Tfh Subsets Research Articles

TCR-CD3 signal strength regulates plastic coexpression of IL-4 and IFN-γ in Tfh-like cells.

The development of T follicular helper (Tfh) cells is an ongoing process resulting in the formation of various Tfh subsets. Despite advancements, the precise impact of T cell receptor (TCR) stimulation on this process remains incompletely understood. This study explores how TCR-CD3 signaling strength influences naive CD4+ T cell differentiation into Tfh-like cells and the concurrent expression of interleukin-21 (IL-21), interleukin-4 (IL-4), and interferon-gamma (IFN-γ). Strong TCR-CD3 stimulation induces proliferation and increased IL-21 expression in Tfh-like cells, which exhibit a characteristic phenotype expressing CXCR5 and PD1. The coexpression of IL-4 and IFN-γ in IL-21-producing Tfh-like cells is controlled by the strength TCR-CD3 stimulation; low stimulation favors IL-4, while strong stimulation enhances IFN-γ secretion. Exogenous addition of the effector cytokines IL-21 and IL-4 further modulate cytokine coexpression. These findings highlight the intricate regulatory mechanisms governing cytokine production and plasticity in Tfh-like cells, providing insights into B cell response modulation. In vivo, antigen availability may regulate Tfh cell plasticity, impacting subsequent B cell differentiation, emphasizing the need for further exploration through animal models or antigen-specific Tfh cell analyses in human lymph node biopsies.

Differential T follicular helper cell phenotypes distinguish IgE-mediated milk allergy from eosinophilic esophagitis in children

IgE-mediated food allergy and eosinophilic esophagitis (EoE) are diseases commonly triggered by milk. Milk-responsive CD4+ T cells producing type 2 cytokines are present in both diseases, yet the clinical manifestation of disease in milk allergy (MA) and EoE are distinct. To identify CD4+ T cell differences between EoE and MA that may be responsible for distinct disease manifestations. The total and milk-specific CD4+ T cell phenotype of children with milk allergy (MA), EoE (active or in remission) and controls was measured using spectral flow cytometry of peripheral blood (all groups) or esophageal biopsies (EoE and control). Circulating milk-responsive T cells could be identified in active (A)-EoE and MA. An increased frequency of Th2A cells was also noted in MA and EoE. In circulating T cells, type 2 cytokine production was elevated in MA, but not EoE. Within the milk-responsive Tfh subset, a dichotomy of phenotype was noted: Tfh13 cells predominated in MA, while IL-10-producing Tfh cells predominated in EoE. In the esophagus, CD4+ T cells were constitutively activated and expressed not only type 2 cytokines, but also IL-10 and IL-21 in A-EoE. There was production of IgG4 from CD38+ plasma cells in close proximity to CD4+ T cells. In vitro activation studies demonstrated that IL-10 and IL-21 elicited strong IgG4 responses in B lymphocytes, while IL-4 and IL-13 promoted IgE production. Our studies demonstrate a dichotomy of Tfh responses that may be the basis for the different clinical manifestations to milk in EoE and MA.

Longitudinal analysis at pre- and post-flare of T peripheral helper and T follicular helper subsets in patients with systemic lupus erythematosus

ObjectiveWe focused to analyze the time-course changes at pre- and post-flare of T peripheral helper (Tph) cells and circulating T follicular helper (Tfh) cells in the blood of patients with systemic lupus erythematosus (SLE) with lupus low disease activity state (LLDAS) before flare. MethodsThis study included inactive (n = 29) and active (n = 55) patients with SLE. Tph subsets, Tfh subsets, CD11chi B cells, and plasma cells in the blood were determined by flow cytometry. The blood levels of cytokines including interferons (IFNs) were measured by electrochemiluminescence assay or cytokine beads array. ResultsActive SLE patients exhibited the increased frequency of Tph1, Tph2, Tfh1, and Tfh2 subsets when compared to inactive patients, but no clear changes in the other subsets. During the treatment with medications, Tph1, Tph2, and Tfh2 subsets were significantly reduced along with disease activity and Tph1 and Tph2 subsets were positively correlated with SLE disease activity index (SLEDAI). The time course analysis of patients at pre- and post-flare revealed that in the patients at LLDAS before flare, Tph subsets and Tfh subsets were relatively low levels. At the flare, Tph cells, particularly Tph1 and Tph2 subsets, were increased and correlated with SLEDAI. Furthermore, the blood levels of IFN-α2a, IFN-γ, and IFN-λ1 were low in the patients with LLDAS before flare but these IFNs, particularly IFN-λ1, were increased along with flare. ConclusionIncreased frequency of Tph1 and Tph2 subsets and elevated levels of serum IFN-λ1 are presumably critical for triggering of flare in SLE.

CCR4+Tfh2 cells specifically produce IL-4 driving the pathological reaction in IgG4-related disease.

Human T follicular helper (Tfh) cells are classified into three subsets: Tfh1, Tfh2, and Tfh17 cells. Among them,Tfh2 cells are defined as CXCR3-negative and CCR6-negative, and may contain diverse cell populations. We examined whether CCR4 serves as a marker for identifying Tfh2 cells that produce interleukin (IL)-4 and its involvement in IgG4-related disease (IgG4-RD). Single cell analysis of IL-4-producing Tfh subset was performed using multi-colour flow cytometry and t-SNE method. Blood samples were obtained from 23 treatment-naïve patients with active IgG4-RD. CCR4+Tfh2 cells were also assessed in affected tissues of IgG4-RD by flow cytometry and immunohistochemical staining. Tfh2 cells expressing CCR4 were identified as Tfh cells that specifically produce IL-4. CCR4+Tfh2 cells showed higher expression of GATA-3 and ICOS than CCR4-Tfh2 cells, while there was no difference in the expression of BCL-6 and FOXP3. The proportion of CCR4+Tfh2 cells in peripheral blood was increased in IgG4-RD compared to healthy controls, and even more CCR4+Tfh2 cells infiltrated into the affected lesions. CCR4+GATA-3+Tfh2 cells diffusely infiltrated tertiary lymphoid tissues and storiform fibrosis lesions. The proportion of CCR4+Tfh2 cells showed a significant correlation specifically with serum IgG4 levels among clinical indicators. Glucocorticoid therapy did not correct the increased proportion of CCR4+Tfh2 cells. CCR4 serves as a marker for identifying Tfh2 cells that specifically produce IL-4. CCR4+Tfh2 cells are a widely present T cell population that infiltrates tertiary lymphoid tissues and storiform fibrosis of IgG4-RD. Glucocorticoid fails to effectively target CCR4+Tfh2 cells that may contribute to a high relapse rate during glucocorticoid tapering in this disease.

#1843 Deletion of IL17-producing follicular helper T cells restrains the germinal center reaction in systemic lupus erythematosus

Abstract Background and Aims Systemic lupus erythematosus (SLE) is an autoimmune disorder in which autoantibody formation can lead to severe kidney pathology. Interleukin (IL)17-producing T cells have been suggested to play an important role in the pathogenesis of SLE, and IL-17 inhibition was shown to ameliorate SLE pathology in lupus-prone mice. Moreover, the frequency of circulating follicular helper T (Tfh) cells, a T cell subset that orchestrates the maturation of high-affinity antibodies in the germinal center of secondary lymphoid organs, is associated with disease activity in SLE. Increased frequencies of IL17-producing Tfh have been reported in SLE patients compared to controls, but their role in SLE pathogenesis is still unknown. Method By leveraging the B6.Sle1NZM2410/AegYaa strain, we generated lupus-prone mice in which IL17-producing Tfh cells could be either fate-mapped (SLE Tfh17-FM, Il17aCRERosaLoxSTOPLox-YFPSle1+/+Yaa+) or fate-mapped and selectively depleted by intraperitoneal diphtheria toxin (DT) administration (SLE Tfh17-DTR, Il17aCRERosaLoxSTOPLox-YFPCxcr5LoxSTOPLox-DTRSle1+/+Yaa+). Tfh17-FM and Tfh17-DTR mice (both Sle1−/−Yaa−) were used as controls. Results Tfh17 comprised approximately 0.4% of total splenic Tfh in SLE mice at 6 weeks of life, and DT administration caused potent and selective depletion of these cells in the SLE Tfh17-DTR strain (Fig. 1A). Early Tfh17 deletion from week 4 to week 9 did not modify the increased Tfh frequency observed at 20 weeks in SLE mice, but resulted in long-term reduction of splenic germinal center (GC) B cells and plasmacells (Fig. 1B-C). IL17 receptor A was overexpressed in non-GC B cells and plasmacells of SLE mice compared to controls, suggesting a possible increased susceptibility of these subsets to IL17 (Fig. 1D). SLE Tfh17-DTR mice treated with DT displayed a trend towards decreased anti-DNA levels compared to SLE Tfh17-FM (Fig. 1E), but both glomerular immunocomplex deposition and renal pathology were not significantly impacted (Fig. 1F-G). Conclusion The germinal center reaction is affected by selective depletion of IL17-producing Tfh cells in SLE mice, with reduced differentiation of GC B cells and plasmacells. The modest effect of Tfh17 depletion on autoantibody levels and lupus nephritis pathology suggests that other Tfh subsets may play a role in GC-derived autoantibody generation. In addition, extrafollicular sources may also contribute to autoantibody production in SLE.

Tailoring Tfh profiles enhances antibody persistence to a clade C HIV-1 vaccine in rhesus macaques

CD4 T follicular helper cells (Tfh) are essential for establishing serological memory and have distinct helper attributes that impact both the quantity and quality of the antibody response. Insights into Tfh subsets that promote antibody persistence and functional capacity can critically inform vaccine design. Based on the Tfh profiles evoked by the live attenuated measles virus vaccine, renowned for its ability to establish durable humoral immunity, we investigated the potential of a Tfh1/17 recall response during the boost phase to enhance persistence of HIV-1 Envelope (Env) antibodies in rhesus macaques. Using a DNA-prime encoding gp160 antigen and Tfh polarizing cytokines (interferon protein-10 (IP-10) and interleukin-6 (IL-6)), followed by a gp140 protein boost formulated in a cationic liposome-based adjuvant (CAF01), we successfully generated germinal center (GC) Tfh1/17 cells. In contrast, a similar DNA-prime (including IP-10) followed by gp140 formulated with monophosphoryl lipid A (MPLA) +QS-21 adjuvant predominantly induced GC Tfh1 cells. While the generation of GC Tfh1/17 cells with CAF01 and GC Tfh1 cells with MPLA +QS-21 induced comparable peak Env antibodies, the latter group demonstrated significantly greater antibody concentrations at week 8 after final immunization which persisted up to 30 weeks (gp140 IgG ng/ml- MPLA; 5500; CAF01, 2155; p<0.05). Notably, interferon γ+Env-specific Tfh responses were consistently higher with gp140 in MPLA +QS-21 and positively correlated with Env antibody persistence. These findings suggest that vaccine platforms maximizing GC Tfh1 induction promote persistent Env antibodies, important for protective immunity against HIV.

Helios characterized circulating follicular helper T cells with enhanced functional phenotypes and was increased in patients with systemic lupus erythematosus

Helios was related to the immunosuppressive capacity and stability of regulatory T cells. However, the significance of Helios in follicular help T (TFH) and follicular regulatory T (TFR) cells is unclear. This research aimed to clarify the significance of Helios (IKZF2) in TFH and TFR cells and its clinical value in systemic lupus erythematosus (SLE). IKZF2 mRNA in different cell subsets was analyzed. Helios+ percentages in TFH and TFR cells were identified in the peripheral blood of 75 SLE patients and 62 HCs (healthy controls). PD-1 and ICOS expression were compared between Helios+ and Helios− cells. The capacity of TFH cells to secrete IL-21 and TFR cells to secrete IL-10 was measured. Correlation analysis and receiver operating characteristic (ROC) curve analysis were conducted to assess the clinical significance of Helios-related TFH and TFR cell subsets in SLE. There was Helios expression in TFH and TFR cells. PD-1 and ICOS were lower in Helios+ TFR than in Helios− TFR. ICOS was increased in Helios+ TFH cells compared with Helios− TFH cells, and ICOS in Helios+ TFH cells was downregulated in SLE. Helios+ TFH cells secreted more IL-21 than Helios− TFH cells, and Helios+ TFH cells from SLE patients had a stronger IL-21 secretion than HCs. Helios+ TFH percentages were negatively correlated with C3 and C4 and positively related to CRP and SLEDAI, and the AUC of Helios+ TFH to distinguish SLE from HC was 0.7959. Helios characterizes circulating TFH cells with enhanced function. Increased Helios+ TFH cells could reflect the autoimmune status of SLE.Graphical abstract

Definition of follicular helper T cell and cytokines expression in synovial fluid of rheumatoid arthritis.

This study aimed to assess the role of synovial fluid (SF) CD4+T, CD19+B, follicular helper cells (Tfh), and cytokines in the pathogenesis of rheumatoid arthritis (RA). This study enrolled 16 patients with RA and 8 patients with osteoarthritis (OA). The frequencies of the SF CD4+ T, CD19+ B, Tfh cells, and Tfh subsets were assessed using flow cytometry. The medical condition in patients with RA was evaluated using The Disease Activity Score 28 (DAS28), the Clinical Disease Activity Index (CDAI), and the Simplified Disease Activity Index (SDAI). Levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), anti-cyclic citrullinated peptide (anti-CCP), and rheumatoid factor (RF) were measured. The cytokines IL-4, IL-13, IL-21, and BLyS were measured by ELISA test. The percentages of SF CD4+T, CD19+B, and PD-1+CXCR5+ Tfh in RA patients were higher than those in OA patients. And the Tfh2 was the main subset among Tfh subsets. In addition, levels of IL-21 and BLyS were higher in patients with RA compared to patients with OA. Furthermore, the treatment of TNF-α inhibitors may be associated with decreased levels of SF Tfh. Elevated SF Tfh, B cell, and cytokines expression profiles were observed in RA patients. Tfh2 was the major subset of the Tfh, and IL-21 and BLyS were significantly enhanced. Additionally, TNF-α inhibitors reduced Tfh in SF. Therefore, Tfh, B, and Tfh2 cells could play a significant role in the progression of RA. Key Points •Tfh cells in the synovial fluid are significantly higher in RA patients and are dominated by the Tfh2 subpopulation. •Synovial fluid Tfh cells decrease in RA patients after anti-TNF-α treatment.

Rituximab induces a transient fluctuation of peripheral and follicular helper T cells in neuromyelitis optica spectrum disorder

Autoreactive CD4+ helper T cells are implicated in the pathogenesis of neuromyelitis optica spectrum disorder (NMOSD). Both PD-1+CXCR5+CD4+ T follicular helper (Tfh) cells and PD-1+CXCR5−CD4+ T peripheral helper (Tph) cells can contribute to B-cell immune responses and the production of antibodies. Here we show the effect of B-cell depletion with rituximab on the homeostasis of Tfh cells, Tph cells and their subsets in patients with NMOSD. After rituximab treatment, total Tph cells, total Tfh cells, Tph17 cells, Tph17.1 cells, Tph1 cells, and Tfh1 cells tended to decrease at month 1, but gradually increased at month 6 and restored at month 12. Besides, Tph17.1 cells and Tfh17.1 cells were correlated with the proportion of CD19− antibody-secreting cells. Our data suggest that rituximab induced a fluctuation of proinflammatory Tph and Tfh subsets within one year after initiation of the treatment.

Chitinase-3-like 1 regulates TH2 cells, TFH cells and IgE responses to helminth infection.

Data from patient cohorts and mouse models of atopic dermatitis, food allergy and asthma strongly support a role for chitinase-3-like-1 protein (CHI3L1) in allergic disease. To address whether Chi3l1 also contributes to TH2 responses following nematode infection, we infected Chi3l1 -/- mice with Heligmosomoides polygyrus (Hp) and analyzed T cell responses. As anticipated, we observed impaired TH2 responses in Hp-infected Chi3l1 -/- mice. However, we also found that T cell intrinsic expression of Chi3l1 was required for ICOS upregulation following activation of naïve CD4 T cells and was necessary for the development of the IL-4+ TFH subset, which supports germinal center B cell reactions and IgE responses. We also observed roles for Chi3l1 in TFH, germinal center B cell, and IgE responses to alum-adjuvanted vaccination. While Chi3l1 was critical for IgE humoral responses it was not required for vaccine or infection-induced IgG1 responses. These results suggest that Chi3l1 modulates IgE responses, which are known to be highly dependent on IL-4-producing TFH cells.

Added value of lymphocyte subpopulations in the classification of Sjögren's syndrome

Sjögren's Syndrome (SjS) is a chronic systemic immune-mediated inflammatory disease characterized by lymphocytic infiltration and consequent lesion of exocrine glands. SjS diagnosis and classification remains a challenge, especially at SjS onset, when patients may have milder phenotypes of the disease or uncommon presentations. New biomarkers are needed for the classification of SjS, thus, we aimed to evaluate the added-value of lymphocyte subpopulations in discriminating SjS and non-Sjögren Sicca patients. Lymphocyte subsets from 62 SjS and 63 Sicca patients were characterized by flow cytometry. The 2002 AECG and the 2016 ACR/EULAR SjS classification criteria were compared with clinical diagnosis. The added discriminative ability of joining lymphocytic populations to classification criteria was assessed by the area under the Receiver-Operating-Characteristic Curve (AUC). Considering clinical diagnosis as the gold-standard, we obtained an AUC = 0.952 (95% CI: 0.916–0.989) for AECG and an AUC = 0.921 (95% CI: 0.875–0.966) for ACR/EULAR criteria. Adding Tfh and Bm1 subsets to AECG criteria, performance increased, attaining an AUC = 0.985 (95% CI: 0.968–1.000) (p = 0.021). Th1/Breg-like CD24hiCD27+ and switched-memory B-cells maximized the AUC of ACR/EULAR criteria to 0.953 (95% CI: 0.916–0.990) (p = 0.043). Our exploratory study supports the potential use of lymphocyte subpopulations, such as unswitched memory B cells, to improve the performance of classification criteria, since their discriminative ability increases when specific subsets are added to the criteria.

Biomedical statistics study on the correlation between peripheral blood follicular helper T cell subsets and primary Sjogren's syndrome.

To study the expressions of follicular helper T cell (Tfh) subsets--Tfh1, Tfh2, and Tfh17, in peripheral blood (PB) of primary Sjogren's syndrome (PSS) patients in the active phase and remission period after treatment, and to analyze the pathogenic effects of Tfh subsets in PSS patients. The proportions of Tfh1, Tfh2, and Tfh17 were measured by flow cytometry in the healthy group, PSS patients group, active phase group, and remission phase group. Enzyme-linked immunosorbent assay was used to detect IL-21 expression in SS patients in active and remission stages. Biomedical statistics was used to analyze the correlation between Tfh subsets and SS disease activity index; and analyze the correlation between the proportions of Tfh subsets in the healthy group, primary group, active stage, and remission stage In contrast with the healthy group, the levels of Tfh1, Tfh2, and Tfh17 in CD4+ T cells of PSS patients were prominently reduced. PSS patients in the active phase had significantly lower Tfh1, Tfh2, and Tfh17 levels but remarkably higher IL-21 levels than in the remission phase. The contents of Tfh1, Tfh2, and Tfh17 are negatively correlated with the severity of PSS.

Elevated levels of circulatory follicular T helper cells in chronic lymphocytic leukemia contribute to B cell expansion.

Chronic lymphocytic leukemia (CLL) is characterized by an expansion of mature B cells in the bone marrow, peripheral lymphoid organs, and blood. CD4 T helper (Th) lymphocytes significantly contribute to the physiopathology of CLL, but the subset(s) of Th cell involved in CLL pathogenesis is (are) still under debate. In this study, we performed flow cytometry analysis of the circulatory T cells of untreated CLL patients and observed an increase in follicular helper T cells (Tfh), which is a subset of T cells specialized in B cell help. Elevated numbers of Tfh cells correlated with disease severity as measured by the Binet staging system. Tfh from CLL patients were activated and skewed toward a Th1 profile as evidenced by their PD-1+IL-21+IFNγ+ phenotype and their CXCR3+CCR6- chemokine receptor profile. Tfh efficiently enhanced B-CLL survival and proliferation through IL-21 but independently of IFNγ. Finally, we observed an inverse correlation between the Tfh1 and IgA and IgG serum levels in patients, suggesting a role for this Tfh subset in the immune dysfunction associated with CLL. Altogether, our data highlight an impairment in circulatory Tfh subsets in CLL patients and their critical role in CLL physiopathology.

Type 2 helper T cells convert into Interleukin-13-expressing follicular helper T cells after antigen repriming

Anaphylaxis caused by allergen sensitization and vaccination is a serious health concern. The severity of anaphylaxis is associated with the presence of immunoglobulin E (IgE) antibodies that bind to allergens with a high affinity. Here, we report the development of a unique Interleukin-13 (IL-13)-producing follicular helper T (TFH) cell subset, designated TFH2 cells, which is tightly associated with the production of high-affinity IgE antibodies. TFH2 cells had a transcriptionally hybrid phenotype between TH2 and TFH cells, which express GATA-binding protein 3 (Gata3) and B-cell/CLL lymphoma 6 (BCL-6), respectively. Adaptive transfer experiments demonstrated that type 2 helper T (TH2) cells were capable of differentiating into TFH2 cells upon secondary antigen stimulation. The type 2 TFH (TFH2) conversion process was entirely attenuated in T cell-specific deficient mice of Bcl6 (Bcl6f/f cd4-cre; Bcl6ΔT). Moreover, the transfer of IL-13 defective TH2 cells partially inhibited IgE responses and significantly decreased the high-affinity IgE, even though TFH development was intact. Therefore, IL-13 from TFH2 cells controlled the selective enrichment of IgE+ B-cells with a high affinity for allergens. A previously undefined unique TFH subset, TFH2, likely contributes to IgE responses. This suggests that the accumulation of antigen-specific TH2 cells in human patients with allergies is a high-risk factor for IgE-dependent allergic diseases.

Dynamics of circulating follicular helper T cell subsets and follicular regulatory T cells in rheumatoid arthritis patients according to HLA-DRB1 locus.

B cells, follicular helper T (Tfh) cells and follicular regulatory T (Tfr) cells are part of a circuit that may play a role in the development or progression of rheumatoid arthritis (RA). With the aim of providing further insight into this topic, here we evaluated the frequency of different subsets of Tfh and Tfr in untreated and long-term treated RA patients from a cohort of Argentina, and their potential association with particular human leukocyte antigen (HLA) class-II variants and disease activity. We observed that the frequency of total Tfh cells as well as of particular Tfh subsets and Tfr cells were increased in seropositive untreated RA patients. Interestingly, when analyzing paired samples, the frequency of Tfh cells was reduced in synovial fluid compared to peripheral blood, while Tfr cells levels were similar in both biological fluids. After treatment, a decrease in the CCR7loPD1hi Tfh subset and an increase in the frequency of Tfr cells was observed in blood. In comparison to healthy donors, seropositive patients with moderate and high disease activity exhibited higher frequency of Tfh cells while seropositive patients with low disease activity presented higher Tfr cell frequency. Finally, we observed that HLA-DRB1*09 presence correlated with higher frequency of Tfh and Tfr cells, while HLA-DRB1*04 was associated with increased Tfr cell frequency. Together, our results increase our knowledge about the dynamics of Tfh and Tfr cell subsets in RA, showing that this is altered after treatment.

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.

Different antibody-associated autoimmune diseases have distinct patterns of T follicular cell dysregulation

Autoantibodies are produced within germinal centers (GC), in a process regulated by interactions between B, T follicular helper (Tfh), and T follicular regulatory (Tfr) cells. The GC dysregulation in human autoimmunity has been inferred from circulating cells, albeit with conflicting results due to diverse experimental approaches. We applied a consistent approach to compare circulating Tfr and Tfh subsets in patients with different autoimmune diseases. We recruited 97 participants, including 72 patients with Hashimoto’s thyroiditis (HT, n = 18), rheumatoid arthritis (RA, n = 16), or systemic lupus erythematosus (SLE, n = 32), and 31 matched healthy donors (HD). We found that the frequency of circulating T follicular subsets differed across diseases. Patients with HT had an increased frequency of blood Tfh cells (p = 0.0215) and a reduced Tfr/Tfh ratio (p = 0.0338) when compared with HD. This was not observed in patients with systemic autoimmune rheumatic diseases (RA, SLE), who had a reduction in both Tfh (p = 0.0494 and p = 0.0392, respectively) and Tfr (p = 0.0003 and p = 0.0001, respectively) cells, resulting in an unchanged Tfr/Tfh ratio. Activated PD-1+ICOS+Tfh and CD4+PD-1+CXCR5–Tph cells were raised only in patients with SLE (p = 0.0022 and p = 0.0054), without association with disease activity. Our data suggest that GC dysregulation, assessed by T follicular subsets, is not uniform in human autoimmunity. Specific patterns of dysregulation may become potential biomarkers for disease and patient stratification.

Modeling the effect of environmental cytokines, nutrient conditions and hypoxia on CD4+ T cell differentiation.

Upon antigen stimulation and co-stimulation, CD4+ T lymphocytes produce soluble factors that promote the activity of other immune cells against pathogens or modified tissues; this task must be performed in presence of a variety of environmental cytokines, nutrient, and oxygen conditions, which necessarily impact T cell function. The complexity of the early intracellular processes taking place upon lymphocyte stimulation is addressed by means of a mathematical model based on a network that integrates variable microenvironmental conditions with intracellular activating, regulatory, and metabolic signals. Besides the phenotype subsets considered in previous works (Th1, Th2, Th17, and Treg) the model includes the main early events in differentiation to the T FH phenotype. The model describes how cytokines, nutrients and oxygen availability regulate the differentiation of naïve CD4+ T cells into distinct subsets. Particularly, it shows that elevated amounts of an all-type mixture of effector cytokines under optimal nutrient and oxygen availability conduces the system towards a highly-polarized Th1 or Th2 state, while reduced cytokine levels allow the expression of the Th17, Treg or T FH subsets, or even hybrid phenotypes. On the other hand, optimal levels of an all-type cytokine mixture in combination with glutamine or tryptophan restriction implies a shift from Th1 to Th2 expression, while decreased levels of the Th2-inducing cytokine IL-4 leads to the rupture of the Th1-Th2 axis, allowing the manifestation of different (or hybrid) subsets. Modeling proposes that, even under reduced levels of pro-inflammatory cytokines, the sole action of hypoxia boost Th17 expression.

The deficiency in Th2-like Tfh cells affects the maturation and quality of HIV-specific B cell response in viremic infection.

Optimal T follicular helper (Tfh) cells function is important to promote the development of germinal centers and maturation of high affinity antigen-specific B cells. We have found that the expression of CXCR3 defines distinct Tfh subsets: CXCR3+ Th1-like Tfh cells mainly producing single IFN-γ and dual IL-21/IFN-γ and CXCR3- Th2-like Tfh cells mainly producing single IL-4 and dual IL-21/IL-4 cytokines. CXCR3- Th2-like Tfhs are significantly reduced during ongoing HIV replication. While the percentage of Th2-like Tfh cells correlates with that of total and cycling HIV-specific B cells, the percentage of CXCR3+ Th1-like Tfhs correlates with HIV-specific B cells expressing T-bet and CXCR3. Of note, only IL-4 and IL-21 cytokines boosted efficient maturation of HIV-specific B cells while IFN-γ induced expression of T-bet and CXCR3 in B cells. Interestingly, total and HIV-specific CXCR3+ B cells showed lower rate of somatic hypermutation, as compared to CXCR3- B cells. Therefore, the imbalance in Th2/Th1-like Tfhs affects B cell responses in viremic HIV infection.

Role of Tfh17 cells in patients with multiple myeloma

ABSTRACT Objective Follicular helper T cells (Tfh) drive proliferation and differentiation of B cells into plasma cells, leading to antibody production; however, their role in multiple myeloma (MM) is unknown. We aimed to determine the alteration of Tfh subsets and their clinical significance in patients with MM. Method Forty-nine patients with MM were recruited in this study, including 12 newly diagnosed patients, 10 relapsed patients, and 8 patients who received autologous hematopoietic stem cell transplantation (ASCT) from Zhejiang Provincial People's Hospital. Total CD4 + CXCR5 + CD25lowCD127intermediate-high Tfh cells, CXCR3 + CCR6−Tfh1 cells, CXCR3−CCR6−Tfh2 cells, and CXCR3−CCR6 + Tfh17 cells from the peripheral blood of these patients were analyzed by flow cytometry. Result Although total Tfh cells were not significantly changed in patients with MM compared to that in healthy controls (HCs), the Tfh17/Tfh ratio was significantly elevated in patients with MM compared to that in HCs (P = 0.0001). Importantly, relapsed patients had higher Tfh17/Tfh ratio than the newly diagnosed patients (P = 0.0077). Moreover, the Tfh17/Tfh ratio was significantly decreased in patients with MM who received ASCT (post-ASCT) when compared to that in HCs and non-ASCT patients (P < 0.0001), but no change was observed between post-ASCT patients and HCs (P = 0.7498). Conclusion The Tfh17/Tfh ratio was significantly elevated in patients with MM, especially in relapsed patients, indicating that Tfh17 cells may play a critical role in the clinical progression of MM.