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

Emergence of a senescent and inflammatory pulmonary CD4+ T cell population prior to lung allograft failure

Survival after lung transplantation is limited by chronic lung allograft dysfunction (CLAD), an alloimmune fibrotic process leading to death or retransplantation after a median of 6 years. Immunosuppression fails to prevent CLAD, suggesting the existence of drug-resistant alloimmune pathways. We used time-of-flight mass cytometry to identify cells enriched in the bronchoalveolar lavage of patients with subsequent acute lung allograft dysfunction (ALAD), a risk factor for CLAD. We show that CD4+CD57+PD1+ T cells emerge in stable patients, conferring risks for ALAD, CLAD, and death. These cells are senescent, secrete inflammatory cytokines, and fall into two oligoclonal subsets with putative cytotoxic and follicular helper functions. Last, they are associated with fibrosis in mouse and human lung allografts, where they localize near airway epithelium and B cells. Together, our findings reveal an inflammatory T cell population that predicts future lung allograft dysfunction and may represent a rational therapeutic target.

Increased sputum peripheral helper T cells are associated with the severity of rheumatoid arthritis but not with the severity of airway disease

Objective

Peripheral helper T (Tph) cells, together with plasma cells, are the major pathogenic lymphocytes in the synovium in rheumatoid arthritis (RA). However, whether these cells are involved in RA-associated lung and/or airway disease is unknown.

Methods

Tph cells in sputum were analyzed by flow cytometry and compared with those in synovial fluid and synovial tissue. Forty RA subjects for whom induced sputum could be collected were analyzed along with sputum Tph cells and several clinical parameters; RA severity was assessed using the Disease Activity Score for 28 joints (DAS28). Lung and airway disease was assessed by chest computed tomography (CT), pulmonary function test, the chronic obstructive pulmonary disease (COPD) Assessment Test (CAT), and sputum culture. Tph cells in the lung of RA subjects were analyzed using lung resection samples in a separate cohort.

Results

Tph cells were observed in the sputum, as well as the lung, synovial fluid, and synovial tissue of RA patients. Sputum Tph cells were increased in patients with airway disease. Among these patients, Tph cells were more frequent in those with high DAS28, high serum immunoglobulin G (IgG), and high sputum IgG. However, there was no association between Tph cells and the severity of airway disease as assessed by chest CT findings, lung function, CAT, and sputum culture.

Conclusions

Tph cells were increased in the airways as well as in the synovium in patients with RA. Airway Tph cells were associated with severity of RA but not with the severity of airway disease. Airway Tph cells may represent a novel target for disease management and treatment.

Global trends in tertiary lymphoid structures: a bibliometric analysis from 2014 to 2023

AIM AND BACKGROUND

Tertiary lymphoid structures (TLS) are increasingly recognized for their role in immunity. Despite growing interest, a systematic bibliometric analysis of TLS-related research has been lacking. To provide a comprehensive overview of current research trends and hotspots, we conducted a bibliometric analysis using data from the Web of Science Core Collection.

METHODS

We retrieved TLS-related publications from the Science Citation Index Expanded within the Web of Science Core Collection from January 2014 to December 2023. Co-occurrence analysis with "VOSviewer" identified current status and research hotspots, while "CiteSpace" was used for co-citation analysis to assess knowledge evolution and bursts. Thematic evolution was explored using bibliometrics to identify emerging keyword trends. Additionally, we examined country/region, institutional, and author contributions and collaborations. Tables were created using Microsoft Word.

RESULTS

A total of 785 publications were analyzed, showing a continuous growth trend from 2017 to 2023, indicating escalating interest in TLS among researchers. Leading countries in TLS research were China (231 publications), the United States (212 publications), and France (89 publications). The most productive institution and author were the "Institut national de la santé et de la recherche médicale" (70 publications) and Catherine Sautes-Fridman (21 publications), respectively. Key topics included TLS, B cells, and immunotherapy. Recent research has focused on mechanisms linking TLS with cancers, such as immunotherapy, tumor microenvironment, tumor-infiltrating lymphocytes, prognosis, and immune checkpoint inhibitors, highlighting an expanding area of study. Additionally, TLS' potential as a biomarker for predicting immunotherapy efficacy across different cancer types remains a burgeoning research direction.

CONCLUSIONS

This study provides a comprehensive analysis of global TLS-related publications, revealing key literature metrics and identifying influential articles and emerging research concerns. These findings contribute valuable insights into the role of TLS in immunotherapy and suggest future directions for this dynamic field.

A detailed quantitative analysis of circulating T peripheral and follicular helper lymphocytes in patients with rheumatoid arthritis and systemic lupus erythematosus

INTRODUCTION AND OBJECTIVE

Peripheral and follicular helper T lymphocytes (Tph and Tfh, respectively) have an important role in B cell immune responses and the pathogenesis of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Although several studies on the number of Tph and Tfh cells in these conditions have been published, different phenotypes have been employed for their analysis. In this study, we assessed the levels and function of Tph and Tfh cells in blood samples from patients with RA and SLE by using an extended immunophenotype.

MATERIALS AND METHODS

In a cross-sectional pilot study, blood samples from twenty-seven patients with RA and fifteen with SLE, and twenty-six healthy controls were studied. The levels of Tph (CD4+PD-1+CXCR5-CD38+CD69+ICOS+) and Tfh (CD4+PD-1+CXCR5+CD38+CD69+ICOS+) cells were analyzed by flow cytometry. In addition, the function of Tph/Tfh cells was estimated by measuring the synthesis of IL-21 by these lymphocytes as well as the number of circulating plasmablasts (CD19+CD27+CD20-CD38hi).

RESULTS

Increased percentages of Tph and Tfh lymphocytes were detected in patients with RA and SLE. Furthermore, the synthesis of IL-21 tended to be higher in both conditions, and higher levels of plasmablasts were detected in these patients, compared to controls. In patients with SLE, the number of Tph cells was associated with disease activity and with the levels of circulating plasmablasts, whereas in patients with RA a significant correlation between Tph cells and evolution time was observed.

DISCUSSION AND CONCLUSIONS

Our data of Tph and Tfh lymphocytes, based in the analysis of an extended phenotype of these cells, provides further evidence on their involvement in the pathogenesis of RA and SLE.

T cell immuno-phenotyping : a source of predictive biomarkers for autoimmune hepatitis relapse

Relapse after immunosuppression (IS) treatment withdrawal is frequent in patients with Autoimmune Hepatitis (AIH), and non-invasive biomarkers predictive of this risk are lacking. We assessed the frequency of circulating T cell subsets as potential biomarkers of disease activity and predictor of the risk of relapse after IS withdrawal. Serum levels of the cytokine B-cell Activating Factor (BAFF) were also investigated. Blood samples from 58 patients with active AIH, 56 AIH patients in remission, and 31 patients with NASH were analyzed. The frequency of activated CD4+ T peripheral helper (TPH) cells (CD4+CD45RA-CXCR5-PD1+CD38+) and of activated CD8+ T cells (CD8+CD45RA-PD1+CD38+) were assessed by flow cytometry. BAFF levels were determined by ELISA. Activated TPH and CD8+ T cell frequencies were significantly increased in patients with active AIH compared to remission AIH or NASH (TPH: 0.88% of total CD3+ vs. 0.42% and 0.39% respectively, p < 0.0001; CD8+ subset: 1.42% vs. 0.09% and 0.11% p < 0.0001). Among patients in remission undergoing treatment withdrawal (n = 18), those with increased frequencies of activated TPH (> 0.5% of total CD3+) and/or activated CD8+ T cells (> 0.18% total CD3+) had a higher risk of relapse (80% vs. 15% after 2 years, p = 0.0071). High BAFF serum concentration (> 213pg/ml) was also associated to a higher risk of relapse (57% vs. 11%, p = 0.0452). In conclusion, high frequency of activated TPH and of activated CD8+, as well as high levels of BAFF, before IS discontinuation, were significantly associated to a greater risk of relapse during the first two years. Thus, they represent promising biomarkers to provide personalized clinical follow-up for patients with AIH.

Cutting Edge: Low-dose Recombinant IL-2 Treatment Prevents Autoantibody Responses in Systemic Lupus Erythematosus via Regulatory T Cell-independent Depletion of T Follicular Helper Cells

The expansion of T follicular helper (Tfh) cells correlates with disease progression in human and murine systemic lupus erythematosus (SLE). Unfortunately, there are no therapies to deplete Tfh cells. Importantly, low-dose rIL-2-based immunotherapy shows potent immunosuppressive effects in SLE patients and lupus-prone mice, primarily attributed to the expansion of regulatory T cells (Tregs). However, IL-2 can also inhibit Tfh cell differentiation. In this study, we investigate the potential of low-dose rIL-2 to deplete Tfh cells and prevent autoantibody responses in SLE. Our data demonstrate that low-dose rIL-2 efficiently depletes autoreactive Tfh cells and prevents autoantibody responses in lupus-prone mice. Importantly, this immunosuppressive effect was independent of the presence of Tregs. The therapeutic potential of eliminating Tfh cells was confirmed by selectively deleting Tfh cells in lupus-prone mice. Our findings demonstrate the critical role of Tfh cells in promoting autoantibody responses and unveil, (to our knowledge), a novel Treg-independent immunosuppressive function of IL-2 in SLE.

Occurrence and role of Tph cells in various renal diseases

A new population of peripheral helper T (Tph) cells has been identified and contributed to various autoimmune diseases. Tph cells can secrete interleukin-21 (IL-21), interferon (IFN) and C-X-C motif chemokine ligand 13 (CXCL13) to moderate renal disease. Moreover, Tph cells can congregate in huge numbers and immerse within inflamed tissue. Compared to Tfh cells, Tph cells express high programmed cell death protein 1 (PD-1), major histocompatibility complex II (MHC-II), C-C chemokine receptor 2 (CCR2) and C-C chemokine receptor 5 (CCR5) but often lack expression of the chemokine receptor C-X-C chemokine receptor 5 (CXCR5). They display features distinct from other T cells, which are uniquely poised to promote responses and antibody production of B cells within pathologically inflamed non-lymphoid tissues and a key feature of Tph cells. In this review, we summarize recent findings on the role of Tph cells in chronic kidney disease, acute kidney injury, kidney transplantation and various renal diseases.

Prognostic and therapeutic monitoring value of plasma and urinary cytokine profile in primary membranous nephropathy: the STARMEN trial cohort

Background

Primary membranous nephropathy (PMN) is usually caused by anti-phospholipase A2 receptor (PLA2R) autoantibodies. There are different therapeutic options according to baseline risk. Novel biomarkers are needed to optimize risk stratification and predict and monitor the response to therapy, as proteinuria responses may be delayed. We hypothesized that plasma or urinary cytokines may provide insights into the course and response to therapy in PMN.

Methods

Overall, 192 data points from 34 participants in the STARMEN trial (NCT01955187), randomized to tacrolimus-rituximab (TAC-RTX) or corticosteroids-cyclophosphamide (GC-CYC), were analysed for plasma and urine cytokines using a highly sensitive chemiluminescence immunoassay providing a high-throughput multiplex analysis.

Results

Baseline (pretreatment) urinary C-X-C motif chemokine ligand 13 (CXCL13) predicted the therapeutic response to TAC-RTX. Cytokine levels evolved over the course of therapy. The levels of nine plasma and six urinary cytokines correlated with analytical parameters of kidney damage and disease activity, such as proteinuria, estimated glomerular filtration rate and circulating anti-PLA2R levels. The correlation with these parameters was most consistent for plasma and urinary growth differentiation factor 15 (GDF15), plasma tumour necrosis factor α and urinary TNF-like weak inducer of apoptosis. Decreasing plasma GDF15 levels were associated with response to GC-CYC. Four clusters of cytokines were associated with different stages of response to therapy in the full cohort, with the less inflammatory cluster associated with remission.

Conclusion

PMN displayed characteristic plasma and urine cytokine patterns that evolved over time as patients responded to therapy. Baseline urinary CXCL13 concentration could be a prognostic marker of response to TAC-RTX.

Exploring the Role of PD-1 in the Autoimmune Response: Insights into Its Implication in Systemic Lupus Erythematosus

Despite advances in understanding systemic lupus erythematosus (SLE), many challenges remain in unraveling the precise mechanisms behind the disease's development and progression. Recent evidence has questioned the role of programmed cell death protein 1 (PD-1) in suppressing autoreactive CD4+ T cells during autoimmune responses. Research has investigated the potential impacts of PD-1 on various CD4+ T-cell subpopulations, including T follicular helper (Tfh) cells, circulating Tfh (cTfh) cells, and T peripheral helper (Tph) cells, all of which exhibit substantial PD-1 expression and are closely related to several autoimmune disorders, including SLE. This review highlights the complex role of PD-1 in autoimmunity and emphasizes the imperative for further research to elucidate its functions during autoreactive T-cell responses. Additionally, we address the potential of PD-1 and its ligands as possible therapeutic targets in SLE.

Sequential immunotherapy: towards cures for autoimmunity

Despite major progress in the treatment of autoimmune diseases in the past two decades, most therapies do not cure disease and can be associated with increased risk of infection through broad suppression of the immune system. However, advances in understanding the causes of autoimmune disease and clinical data from novel therapeutic modalities such as chimeric antigen receptor T cell therapies provide evidence that it may be possible to re-establish immune homeostasis and, potentially, prolong remission or even cure autoimmune diseases. Here, we propose a 'sequential immunotherapy' framework for immune system modulation to help achieve this ambitious goal. This framework encompasses three steps: controlling inflammation; resetting the immune system through elimination of pathogenic immune memory cells; and promoting and maintaining immune homeostasis via immune regulatory agents and tissue repair. We discuss existing drugs and those in development for each of the three steps. We also highlight the importance of causal human biology in identifying and prioritizing novel immunotherapeutic strategies as well as informing their application in specific patient subsets, enabling precision medicine approaches that have the potential to transform clinical care.

[Regulatory effect of lactate on peripheral blood CD4+ T cell subsets in patients with rheumatoid arthritis]

OBJECTIVE

To investigate the serum lactate level in patients with rheumatoid arthritis (RA) and its relationship with disease activity, and to analyze the effect of sodium lactate on the activation of CD4+ T cells, the ability of secreting cytokines and CD4+T cell subsets in peripheral blood of the RA patients.

METHODS

The peripheral blood of healthy controls (HC) and RA patients was collected, and the content of lactate in the supernatant was detected by lactate detection kit, the correlation between the content of lactate and the disease score of the RA patients was analyzed; the activation level of CD4+ T cells, the proportion of CD4+ T cell subsets and the cytokines secreted by CD4+ T cells in peripheral blood of all the RA patients were detected by flow cytometry after being stimulated with sodium lactate.

RESULTS

The serum lactate level in the RA patients (n=66) was significantly higher than that in the HC (n=60, P < 0.001), and there was a certain correlation with disease activity score in 28 joints (DAS28)-C-reactive protein (CRP) (r=0.273, P=0.029), The levels of rheumatoid factor [RF, 197.50 (26.03, 783.00) IU/mL vs. 29.30 (0.00, 102.60) IU/mL, P < 0.01], CRP [37.40 (11.30, 72.60) mg/L vs. 5.83 (2.36, 12.45) mg/L, P < 0.001], were increased in patients with the lactate concentration greater than 5 mmol/L were significantly higher than those in patients with the lactate concentration less than or equal 5 mmol/L, however, there was no significant difference in the expression of erythrocyte sedimentation rate [ESR, 42.00 (19.00, 77.00) mm/h vs. 25.00 (12.50, 45.50) mm/h, P>0.05] and anti-cyclic citrullinated peptied (CCP) antibody [82.35 (17.70, 137.00) RU/mL vs. 68.60 (25.95, 119.70) RU/mL, P>0.05]. Compared with the control group, the expression of PD-1 (46.15%±8.54% vs. 41.67%±9.98%, P < 0.001), inducible costimulatory molecule (ICOS, 5.77%±8.60% vs. 18.65%±7.94%, P < 0.01) and CD25 (25.89%±5.80% vs. 22.25%±4.59%, P < 0.01) on the surface of CD4+ T cells in the RA patients treated with sodium lactate was significantly increased. Compared with the control group, the proportion of Th17 (4.62%±1.74% vs. 2.93%±1.92%, P < 0.05) and Tph (28.02%±6.28% vs. 20.32%±5.82%, P < 0.01) cells in CD4+T cells of the RA patients in the sodium lactate treatment group increased. Compared with the control group, the expression of IL-21 (5.73%±1.59% vs. 4.75%±1.71%, P < 0.05) in CD4+T cells was up-regulated in the RA patients treated with sodium lactate.

CONCLUSION

The level of serum lactate in RA patients is increased, which promotes the activation of CD4+T cells and the secretion of IL-21, and up-regulates the proportion of Th17 and Tph cells in the RA patients.

Dynamic immune status analysis of peripheral blood mononuclear cells in patients with Klebsiella pneumoniae bloodstream infection sepsis using single-cell RNA sequencing

Background

Klebsiella pneumoniae is a common Gram-negative bacterium. Blood infection caused by K. pneumoniae is one of the most common causes of human sepsis, which seriously threatens the life of patients. The immune status of peripheral blood mononuclear cells (PBMCs) based on single-cell RNA sequencing (scRNA-seq) in acute stage and recovery stage of sepsis caused by K. pneumoniae bloodstream infection has not been studied.

Methods

A total of 13 subjects were included in this study, 3 healthy controls, 7 patients with K. pneumoniae bloodstream infection in the acute stage (4 patients died), and 3 patients in the recovery stage. Peripheral blood of all patients was collected and PBMCs were isolated for scRNA-seq analysis. We studied the changes of PBMCs components, signaling pathways, differential genes, and cytokines in acute and recovery stages.

Results

During K. pneumoniae acute infection we observed a decrease in the proportion of T cells, most probably due to apoptosis and the function of T cell subtypes was disorder. The proportion of monocytes increased in acute stage. Although genes related to their phagocytosis function were upregulated, their antigen presentation capacity-associated genes were downregulated. The expression of IL-1β, IL-18, IFNGR1 and IFNGR2 genes was also increased in monocytes. The proportion of DCs was depleted during the acute stage and did not recover during sepsis recovery. DCs antigen presentation was weakened during the acute stage but recovered fast during the recovery stage. pDCs response to MCP-1 chemokine was weakened, they recovered it quickly during the recovery stage. B cells showed apoptosis both in the acute stage and recovery stage. Their response to complement was weakened, but their antigen presentation function was enhanced. The proportion of NK cells stable during all disease's stages, and the expression of IFN-γ gene was upregulated.

Conclusion

The proportion of PBMCs and their immune functions undergo variations throughout the course of the disease, spanning from the acute stage to recovery. These findings provide new insights into the mechanism of PBMCs immune function during K. pneumoniae bloodstream infection sepsis and recovery and sets the basis for further understanding and treatment.

CD4+ T-cell subsets in autoimmune hepatitis: A review

Autoimmune hepatitis (AIH) is a chronic autoimmune liver disease that can lead to hepatocyte destruction, inflammation, liver fibrosis, cirrhosis, and liver failure. The diagnosis of AIH requires the identification of lymphoblast cell interface hepatitis and serum biochemical abnormalities, as well as the exclusion of related diseases. According to different specific autoantibodies, AIH can be divided into AIH-1 and AIH-2. The first-line treatment for AIH is a corticosteroid and azathioprine regimen, and patients with liver failure require liver transplantation. However, the long-term use of corticosteroids has obvious side effects, and patients are prone to relapse after drug withdrawal. Autoimmune diseases are characterized by an imbalance in immune tolerance of self-antigens, activation of autoreactive T cells, overactivity of B cells, and increased production of autoantibodies. CD4+ T cells are key players in adaptive immunity and can secrete cytokines, activate B cells to produce antibodies, and influence the cytotoxicity of CD8+ T cells. According to their characteristics, CD4+ T cells can be divided into different subsets. In this review, we discuss the changes in T helper (Th)1, Th2, Th17, Th9, Th22, regulatory T cell, T follicular helper, and T peripheral helper cells and their related factors in AIH and discuss the therapeutic potential of targeting CD4+ T-cell subsets in AIH.