Increased frequency of PD-1hiCXCR5- T cells and B cells in patients with newly diagnosed IgA nephropathy

Urinary exosomal mRNAs as biomarkers for predicting the therapeutic effect of renin-angiotensin system inhibitors in IgA nephropathy patients

BACKGROUND

Renin-angiotensin system inhibitors (RASi) treatment is the basic therapy for IgA nephropathy (IgAN) patients. However, there is few of biomarker that can predict the efficacy of RASi. This study aimed to find urinary exosomal mRNAs related to the therapeutic effect of RASi in the treatment of proteinuria in IgAN patients.

METHODS

We divided IgAN patients in screening cohort into A1 (proteinuria increase at 3 months), B1 (proteinuria decrease less than 50 % at 3 months), C1 (proteinuria decrease more than 50 % at 3 months) groups according to changes of proteinuria after treatment. The urinary exosomes were collected before biopsy, RNAs were extracted and analyzed with the microarray assay. The candidate genes were screened by differentially expressed genes (DEGs) analysis and then validated by quantitative real-time polymerase chain reaction (qPCR) in a validation cohort. A receiver operating characteristic (ROC) curve was used to evaluate gene performance in predicting therapeutic effect on RASi reducing proteinuria in IgAN patients.

RESULTS

ECE1 and PDE1A mRNAs were significantly different among the three groups, and were gradually decreased among A1, B1 and C1 groups. In the validation cohort, the level of urinary exosomal ECE1 and PDE1A mRNAs were also significantly lower in A2 group compared with C2 group(ECE1, P < 0.001;PDE1A, P < 0.01). Besides, the level of ECE1 mRNA was also lower in B2 group compared with C2 group (P < 0.01). The ROC curve verified that urinary exosomal ECE1 and PDE1A gene level predicted RASi efficacy in IgAN patients with area under curve (AUC) 0.68 and 0.63 respectively.

CONCLUSION

Urinary exosomal ECE1 and PDE1A mRNAs expression can serve as potential biomarkers for predicting the RASi efficacy to reduce proteinuria in IgAN patients.

Leveraging Multi-Tissue, Single-Cell Atlases as Tools to Elucidate Shared Mechanisms of Immune-Mediated Inflammatory Diseases

The observation that certain therapeutic strategies for targeting inflammation benefit patients with distinct immune-mediated inflammatory diseases (IMIDs) is exemplified by the success of TNF blockade in conditions including rheumatoid arthritis, ulcerative colitis, and skin psoriasis, albeit only for subsets of individuals with each condition. This suggests intersecting "nodes" in inflammatory networks at a molecular and cellular level may drive and/or maintain IMIDs, being "shared" between traditionally distinct diagnoses without mapping neatly to a single clinical phenotype. In line with this proposition, integrative tumour tissue analyses in oncology have highlighted novel cell states acting across diverse cancers, with important implications for precision medicine. Drawing upon advances in the oncology field, this narrative review will first summarise learnings from the Human Cell Atlas in health as a platform for interrogating IMID tissues. It will then review cross-disease studies to date that inform this endeavour before considering future directions in the field.

Peripheral helper T cells in human diseases

Peripheral helper T cells (Tph) are a specialized subset of CD4+ T cells with the ability to help B cells and induce antibody production. Although usually located in ectopic lymphoid-like structures (ELS), inside the peripheral blood, Tph cells can also be identified. The aberrant proliferation and functions of Tph cells are commonly found in the patients with disease. In this review, first we will summarize the biological characteristics of Tph cells, such as the expression of surface molecules, transcription factors and cytokines, and discuss its B cell help functions. Tph cells also have roles in a wide range of human diseases, including autoimmune diseases, infectious diseases, malignancies etc. Therefore, there is a strong interest in targeting Tph cells to improve treat strategies of human diseases.

Sinomenine Hydrochloride Protects IgA Nephropathy Through Regulating Cell Growth and Apoptosis of T and B Lymphocytes

Purpose

Sinomenine hydrochloride (SH) is used to treat chronic inflammatory diseases such as rheumatoid arthritis and may also be efficacious against Immunoglobulin A nephropathy (IgAN). However, no trial has investigated the molecular mechanism of SH on IgAN. Therefore, this study aims to investigate the effect and mechanism of SH on IgAN.

Methods

The pathological changes and IgA and C3 depositions in the kidney of an IgAN rat model were detected by periodic acid-Schiff (PAS) and direct immunofluorescence staining. After extracting T and B cells using immunomagnetic beads, we assessed their purity, cell cycle phase, and apoptosis stage through flow cytometry. Furthermore, we quantified cell cycle-related and apoptosis-associated proteins by Western blotting.

Results

SH reduced IgA and C3 depositions in stage 4 IgAN, thereby decreasing inflammatory cellular infiltration and mesangial injury in an IgAN model induced using heteroproteins. Furthermore, SH arrested the cell cycle of lymphocytes T and B from the spleen of IgAN rats. Regarding the mechanism, our results demonstrated that SH regulated the Cyclin D1 and Cyclin E1 protein levels for arresting the cell cycle and it also regulated Bax and Bcl-2 protein levels, thus increasing Cleaved caspase-3 protein levels in Jurkat T and Ramos B cells.

Conclusion

SH exerts a dual regulation on the cell cycle and apoptosis of T and B cells by controlling cell cycle-related and apoptosis-associated proteins; it also reduces inflammatory cellular infiltration and mesangial proliferation. These are the major mechanisms of SH in IgAN.

Yi-shen-hua-shi granules modulate immune and inflammatory damage via the ALG3/PPARγ/NF-κB pathway in the treatment of immunoglobulin a nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Controversy persists regarding the treatment of immunoglobulin A nephropathy (IgAN), thereby highlighting the demand for safer more effective therapeutic drugs. Although supplementary treatment using Yi-Shen-Hua-Shi (YSHS) granules has distinct advantages with respect to improving renal function in IgAN, a lack of clarity regarding the underlying mechanisms limits their clinical application.

AIM OF THE STUDY

In this study, we aimed to elucidate the therapeutic mechanisms underlying the efficacy of YSHS granules in the treatment of IgAN.

MATERIALS AND METHODS

A rat model of IgAN was established based on lipopolysaccharide, carbon tetrachloride, and bovine serum albumin induction. In order to evaluate the effects of YSHS granules, we performed a range of techniques, including immunofluorescence assays, hematoxylin and eosin staining, and flow cytometry, to assess inflammation, immunity, and other relevant factors. Direct data-independent acquisition-mass spectrometry (DIA-MS) analysis and parallel reaction monitoring (PRM) were used for functional characterization and quantitative validation of differentially expressed proteins (DEPs), and Western blot analysis is used to identify downstream proteins associated with DEPs.

RESULTS

Compared with the model group, the levels of proteinuria, urine red blood cells, serum creatinine, blood urea nitrogen, low-density lipoprotein-cholesterol, triglycerides, and pathological kidney damage were reduced in the YSHS group. A high dose of YSHS granules was found to raise the levels of CD8 T cells and reduce the CD4/CD8 ratio in the peripheral serum. To examine the mechanisms underlying the therapeutic effects YSHS granules, we performed direct DIA-MS analysis to identify proteins that were differentially expressed among the model, YSHS, and control groups. A total of 29 proteins were identified as being commonly expressed in all three groups. Further KEGG and protein-protein interaction (PPI) network analysis revealed that YSHS granules can contribute to the regulation of N-glycosylation-associated proteins, such as ALG3 and STT3A, in rats with IgAN. Detected changes in the expression of ALG3 and STT3A were consistent with the PRM results. We also established that the administration of YSHS granules can contribute to regulation of the ALG3-associated PPAR-γ/NF-κB signaling pathway.

CONCLUSIONS

Our findings in this study provide evidence to indicate the efficacy of YSHS granules in the treatment of IgAN, the putative underlying mechanisms of which involve the modulation of N-glycosylation, mediated via the PPAR-γ/NF-κB pathway.

C5a enhances Vδ1 T cells recruitment via the CCL2-CCR2 axis in IgA nephropathy

BACKGROUND

Mucosal immune-associated γδ T cells have been implicated in IgA nephropathy (IgAN). However, the involvement of Vδ1 T cells, the major γδ T cells subtype, in renal damage and the mechanism underlying their migration from peripheral blood to kidney in IgAN remain unclear.

METHODS

Clinical data from IgAN patients and healthy controls (HC) were analyzed. Phenotypes and chemokine receptors of γδ T cell were compared between IgAN patients and HC. Immunohistochemistry and immunofluorescence were performed to assess the infiltration of γδ T cell subsets and the expression of chemokine in renal tissues. In vitro, C5a was used to stimulate the human glomerular mesangial cells (HMCs) and chemotaxis experiment was used to examine Vδ1 T cells migration. Correlation between Vδ1 T cells and related clinical indicators were analyzed.

RESULTS

IgAN patients exhibited decreased Vδ1 T cell in blood but increased levels in kidneys compared to HC. Increased CCR2-expressing Vδ1 T cells and serum level of CCL2 were observed in IgAN patients. CCL2 co-localized with CCR2 in HMCs of IgAN. In vitro, C5a enhanced Vδ1 T cells recruitment by HMCs through CCL2-CCR2 axis. Importantly, circulating Vδ1 T cell levels showed a negatively correlated with both the urinary protein creatinine ratio (UACR) and 24-hour urine protein (UP). Moreover, kidney infiltration of Vδ1 cells positively correlated with UACR, UP, mesangial hyperplasia and renal tubule atrophy/interstitial fibrosis in IgAN.

CONCLUSIONS

C5a-induced production of CCL2 by HMCs facilitates Vδ1 T cells recruitment via the CCL2-CCR2 axis, contributing to renal damage in IgAN.

T peripheral helper cells in autoimmune diseases: What do we know?

The interactions between T cells and B cells are essential for antibody responses and the development of autoimmune diseases. Recently, a distinct subset of T cells capable of helping B cells was established in synovial fluid, and they were termed peripheral helper T (Tph) cells. PD-1hiCXCR5−CD4+ Tph cells express high levels of CXCL13, which drives the formation of lymphoid aggregates and tertiary lymphoid structures, ultimately facilitating the local production of pathogenic autoantibodies. Tph and T follicular helper cells share some key features but can be distinguished by their surface markers, transcriptional regulation, and migration capability. We summarize recent findings on Tph cells in this review and provide a perspective on their potential roles in a range of autoimmune diseases. More clinical and in-depth mechanistic investigations of Tph cells may help to improve the understanding of pathogenesis and further provide novel therapeutic targets in autoimmune diseases.

Heterogeneity of circulating CXCR5-PD-1hiTph cells in patients of type 2 and type 1 diabetes in Chinese population

AIMS

Circulating peripheral helper T (Tph) cells are shown to promote the progression of autoimmune diseases. However, the role of Tph cells in inflammatory diseases such as type 2 diabetes mellitus (T2DM) and the differences between T2DM and autoimmune diabetes remain unclear.

METHODS

We recruited 92 T2DM patients, 106 type 1 diabetes mellitus (T1DM) patients and 84 healthy control individuals. Peripheral blood mononucleated cells were isolated and examined by multicolor flow cytometry. We further evaluated the correlations between circulating Tph cells and clinical biochemical parameters, islet function, disease progression and islet autoantibodies.

RESULTS

Circulating Tph cells were significantly higher in both T2DM and T1DM patients than in healthy control individuals. A significant positive correlation was observed between Tph cells and B cells in T1DM patients and overweight T2DM patients. Furthermore, Tph cells were negatively correlated with the area under the C-peptide curve (C-PAUC), and Tph cells were significantly positively correlated with fasting glucose and glycated hemoglobin levels in T2DM patients. However, no correlation was found between Tph cells and the above clinical indicators in T1DM patients. The frequency of Tph cells positively correlated with the titer of GAD autoantibodies and duration of disease in T1DM patients. In addition, we demonstrated that the frequency of Tph cells was decreased after rituximab therapy in T1DM patients.

CONCLUSIONS

Circulating Tph cells are associated with blood glucose levels and islet function in T2DM patients. In T1DM patients, circulating Tph cells are associated with B cells and islet autoantibodies. This may suggest that Tph cells have different pathogenic mechanisms in the two types of diabetes.

CLINICAL TRIAL INFORMATION

http://ClinicalTrials.gov NCT01280682 (registered July, 2010).

Peripheral Helper T Cell Responses in Human Diseases

A series of rheumatoid arthritis (RA) studies established a PD-1^hiCXCR5^-CD4⁺ T-cell subset that was coined peripheral helper T (Tph) cells. CXCL13 production is a key feature of Tph cells and may contribute to the formation of tertiary lymphoid structures (TLS) in inflamed tissues. In addition, Tph cells provide help to B cells in situ as efficiently as follicular helper T (Tfh) cells, and these features would implicate Tph cells in the pathogenesis of RA. Subsequent studies have revealed that Tph cells are involved in various human diseases such as autoimmune diseases, infectious diseases, and cancers. Although the analysis of human immunity has various limitations, accumulating evidence demonstrated the expansion of B cells with low somatic hypermutation and a link between TLS and immune functions in these diseases. We discuss about the emerging roles of the Tph cell and its relevant immune responses in peripheral tissues including B-cell expansion with atypical features.

T peripheral helper cells in autoimmune diseases

Pathologic T cell-B cell interactions underlie many autoimmune diseases. The T cells that help B cells in autoimmune diseases vary in phenotype and include T cells that lack typical features of T follicular helper cells, such as expression of CXCR5 and BCL6. A population of PD-1hi CXCR5- T peripheral helper (Tph) cells has now been recognized in multiple autoantibody-associated diseases. Tph cells display a distinctive set of features, merging the ability to provide B cell help with the capacity to migrate to inflamed peripheral tissues. Here, we review the scope of immune-related conditions in which Tph cells have been implicated and provide a perspective on their potential contributions to pathologic B cell activation in autoimmune diseases. We discuss Tph cells as a promising therapeutic strategy in autoimmunity and consider the utility of tracking Tph cells in blood as a biomarker to quantify aberrant T cell-B cell activation in patients with autoimmune diseases.

ICOS Gene Polymorphisms (IVS1 + 173 T/C and c. 1624 C/T) in Primary Sjögren's Syndrome Patients: Analysis of ICOS Expression

Background: Primary Sjögren’s syndrome (pSS) is a systemic autoimmune disease, which affects exocrine glands. T cell activation is a trigger mechanism in the immune response. Hyperreactivity of T cells and antibody production are features in pSS. ICOS can be critical in the pathogenesis of pSS. Methods: A total of 134 pSS patients and 134 control subjects (CS) were included. Genotyping was performed by PCR-RFLP. ICOS mRNA expression was quantified by real-time PCR, and CD4+ ICOS+ T cells were determined by flow cytometry. Results: The ICOS IVS1 + 173 T>C polymorphisms were not associated with susceptibility to pSS (p = 0.393, CI = 0.503−1.311). However, the c.1624 C>T polymorphism was associated with a reduction in the risk of development of pSS (p = 0.015, CI = 0.294−0.884). An increase in ICOS mRNA expression in patients was observed (3.7-fold). Furthermore, pSS patients showed an increase in membranal-ICOS expression (mICOS). High expression of mICOS (MFI) was associated with lymphocytic infiltration. Conclusions: The IVS1 + 173 polymorphism is not a genetic marker for the development of pSS, while c.1624 T allele was associated with a low risk. However, elevated mICOS expression in pSS patients with high lymphocytic infiltration was found. ICOS may have an important role in the immunopathogenesis of pSS and should be analyzed in T cell subsets in pSS patients as a possible disease marker.

Increased Circulating PD-1 hi CXCR5 - Peripheral T Helper Cells are Associated with Disease Activity of ANCA-Associated Vasculitis

Newly identified PD-1 hiCXCR5 -CD4 + T cells, termed as peripheral helper T cells (Tph), have been found elevated and playing pathogenic role in some autoimmune diseases like systemic lupus erythematosus (SLE) and rheumatic arthritis (RA). However, the potential role of Tph cells in Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) remains unclear. Here, we explored the potential clinical significance of circulating Tph cells in the pathogenesis of AAV. Comparing 32 active AAV patients and 18 age- and sex-matched healthy controls (HCs), we found that the frequency of circulating Tph cells was significantly expanded in active AAV patients. Besides, programmed death 1 (PD-1) expression on the surface of Tph cells was significantly up-regulated in active AAV patients. Importantly, the frequency of circulating Tph cells was greatly decreased in AAV patients after receiving treatment. Tph cells frequency was positively correlated with the Birmingham Vasculitis Activity Score (BVAS), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), neutrophil lymphocyte ratio (NLR) and cellular crescent in active AAV patients, but negatively correlated with fibrosus crescent. Tph cells frequency was also positively correlated with naïve B cells, serum concentration of MPO-ANCAs, serum tumor necrosis factor-α (TNF-α), IL-4, IL-21 and IL-12. However, serum IL-10 exhibited negative correlation with circulating Tph cells in active AAV patients. These results demonstrated that circulating Tph cells are greatly expanded in active AAV patients and are positively associated with serum MPO-ANCAs and disease activity, thus contributing to the pathogenesis of AAV.

Increased Tim-3+ monocytes/macrophages are associated with disease severity in patients with IgA nephropathy

T-cell immunoglobulin and mucin-domain-containing protein-3 (Tim-3) plays multiple important roles in immune response and participates in the pathogenesis of various inflammatory diseases by regulating macrophage polarization. However, its functions in the development of IgA nephropathy (IgAN) are still unclear. In this study, changes in the relative levels of Tim-3⁺ monocytes/macrophages in peripheral blood and renal tissue, and their clinical significance in patients with IgAN were investigated. The expression of CD68 and Tim-3 in macrophages from patients with IgAN was determined via immunohistochemistry and immunofluorescence staining assays. Peripheral blood of 48 patients with biopsy-proven IgAN and 18 healthy controls (HCs) was collected to determine the frequency of circulating CD14⁺Tim-3⁺ cells using flow cytometry, before and after 24 weeks of prednisolone treatment. Serum interleukin (IL)-10 and tumor necrosis factor α (TNF-α) levels were measured using enzyme-linked immunosorbent assays. The potential association between clinical signs and Tim-3⁺ monocytes/macrophages was analyzed. The percentages of circulating CD14⁺Tim-3⁺ monocytes were higher in samples from patients with IgAN than in those from HCs and were positively associated with the pathological features (segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis) of IgAN, according to the Oxford classification. Tissue staining assays revealed cells positive for both CD68 and Tim-3 in tubulointerstitial lesions of IgAN patients. In addition, elevated levels of serum IL-10 and TNF-α were detected in these patients in comparison to HCs. Furthermore, the frequency of circulating CD14⁺Tim-3⁺ monocytes had a positive correlation with levels of 24-h urinary protein and serum IL-10, and was negatively associated with renal function. After 24 weeks of treatment with prednisolone, the percentages of CD14⁺Tim-3⁺ cells were significantly reduced. In summary, our findings indicate that Tim-3⁺ monocytes/macrophages might be involved in the pathogenesisof IgAN and could be used as a potential indicator to evaluate disease severity.

Increased circulating PD-1hiCXCR5- peripheral helper T cells are associated with disease severity of active ulcerative colitis patients

PURPOSE

A recently identified population of T cells, phenotypically CD4⁺PD-1^hiCXCR5^-, has been firstly termed as peripheral helper T cells (Tph) and found to be pathogenic in autoimmune diseases. However, the potential role of Tph in ulcerative colitis (UC) remains unclear. We aim to investigate the changes of circulating Tph in UC patients and their potential significance in the pathogenesis of UC.

METHODS

Totally 68 UC patients and 34 age- and sex-matched healthy controls were enrolled. Circulating Tph and B cell subsets were analyzed by flow cytometry. Expressions of inducible T-cell co-stimulator (ICOS) on Tph cells were analyzed. Serum IL-4, IL-10, IL-12 and IL-21 were detected using ELISA. Correlation analyses were conducted between Tph cells and disease severity, functional B cell subsets and serum cytokines.

RESULTS

Both the frequency and absolute number of Tph were significantly increased in active UC patients and ICOS levels in Tph cells were also elevated, compared with remission UC patients and healthy controls. Tph and ICOS expression were significantly positively correlated with Mayo score and serum CRP in active UC patients, and were significantly decreased when achieving remission after treatment. Tph levels were correlated with new memory B cells, plasmablasts, serum IL-4 and IL-21. Meanwhile, serum IL-10 showed negative correlation while IL-12 exhibited positive correlation with circulating Tph cells in UC patients.

CONCLUSIONS

Circulating Tph cells are elevated in active UC patients and are associated with the disease activity, which may contribute to the pathogenesis of UC.

Bronchoalveolar Lavage Fluid Reflects a TH1-CD21low B-Cell Interaction in CVID-Related Interstitial Lung Disease

Background

About 20% of patients with common variable immunodeficiency (CVID) suffer from interstitial lung disease (ILD) as part of a systemic immune dysregulation. Current understanding suggests a role of B cells in the pathogenesis based on histology and increased levels of BAFF and IgM associated with active disease corroborated by several reports which demonstrate the successful use of rituximab in CVID-ILD. It is debated whether histological confirmation by biopsy or even video-assisted thoracoscopy is required and currently not investigated whether less invasive methods like a bronchoalveolar lavage (BAL) might provide an informative diagnostic tool.

Objective

To gain insight into potential immune mechanisms underlying granulomatous and lymphocytic interstitial lung disease (GLILD) and to define biomarkers for progressive ILD by characterizing the phenotype of B- and T-cell populations and cytokine profiles in BAL fluid (BALF) of CVID-ILD compared to sarcoidosis patients and healthy donors (HD).

Methods

Sixty-four CVID, six sarcoidosis, and 25 HD BALF samples were analyzed by flow cytometric profiling of B- and T-cells and for cytokines by ELISA and Multiplexing LASER Bead technology.

Results

Both sarcoidosis and CVID-ILD are characterized by a predominantly T-cell mediated lymphocytosis in the BALF. There is an increase in T follicular helper (TFH)-like memory and decrease of regulatory T cells in CVID-ILD BALF. This TFH-like cell subset is clearly skewed toward TH1 cells in CVID-ILD. In contrast to sarcoidosis, CVID-ILD BALF contains a higher percentage of B cells comprising mostly CD21low B cells, but less class-switched memory B cells. BALF analysis showed increased levels of APRIL, CXCL10, and IL-17.

Conclusion

Unlike in sarcoidosis, B cells are expanded in BALF of CVID-ILD patients. This is associated with an expansion of TFH- and TPH-like cells and an increase in APRIL potentially supporting B-cell survival and differentiation and proinflammatory cytokines reflecting not only the previously described TH1 profile seen in CVID patients with secondary immune dysregulation. Thus, the analysis of BALF might be of diagnostic value not only in the diagnosis of CVID-ILD, but also in the evaluation of the activity of the disease and in determining potential treatment targets confirming the prominent role of B-cell targeted strategies.

Shared and distinct roles of T peripheral helper and T follicular helper cells in human diseases

The interactions of CD4⁺ T cells and B cells are fundamental for the generation of protective antibody responses, as well as for the development of harmful autoimmune diseases. Recent studies of human tissues and blood samples have established a new subset of CD4⁺ B helper T cells named peripheral helper T (Tph) cells. Unlike T follicular helper (Tfh) cells, which interact with B cells within lymphoid organs, Tph cells provide help to B cells within inflamed tissues. Tph cells share many B helper-associated functions with Tfh cells and induce B cell differentiation toward antibody-producing cells. The differentiation mechanism is also partly shared between Tph and Tfh cells in humans, and both Tfh and Tph cells can be found within the same tissues, including cancer tissues. However, Tph cells display features distinct from those of Tfh cells, such as the expression of chemokine receptors associated with Tph cell localization within inflamed tissues and a low Bcl-6/Blimp1 ratio. Unlike that of Tfh cells, current evidence shows that the target of Tph cells is limited to memory B cells. In this review, we first summarize recent findings on human Tph cells and discuss how Tph and Tfh cells play shared and distinct roles in human diseases.

T lymphocytes in IgA nephropathy

Immunoglobulin A nephropathy (IgAN), the most common primary glomerulonephritis worldwide, is the main cause of end-stage renal disease. IgAN is characterized by the accumulation of immune complexes in the circulation, which contain abnormal levels of IgA. IgAN primarily results from galactose-deficient IgA1 (Gd-IgA1) and Gd-IgA1 deposition in the renal mesangium, causing local proliferation and matrix expansion. Gd-IgA1 has been confirmed as one of the key effectors in the pathogenesis of IgAN, but the origin of Gd-IgA1 is not clear. Recent studies have shown that Gd-IgA1 deposition could be the result of mucosally primed plasma cells and is associated with T cell dysregulation. T cells contribute to the IgA response and play an important role in the development of IgAN. In the present review, the latest discoveries regarding the role of T lymphocytes in the pathogenesis of IgAN have been summarized. Understanding these advances will allow novel therapeutic strategies for the treatment of IgAN.