detection of PDCoV infections, transference of maternal antibodies, or active surveillance.

The reason why only few coeliac patients develop the cutaneous manifestation of the disease, named dermatitis herpetiformis (DH), is still unknown. Epidermal transglutaminase (TG3) has been described as the main autoantigen of humoral immunity in DH but the mechanisms leading to this autoimmune response remain obscure. Here we characterized T cells from skin, gut and peripheral blood of DH and coeliac disease (CD) patients, evaluated the impact of the gluten-free diet on circulating T lymphocytes' phenotype and investigated antigen specific T cell response toward epidermal and tissue transglutaminase (TG2). DH patients showed an increased frequency of skin-derived T cells producing TNFα when compared to CD patients. Moreover, circulating T cells producing TNFα and IL-17A positively correlated with clinical score of skin disease activity and decreased after gluten-free diet. Finally, TG2 and TG3-specific T cells resulted more reactive to antigens stimulation in DH patients and showed cross reactivity toward the two autoantigens in both the group of patients. Our data suggest a role of TNFα and IL-17A producing cells in the development of DH and, for the first time, show the existence of a crossed T cell response toward the two transglutaminases isoforms, thus suggesting new insights on T cells role in skin damage. [ABSTRACT FROM AUTHOR]

• In silico analysis reveals Per a 5 to be phylogenetically similar with mite, fungal and helminth GSTs. • Recombinant DNA technology was utilized for cloning, expression and purification of Per a 5 protein. • rPer a 5 is a clinically relevant cockroach allergen exhibiting upto 65 % immunoreactivity with hypersensitive patient sera. • rPer a 5 is enzymatically active and cross reactive with GSTs from dust mite and fungal sources. • Recombinant Per a 5 may be employed for accurate molecular diagnosis and therapeutics. GSTs are multifunctional enzymes involved in cellular detoxification and present as potent allergens in several sources. Present study investigates allergenic relevance of GST from P. americana and determine its cross reactive potential with other indoor allergen sources. Computational analysis with FASTA and ConSurf webserver was performed to determine potentially cross reactive allergens. Further, Per a 5 gene was cloned in pET 22b+ vector and expressed in E.coli BL21 cells and the rPer a 5 protein was purified using Ni-NTA affinity chromatography. Enzymatic activity of rPer a 5 was assessed using CDNB and cumene hydroperoxide. ELISA and immunoblot were performed using cockroach hypersensitive patient's sera. Functional activity of rPer a 5 was evaluated by basophil activation test. Inhibition studies were carried out with D. pteronyssinus, A. alternata and C. lunata extracts. Per a 5 demonstrates highest sequence similarity with delta class GST of Blattella germanica (94.9%). It also exhibits significant sequence similarity (50–58%) with mite, fungal and helminth allergenic GSTs. ConSurf analysis reveals high degree of evolutionary similarity in N terminal region of Per a 5, especially at GST dimerization interface. The purified rPer a 5 protein resolved at 27 kDa on SDS-PAGE. The rPer a 5 protein exhibits GST activity and possess upto 65% immunoreactivity with cockroach hypersensitive patient's sera in ELISA and immunoblot. It upregulates expression of CD203c on basophils signifying its biological ability to activate effector cells. rPer a 5 significantly inhibits corresponding GSTs in P. americana , D. pteronyssinus , A. alternata and C. lunata with EC 50 values of 15.5 ng. 38.38 ng, 41.4 ng and 61.66 ng, respectively. Recombinant delta class GST of P. americana is a clinically relevant allergen showing upto 65% immunoreactivity with hypersensitive patient's sera. Per a 5 GST allergen showed phylogenetic similarity with dust mite, fungal and birch allergens thereby demonstrating allergen cross reactivity. [ABSTRACT FROM AUTHOR]

Peanut/tree nut allergy is common and has been associated with particularly severe reactions. Epidemiological data have shown that the prevalence ranges between 0.05% and 4.9% for tree nut and between 0.5% and 3% for peanut. These large variations can be explained by differences in the age of included patients and the geographical region. In addition, the food consumption modality (ie, raw versus roasted) plays a major role, as heat treatment has the capacity to modify the allergenicity of nuts and legumes. Nut allergies tend to persist into adulthood and consequently have a high impact on quality of life.Recently, it has been demonstrated that a significant proportion of nut allergic patients are able to tolerate other nuts. As opposed to the avoidance of all nuts, this approach is currently proposed in several tertiary allergy centers. However, diagnosis of nut allergy is particularly difficult due to co-sensitization leading to high rate of false positive skin prick tests and/or specific IgE to whole allergen extracts. The use of component resolved diagnosis leads to major improvement of diagnosis, particularly to distinguish between primary and secondary nut allergies. The basophil activation test has been suggested to be useful but is still used mainly as a research tool. Thus, diagnosis remains mainly based on the oral food challenge, which is considered as the gold standard.Regarding treatment, avoidance remains the cornerstone of management of nut allergy. Oral immunotherapy is increasingly proposed as an alternative management strategy.

Because of limited data on dengue virus in Burkina Faso, we conducted 4 consecutive age-stratified longitudinal serologic surveys, ≈6 months apart, among persons 1-55 years of age, during June 2015-March 2017, which included a 2016 outbreak. The seroconversion rate before the serosurvey enrollment was estimated by binomial regression, taking age as the duration of exposure, and assuming constant force of infection (FOI) over age and calendar time. We calculated FOI between consecutive surveys and rate ratios for potentially associated characteristics based on seroconversion using the duration of intervals. Among 2,897 persons at enrollment, 66.3% were IgG-positive, and estimated annual FOI was 5.95%. Of 1,269 enrollees participating in all 4 serosurveys, 438 were IgG-negative at enrollment. The annualized FOI ranged from 10% to 20% (during the 2016 outbreak). Overall, we observed high FOI for dengue. These results could support decision-making about control and preventive measures for dengue. [ABSTRACT FROM AUTHOR]

The consumption of drugs of abuse among females in the Health Services is a frequent problem, but often it is not diagnosed. Aims: We have analyzed the variations in the clinical profile of female patients came to obstetric emergency department in a period of sex months and made screening for various drugs to assess the percentage of addicted females in this period of life. Secondly, we have assessed also the accuracy of the presumptive method of detection compared to the confirmatory method. Method: Urine samples were taken from pregnant females came to obstetric emergency department, Beni Suef University hospital and was screened to detect the drugs of abuse that taken by these females by immunoassay and GC- mass and clinical assessment of the babies were done. Results: from 300 females there were 20 cases Tramadol positive by immunoassay but all of them were false positive when GC-mass was used. There was a questioned cross reactivity between Ranitidine and tramadol by Immunoassay needing for more researches. 62.3% of the female were no educated 42% of the female’s husbands were SHISHA smokers. Intra uterine growth retardation was the most common fetal complication Conclusions: scientific survey which done to detect drug abuse among group of people should never depend on immunoassay methods. The belief that women are more biologically complicated than men and that they were too busy caring for their children to participate in studies should be changed. Women should be included in clinical researches. [ABSTRACT FROM AUTHOR]

The aim of this study is to reveal the biological and toxicological activities of the Cerastes cerastes and Macrovipera mauritanica venoms as well as their fractions, and the immunological activity of two monospecific experimental antivenins produced in the horse. Our data demonstrated the hemorrhagic, necrotic, edematous, myotoxic, coagulant, proteolytic, hemolytic, and phospholipasic activities of the studied venoms and their toxic fractions. Microscopically, intradermal and muscle sections showed edema, disruption of muscle fibers, and inflammatory infiltrates. Both monospecific antivenoms were effective in neutralizing the activities studied. However, they remained ineffective against edema-forming and clotting activities in range of antivenoms used. [ABSTRACT FROM AUTHOR]

Background: Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott's test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides). Results: A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott's tests one month after the last treatment. Conclusions: We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides. [ABSTRACT FROM AUTHOR]

Accurate serologic tests to detect host antibodies to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) will be critical for the public health response to the coronavirus disease 2019 pandemic. Many use cases are envisaged, including complementing molecular methods for diagnosis of active disease and estimating immunity for individuals. At the population level, carefully designed seroepidemiologic studies will aid in the characterization of transmission dynamics and refinement of disease burden estimates and will provide insight into the kinetics of humoral immunity. Yet, despite an explosion in the number and availability of serologic assays to test for antibodies against SARS-CoV-2, most have undergone minimal external validation to date. This hinders assay selection and implementation, as well as interpretation of study results. In addition, critical knowledge gaps remain regarding serologic correlates of protection from infection or disease, and the degree to which these assays cross-react with antibodies against related coronaviruses. This article discusses key use cases for SARS-CoV-2 antibody detection tests and their application to serologic studies, reviews currently available assays, highlights key areas of ongoing research, and proposes potential strategies for test implementation. [ABSTRACT FROM AUTHOR]

• Allergen peptides with similar P hysico C hemical P roperties (PCP) can bind IgE. • An IgE epitope PCP-consensus identified similar repeats in diverse plant allergens. • Synthetic consensus peptide (cp) inhibited patient IgE binding to nut extracts. • cp antibodies preferentially bound to allergens containing multiple PCP repeats. • These repeats may contribute to cross reactions and the severity of nut allergies. Many individuals with peanut (PN) allergy have severe reactions to tree nuts (TN) such as walnuts or cashews. Although allergenic proteins in TN and PN have overall low identity, they share discrete sequences similar in physicochemical properties (PCP) to known IgE epitopes. Here, PCP-consensus peptides (cp, 13 aa and 31 aa) were identified from an alignment of epitope rich regions of walnut vicilin, Jug r 2, leader sequence (J2LS) and cross-reactive epitopes in the 2S albumins of peanut and synthesized. A peptide similarity search in the Structural Database of Allergenic Proteins (SDAP) revealed a network of peptides similar (low property distance, PD) to the 13 aa cp (13cp) in many different plant allergens. Peptides similar to the 13cp in PN and TN allergens bound IgE from sera of patients allergic to PN and TN in peptide microarray analysis. The 13cp was used to produce a rabbit consensus peptide antibody (cpAB) that detected proteins containing repeats similar to the 13cp in western blots of various nut extracts, in which reactive proteins were identified by mass spectrometry. The cpAB bound more specifically to allergens and nut extracts containing multiple repeats similar to the 13 cp, such as almond (Pru du 6), peanut (Ara h 2) and walnut (Jug r 2). IgE binding to various nut extracts is inhibited by recombinant J2LS sequence and synthetic 31cp. Thus, several repeated sequences similar to the 13cp are bound by IgE. Multiple similar repeats in several allergens could account for reaction severity and clinically relevant cross-reactivity to PN and TN. These findings may help improve detection, diagnostic, and therapeutic tools. [ABSTRACT FROM AUTHOR]

Background & objectives: In India, certain geographic regions witness simultaneous outbreaks of two or more diseases like scrub typhus, dengue fever, malaria, leptospirosis and chikungunya during monsoon and post-monsoon period, sharing common indication of acute febrile illness. The objective of the present study was to assess the prevalence of coinfections among patients with acute undifferentiated fevers (AUF) admitted in a tertiary care hospital in the northern hilly state of Himachal Pradesh, India. Methods: This was a hospital based open cohort study conducted over a period of two months (September and October) in 2016. All the patients above the age of 18 yr admitted in medical wards and fulfilling the definition of AUF were included. The patients diagnosed with dual infections were the subjects of the study. Standard guidelines were used for case definitions of scrub typhus, dengue, chikungunya, malaria and leptospirosis. Results: Dual infections were noted in 16 patients admitted with AUF. The most common coinfection was scrub typhus and dengue, reported in 10 patients. Scrub typhus and leptospirosis coinfection was observed in three patients. Dengue and chikungunya was observed in one patient. Scrub typhus, dengue and vivax malaria was detected in one patient. Scrub typhus and vivax malaria was detected in one patient. Out of the 10 cases positive for both scrub and dengue, four had no history of travel outside Himachal Pradesh. All three cases positive for both scrub and leptospirosis were indigenous without any history of travel outside Kangra, Himachal Pradesh. The outcome of all the patients was with full recovery. Interpretation & conclusion: The study established the presence of coinfections (mainly dengue fever and leptospirosis) as a cause of AUF in the study area, which is a nonendemic region. The role of easily available and widely performed serological tests in the aetiological diagnosis of AUF is significant. Studies are required to determine the normal titres in the local population before using the imported commercially available serological tests in the diagnosis of AUF.

Contact dermatitis is an inflammatory condition mediated by allergens and irritants, including food. There have been few reports of zucchini causing contact dermatitis outside of ingestion. We report a case of allergic contact dermatitis to zucchini secondary to sensitization by a past squash exposure. The patient was treated with both systemic and topical corticosteroids., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ravichandran et al.)

Classical swine fever virus (CSFV) shares high structural and antigenic homology with bovine viral diarrhea virus (BVDV) and border disease virus (BDV). Because all three viruses can infect swine and elicit cross-reactive antibodies, it is necessary to differentiate among them with regard to serological diagnosis of classical swine fever. To understand the mechanism of cross-reactivity, it is important to define common or specific epitopes of these viruses. For this purpose, epitope mapping of six monoclonal antibodies (mAbs) was performed using recombinant expressed antigenic domains of CSFV and BDV E2 proteins. One CSFV-specific conformational epitope and one CSFV and BDV common epitope within domain B/C of E2 were identified. Site-directed mutagenesis confirmed that residues G725 and V738/I738 of the CSFV-specific epitope and P709/L709 and E713 of the second epitope are important for mAbs binding. Infection of CSFV in porcine cells was significantly reduced after pre-incubation of the cells with the domain B/C of E2 or after pre-incubation of CSFV with the mAbs detecting domain B/C. 3D structural modeling suggested that both epitopes are exposed on the surface of E2. Based on this, the identified epitopes represent a potential target for virus neutralization and might be involved in the early steps of CSFV infection.

L'anesthésie générale implique l'administration de plusieurs médications en une durée de temps très courte. Ces produits peuvent donner plusieurs effets secondaires, notamment des complications allergiques peranesthésiques. Plusieurs études ont évalué l'importance d'un bilan allergologique suite aux accidents peranesthésiques. L'objectif de cette étude est de démontrer l'intérêt du bilan allergologique suite à un accident d'hypersensibilité immédiate péri-anesthésique. À partir de la base de données de pharmacovigilance du centre régional de pharmacovigilance (CRPV) de Sfax, nous avons inclus des cas d'hypersensibilité immédiate aux produits anesthésiques généraux notifiés sur une période de trois ans. Les tests cutanés ont été réalisés en conformité avec les recommandations de l'ENDA/EAACI. Les produits anesthésiques généraux testés ont été les suivants : l'atracurium, le cisatracurium, le suxaméthonium, le midazolam, le propofol et la kétamine. Dans notre étude, 15 cas d'HSI aux produits anesthésiques généraux ont été notifiés dans le CRPV et seulement 7 cas ont fait l'exploration allergologique. Six produits anesthésiques ont été impliqués dans la survenue des réactions d'HSI : le Cisatracurium dans 5 cas, l'atracurium dans 3 cas, le suxaméthonium dans 2 cas, le propofol dans 2 cas, la kétamine dans 1 cas, et le Midazolam dans 2 cas. Les prick tests ont été négatifs dans tous les cas, les intradermo réactions (IDR) ont été positives pour le cisatracurium et la kétamine pour la patiente no 1, pour l'atracurium et le midazolam pour la patiente no 2, pour le cisatracurium pour la patiente no 3, pour l'atracurium et le suxaméthonium pour la patiente no 4, pour le cisatracurium uniquement pour les patientes no 5 et no 6 et pour tous les produits sauf la kétamine pour la patiente no 7. Une réactivité croisée entre les curares a été observée dans un cas et une sensibilisation entre les curares et les hypnotiques a été observée dans 3 cas. La réalisation d'une consultation d'allergologie à la suite d'un accident périanesthésique s'avère importante pour ne pas réexposer le patient à un produit contre lequel il est sensibilisé, et permet de guider le choix d'un anesthésique qui peut être utilisé lors d'une nouvelle anesthésie. General anesthesia involves administration of several medications within a very short time. These agents may cause numerous side effects, including allergic complications. Various studies have evaluated the importance of an allergological assessment following hypersensitivity accidents during anesthesia. The purpose of this study is to demonstrate the value of allergological assessment following an immediate reaction to general anesthetics. We analyzed the cases of immediate hypersensitivity to general anesthetics notified to the regional pharmacovigilance center (RPVC) of Sfax (Tunisia) over a period of three years. Skin tests were performed in accordance with the general guidelines of the European network on Drug Allergy/European Academy of Allergy and Clinical Immunology (ENDA/EAACI). The general anesthetics tested were: atracurium, cisatracurium, suxamethonium, midazolam, propofol and ketamine. In our study, 15 cases were reported to the RPVC and only 7 cases were included. The anesthetics involved in immediate hypersensitivity reactions were as follows: cisatracurium (5 cases), atracurium (3 cases), suxamethonium (2 cases), propofol (2 cases), ketamine (1 case) and Midazolam (2 cases). Skin prick tests were negative in all cases, and the IDRs were positive for cisatracurium and ketamine in patient No. 1, for atracurium and midazolam in patient No. 2, for cisatracurium in patient No. 3, for atracurium and suxamethonium in patient No. 4, for cisatracurium only in patients Nos. 5 and 6, and for all products except ketamine in patient No. 7. Cross reactivity between neuromuscular blocking agents was observed in 1 case, and sensitization between neuromuscular blocking agents and hypnotics was observed in 3 cases. Allergological assessment following immediate reaction to general anesthetics is important in order to avoid exposure of the patient to a drug to which he/she is sensitized, and to guide the choice of anesthetics that may be used during further anesthesia. [ABSTRACT FROM AUTHOR]

Diagnostics of Autoimmune Diseases involve screening of patient samples for containing autoantibodies against various antigens. To ensure quality of diagnostic assays a calibrator is needed in each assay system. Different calibrators as recombinant human monoclonal antibodies as well as chimeric antibodies against the autoantigens of interest are described. A less cost-intensive and also more representative possibility covering different targets on the antigens is the utilization of polyclonal sera from other species. Nevertheless, the detection of human autoantibodies as well as the calibration reagent containing antibodies from other species in one assay constitutes a challenge in terms of assay calibration. We therefore developed a cross-reactive monoclonal antibody which binds human as well as rabbit sera with similar affinities in the nanomolar range. We tested our monoclonal antibody S38CD11B12 successfully in the commercial Serazym ® Anti-Cardiolipin-ß2-GPI IgG/IgM assay and could thereby prove the eligibility of S38CD11B12 as detection antibody in autoimmune diagnostic assays using rabbit derived sera as reference material. • S38CD11B12 is a cross-reactive murine monoclonal antibody specific for human and rabbit IgG • S38CD11B12 binds human IgG as well as rabbit IgG with affinities in the nanomolar range • S38CD11B12 is suitable as detection antibody in autoimmune disease diagnostics using rabbit serum as calibration material [ABSTRACT FROM AUTHOR]

Background: Zika virus (ZIKV) and Dengue virus (DENV) are often co-endemic. The high protein-sequence homology of flaviviruses renders IgG induced by and directed against them highly cross-reactive against their antigen(s), as observed on a large set of sera, leading to poorly reliable sero-diagnosis. Methods: We selected Domain III of the ZIKV Envelope (ZEDIII) sequence, which is virus specific. This recombinant domain was expressed and purified for the specific detection of ZEDIII-induced IgG by ELISA from ZIKV-RT-PCR-positive, ZIKV-IgM-positive, flavivirus-positive but ZIKV-negative, or flavivirus-negative sera. We also assessed the reactivity of ZEDIII-specific human antibodies against EDIII of DENV serotype 4 (D4EDIII) as a specific control. Sera from ZEDIII-immunized mice were also tested. Results: Cross-reactivity of IgG from 5,600 sera against total inactivated DENV or ZIKV was high (71.0% [69.1; 72.2]), whereas the specificity and sensitivity calculated using a representative cohort (242 sera) reached 90% [84.0; 95.8] and 92% [84.5; 99.5], respectively, using a ZEDIII-based ELISA. Moreover, purified human IgG against D2EDIII or D4EDIII did not bind to ZEDIII and we observed no D4EDIII reactivity with ZIKV-induced mouse polyclonal IgGs. Conclusions: We developed a ZEDIII-based ELISA that can discriminate between past or current DENV and ZIKV infections, allowing the detection of a serological scar from other flaviviruses. This could be used to confirm exposure of pregnant women or to follow the spread of an endemic disease. [ABSTRACT FROM AUTHOR]

The strength and breadth of an individual’s antibody repertoire is an important predictor of their response to influenza infection or vaccination. Although progress has been made in understanding qualitatively how repeated exposures shape the antibody mediated immune response, quantitative understanding remains limited. We developed a set of mathematical models describing short-term antibody kinetics following influenza infection or vaccination and fit them to haemagglutination inhibition (HI) titres from 5 groups of ferrets which were exposed to different combinations of trivalent inactivated influenza vaccine (TIV with or without adjuvant), A/H3N2 priming inoculation and post-vaccination A/H1N1 inoculation. We fit models with various immunological mechanisms that have been empirically observed but have not previously been included in mathematical models of antibody landscapes, including; titre ceiling effects, antigenic seniority and exposure-type specific cross reactivity. Based on the parameter estimates of the best supported models, we describe a number of key immunological features. We found quantifiable differences in the degree of homologous and cross-reactive antibody boosting elicited by different exposure types. Infection and adjuvanted vaccination generally resulted in strong, broadly reactive responses whereas unadjuvanted vaccination resulted in a weak, narrow response. We found that the order of exposure mattered: priming with A/H3N2 improved subsequent vaccine response, and the second dose of adjuvanted vaccination resulted in substantially greater antibody boosting than the first. Either antigenic seniority or a titre ceiling effect were included in the two best fitting models, suggesting a role for a mechanism describing diminishing antibody boosting with repeated exposures. Although there was considerable uncertainty in our estimates of antibody waning parameters, our results suggest that both short and long term waning were present and would be identifiable with a larger set of experiments. These results highlight the potential use of repeat exposure animal models in revealing short-term, strain-specific immune dynamics of influenza. [ABSTRACT FROM AUTHOR]

The accurate diagnosis and seroprevalence investigations of Zika virus (ZKV) infections remain complex due to cross reactivity with other flaviviruses. Two assay formats, both using labelled Zika virus NS1 antigen as a revealing agent (a double antigen binding assay, DABA, and an immunoglobulin Ig capture assay, G capture) were initially developed and compared with the indirect EuroimmunZ assay for the detection of anti-Zika antibody. Of 147 pre-Zika period serum samples, 39 (27%) were reactive in the EuroimmunZ or the DABA assays, 28 sera concordantly so. Such false reactivity was influenced by the serotype of Dengue virus (DV) to which individuals had been exposed to. Thus, of sera from patients undergoing secondary Dengue virus infection of known serotype, 91%, 45% and 28% of Dengue virus serotype 2, 3 and 4 respectively were reactive in one or more of the three assays. A novel method of quenching false sero-reactivity was therefore developed for the DABA and G capture assays. Initial addition of a single homologous Dengue virus serotype 3 NS1Ag quench significantly ablated false reactivities in the pre-Zika period sera. An equipotent quadrivalent quench comprising homologous Dengue virus serotypes 1 to 4 NS1Ag was shown to be optimum yet retained sensitivity for the detection of specific anti-Zika antibody. Comparing DABA and G capture assays using quenched and unquenched conjugates in comparison with EuroimmunZ early in the course of PCR-confirmed infection indicated that a significant component of the apparent early anti-ZIKA antibody response is likely to be due to a Zika virus-driven anamnestic anti-Dengue virus response. The increased specificity provided by homologous antigen quenching is likely to provide a significant improvement in sero-diagnostics and to be of clinical value. [ABSTRACT FROM AUTHOR]