Helper T-cell Subsets Research Articles

Differential Diagnosis of Tuberculosis and Sarcoidosis by Immunological Features Using Machine Learning.

Despite the achievements of modern medicine, tuberculosis remains one of the leading causes of mortality globally. The difficulties in differential diagnosis have particular relevance in the case of suspicion of tuberculosis with other granulomatous diseases. The most similar clinical and radiologic changes are sarcoidosis. The aim of this study is to apply mathematical modeling to determine diagnostically significant immunological parameters and an algorithm for the differential diagnosis of tuberculosis and sarcoidosis. Materials and methods: The serum samples of patients with sarcoidosis (SD) (n = 29), patients with pulmonary tuberculosis (TB) (n = 32) and the control group (n = 31) (healthy subjects) collected from 2017 to 2022 (the average age 43.4 ± 5.3 years) were examined. Circulating 'polarized' T-helper cell subsets were analyzed by multicolor flow cytometry. A symbolic regression method was used to find general mathematical relations between cell concentrations and diagnosis. The parameters of the selected model were finally fitted through multi-objective optimization applied to two conflicting indices: sensitivity to sarcoidosis and sensitivity to tuberculosis. Results: The difference in Bm2 and CD5-CD27- concentrations was found to be more significant for the differential diagnosis of sarcoidosis and tuberculosis than any individual concentrations: the combined feature Bm2 - [CD5-CD27-] differentiates sarcoidosis and tuberculosis with p < 0.00001 and AUC = 0.823. An algorithm for differential diagnosis was developed. It is based on the linear model with two variables: the first variable is the difference Bm2 - [CD5-CD27-] mentioned above, and the second is the naïve-Tregs concentration. The algorithm uses the model twice and returns "dubious" in 26.7% of cases for patients with sarcoidosis and in 16.1% of cases for patients with tuberculosis. For the remaining patients with one of these two diagnoses, its sensitivity to sarcoidosis is 90.5%, and its sensitivity to tuberculosis is 88.5%. Conclusions: A simple algorithm was developed that can distinguish, by certain immunological features, the cases in which sarcoidosis is likely to be present instead of tuberculosis. Such cases may be further investigated to rule out tuberculosis conclusively. The mathematical model underlying the algorithm is based on the analysis of "naive" T-regulatory cells and "naive" B-cells. This may be a promising approach for differential diagnosis between pulmonary sarcoidosis and pulmonary tuberculosis. The findings may be useful in the absence of clear differential diagnostic criteria between pulmonary tuberculosis and sarcoidosis.

TH1 Cell Frequency and Neutrophil-to-Lymphocyte Ratio in Hemodialysis: Potential Contributions to Patient Monitoring.

Introduction: Patients undergoing hemodialysis (HD) often exhibit an impaired cellular immune response, which may contribute to an increased susceptibility to infections and other complications. Th1 cells, a subset of T-helper cells, play a crucial role in cellular immunity. However, the modulation of Th1 cells by HD treatment remains unclear. Objective: This study aims to investigate the levels of circulating T cells, especially Th1 cells, and the neutrophil-to-lymphocyte ratio (NLR) in HD patients. Methods: We recruited 26 HD patients and 10 healthy volunteers. Demographical data were collected, and peripheral blood samples were analyzed. Absolute blood cell counts were determined, and T-cell populations were identified using flow cytometry. Th1 cells were defined as IFN-γ-producing CD4+ T cells after in vitro activation, and NLR was calculated through the ratio between the neutrophil and lymphocyte counts measured in peripheral blood. Results: We have observed a significant decrease in Th1 subpopulation frequency in HD patients, as well as significant correlations between immunological and demographic parameters, among which are the NLR values and the absolute values of T-cell subsets. Conclusions: These results seem to clarify the role of Th1 cells in modulating the immune responses of hemodialysis-treated patients, potentially considering its frequency as an indicator for CKD development.

Spatial phenotyping of nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B-cell lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma with sparse tumor B-cells and a favorable prognosis. Variant growth patterns of NLPHL, however, often show advanced stage, progression to T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) and a worse prognosis. We studied the tumor microenvironment (TME) of NLPHL and THRLBCL using highplex imaging and spatial profiling at the single cell level. Our findings show distinct differences in TME composition and spatial configuration that differ among typical and variant NLPHL and THRLBCL. Typical NLPHL show abundant helper T-cell subsets, while THRLBCL show abundant cytotoxic T-cells and macrophages. Tumor B-cell size and content is lowest in typical NLPHL, followed by variant NLPHL, and highest in THRLBCL, whereas an opposite trend characterized TME B-cells. CD4/CD8 double-positive T-cells are seen in all NLPHL but not in the majority of THRLBCL and are spatially distant from LP-cells and TFH-rosettes. The differences in macrophage/monocyte content in distinguishing NLPHL pattern E from THRLBCL is further corroborated in independent cohorts of cases. Our results validate the current approach to classification and in addition provide novel insights that could be leveraged to refine clinical management for patients with this spectrum of lymphomas.

Study of pathogenic T-helper cell subsets in Asian Indian patients with Takayasu arteritis.

The relapses and refractory disease are a challenge in themanagement of patients with Takayasu arteritis (TAK). We quantified pathogenic CD4 + memory T helper cells bearing surface markers CD161 and/or p-glycoprotein (MDR1) in patients with TAK. Peripheral blood mononuclear cells of 21 patients with TAK and 16 age-matched controls were stained with anti-CD3, anti-CD4, anti-CD45RA, anti-CD161 and anti-p-glycoprotein antibodies and subjected to flow cytometry by FACS ARIAIII. Eighteen patients underwent follow-up immunophenotyping. Intracellular staining for interleukin-17 and interferon-γ was performed for 18 patients and 11 controls. Surgical arterial biopsies of 6 TAK and 5 non-inflammatory controls were subjected to immunohistochemistry with anti-CD161 and anti-p-glycoprotein. At baseline the frequency ofMDR1 + CD4 + and CD161 + MDR1 + CD4 + memory T cells was higher in TAK than controls (p = 0.002 and 0.01, respectively). After stimulation, the frequency ofIFN-y + CD161 + cells was higher in TAK than controls (p = 0.028). Modal fluorescence intensity of CD161 + MDR1 + CD45RA - CD4 + cells was higher in active as compared with stable disease (p = 0.041). At 6months, MDR1 + and CD161 + MDR1 + memory CD4 + T cells decreased significantly only in patients who had complete/partial response to treatment (p = 0.047 and 0.02, respectively). To conclude,MDR1 + and MDR1 + CD161 + CD4 + memory T-helper cells are increased in patients with TAK. These cells decreased only in patients with response to treatment during subsequent follow-up.

New Insights into HIV Life Cycle, Th1/Th2 Shift during HIV Infection and Preferential Virus Infection of Th2 Cells: Implications of Early HIV Treatment Initiation and Care.

The theory of immune regulation involves a homeostatic balance between T-helper 1 (Th1) and T-helper 2 (Th2) responses. The Th1 and Th2 theories were introduced in 1986 as a result of studies in mice, whereby T-helper cell subsets were found to direct different immune response pathways. Subsequently, this hypothesis was extended to human immunity, with Th1 cells mediating cellular immunity to fight intracellular pathogens, while Th2 cells mediated humoral immunity to fight extracellular pathogens. Several disease conditions were later found to tilt the balance between Th1 and Th2 immune response pathways, including HIV infection, but the exact mechanism for the shift from Th1 to Th2 cells was poorly understood. This review provides new insights into the molecular biology of HIV, wherein the HIV life cycle is discussed in detail. Insights into the possible mechanism for the Th1 to Th2 shift during HIV infection and the preferential infection of Th2 cells during the late symptomatic stage of HIV disease are also discussed.

The role of biogenic amines in the modulation of monocytes in autoimmune neuroinflammation.

Multiple sclerosis (MS) is inflammatory demyelinating and neurodegenerative disease of the central nervous system (CNS) with autoimmune mechanism of development. The study of the neuroimmune interactions is one of the most developing directions in the research of the pathogenesis of MS. The influence of biogenic amines on the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and MS was shown by the modulation of subsets of T-helper cells and B-cells, which plays a crucial role in the autoimmunity of the CNS. However, along with T- and B-cells the critical involvement of mononuclear phagocytes such as dendritic cells, macrophages, and monocytes in the development of neuroinflammation also was shown. It was demonstrated that the activation of microglial cells (resident macrophages of the CNS) could initiate the neuroinflammation in the EAE, suggesting their role at an early stage of the disease. In contrast, monocytes, which migrate from the periphery into the CNS through the blood-brain barrier, mediate the effector phase of the disease and cause neurological disability in EAE. In addition, the clinical efficacy of the therapy with depletion of the monocytes in EAE was shown, suggesting their crucial role in the autoimmunity of the CNS. Biogenic amines, such as epinephrine, norepinephrine, dopamine, and serotonin are direct mediators of the neuroimmune interaction and may affect the pathogenesis of EAE and MS by modulating the immune cell activity and cytokine production. The anti-inflammatory effect of targeting the biogenic amines receptors on the pathogenesis of EAE and MS by suppression of Th17- and Th1-cells, which are critical for the CNS autoimmunity, was shown. However, the latest data showed the potential ability of biogenic amines to affect the functions of the mononuclear phagocytes and their involvement in the modulation of neuroinflammation. This article reviews the literature data on the role of monocytes in the pathogenesis of EAE and MS. The data on the effect of targeting of biogenic amine receptors on the function of monocytes are presented.

CCR4 predicts the efficacy ofabatacept inrheumatoid arthritis patients through the estimation ofTh17 andTreg cell abundance.

Predicting the efficacy of biological disease-modifying antirheumatic drugs is challenging. In this study, we aimed to explore markers that predict the efficacy of abatacept in rheumatoid arthritis (RA) patients. Thirty RA patients receiving abatacept were recruited, and peripheral blood mononuclear cells from the participants were subjected to DNA microarray analysis. The expression of CC chemokine receptor 4 (CCR4), which was selected by the result of DNA microarray, was determined by flow cytometry in 16 newly diagnosed treatment-naïve RA patients. CCR4 expression on each helper T-cell subset was also measured. CCR4 was upregulated in the abatacept responder. The expression levels of CCR4 were significantly correlated with the improvement of the Clinical Disease Activity Index. CCR4 expression was predominantly observed in CD4+ T cells in peripheral blood mononuclear cells. The percentage of CCR4-expressing CD4+ T cells was significantly higher in RA patients than in healthy individuals. Interestingly, Th17 and Treg cells expressed high levels of CCR4 compared to non-Th17-related helper T cells. CCR4 is a Th17- and Treg-related gene, and the high CCR4 expression in peripheral blood samples may predict the efficacy of abatacept in RA.

Yeast cell wall extracts from Saccharomyces cerevisiae varying in structure and composition differentially shape the innate immunity and mucosal tissue responses of the intestine of zebrafish (Danio rerio).

With the rising awareness of antimicrobial resistance, the development and use of functional feed additives (FFAs) as an alternative prophylactic approach to improve animal health and performance is increasing. Although the FFAs from yeasts are widely used in animal and human pharma applications already, the success of future candidates resides in linking their structural functional properties to their efficacy in vivo. Herein, this study aimed to characterise the biochemical and molecular properties of four proprietary yeast cell wall extracts from S. cerevisiae in relation to their potential effect on the intestinal immune responses when given orally. Dietary supplementation of the YCW fractions identified that the α-mannan content was a potent driver of mucus cell and intraepithelial lymphocyte hyperplasia within the intestinal mucosal tissue. Furthermore, the differences in α-mannan and β-1,3-glucans chain lengths of each YCW fraction affected their capacity to be recognised by different PRRs. As a result, this affected the downstream signalling and shaping of the innate cytokine milieu to elicit the preferential mobilisation of effector T-helper cell subsets namely Th17, Th1, Tr1 and FoxP3+-Tregs. Together these findings demonstrate the importance of characterising the molecular and biochemical properties of YCW fractions when assessing and concluding their immune potential. Additionally, this study offers novel perspectives in the development specific YCW fractions derived from S. cerievisae for use in precision animal feeds.

Exosomes mediate immune activation post-myocardial infarction

Myocardial infarction (MI) and ischemic heart failure (HF) are associated with immune activation in the bone-marrow and the lymphoid tissues. Our studies also show that spleens lose 58% of their weight by 1-day post-MI as compared to sham-operation. Flow cytometric analysis further showed that, as compared to sham-operated mice, spleens of 1d post-MI mice contained 2-3-fold lower numbers of leukocytes (16.9X10 6 vs. 47.7X10 6 ), CD11c + dendritic cells (DCs; 0.22X10 6 vs. 0.56X10 6 ), Ly6G + neutrophils (0.45X10 6 vs. 1.08X10 6 ), CD11b + myeloid cells (1.2X10 6 vs. 2.8X10 6 ), and Ly6C + monocytes (0.4X10 6 vs. 1.0X10 6 ). Activation of antigen-presenting innate immune cells would also suggest activation of adaptive immune responses. Thus, using flow cytometry we also measured CD4 + and CD8 + T-cells in the spleens of 1d MI and sham mice and found that both of these cell types (2.2X10 6 vs. 5.7X10 6 for CD4 + T-cells and 1.5X10 6 vs. 3.8X10 6 for CD8 + cytotoxic T-cells) were also decreased. These data suggest that damage-associated signals from the infarcted heart are communicated to the splenic innate and adaptive immune cells leading to their efflux and trafficking to the heart. However, the communication vehicles that relay these damage-associated signals from the heart to the spleen are unknown. We further hypothesized that these signals are carried by the exosomes, small (100-200 nm) extracellular vesicles released by all cells. To test our hypothesis, we isolated exosomes from the plasma of 1d MI and sham mice, injected them into the tail-veins of naïve mice and using echocardiography measured their cardiac function at 8 weeks post-injection to assess if they developed HF-like systolic dysfunction. We found that, at 8 weeks, mice injected with 1d MI exosomes developed significant systolic dysfunction with increased end-systolic and end-diastolic volumes, and decreased ejection fraction. These changes were not seen in mice injected with 1d sham exosomes. Further, using flow cytometry we also measured different splenic immune cells in the recipient mice. Our data show that spleens of mice injected with 1d MI exosomes, as compared to 1d sham exosomes, contained higher numbers of activated immune cells and showed increased levels of proinflammatory monocytes (without any changes in anti-inflammatory monocytes), CD11c + conventional and monocyte-derived DCs and helper T-cell subsets such as T-regs, Th1, Th2, Th17. Our results suggest that exosomal signals could be a novel potential mechanism by which cardiac injury is communicated to the lymphoid tissues to affect immune cell recruitment following MI. This work was supported by the National Institutes of Health grants to. Dr Shyam S. Bansal (R00 HL132123 and R01 HL153164). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Follicular helper T lymphocytes in the endometria of patients with reproductive failure: Association with pregnancy outcomes and inflammatory status of the endometria.

The phenotypes and functions of B and CD4+ T-helper cell subsets during chronic inflammation of the endometria remain largely unexplored. This study aimed to investigate the characteristics and functions of follicular helper T (Tfh) cells to understand the pathological mechanisms of chronic endometritis (CE). Eighty patients who underwent hysteroscopic and histopathological examinations for CE were divided into three groups-those with positive results for hysteroscopy and CD138 staining (DP), negative results for hysteroscopy but positive CD138 staining (SP), and negative results for hysteroscopy and CD138 staining (DN). The phenotypes of B cells and CD4+ T-cell subsets were analyzed using flow cytometry. CD38+ and CD138+ cells were mainly expressed in the non-leukocyte population of the endometria, and the endometrial CD19+ CD138+ B cells were fewer than the CD3+ CD138+ T cells. The percentage of Tfh cells increased with chronic inflammation in the endometria. Additionally, the elevated percentage of Tfh cells correlated with the number of miscarriages. CD4+ T cells, particularly Tfh cells, may be critical in chronic endometrial inflammation and affect its microenvironment, thereby regulating endometrial receptivity, compared to B cells.

The Search for the Pathogenic T Cells in the Joint of Rheumatoid Arthritis: Which T-Cell Subset Drives Autoimmune Inflammation?

Rheumatoid arthritis (RA) is a chronic inflammatory disorder affecting systemic synovial tissues, leading to the destruction of multiple joints. Its etiology is still unknown, but T-cell-mediated autoimmunity has been thought to play critical roles, which is supported by experimental as well as clinical observations. Therefore, efforts have been made to elucidate the functions and antigen specificity of pathogenic autoreactive T cells, which could be a therapeutic target for disease treatment. Historically, T-helper (Th)1 and Th17 cells are hypothesized to be pathogenic T cells in RA joints; however, lines of evidence do not fully support this hypothesis, showing polyfunctionality of the T cells. Recent progress in single-cell analysis technology has led to the discovery of a novel helper T-cell subset, peripheral helper T cells, and attracted attention to the previously unappreciated T-cell subsets, such as cytotoxic CD4 and CD8 T cells, in RA joints. It also enables a comprehensive view of T-cell clonality and function. Furthermore, the antigen specificity of the expanded T-cell clones can be determined. Despite such progress, which T-cell subset drives inflammation is yet known.

Bach2 in CD4+ T cells from SLE patients modulates B-cell differentiation and IgG production.

T and B cells participate in the development of systemic lupus erythematosus (SLE). BTB and CNC homology 2 (Bach2) is an irreplaceable regulator in the T and B lineages that helps to maintain immune homeostasis. However, the function of Bach2 in the pathogenesis of SLE has not been studied in depth. Flow cytometry and qRT-PCR were used to assess Bach2 levels, bisulfite sequencing PCR was used to measure the methylation level, and silencing by electroporation and stimulation with a cytokine concentration gradient were used to investigate the effect of Bach2 on T cells. Bach2 expression was elevated in the helper T-cell subsets (T follicular helper, Th1, Th2, Th17, and Treg cells) of SLE patients and negatively correlated with disease severity and autoantibody levels. CD4+ T cells from SLE patients had decreased methylation levels in the Bach2 promoter region. Silencing Bach2 in CD4+ T cells induced increases in the CD19+ B-cell count, plasmablasts, and secretion of IgG by prompting the secretion of cytokines. The activation signals CD3/CD28, IL-6, and IL-21 upregulated Bach2 expression in CD4+ T cells. The regulation of Bach2 by cytokines and T-cell activation signals in CD4+ T cells was shown to act on B cells and play a protective role against SLE.

Post-Gam-COVID-Vac combined vector vaccine cellular and humoral immune response

Currently, as the SARS-CoV-2 pandemic evolves, there has been increasingly more attention paid to building natural and vaccine-induced immunity against SARS-CoV-2 and related disease known as COVID-19. Widespread preventive vaccination plays an important role in effectively protecting people from viral infections and can reduce national economic costs. Purpose to study peripheral blood cell subset composition and magnitude of humoral response in vaccinated Gam-COVID-Vac subjects. The prospective study included 352 patients, of which 194 (119 women and 75 men) underwent an immunogram study and assessed level of anti-SARS-CoV-2 antibodies. In patients, the study of the lymphocyte subset composition and estimation of anti-SARS-CoV-2 antibodies was carried out at two time points prior to vaccination and 90 days after inoculated component 1 of the Gam-COVID-Vac vaccine. In general, vaccination was well tolerated by patients, with no serious adverse events after immunization. The reaction to the vaccine (fever, malaise, headache, local reactions) was short-term (12 days) and more often noted after inoculated vaccine component 2. Comparatively analyzed immunogram parameters in females before and after vaccination revealed increased relative level of T-lymphocytes (CD3+), T-helper cell subset (CD3+CD4+), increased absolute and relative level of activated CD3+CD25+ T-lymphocytes, but decreased absolute and relative level of natural killer (CD3CD56+CD16+) and natural killer T-cell (CD3+CD56+CD16+) cell subsets as well as decreased CD147 receptor expression on T-lymphocytes. Similar patterns were also found while examining the immunogram in males exepting increased level of lymphocytes and lowered CD147 expression on both T- and B-lymphocytes. No changes in the parameters of the immune T-cell arm was found. The high efficacy of the vaccine was confirmed by development of SARS-CoV-2-specific class G antiviral antibodies in 97.5% and 92.3% of vaccinated females and males, respectively. The data obtained evidence that: 1) vaccination induces a specific humoral immune response determined three months post-vaccination, and 2) it caused no serious disturbances in the immune system functioning, which could be reflected in the peripheral blood lymphocyte subset composition. Thus, the data presented allow to conclude that Gam-COVID-Vac is effective vaccine against SARS-CoV-2 infection.

Circulating plasmablasts and follicular helper T-cell subsets are associated with antibody-positive autoimmune epilepsy.

Autoimmune epilepsy (AE) is an inflammatory disease of the central nervous system with symptoms that have seizures that are refractory to antiepileptic drugs. Since the diagnosis of AE tends to rely on a limited number of anti-neuronal antibody tests, a more comprehensive analysis of the immune background could achieve better diagnostic accuracy. This study aimed to compare the characteristics of anti-neuronal antibody-positive autoimmune epilepsy (AE/Ab(+)) and antibody-negative suspected autoimmune epilepsy (AE/Ab(-)) groups. A total of 23 patients who met the diagnostic criteria for autoimmune encephalitis with seizures and 11 healthy controls (HC) were enrolled. All patients were comprehensively analyzed for anti-neuronal antibodies; 13 patients were identified in the AE/Ab(+) group and 10 in the AE/Ab(-) group. Differences in clinical characteristics, including laboratory and imaging findings, were evaluated between the groups. In addition, the immunophenotype of peripheral blood mononuclear cells (PBMCs) and CSF mononuclear cells, particularly B cells and circulating Tfh (cTfh) subsets, and multiplex assays of serum and CSF were analyzed using flow cytometry. Patients with AE/Ab(+) did not show any differences in clinical parameters compared to patients with AE/Ab(-). However, the frequency of plasmablasts within PBMCs and CSF in patients with AE/Ab(+) was higher than that in patients with AE/Ab(-) and HC, and the frequency of cTfh17 cells and inducible T-cell co-stimulator (ICOS) expressing cTfh17 cells within cTfh subsets was higher than that in patients with AE/Ab(-). Furthermore, the frequency of ICOShighcTfh17 cells was positively correlated with that of the unswitched memory B cells. We also found that IL-12, IL-23, IL-6, IL-17A, and IFN-γ levels were elevated in the serum and IL-17A and IL-6 levels were elevated in the CSF of patients with AE/Ab(+). Our findings indicate that patients with AE/Ab(+) showed increased differentiation of B cells and cTfh subsets associated with antibody production. The elevated frequency of plasmablasts and ICOS expressing cTfh17 shift in PBMCs may be indicative of the presence of antibodies in patients with AE.

The Effect of Aerobic Exercise and Low-Impact Pilates Workout on the Adaptive Immune System.

Growing evidence indicates the pronounced effects of physical activity on immune functions, which may largely depend on the type of exercise, intensity, and duration. However, limited information is available regarding the effects of low-impact exercises, especially on the level of adaptive immune system. Our study aimed to investigate and compare the changes in a broad spectrum of lymphocyte subtypes after 14 weeks of aerobic-type total-body-shaping workouts (TBSW) and Pilates workouts (PW) among healthy individuals. We determined the percentages of peripheral natural killer cells and different T and B lymphocyte subtypes with flow cytometry. At the end of the exercise program, significant changes in naïve and memory lymphocyte ratios were observed in TBSW group. Percentages of naïve cytotoxic T (Tc) cells elevated, frequencies of memory Tc and T-helper cell subsets decreased, and distribution of naïve and memory B cells rearranged. Proportions of activated T cells also showed significant changes. Nonetheless, percentages of anti-inflammatory interleukin (IL)-10-producing regulatory type 1 cells and immunosuppressive CD4+CD127lo/-CD25bright T regulative cells decreased not only after TBSW but also after PW. Although weekly performed aerobic workouts may have a more pronounced impact on the adaptive immune system than low-impact exercises, both still affect immune regulation in healthy individuals.

A germline STAT6 gain-of-function variant is associated with early-onset allergies

The signal transducer and activator of transcription 6 (STAT6) signaling pathway plays a central role in allergic inflammation. To date, however, there have been no descriptions of STAT6 gain-of-function variants leading to allergies in humans. We report a STAT6 gain-of-function variant associated with early-onset multiorgan allergies in a family with 3 affected members. Exome sequencing and immunophenotyping of T-helper cell subsets were conducted. The function of the STAT6 protein was analyzed by Western blot, immunofluorescence, electrophoretic mobility shift assays, and luciferase assays. Gastric organoids obtained from the index patient were used to study downstream effector cytokines. We identified a heterozygous missense variant (c.1129G>A;p.Glu377Lys) in the DNA binding domain of STAT6 that was de novo in the index patient's father and was inherited by 2 of his 3 children. Severe atopic dermatitis and food allergy were key presentations. Clinical heterogeneity was observed among the affected individuals. Higher levels of peripheral blood TH2 lymphocytes were detected. The mutant STAT6 displayed a strong preference for nuclear localization, increased DNA binding affinity, and spontaneous transcriptional activity. Moreover, gastric organoids showed constitutive activation of STAT6 downstream signaling molecules. A germline STAT6 gain-of-function variant results in spontaneous activation of the STAT6 signaling pathway and is associated with an early-onset and severe allergic phenotype in humans. These observations enhance our knowledge of the molecular mechanisms underlying allergic diseases and will potentially contribute to novel therapeutic interventions.

Autoimmune Regulator (AIRE) Deficiency Does Not Affect Atherosclerosis and CD4 T Cell Immune Tolerance to Apolipoprotein B.

Atherosclerosis is a chronic, lipid-driven disease of medium sized arteries which causes myocardial infarction and stroke. Recently, an adaptive immune response against the plaque-associated autoantigen Apolipoprotein B100 (ApoB), the structural protein component of low-density lipoprotein, has been implicated in atherogenesis. In healthy individuals, CD4+ T cells responding to ApoB mainly comprised regulatory T cells, which confer immune tolerance and atheroprotection. Mice and patients with atherosclerosis harbor increased numbers of proatherogenic ApoB-reactive T-helper cell subsets. Given the lack of therapies targeting proatherogenic immunity, clarification of the underlying mechanisms is of high clinical relevance. T cells develop in the thymus, where strong autoreactive T cells are eliminated in the process of negative selection. Herein, we investigated whether the transcription factor autoimmune regulator (AIRE), which controls expression of numerous tissue-restricted self-antigens in the thymus, is involved in mediating tolerance to ApoB and whether Aire deficiency might contribute to atherogenesis. Mice deficient for Aire were crossbred to apolipoprotein E-deficient mice to obtain atherosclerosis-prone Aire−/− Apoe−/− mice, which were fed a regular chow diet (CD) or western-type diet (WD). CD4+ T cells responding to the ApoB peptide p6 were analyzed by flow cytometry. We demonstrate that Aire deficiency influences neither generation nor activation of ApoB-reactive T cells and has only minor and overall inconsistent impacts on their phenotype. Furthermore, we show that atherosclerotic plaque size is not affected in Aire−/− Apoe−/− compared to Aire+/+ Apoe−/−, irrespective of diet and gender. In conclusion, our data suggests that AIRE is not involved in regulating thymic expression of ApoB or atherosclerosis. Alternative mechanisms how ApoB-reactive CD4 T cells are selected in the thymus will have to be investigated.

Role of pathogenic T-helper cells-17 in chronic antibody-mediated rejection in renal allograft recipients

Background: Both T-cell and B-cell activities are interlinked. The role of a new subset of T-helper cells (Th17), which is thought to be more pathogenic than other effector T cells, is not much studied in cases of chronic antibody-mediated rejection (CABMR). Therefore, we aimed to determine the circulating frequency of Th17, Pgp+ Th17, Pgp+ CD4T cell, and serum interleukin (IL)-17A cytokine level in patients of CABMR and stable graft function (SGF). Materials and Methods: We had recruited 42 patients of biopsy-proven CABMR (n = 32) and SGF (n = 10). The frequency of Pgp+ CD4Tcells, Pgp+ Th17 and Th17 cell was quantified in circulating blood by flow cytometry, and IL-17A level was determined in serum by ELISA techniques. Results: We observed that the frequency of Th17 cell (2.30 ± 1.15 and 4.46 ± 2.05; P = 0.003), Pgp+ CD4T (15.73 ± 4.38 and 25.27 ± 5.15; P < 0.001), and Pgp+ Th17 (0.78 ± 0.65 and 2.19 ± 0.93; P < 0.001) was higher in CABMR as compared to that of SGF. The ratio of Th17/CD4T cell (0.077 ± 0.045 and 0.14 ± 0.06; P = 0.004), and Pgp+ CD4T/CD4T cell (0.51 ± 0.14 and 0.81 ± 0.17, P < 0.001) was also higher in CABMR as compared to SGF. Serum cytokine IL-17A level was (42.39 ± 13.25 and 66.97 ± 18.27; P < 0.001) pg/ml was also higher in CABMR than that of SGF. The frequency of Pgp+ Th17 cell was positively correlating with 24-h proteinuria (r = 0.309; P = 0.04), serum creatinine (r = 0.423; P = 0.005), and negatively correlating with eGFR (r = −0.468; P = 0.002). Similarly, the frequency of Pgp+ CD4T cell was positively correlating with 24-h proteinuria (r = 0.351; P = 0.023), serum creatinine (r = 0.310; P = 0.04), and negatively correlating with eGFR (r = −0.414; P = 0.006). Conclusions: Higher Pgp+ TH17 cell is associated with CABMR, proteinuria, and graft dysfuntion.

Alterations in B Cell and Follicular T-Helper Cell Subsets in Patients with Acute COVID-19 and COVID-19 Convalescents.

Background. Humoral immunity requires interaction between B cell and T follicular helper cells (Tfh) to produce effective immune response, but the data regarding a role of B cells and Tfh in SARS-CoV-2 defense are still sparse. Methods. Blood samples from patients with acute COVID-19 (n = 64), convalescents patients who had specific IgG to SARS-CoV-2 N-protein (n = 55), and healthy donors with no detectable antibodies to any SARS-CoV-2 proteins (HC, n = 44) were analyses by multicolor flow cytometry. Results. Patients with acute COVID-19 showed decreased levels of memory B cells subsets and increased proportion plasma cell precursors compared to HC and COVID-19 convalescent patients, whereas for the latter the elevated numbers of virgin naïve, Bm2′ and “Bm3+Bm4” was found if compared with HC. During acute COVID-19 CXCR3+CCR6− Tfh1-like cells were decreased and the levels of CXCR3−CCR6+ Tfh17-like were increased then in HC and convalescent patients. Finally, COVID-19 convalescent patients had increased levels of Tfh2-, Tfh17- and DP Tfh-like cells while comparing their amount with HC. Conclusions. Our data indicate that COVID-19 can impact the humoral immunity in the long-term.

Quantitative assessment of inflammatory infiltrates in kidney transplant biopsies using multiplex tyramide signal amplification and deep learning

Delayed graft function (DGF) is a strong risk factor for development of interstitial fibrosis and tubular atrophy (IFTA) in kidney transplants. Quantitative assessment of inflammatory infiltrates in kidney biopsies of DGF patients can reveal predictive markers for IFTA development. In this study, we combined multiplex tyramide signal amplification (mTSA) and convolutional neural networks (CNNs) to assess the inflammatory microenvironment in kidney biopsies of DGF patients (n = 22) taken at 6 weeks post-transplantation. Patients were stratified for IFTA development (<10% versus ≥10%) from 6 weeks to 6 months post-transplantation, based on histopathological assessment by three kidney pathologists. One mTSA panel was developed for visualization of capillaries, T- and B-lymphocytes and macrophages and a second mTSA panel for T-helper cell and macrophage subsets. The slides were multi spectrally imaged and custom-made python scripts enabled conversion to artificial brightfield whole-slide images (WSI). We used an existing CNN for the detection of lymphocytes with cytoplasmatic staining patterns in immunohistochemistry and developed two new CNNs for the detection of macrophages and nuclear-stained lymphocytes. F1-scores were 0.77 (nuclear-stained lymphocytes), 0.81 (cytoplasmatic-stained lymphocytes), and 0.82 (macrophages) on a test set of artificial brightfield WSI. The CNNs were used to detect inflammatory cells, after which we assessed the peritubular capillary extent, cell density, cell ratios, and cell distance in the two patient groups. In this cohort, distance of macrophages to other immune cells and peritubular capillary extent did not vary significantly at 6 weeks post-transplantation between patient groups. CD163+ cell density was higher in patients with ≥10% IFTA development 6 months post-transplantation (p < 0.05). CD3+CD8−/CD3+CD8+ ratios were higher in patients with <10% IFTA development (p < 0.05). We observed a high correlation between CD163+ and CD4+GATA3+ cell density (R = 0.74, p < 0.001). Our study demonstrates that CNNs can be used to leverage reliable, quantitative results from mTSA-stained, multi spectrally imaged slides of kidney transplant biopsies.This study describes a methodology to assess the microenvironment in sparse tissue samples. Deep learning, multiplex immunohistochemistry, and mathematical image processing techniques were incorporated to quantify lymphocytes, macrophages, and capillaries in kidney transplant biopsies of delayed graft function patients. The quantitative results were used to assess correlations with development of interstitial fibrosis and tubular atrophy.