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Background: China is experiencing rapid growth in its population of older adults, which may lead to increased susceptibility to tuberculous pleural effusion (TPE) due to age-related changes in the immune system. This study aimed to investigate the diagnostic potential of multiple biomarkers in individuals aged 60 years and above with pleural effusion., Methods: A total of 519 adult patients from Ningbo First Hospital were included in the study, with 7 biomarkers and their ratios in serum and pleural effusion analyzed using logistic regression analysis. Effusion Adenosine Deaminase(ADA), γ-Interferon Release Assay(IGRA), and Effusion lactatedehy drogenase(LDH)/Effusion ADA were identified as valuable parameters for differentiating TPE from non-TPE, particularly in individuals aged 60 years and older., Results: Effusion ADA, IGRA, and Effusion LDH/Effusion ADA were identified as valuable parameters for the differential diagnosis of TPE from non-TPE, showing good diagnostic performance in individuals aged 60 years and older. The combined diagnosis of these three indexes achieved the highest diagnostic accuracy for TPE in this age group, with an AUC of 0.925, sensitivity of 85.23%, and specificity of 89.57%., Conclusions: Overall, the study highlights the importance of using multiple indicators for a combined diagnosis to improve diagnostic efficacy in detecting tuberculous pleurisy in older individuals as for young patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Guo, Huimin, Xia, Xu, Jin and Liu.)

The concept of enzyme stability is typically used to refer to an enzyme's thermostability - its ability to retain structure and activity as temperature increases. For a therapeutic enzyme, other measures of stability may also be critical, particularly its ability to retain function in human serum at 37 °C, which we refer to as serum stability. Here, we describe an in vitro assay to assess the serum stability of the wildtype Homo sapiens adenosine deaminase I (HsADA1) enzyme using an absorbance-based microplate procedure. Specifically, this manuscript describes the preparation of buffers and reagents, a method arranging for the coincubation of HsADA1 in serum, a method to analyze the test samples using a microplate reader, and an accompanying analysis to determine the fraction of activity that an HsADA1 enzyme retains in serum as a function of time. We further discuss considerations to adapt this protocol to other enzymes, using an example of a Homo sapiens kynureninase enzyme, to help aid the protocol's adaptation to other enzymes where serum stability is of interest.

Introduction: Dynamic cellular and molecular adaptations in early life significantly impact health and disease. Upon birth, newborns are immediately challenged by their environment, placing urgent demands on the infant immune system. Adenosine deaminases (ADAs) are enzymatic immune modulators present in two isoforms - ADA-1 and ADA-2. Infants exhibit low ADA activity, resulting in high plasma adenosine concentrations and a consequent anti-inflammatory/anti-Th1 bias. While longitudinal studies of plasma ADA have been conducted in infants in The Gambia (GAM), little is known regarding ADA trajectories in other parts of the world., Methods: Herein, we characterized plasma ADA activity in an infant cohort in Papua New Guinea (PNG; n=83) and compared to ontogeny of ADA activity in a larger cohort in GAM (n=646). Heparinized peripheral blood samples were collected at day of life (DOL) 0, DOL7, DOL30, and DOL128. Plasma ADA-1, ADA-2, and total ADA activities were measured by chromogenic assay., Results: Compared to GAM infants, PNG infants had significantly lower ADA-1 (0.9-fold), ADA-2 (0.42-fold), and total ADA (0.84-fold) activities at birth which converged by DOL30., Discussion: Overall, discovery of a distinct baseline and a consistent pattern of increasing plasma ADA activity in early life in two genetically and geographically distinct populations validates and extends previous findings on the robustness of early life immune ontogeny., Competing Interests: OL is a named inventor on patents held by Boston Children’s Hospital related to vaccine adjuvants and human in vitro systems that model immune responses. He has served as a consultant to GlaxoSmithKline GSK and Hillevax and is a co-founder of and advisor to Ovax Inc. The sponsors had no role in the design, execution, interpretation, or writing of the study. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.​, (Copyright © 2024 Kouyate, Nguyen, Plotkin, Ford, Idoko, Odumade, Masiria, Jude, Diray-Arce, McEnaney, Ozonoff, Steen, Kollmann, Richmond, van den Biggelaar, Kampmann, Pomat, Levy and Smolen.)

Objective: This study aimed to analyze the diagnostic efficacy of serum biomarkers in liver cirrhosis patients categorized by Child-Pugh scores., Methods: An observational cross-sectional study design was employed. A total of 110 liver cirrhosis patients, classified according to Child-Pugh scores and 60 healthy individuals were included in this study. Serum levels of adenosine deaminase (ADA), adiponectin (APN), matrix metalloproteinase-2 (MMP-2), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured., Results: The levels of ADA, APN, MMP-2, ALP, ALT, and AST were significantly higher in the study group compared to the control group (P < .05). Furthermore, these levels increased with the severity of liver cirrhosis, with higher levels observed in patients with Child-Pugh class C. The positive diagnostic rates for joint detection in Child-Pugh class A, B, and C were 93.75% (30/32), 100% (34/34), and 100% (44/44), respectively., Conclusions: Combined detection of serum biomarkers improves the diagnostic efficacy of liver cirrhosis. The diagnostic rates were higher when considering Child-Pugh scores, with the highest rates observed in class C.

Multisystem inflammatory syndrome in children (MIS-C) shares several clinical and immunological features with Kawasaki Disease (KD) and pediatric hyperinflammation, but the immuno-phenotypic overlap among these clinical mimics is still incompletely understood. Here we analyzed serum samples from treatment-naïve patients with MIS-C (n = 31) and KD (n = 11), pediatric hyperinflammation (n = 13) and healthy controls (HC, n = 10) by proximity extension assay (PEA) to profile 184 blood biomarkers. Collectively, immunophenotypic overlap between MIS-C and hyperinflammation exceeds overlap with KD. Overexpression of IL-17A in MIS-C and KD could best separate these conditions from hyperinflammatory conditions, while those were hallmarked by overabundance of adenosin deaminase and IL-18. Depletion in serum TNF-related subfamily member 9 (TNFRSF9) and apoptosis inducing ligand (TRAIL) linked with cardiovascular manifestations and myocarditis in MIS-C. Altogether, our analysis highlights important differences in molecular marker signatures also across different MIS-C and KD cohorts and suggests several previously unidentified molecular associations in context of cardiovascular inflammation., Competing Interests: Declaration of competing interest CH has received honoraria (lecture fees) from Novartis; HW has received honoraria (lecture fees) from Novartis and Takeda, and travel support from Octapharma and CSL-Behring; DF received speaker fees/honoraria from Chugai-Roche, Novartis and SOBI as well as research support from Novartis, Pfizer and SOBI. CK has received consulting fees from Novartis and Swedish Orphan Biovitrum (SOBI) (< $10,000 each) and receives research support from Novartis (> $10,000). No other disclosures relevant to this article were reported., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the role of serum adenosine deaminase (ADA) combined with globulin (GLB), creatinine (CREA), β 2 -microglobulin (β 2 -MG) and hemoglobin (HGB) in the initial screening of multiple myeloma (MM), in order to reduce missed diagnosis and misdiagnosis of MM., Methods: A retrospective analysis was performed on 62 newly diagnosed multiple myeloma (NDMM) patients who were admitted to the Department of Hematology of the First Affiliated Hospital of Chengdu Medical College from April 2018 to December 2021, and 33 patients with benign hematologic diseases and 30 healthy subjects were selected as the control group. The expression of ADA in pan-cancer was analyzed using TCGA and GTEx databases. The general data and laboratory indicators of the subjects were collected, and the differences of ADA activity and other laboratory indicators in each group were compared. The relationship between serum ADA activity and clinical data of NDMM patients was analyzed. The changes of ADA activity before and after chemotherapy in NDMM patients and the differences of ADA activity in NDMM patients with different DS and ISS stages were compared. Multivariate logistic regression was used to analyze the risk factors of NDMM. The receiver operating characteristic(ROC) curve was used to evaluate the diagnostic efficacy of ADA and other laboratory indicators in MM. Bioinformatics method was used to analyze the co-expression networks and enrichment pathways of ADA., Results: ADA level was significantly upregulated in tissues of 14 types of cancer in TCGA database, and ADA was highly expressed in 11 types of cancer in TCGA combined with GTEx databases. The serum levels of ADA, GLB, uric acid (UA), cystatin C (CysC) and β 2 -MG in the NDMM group were significantly higher than those in benign hematologic disease group and healthy control group ( P < 0.05), while the levels of ALB and the value of albumin to globulin ratio (A∶G) in the NDMM group were significantly lower than those in the other two groups ( P < 0.001). There were significant differences in DS stage ( P =0.036), ISS stage ( P =0.019) and the levels of CREA ( P =0.036), UA ( P =0.034), β 2 -MG ( P =0.019) in NDMM patients with different ADA activity levels. After primary chemotherapy, ADA activity and β 2 -MG concentration were decreased in NDMM patients ( P < 0.01). The comparison results of patients in different stages showed that ADA activity of patients in DS stage I+II was significantly lower than that of patients in DS stage III ( P <0.05), and ADA activity of patiens in ISS stage I+II was significantly lower than that of patients in ISS stage III ( P < 0.01). Multivariate logistic regression analysis showed that increased GLB, increased ADA activity, increased CREA, increased β 2 -MG and decreased HGB were independent risk factors for NDMM. The area under the curve (AUC) of ADA in the diagnosis of MM was 0.847, and the AUC of ADA combined with GLB, CREA, β 2 -MG and HGB in the diagnosis of MM was 0.940. The results of co-expression network and enrichment pathway analysis showed that ADA bounded to 20 proteins and it was significantly associated with the metabolic pathways of purine, pyrimidine, nicotinate and nicotinamide., Conclusion: The detection of ADA activity in serum is of positive significance for the auxiliary diagnosis, therapeutic evaluation and monitoring the progress of NDMM patients. ADA combined with GLB, CREA, β 2 -MG and HGB can improve the detection rate of MM, and reduce missed diagnosis and misdiagnosis to a certain extent.

Background: Pleural fluid is one of the common complications of thoracic diseases, and tuberculous pleural effusion (TPE) is the most common cause of pleural effusion in TB-endemic areas and the most common type of exudative pleural effusion in China. In clinical practice, distinguishing TPE from pleural effusion caused by other reasons remains a relatively challenging issue. The objective of present study was to explore the clinical significance of the pleural fluid lactate dehydrogenase/adenosine deaminase ratio (pfLDH/pfADA) in the diagnosis of TPE., Methods: The clinical data of 618 patients with pleural effusion were retrospectively collected, and the patients were divided into 3 groups: the TPE group (412 patients), the parapneumonic pleural effusion (PPE) group (106 patients), and the malignant pleural effusion (MPE) group (100 patients). The differences in the ratios of pleural effusion-related and serology-related indicators were compared among the three groups, and receiver operating characteristic curves were drawn to analyze the sensitivity and specificity of the parameter ratios of different indicators for the diagnosis of TPE., Results: The median serum ADA level was higher in the TPE group (13 U/L) than in the PPE group (10 U/L, P < 0.01) and MPE group (10 U/L, P < 0.001). The median pfADA level in the TPE group was 41 (32, 52) U/L; it was lowest in the MPE group at 9 (7, 12) U/L and highest in the PPE group at 43 (23, 145) U/L. The pfLDH level in the PPE group was 2542 (1109, 6219) U/L, which was significantly higher than that in the TPE group 449 (293, 664) U/L. In the differential diagnosis between TPE and non-TPE, the AUC of pfLDH/pfADA for diagnosing TPE was the highest at 0.946 (0.925, 0.966), with an optimal cutoff value of 23.20, sensitivity of 93.9%, specificity of 87.0%, and Youden index of 0.809. In the differential diagnosis of TPE and PPE, the AUC of pfLDH/pfADA was the highest at 0.964 (0.939, 0.989), with an optimal cutoff value of 24.32, sensitivity of 94.6%, and specificity of 94.4%; this indicated significantly better diagnostic efficacy than that of the single index of pfLDH. In the differential diagnosis between TPE and MPE, the AUC of pfLDH/pfADA was 0.926 (0.896, 0.956), with a sensitivity of 93.4% and specificity of 80.0%; this was not significantly different from the diagnostic efficacy of pfADA., Conclusions: Compared with single biomarkers, pfLDH/pfADA has higher diagnostic value for TPE and can identify patients with TPE early, easily, and economically., (© 2024. The Author(s).)

Enzyme adenosine deaminase (ADA) is a marker of inflammation in domestic animals, but it is unclear whether it is a reliable marker of oxidative stress, especially in the transition period in dairy cows. This study aims to assess if ADA and redox status measurements in saliva provide the same utility to detect disease condition as that obtained from serum. Sixty-eight multiparous Holstein cows, between 2 and 3 weeks postpartum were selected. Five study groups were established: control (healthy), and cows with ketosis, mastitis, laminitis, and metritis. The parameters measured were ADA activity, total oxidants (TOS), antioxidants (TAC), and OSi ratio.Regarding redox status, no significant differences arise in both saliva and serum being the correlations negative and not significant. In saliva, ADA activity in healthy cows differs from those with pathological processes, having the lowest activities. In serum, ADA activity is similar in the healthy and ketosis cows, showing the lowest activities meanwhile animals with mastitis, laminitis, or metritis have significantly higher activities. In conclusion, the measurement of ADA activities and redox status in saliva does not give consistent results, being preferable to measure them in serum during the transition period., (© 2023. The Author(s).)

Background: Adult-onset Still's disease (AOSD) is a systemic inflammatory disease of unknown etiology, lacking specific diagnosis and disease activity evaluation indicators. This study will analyze the activity and clinical significance of Adenosine deaminase (ADA) in AOSD patients., Methods: Totally 53 AOSD patients, 60 patients with other autoimmune diseases including systemic lupus erythematosus (SLE), sjogren syndrome (SS) and rheumatoid arthritis (RA), as well as 60 healthy subjects were included in this study. AOSD activity was determined by Pouchot score. We analyzed the correlation between ADA activity and clinical parameters. In addition, the correlation between ADA activity and disease activity score was also analyzed., Results: This study showed that the activity of ADA in AOSD patients was significantly higher than that of healthy controls, SLE, SS and RA patient groups (p < 0.0001). The ADA activity of AOSD patients decreased significantly after systemic treatment (p < 0.0001). Correlation analysis showed that ADA activity was positively correlated with ALT(r = 0.54, p < 0.0001), AST (r = 0.82, p < 0.0001) and serum ferritin (r = 0.67, p < 0.001). ADA activity was negatively correlated with white blood cell (r = - 0.42, p = 0.002) and platelet counts (r = - 0.44, p = 0.001). We also found a significant positive correlation between the activity of ADA and Pouchot score in AOSD patients (r = 0.51, p = 0.001). Receiver operating characteristic (ROC) curve analysis showed that ADA activity had a sensitivity of 93.3%, and a specificity of 83% for the diagnosis of AOSD, with an area under the curve of 0.93., Conclusion: This study showed that serum ADA activity can be used as a potential biomarker for AOSD diagnosis and disease activity assessment., (© 2022. The Author(s).)

Background: Deficiency of adenosine deaminase 2 (DADA2) is an autoinflammatory disease caused by deleterious ADA2 variants. The frequency of these variants in the general population, and hence the expected disease prevalence, remain unknown., Objective: We aimed to characterize the functional impact and carrier frequency of ADA2 variants., Methods: We performed functional studies and in silico analysis on 163 ADA2 variants, including DADA2-associated variants and population variants identified in the Genome Aggregation Database. We estimated the carrier rate using the aggregate frequency of deleterious variants., Results: Functional studies of ADA2 variants revealed that 77 (91%) of 85 of DADA2-associated variants reduced ADA2 enzymatic function by >75%. Analysis of 100 ADA2 variants in the database showed a full spectrum of impact on ADA2 function, rather than a dichotomy of benign versus deleterious variants. We found several in silico algorithms that effectively predicted the impact of ADA2 variants with high sensitivity and specificity, and confirmed a correlation between the residual function of ADA2 variants in vitro and the plasma ADA2 activity of individuals carrying these variants (n = 45; r = 0.649; P < .0001). Using <25% residual enzymatic activity as the cutoff to define potential pathogenicity, integration of our results with the database population data revealed an estimated carrier frequency of at least 1 in 236 individuals, corresponding to an expected DADA2 disease prevalence of ~1 in 222,000 individuals., Conclusions: Functional annotation guides the interpretation of ADA2 variants to create a framework that enables estimation of DADA2 carrier frequency and disease prevalence., (Copyright © 2021 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Objective: This study aimed to assess the diagnostic accuracy of serum LDH to pleural ADA ratio (cancer ratio, CR)for malignant pleural effusion (MPE) through an original study and meta-analysis., Methods: We retrospectively collected data from 145 patients with MPE and 117 cases of benign pleural effusions (BPE). The diagnostic performance of CR and a typical biomarker of MPE, carcinoembryonic antigen (CEA), were analysed using the receiver operating characteristic (ROC) curves and the area under the curve (AUC) as a measure of accuracy. The overall diagnostic accuracy of CR was summarised by a standard diagnostic meta-analysis., Results: Significantly higher CR and pleural CEA values were observed in the MPE patients than in the BPE patients. At a cut-off value of 14.97, CR showed high sensitivity (0.91), low specificity (0.67), and high AUC (0.85). The combination of CEA and CR increased the AUC to 0.98. The meta-analysis included seven studies involving 2,078 patients. The pooled values for sensitivity, specificity, positive/negative likelihood ratio, and diagnostic odds ratio of CR were 0.96, 0.88, 7.70, 0.05, and 169, respectively. The AUC of the summary ROC of CR was 0.98., Conclusion: CR has a high diagnostic accuracy for predicting MPE, especially when used in combination with pleural CEA.

Purpose: Deficiency of adenosine deaminase type 2 (ADA2) (DADA2) is a rare inborn error of immunity caused by deleterious biallelic mutations in ADA2. Clinical manifestations are diverse, ranging from severe vasculopathy with lacunar strokes to immunodeficiency with viral infections, hypogammaglobulinemia and bone marrow failure. Limited data are available on the phenotype and function of leukocytes from DADA2 patients. The aim of this study was to perform in-depth immunophenotyping and functional analysis of the impact of DADA2 on human lymphocytes., Methods: In-depth immunophenotyping and functional analyses were performed on ten patients with confirmed DADA2 and compared to heterozygous carriers of pathogenic ADA2 mutations and normal healthy controls., Results: The median age of the patients was 10 years (mean 20.7 years, range 1-44 years). Four out of ten patients were on treatment with steroids and/or etanercept or other immunosuppressives. We confirmed a defect in terminal B cell differentiation in DADA2 and reveal a block in B cell development in the bone marrow at the pro-B to pre-B cell stage. We also show impaired differentiation of CD4 + and CD8 + memory T cells, accelerated exhaustion/senescence, and impaired survival and granzyme production by ADA2 deficient CD8 + T cells. Unconventional T cells (i.e. iNKT, MAIT, Vδ2 + γδT) were diminished whereas pro-inflammatory monocytes and CD56 brigh t immature NK cells were increased. Expression of the IFN-induced lectin SIGLEC1 was increased on all monocyte subsets in DADA2 patients compared to healthy donors. Interestingly, the phenotype and function of lymphocytes from healthy heterozygous carriers were often intermediate to that of healthy donors and ADA2-deficient patients., Conclusion: Extended immunophenotyping in DADA2 patients shows a complex immunophenotype. Our findings provide insight into the cellular mechanisms underlying some of the complex and heterogenous clinical features of DADA2. More research is needed to design targeted therapy to prevent viral infections in these patients with excessive inflammation as the overarching phenotype., (© 2021. The Author(s).)

Introduction: There is an urgent medical need to differentiate active tuberculosis (ATB) from latent tuberculosis infection (LTBI) and prevent undertreatment and overtreatment. The aim of this study was to identify biomarker profiles that may support the differentiation between ATB and LTBI and to validate these signatures., Materials and Methods: The discovery cohort included adult individuals classified in four groups: ATB (n = 20), LTBI without prophylaxis (untreated LTBI; n = 20), LTBI after completion of prophylaxis (treated LTBI; n = 20), and healthy controls (HC; n = 20). Their sera were analyzed for 40 cytokines/chemokines and activity of adenosine deaminase (ADA) isozymes. A prediction model was designed to differentiate ATB from untreated LTBI using sparse partial least squares (sPLS) and logistic regression analyses. Serum samples of two independent cohorts (national and international) were used for validation., Results: sPLS regression analyses identified C-C motif chemokine ligand 1 (CCL1), C-reactive protein (CRP), C-X-C motif chemokine ligand 10 (CXCL10), and vascular endothelial growth factor (VEGF) as the most discriminating biomarkers. These markers and ADA(2) activity were significantly increased in ATB compared to untreated LTBI (p ≤ 0.007). Combining CCL1, CXCL10, VEGF, and ADA2 activity yielded a sensitivity and specificity of 95% and 90%, respectively, in differentiating ATB from untreated LTBI. These findings were confirmed in the validation cohort including remotely acquired untreated LTBI participants., Conclusion: The biomarker signature of CCL1, CXCL10, VEGF, and ADA2 activity provides a promising tool for differentiating patients with ATB from non-treated LTBI individuals., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer HD declared a past co-authorship with the authors SJ and TO to the handling editor., (Copyright © 2021 Delemarre, van Hoorn, Bossink, Drylewicz, Joosten, Ottenhoff, Akkerman, Goletti, Petruccioli, Navarra, van den Broek, Paardekooper, van Haeften, Koenderman, Lammers, Thijsen, Hofland and Nierkens.)

Background: Acute and chronic besnoitiosis in extensive natural-service herds can have relevant effects in the health of bulls and negative consequences in their productive performance. Recent progress has been made in order to elucidate the pathogenesis of this disease. In this context, the study of biomarkers of inflammation in serum would contribute to gaining knowledge about the physiopathology of bovine besnoitiosis. Serological biomarkers could help in early diagnosis and prognosis, as seropositive bulls may have mild or severe testicular lesions., Methods: Herein, we have investigated the diagnostic and/or prognostic value of a panel of serum (serological) biomarkers related to inflammation, including total protein, globulin and albumin, haptoglobin (Hp), adenosine deaminase (ADA) paraoxonase-1 (PON-1) and acetylcholinesterase (AChE) in naturally and experimentally B. besnoiti-infected males classified according to different clinical phases of the disease (acute, chronic and subclinical besnoitiosis)., Results: Results showed a similar response pattern in these biomarkers for naturally and experimentally infected cattle, with a few relevant variations. Most significant changes occurred during the acute phase of infection, although significant changes in a few biomarkers were also observed during the chronic infection. Haptoglobin, albumin, PON-1 and ADA were identified as the biomarkers that showed changes of higher magnitude in the acute phase of the infection, whereas high total protein and globulin values were found in chronically infected cattle. We have described the changes of a panel of inflammatory biomarkers of acute and chronic bovine besnoitiosis., Conclusions: In summary, several biomarkers with promising diagnostic value have been identified. The biomarkers associated with acute infection are related to previously reported molecular biomarkers in testicular parenchyma of infected bulls and could help in the diagnosis of early infections and complement results from specific immunoglobulin M (IgM) detection., (© 2021. The Author(s).)

Adenosine Deaminase 2 Deficiency (DADA2) (OMIM: 607575) is a monogenic, autoinflammatory disease caused by the loss of functional homozygous or heterozygous mutations in the ADA 2 gene (previously CECR1, Cat Eye Syndrome Chromosome Region 1). A timely diagnosis is crucial to start Anti-TNF therapies that are efficacious in controlling the disease. The confirmation of DADA2 is based on DNA sequencing and enzymatic assay. It is, thus, very important to have robust and reliable assays that can be rapidly utilized in specialized laboratories that can centralize samples from other centers. In this paper, we show a novel enzymatic assay based on liquid chromatography-tandem mass spectrometry that allows the accurate determination of the ADA2 enzyme activity starting from very small amounts of plasma spotted on filter paper (dried plasma spot). The method allows significantly distinguishing healthy controls from affected patients and carriers and could be of help in implementing the diagnostic workflow of DADA2.

Background: Deficiency of adenosine deaminase 2 (DADA2) is an autoinflammatory disease caused by mutations in the adenosine deaminase 2 (ADA2) gene. Loss of functional ADA2 activity results in vasculitis syndrome, immunodeficiency, and hematopoietic disorders. Early diagnosis is required for effective treatment., Methods: We developed a dried blood spot (DBS)-based ADA2 activity colorimetric assay. Heparin-affinity purification was used during sample preparation to improve the assay more efficiently. The stability of ADA2 during DBS storage and ADA2 activity of DADA2 patients and healthy controls were examined., Results: Active ADA2 was extracted from the DBS of healthy controls. ADA2 activity in DBS, stored either frozen or refrigerated, remained stable for at least 90 days. A significant difference in ADA2 activity was observed between healthy controls and patients. No ADA2 activity was detected in DBS from patients., Conclusions: Our new DBS ADA2 activity assay is experimentally simple, highly adaptable, and requires no special equipment except for a microplate reader. A low background was achieved with heparin-affinity purification. The method differentiates clearly between healthy controls and patients. ADA2 activity can be reliably measured in DBS, providing an opportunity to diagnose DADA2 at an early stage., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Persistent lymphadenopathy with or without fever is often a diagnostic challenge to the physician which are usually caused by infection like tuberculosis, hematological malignancy (lymphoma, leukemia), connective tissue diseases (SLE, RA, Sjogren's syndrome etc.), sarcoidosis, storage diseases, drugs (like phenytoin) in Bangladesh. To establish the cause of lymphadenopathy, we need to do a good number of investigations including invasive tests like FNAC or histopathology of the involved lymph node. In many instances these are not possible due to unavailability or cost. But for last few years the adenosine deaminase is an enzyme involved in purine catabolism and its significance in the diagnosis of tuberculosis has been demonstrated by many studies. In addition to tuberculosis, elevated serum adenosine deaminase has also been found in lymphoma, sarcoidosis and some connective tissue diseases. The study was intended to assess if there are any significant diagnostic difference in the level of elevated adenosine deaminase between tubercular and different types of non tubercular lymphadenopathy. It included 68 patients, equally divided into two groups, tuberculous lymphadenitis and non-tuberculous lymphadenopathy. Epitheloid granuloma with caseation necrosis in biopsy or FNAC was taken as case definition of tuberculous lymphadenitis. Causes of non-tuberculous lymphadenopathy were established on the basis of clinical findings, laboratory investigations and histopathological diagnosis of biopsy or FNAc materials. This cross-sectional observational study was done in Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh over a period of one year and participants of 18 years and above of both genders were included as per consecutive sampling technique. Serum ADA concentrations were estimated by enzymatic method. Mean serum ADA concentration was 25.52±7.11 in tuberculous lymphadenitis and in non-tuberculous lymphadenopathy patients it was 27.29±15.91U/L with no significant difference (p=0.480). The non-tuberculous lymphadenopathy group consisted of Hodgkin disease (n=9), non-Hodgkin lymphoma (n=10), sarcoidosis (n=2), reactive lymphadenitis (n=9) and other lymphadenopathy group (n=4) (that consisted one case of each of follicular hyperplasia, adult Still disease, sinus histiocytosis and Castleman's disease). The mean ADA of these groups was 32.77±13.14U/L, 46.40±46.10U/L, 13.94±2.81U/L and 21.75±3.17U/L respectively. Tuberculous lymphadenitis patients had significantly higher serum ADA than persistent reactive lymphadenitis. On the other hand, there were statistically significant elevation of serum ADA in non-Hodgkin lymphoma and sarcoidosis than in tuberculous lymphadenitis.

Background: Human adenosine deaminases (ADAs) modulate the immune response: ADA1 via metabolizing adenosine, a purine metabolite that inhibits pro-inflammatory and Th1 cytokine production, and the multi-functional ADA2, by enhancing T-cell proliferation and monocyte differentiation. Newborns are relatively deficient in ADA1 resulting in elevated plasma adenosine concentrations and a Th2/anti-inflammatory bias compared to adults. Despite the growing recognition of the role of ADAs in immune regulation, little is known about the ontogeny of ADA concentrations., Methods: In a subgroup of the EPIC002-study, clinical data and plasma samples were collected from 540 Gambian infants at four time-points: day of birth; first week of life; one month of age; and four months of age. Concentrations of total extracellular ADA, ADA1, and ADA2 were measured by chromogenic assay and evaluated in relation to clinical data. Plasma cytokines/chemokine were measured across the first week of life and correlated to ADA concentrations., Results: ADA2 demonstrated a steady rise across the first months of life, while ADA1 concentration significantly decreased 0.79-fold across the first week then increased 1.4-fold by four months of life. Males demonstrated significantly higher concentrations of ADA2 (1.1-fold) than females at four months; newborns with early-term (37 to <39 weeks) and late-term (≥41 weeks) gestational age demonstrated significantly higher ADA1 at birth (1.1-fold), and those born to mothers with advanced maternal age (≥35 years) had lower plasma concentrations of ADA2 at one month (0.93-fold). Plasma ADA1 concentrations were positively correlated with plasma CXCL8 during the first week of life, while ADA2 concentrations correlated positively with TNFα, IFNγ and CXCL10, and negatively with IL-6 and CXCL8., Conclusions: The ratio of plasma ADA2/ADA1 concentration increased during the first week of life, after which both ADA1 and ADA2 increased across the first four months of life suggesting a gradual development of Th1/Th2 balanced immunity. Furthermore, ADA1 and ADA2 were positively correlated with cytokines/chemokines during the first week of life. Overall, ADA isoforms demonstrate robust ontogeny in newborns and infants but further mechanistic studies are needed to clarify their roles in early life immune development and the correlations with sex, gestational age, and maternal age that were observed., Competing Interests: OL is a named inventor on several patents related to microphysiologic platforms that model human immunity in vitro, anti-infective proteins, and vaccine adjuvants. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Odumade, Plotkin, Pak, Idoko, Pettengill, Kollmann, Ozonoff, Kampmann, Levy and Smolen.)

Several lines of evidence suggest that altered adenosine deaminase (ADA) activity, especially its ADA2 iso-enzyme, is associated with malignant breast cancer (BC) development. Triple-negative breast cancer (TNBC) is currently the most challenging BC subtype due to its metastatic potential and recurrence. Herein, we analyzed the sources of ADA iso-enzymes in TNBC by investigating the effects of cell-to-cell interactions between TNBC cells, macrophages, lymphocytes, and endothelial cells. We also examined the potential relationship between ADA activity and cancer progression in TNBC patients. In vitro analyses demonstrated that the interactions of immune and endothelial cells with MDA-MB-231 triple negative BC cells modulated their extracellular adenosine metabolism pattern. However, they caused an increase in the ADA1 activity, and did not alter ADA2 activity in cancer cells. In turn, the co-culture of MDA-MB-231 cells with THP-1 monocyte/macrophages, Jurkat cells, and human lung microvascular endothelial cells (HULEC) caused the increase in ADA2 activity on THP-1 cells and ADA1 activity on Jurkat cells and HULEC. Clinical sample analysis revealed that TNBC patients had higher plasma ADA2 activities and lower ADA1/ADA2 ratio at advanced stages of cancer development than in the initial stages, while patients with hormone receptor positive, HER2 negative (HR+HER2-), and triple positive (HR+HER2+) breast cancers at the same stages showed opposite trends. TNBC patients also demonstrated positive associations between plasma ADA2 activity and pro-tumor M2 macrophage markers, as well as between ADA1 activity and endothelial dysfunction or inflammatory parameters. The analysis of TNBC patients, at 6 and 12 months following cancer treatment, did not showed significant changes in plasma ADA activities and macrophage polarization markers, which may be the cause of their therapeutic failure. We conclude that alterations in both ADA iso-enzymes can play a role in breast cancer development and progression by the modulation of extracellular adenosine-dependent pathways. Additionally, the changes in ADA2 activity that may contribute to the differentiation of macrophages into unfavorable pro-tumor M2 phenotype deserve special attention in TNBC.

Rationale: Levels of pleural fluid adenosine deaminase (ADA), a useful marker for the diagnosis of tuberculous pleurisy, are elevated in some reports of immunoglobulin G4 (IgG4)-related pleural effusion. We describe a patient with IgG4-related pleural effusion who exhibited a high concentration of ADA. Furthermore, we reviewed the literature to compare patients with IgG4-related pleural effusion and tuberculous pleurisy., Patient Concerns: A 75-year-old male patient had dyspnea for 1 month with a left pleural effusion that was exudative, lymphocyte dominant. The pleural fluid test results revealed a total protein (TP) concentration of 6.60 g/dl, a lactate dehydrogenase (LDH) level of 383 IU/dl, and an ADA concentration of 54.5 U/L. An interferon gamma release assay showed a negative result., Diagnoses: Histological analysis of the thoracoscopic pleural biopsy revealed lymphoplasmacytic infiltration, with 80 IgG4-positive plasma cells/high-power field, and an IgG4/IgG ratio of approximately 40% to 50%. Other diseases were ruled out based on symptoms, negative autoimmune antigen results, and histopathologic findings. Thus, he was diagnosed with IgG4-related pleural effusion., Interventions: He received 15 mg of prednisolone as therapy., Outcomes: His pleural effusion and symptoms improved gradually within several months, and prednisolone was tapered to 6 mg daily., Lessons: It is important to distinguish between IgG4-related pleural effusion and tuberculous pleurisy. Therefore, we compared 22 patients with IgG4-related pleural effusion from PubMed and the Japan Medical Abstracts Society to 40 patients with tuberculous pleurisy at Fukujuji Hospital from January 2017 to May 2019. According to thoracentesis findings, 14 of 18 patients with IgG4-related pleural effusion had high ADA more than 40 U/L. The pleural effusion of patients with IgG4-related pleural effusion showed higher TP levels (P < .001) and lower LDH (P < .001) and ADA levels (P = .002) than those with tuberculous pleurisy. Moreover, the pleural fluid ADA/TP ratio was a good predictor for differentiating IgG4-related pleural effusion and tuberculous pleurisy (area under the receiver operating characteristic curve of 0.909; 95% confidence level: 0.824-0.994)., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Previous studies have revealed the disadvantages of traditional methods for the diagnosis of tuberculous pleural effusions (TPEs) and have created interest in exploring other effective biomarkers. Many studies have focused on the correlation between pulmonary diseases and serum creatinine (Cr), a representative biomarker of renal function, but little is known about the direct relationship between Cr and TPE. Our study aimed to explore whether Cr can act as a biomarker for the diagnosis of TPE and to evaluate the correlation between Cr and TPE., Materials and Methods: Patients with pleural effusions (PEs) were enrolled in this study. By comparing the concentrations of Cr and adenosine deaminase (ADA) in patients with TPEs and non-TPEs, we determined the sensitivity, specificity, Youden index, and area under the curve for these biomarkers. We generated receiver operating characteristic curves and quantifications to evaluate the diagnostic accuracy., Results: In total, 86 patients (44 with TPE, 25 with malignant pleural effusion (MPE) and 17 with non-tuberculosis infectious PE (NTIPE)) were enrolled in the study. The concentrations of Cr in TPE were significantly higher than those in non-TPE. However, a similar trend was not observed for NTIPE and MPE. The levels of ADA in TPE were significantly higher than those in NTIPE and MPE., Conclusion: Cr has the potential for the diagnosis of TPE to some extent though its accuracy is not as good as that of ADA. Further studies are necessary for Cr to be applied in clinical practice for the diagnosis of TPE., (Copyright © 2020 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Background: Tuberculous pleural effusion (TPE) is the most common extrapulmonary manifestation and may have lasting effect on lung function. However conventional diagnostic tests for TPE register multiple limitations. This study estimates diagnostic efficacy of the interferon gamma release assay (IGRA: T-SPOT.TB) in TPE patients of different characteristics., Methods: We performed a prospective, single-centre study including all suspected pleural effusion patients consecutively enrolled from June 2015 to October 2018. Through receiver operating characteristic (ROC) curves, technical cut-offs and the utility of T-SPOT on pleural fluid (PF) were determined and analysed. Logistic regression analysis was performed to obtain the independent risk factors for TPE, and evaluated the performance of the T-SPOT assay stratified by risk factors in comparison to ADA., Results: A total of 601 individuals were consecutively recruited. The maximum spot-forming cells (SFCs) of early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) in the PF T-SPOT assay had the best diagnostic efficiency in our study, which was equal to ADA (0.885 vs 0.887, P = 0.957) and superior to peripheral blood (PB), with a sensitivity of 83.0% and a specificity of 83.1% (The cut-off value was 466 SFCs/10 6 mononuclear cells). Among the TPE patients with low ADA (< 40 IU/L), the sensitivity and specificity of PF T-SPOT were still 87.9 and 90.5%, respectively. The utility of ADA was negatively related to increasing age, but the PF T-SPOT test had a steady performance at all ages. Age (< 45 yrs.; odds ratio (OR) = 5.61, 95% confidence interval (CI) 3.59-8.78; P < 0.001), gender (male; OR = 2.68, 95% CI 1.75-2.88; P < 0.001) and body mass index (BMI) (< 22; OR = 1.93, 95% CI 1.30-2.88; P = 0.001) were independently associated with the risk of TB by multivariate logistic regression analysis. Notably, when stratified by risk factor, the sensitivity of PF T-SPOT was superior to the sensitivity for ADA (76.5% vs. 23.5%, P = 0.016) and had noninferior specificity (84.4% vs. 96.9%, P = 0.370)., Conclusions: In conclusion, the PF T-SPOT assay can effectively discriminate TPE patients whose ADA is lower than 40 IU/L and is superior to ADA in unconventional TPE patients (age ≥ 45 yrs., female or BMI ≥ 22). The PF T-SPOT assay is an excellent choice to supplement ADA to diagnose TPE.

We investigated the association between serum adenosine deaminase and coronary artery calcification (CAC) in type 2 diabetes mellitus (T2DM) patients. The cross-sectional study included 459 patients with T2DM, the clinical and laboratory tests were performed, and all T2DM patients were separated into the 3 groups based on the tertile of serum adenosine deaminase levels. In the baseline data, the CAC score had statistically significant differences between the 3 groups (p < 0.001). Serum adenosine deaminase levels were positively correlated with CAC score in T2DM patients (r = 0.355, p < 0.001). The results of multiple linear regression analysis showed that serum adenosine deaminase was independent positively correlated with CAC score in T2DM patients (r = 0.255, p < 0.001). Receiver-operating characteristic curve analysis showed that area under curve was 0.750 to identify T2DM patients with CAC. Serum adenosine deaminase levels are correlated with CAC scores in T2DM patients, clinically, serum adenosine deaminase should be considered as an underlying marker to determine the severity of atherosclerosis in T2DM patients.

Background: Measurement of adenosine deaminase (ADA) can provide information about cell-mediated immunity. This report's objective was to study the enzymatic activity of total ADA (tADA) and its isoenzymes ADA1 and ADA2 in canine, equine, porcine, and bovine serum and saliva and their changes in different inflammatory situations in each species. Besides, an automated method for ADA2 measurement was developed and validated., Results: tADA was present in serum and saliva of healthy animals of the four species. Erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) concentration of 0.47 mM was needed for ADA1 inhibition in canine and porcine samples (serum and saliva) and bovine saliva, whereas for equine saliva 0.94 mM was needed. ADA2 activity was not detected in bovine serum and was very low or absent in equine serum and bovine saliva. An automated procedure to measure ADA2 consisting of adding EHNA to a commercial reagent for tADA measurement provided repetitive (coefficients of variation < 8.8% in serum and < 10% in saliva) and accurate (linearity of serial sample dilutions with R 2  > 0.90) results, being equivalent to a manual incubation of the sample with EHNA at a similar concentration. Salivary tADA, as well as ADA1 and ADA2, were higher in dogs with leishmaniosis, horses with acute abdominal disease and pigs with lameness than in healthy animals. tADA and isoenzymes in saliva showed a positive significant correlation with serum ferritin in dogs (r = 0.602, P < 0.01; r = 0.555, P < 0.05; and r = 0.632, P < 0.01; respectively for tADA, ADA1 and ADA2) and serum C-reactive protein in pigs (r = 0.700, P < 0.01, for both tADA and ADA1; r = 0.770, P < 0.001, for ADA2), whereas salivary ADA2 significantly correlated with serum amyloid A in horses (r = 0.649, P < 0.01). In cows, salivary tADA and ADA1 significantly increased after calving, correlating with total white blood cell count (r = 0.487, P < 0.05, for both tADA and ADA1)., Conclusions: The activity of total ADA and its different isoenzymes, can be measured in serum and saliva of dogs, horses, pigs and cows by a simple and fast procedure described in this report. When measured in saliva, these analytes correlated with other biomarkers of inflammation and it could potentially be used as a biomarkers of inflammation and immune activation in the species of this study.

The diagnosis of tuberculous pericarditis (TBP) remains challenging. This prospective study evaluated the diagnostic value of Xpert MTB/RIF (Xpert) and T-SPOT.TB and adenosine deaminase (ADA) for TBP in a high burden setting. A total of 123 HIV-negative patients with suspected TBP were enrolled at a tertiary referral hospital in China. Pericardial fluids were collected and subjected to the three rapid tests, and the results were compared with the final confirmed diagnosis. Of 105 patients in the final analysis, 39 (37.1%) were microbiologically, histopathologically or clinically diagnosed with TBP. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio (DOR) for Xpert were 66.7%, 98.5%, 96.3%, 83.3%, 44.0, 0.338, and 130.0, respectively, compared to 92.3%, 87.9%, 81.8%, 95.1%, 7.6, 0.088, and 87.0, respectively, for T-SPOT.TB, and 82.1%, 92.4%, 86.5%, 89.7%, 10.8, 0.194, and 55.8, respectively, for ADA (≥ 40 U/L). ROC curve analysis revealed a cut-off point of 48.5 spot-forming cells per million pericardial effusion mononuclear cells for T-SPOT.TB, which had a DOR value of 183.8, while a cut-off point of 41.5 U/L for ADA had a DOR value of 70.9. Xpert (Step 1: rule-in) followed by T-SPOT.TB [cut-off point] (Step 2: rule-out) showed the highest DOR value of 252.0, with only 5.7% (6/105) of patients misdiagnosed. The two-step algorithm consisting of Xpert and T-SPOT.TB could offer rapid and accurate diagnosis of TBP.

Diamond-Blackfan anemia (DBA) was the first ribosomopathy described and is a constitutional inherited bone marrow failure syndrome. Erythroblastopenia is the major characteristic of the disease, which is a model for ribosomal diseases, related to a heterozygous allelic variation in 1 of the 20 ribosomal protein genes of either the small or large ribosomal subunit. The salient feature of classical DBA is a defect in ribosomal RNA maturation that generates nucleolar stress, leading to stabilization of p53 and activation of its targets, resulting in cell-cycle arrest and apoptosis. Although activation of p53 may not explain all aspects of DBA erythroid tropism, involvement of GATA1/HSP70 and globin/heme imbalance, with an excess of the toxic free heme leading to reactive oxygen species production, account for defective erythropoiesis in DBA. Despite significant progress in defining the molecular basis of DBA and increased understanding of the mechanistic basis for DBA pathophysiology, progress in developing new therapeutic options has been limited. However, recent advances in gene therapy, better outcomes with stem cell transplantation, and discoveries of putative new drugs through systematic drug screening using large chemical libraries provide hope for improvement., (© 2020 by The American Society of Hematology.)

Background: Human adenosine deaminase 2 (ADA2) is an extracellular enzyme that negatively regulates adenosine-mediated cell signaling by converting adenosine to inosine. Altered ADA2 enzyme activity has been associated with some viral infections and rheumatic diseases. The potential utility of ADA2 as a biomarker is, however, limited by the absence of established ranges of ADA2 concentration and enzyme activity in the healthy population. It is known that ADA2 enzyme activity is lower in adults, but when (and why) this decline happens is not known. The purpose of this study was to establish normative ranges of ADA2 enzyme activity and protein concentration in the healthy pediatric population., Methods: We modified a commercially available ADA2 enzyme activity assay to enable higher throughput analysis of fresh, frozen and hemolyzed blood samples. With this assay and ADA2 protein immunoblotting, we analyzed ADA2 enzyme activity and protein concentration in blood plasma from a cohort of children and adolescents (n = 94) aged 5 months to 18 years. One-way ANOVA with subsequent Tukey multiple comparison test was used to analyze group differences. Reference intervals were generated using the central 95% of the population (2-97.5 percentiles)., Results: ADA2 enzyme activity was consistent in fresh, frozen, and hemolyzed sera and plasma as measured by our modified assay. Analysis of plasma samples from the healthy pediatric cohort revealed that ADA2 enzyme activity is significantly lower in older children than in younger children (p < 0.0001). In contrast, there was no significant correlation between ADA2 protein concentration and either age or ADA2 enzyme activity., Conclusion: We observed that ADA2 enzyme activity, but not ADA2 protein concentration, negatively correlates with age in a cohort of children and adolescents. Our findings stress the importance of appropriate age-matched controls for assessing ADA2 enzyme activity in the clinical setting.

Objectives: The application of Light's criteria misidentifies approximately 30% of transudates as exudates, particularly in patients on diuretics with cardiac effusions. The purpose of this study was to establish a predictive model to effectively identify cardiac effusions misclassified by Light's criteria., Methods: We retrospectively studied 675 consecutive patients with pleural effusion diagnosed by Light's criteria as exudates, of which 43 were heart failure patients. A multivariate logistic model was developed to predict cardiac effusions. The performance of the predictive model was assessed by receiver operating characteristic (ROC) curves, as well as by examining the calibration., Results: It was found that protein gradient of >23 g/L, pleural fluid lactate dehydrogenase (PF-LDH) levels, ratio of pleural fluid LDH to serum LDH level (P/S LDH), pleural fluid adenosine deaminase (PF-ADA) levels, and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels had a significant impact on the identification of cardiac effusions, and those were simultaneously analyzed by multivariate regression analysis. The area under the curve (AUC) value of the model was 0.953. The model also had higher discriminatory properties than protein gradients (AUC, 0.760) and NT-pro-BNP (AUC, 0.906), all at a P value of <.01., Conclusion: In cases of suspected cardiac effusion, or where clinicians cannot identify the cause of an exudative effusion, this model may assist in the correct identification of exudative effusions as cardiac effusions., (© American Society for Clinical Pathology 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The differentiation between tuberculous plural effusion (TPE) and malignant plural effusion (MPE) remains a major clinical challenge in the diagnosis and management of pleural effusions, especially in developing countries with a high incidence of tuberculosis. We aimed to evaluate the diagnostic value of cytokines, tumor markers and biochemical markers in the differentiation of TPE and MPE. Two hundred and forty-two patients were included, of whom 134 were diagnosed with MPE and 108 were diagnosed with TPE. In total, 12 markers were tested in pleural effusion samples from all subjects: Interleukin-2 (IL-2), Tumor necrosis factor alpha (TNF-α), Interferon (IFN)-γ, interleukins-4, 6, 10 (IL-4,6,10), cytokeratin-19 fragment (CYFRA 21-1), carcinoembryonic antigen (CEA), neuron specific enolase (NSE), adenosine deaminase (ADA), lactate dehydrogenase (LDH) and high sensitivity C- reactive protein (Hs-CRP). The diagnostic value of each marker was evaluated and compared by receiver operating characteristic (ROC) curves. In the 12 markers evaluated, TNF-α, IFN-γ, IL-6, CYFRA 21-1, CEA, ADA and Hs-CRP were significantly different between the TPE and MPE groups, and the areas under the ROC curves were 0.624, 0.942, 0.619, 0.808, 0.903, 0.842 and 0.917, respectively. IFN-γ showed a better diagnostic performance than the other markers. With a cut-off value of >2.45 pg/mL, the sensitivity and specificity of IFN-γ were 91.11 and 91.94%, respectively. TNF-α, IFN-γ, IL-6, CYFRA 21-1, CEA, ADA and Hs-CRP were useful in the differentiation between the TPE and MPE groups. IFN-γ showed a better diagnostic performance than the multitude of other markers evaluated in this study, which is satisfactory for the discrimination of TPE and MPE.

Plasma levels of adenosine deaminase (ADA), an enzyme that deaminates adenosine to inosine, are increased during inflammation. An increase in ADA activity occurs with lower human immunodeficiency virus (HIV) viral load and higher CD4 + T cell counts. We aimed to investigate the role of plasma ADA as a biomarker of inflammation in treatment-naïve HIV patients who received tenofovir or another nucleoside analog for comparison. Ninety-two treatment-naïve patients were included in the study and grouped by treatment, i.e., tenofovir disoproxil fumarate (TDF), tenofovir alafenamide (TAF) or Triumeq. ADA activity was measured in plasma and cytokines were analyzed by MILLIPLEX ® MAP-Luminex ® Technology. Plasma concentration of monocytes and neutrophils was measured at 0, 3, and 12 months post-treatment. Treatment-naïve HIV patients had increased ADA concentrations (over 15 U/L) that decreased after treatment with TAF and Triumeq, though this did not occur in TDF-treated patients. However, all groups exhibited a pro-inflammatory systemic profile at 12 months of treatment. Plasma GM-CSF levels decreased after 12 months of treatment in the TDF group, with a concomitant decrease in blood monocyte count, and a negative correlation with ADA values was found. In conclusion, ADA levels may be modulated by antiretroviral therapy in HIV patients, possibly affecting inflammatory status., Competing Interests: A.M. has filed a patent for the use of adenosine A2AR agonists to prevent prosthesis loosening (pending) and a separate patent concerning the use of A2AR agonists and agents that increase adenosine levels to promote bone formation/regeneration. F.M.C.-B. and P.A. have no disclosures. P.L.-G. has filed a patent on the use if lipocalin-2 as treatment in abdominal aortic aneurysm, R.L. and G.H.-B. have filed a patent on the use of 6-shogaol in osteoarthritis. A.C. has received honoraria and speakers’ fees from Gilead Sciences, MSD, and ViiV. M.G. has received speakers’ fees from ViiV. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

The absence of adenosine deaminase (ADA) causes severe combined immune deficiency (SCID), which has been treated with PEGylated bovine-extracted ADA (ADAGEN). ADAGEN was recently replaced by a PEGylated recombinant bovine ADA, expressed in Escherichia coli (elapegademase, ELA-ADA). Limited information on ELA-ADA is available.  ADA enzymatic activity of ELA-ADA and ADAGEN was assessed in vitro at diverse dilutions. ADA activity and immune reconstitution in an ADA-SCID patient treated with ELA-ADA were compared with age-matched patients previously treated with ADAGEN. ADA activity and thymus reconstitution were evaluated in ADA-deficient mice following ELA-ADA or ADAGEN administered from 7 days postpartum. In vitro, ADA activity of ELA-ADA and ADAGEN were similar at all dilutions. In an ADA-SCID patient, ELA-ADA treatment led to a marked increase in trough plasma ADA activity, which was 20% higher than in a patient previously treated with ADAGEN. A marked increase in T cell numbers and generation of naive T cells was evident following 3 months of ELA-ADA treatment, while T cell numbers increased following 4 months in 3 patients previously treated with ADAGEN. T cell proliferations stimulation normalized and thymus shadow became evident following ELA-ADA treatment. ADA activity was significantly increased in the blood of ADA-deficient mice following ELA-ADA compared to ADAGEN, while both treatments improved the mice weights, the weight, number of cells in their thymus and thymocyte subpopulations. ELA-ADA has similar in- vitro and possibly better in-vivo activity than ADAGEN. Future studies will determine whether ELA-ADA results in improved long-term immune reconstitution., (© 2020 British Society for Immunology.)

A simple turn-on fluorescence strategy is proposed for the detection of ATP based on DNA-stabilized copper/silver nanoclusters (DNA-Cu/Ag NCs). The fluorescence intensity of DNA-Cu/Ag NCs increases significantly in the presence of ATP, because the specific interaction between ATP and its aptamer causes two darkish Cu/Ag NCs to be situated at the 5' and 3' termini close to each other. A limit of detection (LOD) of 7.0 μM is found, in a linear range of 2-18 mM, and the proposed sensor is simple, sensitive, and selective. Additionally, the DNA-Cu/Ag NCs/ATP system is further developed into a sensor for ADA detection and demonstrates a linear response to ADA from 5 to 50 U/L with a LOD of 5 U/L. The proposed method is also shown to be successful in detecting ATP and ADA in a solution of fetal bovine serum.

Objective: Macrophage activation syndrome (MAS) is a life-threatening complication of systemic juvenile idiopathic arthritis (sJIA) characterised by a vicious cycle of immune amplification that can culminate in overwhelming inflammation and multiorgan failure. The clinical features of MAS overlap with those of active sJIA, complicating early diagnosis and treatment. We evaluated adenosine deaminase 2 (ADA2), a protein of unknown function released principally by monocytes and macrophages, as a novel biomarker of MAS., Methods: We established age-based normal ranges of peripheral blood ADA2 activity in 324 healthy children and adults. We compared these ranges with 173 children with inflammatory and immune-mediated diseases, including systemic and non-systemic JIA, Kawasaki disease, paediatric systemic lupus erythematosus and juvenile dermatomyositis., Results: ADA2 elevation beyond the upper limit of normal in children was largely restricted to sJIA with concomitant MAS, a finding confirmed in a validation cohort of sJIA patients with inactive disease, active sJIA without MAS or sJIA with MAS. ADA2 activity strongly correlated with MAS biomarkers including ferritin, interleukin (IL)-18 and the interferon (IFN)-γ-inducible chemokine CXCL9 but displayed minimal association with the inflammatory markers C reactive protein and erythrocyte sedimentation rate. Correspondingly, ADA2 paralleled disease activity based on serial measurements in patients with recurrent MAS episodes. IL-18 and IFN-γ elicited ADA2 production by peripheral blood mononuclear cells, and ADA2 was abundant in MAS haemophagocytes., Conclusions: These findings collectively identify the utility of plasma ADA2 activity as a biomarker of MAS and lend further support to a pivotal role of macrophage activation in this condition., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive autoinflammatory disorder associated with ADA2 mutations. We aimed to investigate the characteristics and ADA2 enzyme activities of patients with DADA2 compared to non-DADA2 patients., Methods: This is a descriptive study of 24 patients with DADA2 who were admitted to the Adult and Pediatric Rheumatology, Pediatric Haematology, and Pediatric Immunology Departments of Hacettepe University. All ADA2 exons were screened by Sanger sequencing. Serum ADA2 enzyme activity was measured by modified spectrophotometric method., Results: Twenty-four patients with DADA2 were included: 14 with polyarteritis nodosa (PAN)-like phenotype (Group 1); 9 with Diamond-Blackfan anemia (DBA)-like features, and 1 with immunodeficiency (Group 2). Fourteen PAN-like DADA2 patients did not have the typical thrombocytosis seen in classic PAN. Inflammatory attacks were evident only in Group 1 patients. Serum ADA2 activity was low in all patients with DADA2 except one, who was tested after hematopoietic stem cell transplantation. There was no significant difference in ADA2 activities between PAN-like and DBA-like patients. In DADA2 patients with one ADA2 mutation, serum ADA2 activities were as low as those of patients with homozygote DADA2. ADA2 activities were normal in non-DADA2 patients. ADA2 mutations were affecting the dimerization domain in Group 1 patients and the catalytic domain in Group 2 patients., Conclusion: We suggest assessing ADA2 activity along with genetic analysis because there are patients with one ADA2 mutation and absent enzyme activity. Our data suggest a possible genotype-phenotype correlation in which dimerization domain mutations are associated with PAN-like phenotype, and catalytic domain mutations are associated with hematological manifestations.

Adenosine deaminase (ADA) is a key enzyme of adenosine metabolism. There are currently various kits and systems available for ADA measurement, and all yield variable results. This study optimized a reference measurement procedure (RMP) for serum ADA for the standardization of routine methods. ADA coupled with purine-nucleoside-phosphorylase, xanthine-oxidase and peroxidase was selected as the basic method and was optimized using Response Surface Methodology. Then the performance was validated and the results were compared after replication by 3 other reference laboratories. A reference interval was also developed. In addition, this optimized method was applied to calibrate a routine system. The intra-assay precision was 0.44% at both concentrations of 29.8 and 100.4 U/L, and inter-assay precision was 1.01% and 0.95% at 30.1 and 100.3 U/L, respectively. The linearity was up to 351.9 U/L (R 2  = 0.9998), with no significant interference or carryover (<5%). A Comparison among 4 reference laboratories showed good reproducibility (R 2  ≥ 0.9975). The procedure proved valid for a reference interval of 11.7-38.5 U/L. The mean relative deviation for a routine system was -55.9% and -3.7% before and after calibration. This candidate RMP for serum ADA can potentially be used for standardization of clinical systems., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Treatment-emergent depression is a common complication in patients with chronic hepatitis C virus (HCV) infection undergoing antiviral combination therapy with IFN-α and ribavirin. It has recently been shown that changes in A-to-I RNA editing rates are associated with various pathologies such as inflammatory disorders, depression and suicide. Interestingly, IFN-α induces gene expression of the RNA editing enzyme ADAR1-1 (ADAR1a-p150) and alters overall RNA editing activity. In this study, we took advantage of the high prevalence of pharmacologically induced depression in patients treated with IFN-α and ribavirin to test the interest of RNA editing-related biomarkers in white blood cells of patients. In this 16-week longitudinal study, a small cohort of patients was clinically evaluated using standard assessment methods prior to and during antiviral therapy and blood samples were collected to analyse RNA editing modifications. A-I RNA editing activity on the phosphodiesterase 8A (PDE8A) gene, a previously identified RNA editing hotspot in the context of lupus erythematosus, was quantified by using an ultra-deep next-generation sequencing approach. We also monitored gene expression levels of the ADAR enzymes and the PDE8A gene during treatment by qPCR. As expected, psychiatric evaluation could track treatment-emergent depression, which occurred in 30% of HCV patients. We show that PDE8A RNA editing is increased in all patients following interferon treatment, but differently in 30% of patients. This effect was mimicked in a cellular model using SHSY-5Y neuroblastoma cells. By combining the data of A-I RNA editing and gene expression, we generated an algorithm that allowed discrimination between the group of patients who developed a treatment-emergent depression and those who did not. The current model of drug-induced depression identified A-I RNA editing biomarkers as useful tools for the identification of individuals at risk of developing depression in an objective, quantifiable biological blood test.

Both oxidative stress and alterations in adenosinergic and cholinergic systems participate in initiation and progression of parasitic infectious diseases. Nevertheless, the involvement of these pathways during eimeriosis remains poorly understood. Therefore, the aim of this study was to evaluate the involvement of adenosinergic and cholinergic systems in regulation of inflammatory response and oxidative stress in chicken chicks experimentally infected with Eimeria spp. Two groups were formed for comparison at 3 time points (days 5, 10 and 15) of infection (PI): uninfected (control) and infected. Erythrocyte counts, hematocrit and hemoglobin levels were lower in infected chicks on day 15 post-infection (PI). Total leukocytes, heterophil and lymphocyte counts were higher in infected chicks on days 5 and 10 PI, while eosinophil counts were higher only on day 10 PI. Serum levels of total protein and globulins were higher in infected chicks on days 10 and 15 PI, while triglycerides and cholesterol levels were lower on day 15 PI. Acetylcholinesterase activity in total blood and butyrylcholinesterase activity in serum were higher in infected chicks on day 15 PI, while adenosine deaminase activity was higher on day 10 PI and lower on day 15 PI compared with the respective control. Finally, serum levels of reactive oxygen species and catalase activity in total blood were higher in infected chicks on day 15 PI, while superoxide dismutase activity in total blood was lower at the same time of infection. These data suggest that cholinergic and adenosinergic systems display a pro-inflammatory profile that contributes to impairment of immune and inflammatory responses in a mixed Eimeria infection. Furthermore, oxidative stress may contribute to clinical signs of disease as well as to pathogenesis. In summary, the impairment of immune response and alterations in blood antioxidant/oxidant status contributes to disease pathophysiology., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background : Tuberculosis (TB) is the world's leading cause of death from infectious disease. The World Health Organization (WHO) recognized 6.3 million new TB cases in 2017, 16% corresponding to extrapulmonary forms; pleural tuberculosis (PT) is the most common extrapulmonary form in adults. PT diagnosis is often challenging because the scarcity of bacilli in pleural fluid (PF), sometimes requiring invasive procedures to obtain pleural tissue for histological, microbiological or molecular examination. In regions of medium and high disease prevalence, adenosine deaminase (ADA), interferon gamma (IFN-γ) and interleukin 27 (IL-27) dosages are useful to establish presumptive diagnosis in patients with compatible clinical/radiological picture who present with lymphocytic pleural effusion. PT treatment is similar to the pulmonary TB treatment regimen recommended by WHO. Area covered : In this update, we present a PT review, including epidemiology, pathogenesis, clinical features, diagnosis, and therapy. Expert opinion : There is no PF test alone accurate for PT diagnosis, despite the evolution in clinical laboratory. ADA, IFN-γ and IL-27 are valuable laboratory biomarkers; however, IFN-γ and IL-27 are quite expensive. Molecular tests present low sensitivity in PF, being useful for diagnostic confirmation. Multidrug therapy remains the PT treatment choice. Advancing research in immunotherapy may bring benefits to PT patients.

Dipeptidyl peptidase-4 (DPP-4) plays a role in metabolic and inflammatory diseases. Increased adenosine deaminase (ADA) has been suggested to induce insulin resistance and inflammation. We measured serum DPP-4 and ADA activities. Serum ADA activity was significantly higher in PCOS group ( p  = .006), whereas there was no difference in serum DPP-4 activity between the groups ( p  > .05). When the study subjects were divided into four groups in terms of obesity; an increasing trend in serum ADA activity between the groups was observed and ADA activity was significantly higher in overweight and obese patients with PCOS than nonobese controls ( p  = .016), there were no significant differences between the other groups ( p  > .05). A positive correlation was found between ADA and BMI in the whole group ( p  = .022). Multivariate regression analyses revealed that significant determinants were diastolic blood pressure, ADA, and the presence of PCOS for DPP-4 ( R 2  = 0.344, F  = 9.079, p  < .001); the presence of PCOS and DPP-4 for ADA ( R 2  = 0.123, F  = 6.302, p  = .003). We demonstrated increased serum ADA activity as well as its association with obesity in PCOS, while there was no change in serum DPP-4 activity in women with PCOS.

Purpose of Review: The direct modification of RNA is now understood to be widespread, evolutionarily conserved and of consequence to cellular and organismal homeostasis. adenosine-to-inosine (A-to-I) RNA editing is one of the most common mammalian RNA modifications. Transcriptome-wide maps of the A-to-I editing exist, yet functions for the majority of editing sites remain opaque. Herein we discuss how hematology has been applied to determine physiological and malignant functions of A-to-I editing., Recent Findings: Functional studies have established that A-to-I editing and ADAR1, responsible for the majority of editing in blood cells, are essential for normal blood cell homeostasis. ADAR1 edits endogenous RNA and reshapes its secondary structure, preventing MDA5 from perceiving the cells own RNA as pathogenic. Roles for ADAR1 in human leukaemia, and most recently, cancer cell intrinsic and extrinsic functions of ADAR1 have been identified that highlight ADAR1 as a therapeutic target in cancer., Summary: The studies reviewed have identified the key physiological function of ADAR1 and mechanistic basis for A-to-I editing in normal physiology and have now been extended to cancer. As our understanding of the biology and consequences of A-to-I editing evolve, it may be possible to target ADAR1 function advantageously in a number of settings.

Objective: Serum adenosine deaminase (ADA) activity is a marker of immune reaction to several diseases. We evaluated changes in serum ADA in patients with lung cancer undergoing chemotherapy or anti-programmed cell death-1 (PD-1) therapy to examine the correlation between serum ADA and the therapy efficacy., Materials and Methods: We assessed 50 patients with advanced lung cancer receiving chemotherapy or anti-PD-1 therapy. Serum ADA was measured before and on day 7 of the first treatment cycle and day 0 of subsequent cycles. Correlations between ADA change and efficacy of treatment were evaluated., Results: Of the 50 patients, 20 were treated with chemotherapy and 30 were treated with anti-PD-1 therapy. Serum ADA decreased significantly between baseline and day 7 of the first cycle in patients undergoing chemotherapy, regardless of response (partial response [PR] or stable disease [SD]: -23% [-38 to +32; p =  0.002]; progressive disease [PD]: -12% [-42 to +6; p =  0.500]). Conversely, in patients undergoing anti-PD-1 therapy, serum ADA increased significantly between baseline and 7 days after the first dose and before subsequent doses in patients who had PR or SD. (day 7 of first cycle: +6% [-10 to +34; p =  0.034], day 0 of second cycle: 8% [-5 to +37; p =  0.002], day 0 of third cycle: 9% [-3 to +55; p =  0.002]). However, serum ADA did not significant change in PD patients undergoing anti-PD-1 therapy. Furthermore, early increases in serum ADA were associated with longer progression-free survival in patients receiving anti-PD-1 therapy (p =  0.006)., Conclusion: Changes in serum ADA could be used to predict clinical benefit from anti-PD-1 therapy in patients with lung cancer. The association between changes in serum ADA and the efficacy of ant-PD-1 therapy thus remains inconclusive and requires further study., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this paper, a split aptamer based fluorescence resonance energy transfer (FRET) platform was constructed for the determination of adenosine deaminase (ADA) activity by using gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs). A single adenosine triphosphate (ATP) aptamer was split into two fragments (referred to as P1 and P2). P1 was covalently attached to the AuNCs at the 5' end (P1-AuNCs), and P2 was labeled with AuNPs at the 3' end (P2-AuNPs). In the presence of ATP, ATP bound with the two fragments with high affinity to link P1-AuNCs and P2-AuNPs together, thus the fluorescence of P1-AuNCs was quenched via FRET from P1-AuNCs to P2-AuNPs. With the addition of ADA, ATP was transformed into inosine triphosphate (ITP), and then P1 and P2 were released to cause the fluorescence recovery of the system. So a split aptamer based FRET platform for ADA detection can be established via the fluorescence intensity change of the system. This platform showed a good linear relationship between the fluorescence intensity and ADA concentration in the range of 2-120 U L -1 , and the limit of detection (LOD) was 0.72 U L -1 . Moreover, the detection of ATP in human serum sample demonstrated the accuracy and applicability of the method for ADA detection in real sample., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The present cross-sectional, hospital-based study was carried out on 146 Egyptian male children, 73 males with autism who were comparable with another 73 healthy age- and sex-matched children, recruited from the outpatients' psychiatric clinics of the Neuropsychiatric and Pediatric Departments of South Valley and Assiut University Hospitals, Egypt. Neuropsychological assessments of autistic males were done using CARS, short sensory profile and intelligent quotients. Serum markers of mitochondrial dysfunction (lactate, pyruvate, and lactate to pyruvate ratio, creatine kinase (CK), L-carnitine, ammonia, lactate dehydrogenase, pyruvate kinase, alanine transaminase and aspartate transaminase), oxidative stress and blood levels of heavy metals (mercury, lead and aluminium) were measured. Serum cholesterol, cortisol, free testosterone, estradiol, dehydroepiandrostenedione, adenosine deaminase and Helicobacter pylori antigen in stool were also performed. There was evidence of mitochondrial dysfunction among autistic children. Additionally, there were significantly lower serum total cholesterol, cortisol and estradiol as well as significantly higher dehydroepiandrostenedione (DHEA) and free testosterone (p < 0.05 for all markers). Twenty-eight (38%) cases were positive for H. pylori antigen in their stool with significant higher serum ammonia and lower adenosine deaminase than in H. pylori-negative autistic children. Mitochondrial dysfunction, H. pylori infection and low cholesterol were prevalent among autistic male children, which should be targeted during autism management.

Background: Rheumatoid Arthritis (RA) is a chronic multi systemic disorder with the unclarified ethiopathology. Although several markers have been presented for recognition of RA, but none of them has been specific. New markers such as HLA typing and activity of Adenosine Deaminase (ADA) isoenzymes could be useful and specific., Objective: The aim of this study is to evaluate the pattern of ADA isoenzymes activity and HLA typing in both RA patients and healthy cases., Methods: Blood samples were collected from 55 RA patients and 60 healthy subjects, over a period of 6 months. Levels of C-reactive Protein (CRP), Rheumatoid Factor (RF) and ADA (ADA1, ADA2, total ADA) were measured using AVITEX kit and HITACHI Auto Analyzer. In addition, HLA-DRB1*01,*04 and *10 was detected using PCR-SSP., Results: ADA activity, particularly ADA2 level, was significantly higher among RA group (Pv <0.05). The concentrations of tADA in patients with RF and CRP positive were significantly higher (Pv <0.05). The allele prevalence of DRB1*01 was significantly higher in RA patients (13.1%) compared with control group (5.5%, respectively) (P <0.05, Bonferroni adjustment P<0.003). Calculated sensitivity and specificity for diagnostic tests in this study are listed as: CRP (75%), RF (80%), ADA (84%) and RF (90%), ADA (83%), CRP (72%), respectively., Conclusion: Increased tADA level and the frequency of DRB1*10 and *01 caused susceptibility to RA., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)