Germinal Center-Related G Protein-Coupled Receptors in Antibody-Mediated Autoimmune Skin Diseases: from Basic Research to Clinical Trials.

Germinal center (GC) reaction greatly contributes to the humoral immune response, which begins in lymph nodes or other secondary lymphoid organs after follicular B cells are activated by T-dependent antigens. The GCs then serve as a platform for follicular B cells to complete clonal expansion and somatic hypermutation and then interact with follicular dendritic cells (FDC) and follicular helper T cells (Tfh). Through the interaction between the immune cells, significant processes of the humoral immune response are accomplished, such as antibody affinity maturation, class switching, and production of memory B cells and plasma cells. Cell positioning during the GC reaction is mainly mediated by the chemokine receptors and lipid receptors, which both belong to G protein-coupled receptors (GPCRs) family. There are some orphan GPCRs whose endogenous ligands are unclear yet contribute to the regulation of GC reaction as well. This review will give an introduction on the ligands and functions of two types of GC-relating GPCRs-chemokine receptors like CXCR4 and CXCR5, as well as emerging de-orphanized GPCRs like GPR183, GPR174, and P2RY8. The roles these GPCRs play in several antibody-mediated autoimmune skin diseases will be also discussed, including systemic lupus erythematosus (SLE), pemphigus, scleroderma, and dermatomyositis. Besides, GPCRs are excellent drug targets due to the unique structure and vital functions. Therefore, this review is aimed at providing readers with a focused knowledge about the role that GPCRs play in GC reaction, as well as in provoking the development of GPCR-targeting agents for immune-mediated diseases besides autoimmune diseases.

[Observation of PD-1+CXCR5+CD4+T lymphocyte and sPD-1 levels in HBeAg positive chronic hepatitis B virus carriers treated with entecavir].

Objective: To dynamically observe the clinical efficacy of entecavir and the changes of PD-1+CXCR5+CD4+T lymphocytes and sPD-1 levels in peripheral blood of HBeAg-positive chronic hepatitis B virus carriers treated with entecavir, and further explore its clinical significance. Methods: There were 31 cases of chronic hepatitis B virus carriers in the treatment group (A), 32 cases of chronic hepatitis B virus carriers in the treatment group (B), and 15 cases of chronic hepatitis B virus carriers in the non-treatment group (C).Three groups peripheral blood samples and clinical data at 0, 24 and 48 weeks were collected and compared. PD-1+CXCR5+CD4+T lymphocytes were detected by flow cytometry, and the level of sPD-1 was detected by enzyme-linked immunosorbent assay. ANOVA and Spearman correlation analysis were performed on the measurement data among the three groups. Results: At week 0, the serum levels of HBsAg, HBeAg and HBV DNA were significantly higher in groups A and C than group B. PD-1+CXCR5+CD4+T lymphocytes in peripheral blood were significantly higher in group B (4.70%±1.58%) than group A (3.25%±1.01%) and group C (2.77%±0.67%) (F=16.65, P<0.05). There was no significant difference between group A and group C (P>0.05). Peripheral blood sPD-1 in group B [(1 866.62±1 472.70) pg/ml] was significantly higher than group A [(824.86±538.66) pg/ml] and group C [(618.19±602.62) pg/ml] (F=10.95, P<0.05). There was no significant difference between group A and group C (P>0.05). At 48 weeks, the serum HBsAg did not decrease significantly in groups A and C than baseline (P>0.05), but were significantly higher than group B (P<0.05). Serum HBeAg levels were decreased significantly in groups A and B than baseline (P<0.05). <0.05), but group A was significantly higher than group B (P<0.05), and there was no significant difference between group A and group C (P>0.05). Serum HBV DNA level was significantly lower in groups A and B than group C (P<0.05), and there was no significant difference between group A and group B (P>0.05). Peripheral blood PD-1+CXCR5+CD4+T lymphocytes were significantly lower in Group A (1.56%±0.73%) and group B (1.32%±0.43%) than group C (2.64%±0.85%) (P<0.05). Peripheral blood sPD-1 were significantly lower in group A [(289.05±215.86) pg/ml] and group B [(236.01±173.92) pg/ml] than group C [(650.34±598.46) pg/ml] (P<0.05). There was no significant difference between group A and group B. Correlation analysis results: In group A at 48 weeks, the decreased level of PD-1+CXCR5+CD4+T lymphocyte ratio had no correlation with the decreased level of HBsAg and HBV DNA, but was positively correlated with the decreased level of HBeAg (r=0.376, P<0.05). The decreased level of sPD-1 had no correlation with the changes of HBsAg, but was positively correlated with the decreased levels of HBeAg and HBV DNA (r=0.598 and 0.384, P<0.05). In group B at 48 weeks, the decreased levels of PD-1+CXCR5+CD4+T lymphocytes and sPD-1 were positively correlated with the decreased levels of HBsAg, HBeAg, and HBV DNA (P<0.05). Conclusion: Hepatitis B virus replication and expressions in HBeAg-positive chronic hepatitis B virus carriers were significantly inhibited after 48 weeks of antiviral treatment, which is related not only to entecavir treatment, but also to the immunological mechanism involved in sPD-1. Moreover, the inhibition of HBeAg expression is associated with a decrease in the number and/or activity of PD-1+CXCR5+CD4+T lymphocytes.

Altered levels of circulating CD8+CXCR5+PD-1+T follicular cytotoxic cells in primary Sjögren's syndrome.

BACKGROUND: Circulating CD8+ T-cells expressing the C-X-C chemokine receptor type 5 (CXCR5) (CD8+CXCR5+T), a recently identified follicular cytotoxic T cell subset, are involved in antiviral immunity and autoimmunity, but their abundance and role in the pathogenesis of primary Sjögren syndrome (pSS) are unknown. METHODS: Circulating CD8+CXCR5+T cell and CD8+ regulatory T cells (CD8+Treg) were evaluated in 49 pSS patients (19 patients with pulmonary involvement) and 24 age- and sex-matched healthy controls (HCs) by flow cytometry. Orthogonal partial least squares discriminant analysis (OPLS-DA) was performed, and receiver operating characteristic curves (ROC) were generated to identify characteristic cell subsets. Spearman's correlation analysis was conducted to examine the relationships between CD8+ T cell subsets and clinical features. RESULTS: The proportions and numbers of CD8+CXCR5+, CD8 + CXCR5+ programmed death 1-positive (PD-1+), and CD8+CXCR5-PD-1+T cells were significantly higher, whereas those of CD8+Treg were markedly lower, in pSS patients than HCs. The CD8+CXCR5+PD-1+T cell to CD8+Treg ratio had the greatest discriminatory power for pSS and HCs according to OPLS-DA and ROC analyses. The increased numbers of CD8+CXCR5+T cells and CD8+CXCR5+PD-1+T cells were strongly associated with those of CD4+CXCR5+T and B cells. The proportions and numbers of CD8+CXCR5+PD-1+T cells were increased in pSS patients with lung involvement. CONCLUSIONS: We identified a new CD8+CXCR5+PD-1+T subset, which was increased in abundance in pSS patients, particularly those with lung involvement, compared with HCs. Also, the CD8+CXCR5+PD-1+T to CD8+Treg ratio may be useful for identifying pSS. Our findings suggest that targeting follicular CD8+T cell subsets has therapeutic potential for pSS. Key Points • CD8+CXCR5+ T cells were expanded in the circulation of patients with pSS. • Reduced numbers CD8+Treg cells in pSS patients. • Increased CD8+CXCR5+PD-1+T cells in pSS patients with pulmonary involvement.

Extrafollicular PD-1highCXCR5-CD4+ T cells participate in local immunoglobulin production in nasal polyps.

BACKGROUND: Local immunoglobulin hyperproduction is observed in nasal polyps (NPs) with and without ectopic lymphoid tissues (eLTs). OBJECTIVE: Our aim was to identify the T-cell subsets involved in local immunoglobulin production independent of eLTs in NPs. METHODS: The localization, abundance, and phenotype of CD4+ T-cell subsets were studied by immunofluorescence, flow cytometry, and single-cell RNA sequencing. Purified nasal T-cell subsets were cultured with autologous peripheral naive B cells to explore their function. Programmed death ligand 1 and programmed death ligand 2 expression in NPs was investigated by immunofluorescence staining and flow cytometry. RESULTS: Accumulation of PD-1highCXCR5-CD4+ T cells outside lymphoid aggregates was found in NPs. Nasal PD-1highCXCR5-CD4+ T cells were characterized by a unique phenotype that was related to B-cell help and tissue residency and distinct from PD-1-/intCXCR5- and CXCR5+ CD4+ T cells in NPs as well as PD-1highCXCR5highCD4+ follicular helper T cells in tonsils. Compared with the frequencies of PD-1highCXCR5-CD4+ T cells and their IFN-γ+, IL-17A+, and IL-21+ subsets in the control inferior turbinate tissues, the frequencies of these cells and their subsets were increased in both eosinophilic and noneosinophilic NPs, whereas the frequencies of the IL-4+ and IL-4+IL-21+ subsets were increased only in eosinophilic NPs. Nasal PD-1highCXCR5-CD4+ T cells induced immunoglobulin production from B cells in a potency comparable to that induced by tonsillar follicular helper T cells. PD-1highCXCR5-CD4+ T-cell frequencies were correlated with IgE levels in eosinophilic NPs. PD-L1 and PD-L2 suppressed the function of PD-1highCXCR5-CD4+ T cells, and their levels were reduced in NPs. PD-1highCXCR5-CD4+ T-cell abundance was associated with the postsurgical relapse of NPs. CONCLUSION: PD-1highCXCR5-CD4+ T cells participate in local immunoglobulin production independent of eLTs in NPs.

Programmed death 1 expressing CD8+ CXCR5+ follicular T cells constitute effector rather than exhaustive phenotype in patients with chronic hepatitis B.

BACKGROUND AND AIMS: Classical CD8 T cells are implicated for protective and pathogenic roles in chronic hepatitis B (CHB) infection. Recently, a subset of CD8 T cells expressing C-X-C chemokine receptor type 5 (CXCR5) and exhibiting features of TFH cells has been identified during chronic viral infections. However, in CHB, knowledge of their roles is limited. APPROACH AND RESULTS: We characterized circulating CD8+ CXCR5+/- cells and investigated their association with clinical and viral factors. We found that CHB infection did not influence the overall frequencies of CD8+ CXCR5+ cells whereas CD8+ CXCR5- cells were increased. However, among CHB, CD8+ CXCR5+ cells were higher in patients with low HBsAg and HBV-DNA levels, patients who were HBeAg negative and had high fibrosis scores, and these cells exhibited a significant association with HBsAg and HBV-DNA reduction. Contrarily, CD8+ CXCR5- cells were expanded and positively correlated with patients having high HBsAg, HBV-DNA, and alanine aminotransferase levels. CD8+ CXCR5+ cells express costimulatory molecules ICOS, OX40, CD40 ligand, inhibitory molecule programmed death 1, transcription factors B-cell lymphoma (BCL)-2, BCL-6, and signal transducer and activator of transcription 3, and are enriched in effector and central memory phenotype. Moreover, these cells are heterogeneous in nature given that they constitute different subsets of cytotoxic follicular T cells (TCF), including TCF1, TCF2, TCF17, and TCF22. Despite expressing high PD-1, CD8+ CXCR5+ cells are activated, proliferating, secreting more IFN-γ, IL-21, and IL-22, and have better cytolytic potential than CD8+ CXCR5- cells, which were inhibited after PD-1/PD-L1 blockade. CD8+ CXCR5+ cells are efficient in helping B cells in terms of plasmablasts and plasma cell generation. CONCLUSIONS: In conclusion, CD8+ CXCR5+ cells are enriched in effector phenotypes, produce HBV-specific cytokines despite increased PD-1, and are associated with HBsAg and HBV-DNA reduction. These cells competently support B-cell function, required for viral clearance, which may serve as potential therapeutic targets for CHB.

Observation of PD-1+CXCR5+CD4+T lymphocyte and sPD-1 levels in HBeAg positive chronic hepatitis B virus carriers treated with entecavir / 中华肝脏病杂志

Objective: To dynamically observe the clinical efficacy of entecavir and the changes of PD-1+CXCR5+CD4+T lymphocytes and sPD-1 levels in peripheral blood of HBeAg-positive chronic hepatitis B virus carriers treated with entecavir, and further explore its clinical significance. Methods: There were 31 cases of chronic hepatitis B virus carriers in the treatment group (A), 32 cases of chronic hepatitis B virus carriers in the treatment group (B), and 15 cases of chronic hepatitis B virus carriers in the non-treatment group (C).Three groups peripheral blood samples and clinical data at 0, 24 and 48 weeks were collected and compared. PD-1+CXCR5+CD4+T lymphocytes were detected by flow cytometry, and the level of sPD-1 was detected by enzyme-linked immunosorbent assay. ANOVA and Spearman correlation analysis were performed on the measurement data among the three groups. Results: At week 0, the serum levels of HBsAg, HBeAg and HBV DNA were significantly higher in groups A and C than group B. PD-1+CXCR5+CD4+T lymphocytes in peripheral blood were significantly higher in group B (4.70%±1.58%) than group A (3.25%±1.01%) and group C (2.77%±0.67%) (F=16.65, P<0.05). There was no significant difference between group A and group C (P>0.05). Peripheral blood sPD-1 in group B [(1 866.62±1 472.70) pg/ml] was significantly higher than group A [(824.86±538.66) pg/ml] and group C [(618.19±602.62) pg/ml] (F=10.95, P<0.05). There was no significant difference between group A and group C (P>0.05). At 48 weeks, the serum HBsAg did not decrease significantly in groups A and C than baseline (P>0.05), but were significantly higher than group B (P<0.05). Serum HBeAg levels were decreased significantly in groups A and B than baseline (P<0.05). <0.05), but group A was significantly higher than group B (P<0.05), and there was no significant difference between group A and group C (P>0.05). Serum HBV DNA level was significantly lower in groups A and B than group C (P<0.05), and there was no significant difference between group A and group B (P>0.05). Peripheral blood PD-1+CXCR5+CD4+T lymphocytes were significantly lower in Group A (1.56%±0.73%) and group B (1.32%±0.43%) than group C (2.64%±0.85%) (P<0.05). Peripheral blood sPD-1 were significantly lower in group A [(289.05±215.86) pg/ml] and group B [(236.01±173.92) pg/ml] than group C [(650.34±598.46) pg/ml] (P<0.05). There was no significant difference between group A and group B. Correlation analysis results: In group A at 48 weeks, the decreased level of PD-1+CXCR5+CD4+T lymphocyte ratio had no correlation with the decreased level of HBsAg and HBV DNA, but was positively correlated with the decreased level of HBeAg (r=0.376, P<0.05). The decreased level of sPD-1 had no correlation with the changes of HBsAg, but was positively correlated with the decreased levels of HBeAg and HBV DNA (r=0.598 and 0.384, P<0.05). In group B at 48 weeks, the decreased levels of PD-1+CXCR5+CD4+T lymphocytes and sPD-1 were positively correlated with the decreased levels of HBsAg, HBeAg, and HBV DNA (P<0.05). Conclusion: Hepatitis B virus replication and expressions in HBeAg-positive chronic hepatitis B virus carriers were significantly inhibited after 48 weeks of antiviral treatment, which is related not only to entecavir treatment, but also to the immunological mechanism involved in sPD-1. Moreover, the inhibition of HBeAg expression is associated with a decrease in the number and/or activity of PD-1+CXCR5+CD4+T lymphocytes.

The Tonsil Lymphocyte Landscape in Pediatric Tonsil Hyperplasia and Obstructive Sleep Apnea.

Tonsil hyperplasia is the most common cause of pediatric obstructive sleep apnea (OSA). Despite the growing knowledge in tissue immunology of tonsils, the immunopathology driving tonsil hyperplasia and OSA remains unknown. Here we used multi-parametric flow cytometry to analyze the composition and phenotype of tonsillar innate lymphoid cells (ILCs), T cells, and B cells from pediatric patients with OSA, who had previous polysomnography. Unbiased clustering analysis was used to delineate and compare lymphocyte heterogeneity between two patient groups: children with small tonsils and moderate OSA (n = 6) or large tonsils and very severe OSA (n = 13). We detected disturbed ILC and B cell proportions in patients with large tonsils, characterized by an increase in the frequency of naïve CD27-CD21hi B cells and a relative reduction of ILCs. The enrichment of naïve B cells was not commensurate with elevated Ki67 expression, suggesting defective differentiation and/or migration rather than cellular proliferation to be the causative mechanism. Finally, yet importantly, we provide the flow cytometry data to be used as a resource for additional translational studies aimed at investigating the immunological mechanisms of pediatric tonsil hyperplasia and OSA.

Functional Th1-oriented T follicular helper cells that infiltrate human breast cancer promote effective adaptive immunity.

We previously demonstrated that tumor-infiltrating lymphocytes (TIL) in human breast cancer sometimes form organized tertiary lymphoid structures (TLS) characterized by CXCL13-producing T follicular helper (Tfh) cells. The present study found that CD4+ Tfh TIL, CD8+ TIL, and TIL-B, colocalizing in TLS, all express the CXCL13 receptor CXCR5. An ex vivo functional assay determined that only activated, functional Th1-oriented Tfh TIL (PD-1hiICOSint phenotype) provide help for immunoglobulin and IFN-γ production. A functional Tfh TIL presence signals an active TLS, characterized by humoral (immunoglobulins, Ki-67+ TIL-B in active germinal centers) and cytotoxic (GZMB+CD8+ and GZMB+CD68+ TIL plus Th1 gene expression) immune responses. Analysis of active versus inactive TLS in untreated patients revealed that the former are associated with positive clinical outcomes. TLS also contain functional T follicular regulatory (Tfr) TIL, which are characterized by a CD25+CXCR5+GARP+FOXP3+ phenotype and a demethylated FOXP3 gene. Functional Tfr inhibited functional Tfh activities via a glycoprotein A repetitions predominant (GARP)-associated TGF-ß-dependent mechanism. The activity of tumor-associated TLS was dictated by the relative balance between functional Tfh TIL and functional Tfr TIL. These data provide mechanistic insight into TLS processes orchestrated by functional Th1-oriented Tfh TIL, including TIL-B and CD8+ TIL activation and immunological memory generation. Tfh TIL, regulated by functional Tfr TIL, are an expected key target of PD-1/PD-L1 blockade.

The potential role of follicular helper T cells and helper T cells type 1 in Warthin tumour.

Warthin tumour (WT) is a benign tumour of the salivary gland that proliferates in both glandular epithelial and lymphoid tissue components, and rarely exhibits cystic changes. T follicular helper cells (Tfh) are involved in the formation and maintenance of germinal centres, the differentiation of B cells into plasma cells, and the maintenance of helper T cell type 2 (Th2)-dominant humoral immune responses. T-bet induces differentiation into helper T cell type 1 (Th1) by suppressing differentiation into Tfh and enhances cellular immune responses. The objective of this study was to enhance our understanding of the immune responses and relationship between Tfh and Th1 cells in patients with WTs. In this study, we classified WTs (n = 64) into solid-type (n = 25) and cyst-type (n = 39). We also performed immunostaining of the Tfh markers CXCR5 and CD40 L, and the Th1 marker T-bet for statistical analysis. The cyst-type exhibited significant atrophy of the germinal centre area (P = 0.0019), significantly fewer Tfh-positive lymphocytes in germinal centres (P < 0.0001), and significantly more T-bet-positive lymphocytes in the epithelium (P = 0.0017). We observed that Tfh were involved in the formation and maintenance of lymphoid follicles in WTs. In the cyst-type, Th2-dominant humoral immune responses were suppressed, and Th1-dominant cellular immune responses may have caused damage to tumour tissue.

A Combination of Anti-PD-L1 Treatment and Therapeutic Vaccination Facilitates Improved Retroviral Clearance via Reactivation of Highly Exhausted T Cells.

PD-1-targeted therapies have shown modest antiviral effects in preclinical models of chronic viral infection. Thus, novel therapy protocols are necessary to enhance T cell immunity and viral control to overcome T cell dysfunction and immunosuppression. Here, we demonstrate that nanoparticle-based therapeutic vaccination improved PD-1-targeted therapy during chronic infection with Friend retrovirus (FV). Prevention of inhibitory signals by blocking PD-L1 in combination with therapeutic vaccination with nanoparticles containing the microbial compound CpG and a CD8+ T cell Gag epitope peptide synergistically enhanced functional virus-specific CD8+ T cell responses and improved viral clearance. We characterized the CD8+ T cell populations that were affected by this combination therapy, demonstrating that new effector cells were generated and that exhausted CD8+ T cells were reactivated at the same time. While CD8+ T cells with high PD-1 (PD-1hi) expression turned into a large population of granzyme B-expressing CD8+ T cells after combination therapy, CXCR5-expressing follicular cytotoxic CD8+ T cells also expanded to a high degree. Thus, our study describes a very efficient approach to enhance virus control and may help us to understand the mechanisms of combination immunotherapy reactivating CD8+ T cell immunity. A better understanding of CD8+ T cell immunity during combination therapy will be important for developing efficient checkpoint therapies against chronic viral infections and cancer.IMPORTANCE Despite significant efforts, vaccines are not yet available for every infectious pathogen, and the search for a protective approach to prevent the establishment of chronic infections, i.e., with HIV, continues. Immune checkpoint therapies targeting inhibitory receptors, such as PD-1, have shown impressive results against solid tumors. However, immune checkpoint therapies have not yet been licensed to treat chronic viral infections, since a blockade of inhibitory receptors alone provides only limited benefit, as demonstrated in preclinical models of chronic viral infection. Thus, there is a high interest in the development of potent combination immunotherapies. Here, we tested whether the combination of a PD-L1 blockade and therapeutic vaccination with functionalized nanoparticles is a potent therapy during chronic Friend retrovirus infection. We demonstrate that the combination therapy induced a synergistic reinvigoration of the exhausted virus-specific CD8+ T cell immunity. Taken together, our results provide further information on how to improve PD-1-targeted therapies during chronic viral infection and cancer.

Tissue Infiltrating LTi-Like Group 3 Innate Lymphoid Cells and T Follicular Helper Cells in Graves' and Hashimoto's Thyroiditis.

Background: Hashimoto's thyroiditis (HT) and Graves' disease (GD) are autoimmune thyroid disorders (AITDs). These conditions have been associated to abnormalities in circulating regulatory T cells (Tregs). We postulated that immune perturbations could be more pronounced at the thyroid tissue level. Methods: The phenotype of PBMCs and immune cells infiltrating thyroid tissue from 19 patients with HT, 21 patients with GD, and 30 controls has been analyzed by flow cytometry. Results: We report that blood and thyroid Treg cell subsets are similarly represented in all AITDs patients and controls. Increased Lymphoid tissue inducer (LTi)-like ILC3 and CXCR5+ PD-1hi CD4+ T follicular helper cells (Tfh) tissue-infiltrating cells, together with the prevalence of tertiary lymphoid structures (TLS) and germinal centers (GCs) represented a typical immune signature in all HT and 60% of GD patients. In the remaining group of GD patients, the absence of the aforementioned abnormalities was associated with a higher prevalence of ophthalmopathy. Conclusion: Tissue infiltrating Lymphoid Tissue inducer-like group 3 Innate Lymphoid cells and T follicular helper cells are increased in most thyroid autoimmune disease.

Enhanced Phenotype Definition for Precision Isolation of Precursor Exhausted Tumor-Infiltrating CD8 T Cells.

In the context of adoptive T cell transfer (ACT) for cancer treatment, it is crucial to generate in vitro large amounts of tumor-specific CD8 T cells with high potential to persist in vivo. PD-1, Tim3, and CD39 have been proposed as markers of tumor-specific tumor-infiltrating CD8 T lymphocytes (CD8 TILs). However, these molecules are highly expressed by terminally differentiated exhausted CD8 T cells (Tex) that lack proliferation potential. Therefore, optimized strategies to isolate tumor-specific TILs with high proliferative potential, such as Tcf1+ precursor exhausted T cells (Tpe) are needed to improve in vivo persistence of ACT. Here we aimed at defining cell surface markers that would unequivocally identify Types for precision cell sorting increasing the purity of tumor-specific PD-1+ Tcf1+ Tpe from total TILs. Transcriptomic analysis of Tpe vs. Tex CD8 TIL subsets from B16 tumors and primary human melanoma tumors revealed that Tpes are enriched in Slamf6 and lack Entpd1 and Havcr2 expression, which encode Slamf6, CD39, and Tim3 cell surface proteins, respectively. Indeed, we observed by flow cytometry that CD39- Tim3- Slamf6+ PD-1+ cells yielded maximum enrichment for tumor specific PD-1+ Tcf1+ OT1 TILs in B16.OVA tumors. Moreover, this population showed higher re-expansion capacity upon an acute infection recall response compared to the CD39+ counterparts or bulk PD-1+ TILs. Hence, we report an enhanced sorting strategy (CD39- Tim3- Slamf6+ PD-1+) of Tpes. In conclusion, we show that optimization of CD8 TIL cell sorting strategy is a viable approach to improve recall capacity and in vivo persistence of transferred cells in the context of ACT.

Protective role of follicular CXCR5+CD8+ T cells against dengue virus 2 infection.

Follicular CXCR5+CD8+ T cells have antiviral effects in chronic virus infection, but the roles of these cells during dengue virus 2 (DENV2) infection remain poorly understood. OBJECTIVE: This study was conducted to analyzed in detail the dynamic changes and functional properties of circulating follicular CXCR5+CD8+ T cells to explore their effects on DENV2 infection. METHODS: Circulating follicular CXCR5+CD8+ T cells and cytokines were analyzed by flow cytometry in DENV2 patients at difference days after DENV2 infection. CD8+ T cells were isolated and purified from DENV2 patients, then were stimulated with NS1 peptides and TCR stimulant. After cultivation, multiple parameters were tested. RESULTS: (1) CXCR5+CD8+ T cells emerged after DENV2 infection, with high PD-1 expression, and were correlated with the reduction in DENV2 RNA viral loads. (2) PD-1+CXCR5+CD8+ T cells were negatively associated with disease progression. (3) Serum IFN-γ, IL-6 and IL-10 levels were increased late in the course of DENV2 infection. (4) CXCR5+CD8+ T cells from DENV2 patients exhibited increased cytotoxicity and IFN-γ and IL-10 secretion. CONCLUSION: CXCR5+CD8+ T cells could play a protective role in dengue pathogenesis and may be a novel strategy for controlling DENV2 infection and vaccine development.

Imbalance of circulating Tfr/Tfh ratio in patients with rheumatoid arthritis.

Follicular helper T(Tfh) cells and follicular regulatory T(Tfr) cells are critical for the development and maintenance of germinal center and humoral immune responses. Accumulating evidence has demonstrated that the dysregulation of either Tfh or Tfr cells contributes to the pathogenesis of autoimmune diseases. The aim of this study was to examine the numbers of Tfh and Tfr cells in patients with rheumatoid arthritis (RA). Twenty-four patients with RA patients and 20 health controls (HCs) were enrolled in this study. We analyzed the numbers of Tfh (CD4+ CXCR5+ PD-1hi) cells and Tfr (CD4+ CXCR5+CD127lo) cells in 24 RA patients via flow cytometry. The level of the soluble PD-1 and its ligands (sPD-L1 and sPDL-2) were examined by ELISA. Flow cytometry revealed that both circulating Tfh and Tfr cells were increased in RA patients compared with HCs. More importantly, the ratio of Tfr/Tfh was decreased, indicating a disruption of the balance between Tfh and Tfr. The Tfr/Tfh ratio was inversely correlated with level of serum CRP, ESR, RF, anti-CCP, IgG and DAS28 index. We also found that the serum level of sPD-1 was significantly elevated in the RA patients, which was positively correlated with CRP, ESR and the number of Tfh cells. These results indicate that an imbalance of circulating Tfr and Tfh cells may be involved in the immunopathogenesis of RA and may provide novel insight for the development of RA therapies.

Increased susceptibility to oral Trichuris muris infection in the specific absence of CXCR5+ CD11c+ cells.

Trichuris muris is a natural mouse helminth pathogen which establishes infection specifically in the caecum and proximal colon. The rapid expulsion of T. muris in resistant mouse strains is associated with the induction of a protective T helper cell type 2 (Th2)-polarized immune response. Susceptible mouse strains, in contrast, mount an inappropriate Th1 response to T. muris infection. Expression of the chemokine CXCL13 by stromal follicular dendritic cells attracts CXCR5-expressing cells towards the B-cell follicles. Previous studies using a complex in vivo depletion model have suggested that CXCR5-expressing conventional dendritic cells (cDC) help regulate the induction of Th2-polarized responses. Here, transgenic mice with CXCR5 deficiency specifically restricted to CD11c+ cells were used to determine whether the specific absence CXCR5 on CD11c+ cells such as cDC would influence susceptibility to oral T. muris infection by affecting the Th1/Th2 balance. We show that in contrast to control mice, those which lacked CXCR5 expression on CD11c+ cells failed to clear T. muris infection and developed cytokine and antibody responses that suggested a disturbed Th1/Th2 balance with enhanced IFN-γ expression. These data suggest an important role of CXCR5-expressing CD11c+ cells such as cDC in immunity to oral T. muris infection.

Circulating CXCR5-Expressing CD8+ T-Cells Are Major Producers of IL-21 and Associate With Limited HIV Replication.

BACKGROUND: Despite advances made with the highly active antiretroviral therapy (HAART) in the control of the HIV 1 infection, a cure has not been achieved because of the persistence of viral reservoirs. The major HIV reservoirs remain in the lymphoid follicles because of, among other factors, the partial absence of CD8 T-cells in these structures. Recently, lymphoid follicle-confined and circulating CD8 T-cells expressing the C-X-C chemokine receptor type 5 (CXCR5) were described, possessing antiviral mechanisms that could help to control HIV replication. SETTING AND METHODS: By flow cytometry, we characterized the phenotype and function of circulating CXCR5-expressing CD8 T-cells in HIV-infected patients with natural or HAART-induced control of HIV replication. RESULTS: Circulating CXCR5-expressing CD8 T-cells exhibited low or null expression of the C-C chemokine receptor type 7 (CCR7) and had a transitional memory phenotype. Particular redistributions of CXCR5-expressing CD8 T-cells were found in HIV-infected patients, and they were partially restored by HAART. The frequency of CXCR5CCR7 CD8 T-cells was higher in spontaneous HIV controllers and negatively correlated with plasma HIV RNA levels. Total and HIV-specific CXCR5 CD8 T-cells were major producers of interleukin-21, and this function was positively associated with their interferon-γ production. CONCLUSIONS: Circulating CXCR5-expressing CD8 T-cells are associated with low-level HIV replication; these cells could be novel correlates of protection, and potentially useful in the eradication of HIV reservoirs.

Increased Circulating Follicular Regulatory T-Like Cells May Play a Critical Role in Chronic Hepatitis B Virus Infection and Disease Progression.

Follicular helper T cells (TFH) and follicular regulatory T cells (TFR), subsets of T cells, co-regulate the reactions of germinal center (GC) B cells. TFH provide help to the GC response, while the TFR suppress those processes. Nevertheless, the role of circulating TFR (cTFR) and circulating TFH (cTFH) in chronic hepatitis B virus (HBV) infection remains limited. Twenty healthy controls (HCs), 24 patients with chronic hepatitis B (CHB), 23 with HBV-related liver cirrhosis (LC), and 18 with HBV-related hepatocellular carcinoma were enrolled in our study between October 2015 and September 2016. We detected the frequencies of cTFR-like cells and cTFH-like cells, the percentage of programmed cell death-1 (PD-1), inducible co-stimulator (ICOS), and interleukin-21 (IL-21) expressed on circulating CD4+CXCR5+ T cells by flow cytometry. Compared to the HC group, the percentage of cTFR-like cells and ratio of cTFR-like/cTFH-like were significantly increased in patients with HBV infection. A raised percentage of PD-1 on circulating CD4+CXCR5+ cells and decreased IL-21-producing circulating CD4+CXCR5+ cells were observed in CHB and LC. The production of IL-21 by circulating CD4+CXCR5+ cells was significantly higher in HBeAg negative group than the positive one. Patients with high levels of alanine aminotransferase and HBV-DNA accompanied increased CXCR5+PD-1+CD4+ T cells. In addition, the frequency of cTFR-like cells and the ratio of cTFR-like/cTFH-like were positively correlated with FIB-4 and APRI. Increased cTFR-like cells and impairment of circulating CD4+CXCR5+ T cells might participate in HBV chronic infection and HBV-related diseases.

Preservation of Peripheral T Follicular Helper Cell Function in HIV Controllers.

The maturation process of high-affinity antibodies is a result of intricate interactions between B cells and follicular helper T (Tfh) cells occurring in lymphoid germinal centers. HIV infection induces significant chronic immune activation, phenotypic skewing, and inflammation driven by years of continuous viral replication. High levels of viremia as well as immune activation and dysfunction have been demonstrated to have a perturbing impact on the B cell memory compartment and contribute to B cell exhaustion. Counterintuitively, the factors associated with perturbation of the B cell compartment seem to be favorable for the generation of highly affinity-matured Env-specific antibodies in a minority of HIV-infected individuals. Thus, the impact of HIV antigenemia on B cells and Tfh cell interactions warrants further exploration. We therefore studied immunophenotypes of HIV-specific B cells in individuals with differing levels of viral control using HIV Env gp120 probes and characterized the functionality of matched T cells in peripheral blood. While CXCR5+ CD4+ T cells were significantly diminished in HIV progressors, we found that a small subset of gp120-specific interleukin-21 (IL-21)-secreting CXCR5+ CD4+ T cells were significantly associated with gp120-specific B cell frequencies. In contrast, neither bulk CXCR5+ CD4+ T cells nor other HIV antigen specificities were associated with gp120-specific B cell levels. HIV-specific B cells derived from elite controllers displayed greater amounts of gp120-specific B cells in the resting memory subset, whereas HIV-specific B cells in progressors accumulated in tissue-like and activated memory subsets. Furthermore, CXCR5+ CD4+ T cells from elite controllers showed a stronger ex vivo capacity to induce B cell maturation and immunoglobulin class switching than cells from HIV progressors.IMPORTANCE Dissecting the factors that are involved in B cell maturation and antibody development is important for HIV vaccine design. In this study, we found that HIV Env-specific CXCR5+ CD4+ T cells that secrete interleukin-21 are strongly associated with B cell memory phenotypes and function. Moreover, we found that the immune responses of HIV controllers showed intrinsically better helper activity than those of HIV progressors.

Efficacy and Safety of Sofosbuvir Plus Daclatasvir for Treatment of HCV-Associated Cryoglobulinemia Vasculitis.

Circulating mixed cryoglobulins are detected in 40%-60% of patients with hepatitis C virus (HCV) infection, and overt cryoglobulinemia vasculitis (CryoVas) develops in approximately 15% of patients. Remission of vasculitis has been associated with viral clearance, but few studies have reported the effectiveness of direct-acting antiviral drugs in these patients. We performed an open-label, prospective, multicenter study of the effectiveness and tolerance of an all-oral, interferon- and ribavirin-free regimen of sofosbuvir plus daclatasvir in patients with HCV-associated CryoVas. Forty-one consecutive patients with active HCV-associated CryoVas (median age, 56 y; 53.6% women) were recruited from hospitals in Paris, France, from 2014 through 2016. They received sofosbuvir (400 mg/day) plus daclatasvir (60 mg/day) for 12 weeks (n = 32) or 24 weeks (n = 9), and were evaluated every 4 weeks until week 24 and at week 36. Blood samples were analyzed for complete blood count, serum chemistry profile, level of alanine aminotransferase, rheumatoid factor activity, C4 fraction of complement, and cryoglobulin; peripheral blood mononuclear cells were isolated for flow cytometry analysis. Thirty-seven patients (90.2%) had a complete clinical response (defined by improvement of all the affected organs involved at baseline and no clinical relapse) after a median time of 12 weeks of therapy; all had a sustained virologic response (no detectable serum HCV RNA 12 weeks after the end of antiviral therapy). Patients' mean cryoglobulin level decreased from 0.56 ± 0.18 at baseline to 0.21 ± 0.14 g/L at week 36, and no cryoglobulin was detected in 50% of patients at this time point. After antiviral therapy, patients had increased numbers of T-regulatory cells, IgM+CD21-/low-memory B cells, CD4+CXCR5+ interleukin 21+ cells, and T-helper 17 cells, compared with before therapy. After a median follow-up period of 26 months (interquartile range, 20-30 mo), no patients had a serious adverse event or relapse of vasculitis.