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Multicentric Castleman disease-thrombocytopenia, anasarca, reticulin fibrosis of bone marrow, renal dysfunction and organomegaly (MCD-TAFRO)-is an emergent phenotype characterized by lymphoproliferation, fluid collection, hemocytopenia and multiple organopathy. Although studies have demonstrated an aberrant blood cytokine/chemokine profile referred to as "chemokine storm", the pathogenesis remains unclear. We aimed to identify pathogenic key molecules, potential diagnostic targets and therapeutic markers in MCD-TAFRO using serum cytokine/chemokine profiles. We performed the targeted cytokine/chemokine multiplex analysis in six cases of MCD-TAFRO with remission or non-remission status. We observed significant changes in serum concentrations of CCL2, CCL5, and Chitinase-3-like-1 in the MCD-TAFRO patients with active state compared to inactive state. Ingenuity pathway analysis revealed that glycogen synthase kinase 3 (GSK3) and CCR6, which is expressed in megakaryocytes, were detected as upstream positive regulators for activating MCD-TAFRO status. More GSK3β + CCR6 + cells like megakaryocytes were detected in the bone marrow of patients with MCD-TAFRO than in those with systemic lupus erythematosus, MCD-not otherwise specified or autoimmune haemophagocytic lymphohistiocytosis. The cellularity of GSK3β + CCR6 + cells was correlated with disease activity, including thrombocytopenia and anaemia. In conclusion, GSK3β and CCR6 of bone marrow cells were potentially involved in the pathogenesis of MCD-TAFRO and may act as diagnostic targets and therapeutic markers., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Human regulatory T (Treg) cells play a central role in controlling allergic inflammation in the airways. A reduced number of peripheral Treg cells and decreased suppressive function have been previously reported in the pathogenesis of allergic asthma. However, the characteristic role of specific Treg cell subsets and their mechanisms in the pathogenesis of allergic asthma remain unclear. In this study, we examined the proportion of different Treg cell subsets in both healthy subjects and patients with allergic asthma using flow cytometry and single-cell RNA sequencing. The migration function of the cells was compared using cell sorting and Transwell experiments. Furthermore, two allergen-challenged mouse models and a cell transfer experiment were used to examine the role of these Treg subsets. We found that the proportion of CD25 + Foxp3 + CD127 - Treg cells in the peripheral blood of patients with allergic asthma was lower than in those of healthy subjects. Furthermore, the circulating Treg cells expressed lower levels of CCR6 and IL-17 compared with healthy subjects. The chemokine from the airway mucosa, CCL20, was abundantly expressed, and Transwell experiments further proved that this chemokine promoted CCR6 + Treg cell migration in vitro . A mouse model induced by house dust mite (HDM) revealed that the number of CCR6 + Treg cells in the lung tissue increased remarkably. The incidence of allergic asthma may be related to an increase in Treg cells secreting IL-17 in the lung tissue. Recruited CCR6 + Treg cells are likely to differentiate into Th17-like cells under the Th17 environment present in the lungs. IL-17 derived from Th17-like cells could be associated with the pathology of allergic asthma by promoting Th17 responses, thereby favoring HDM-induced asthma exacerbations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Shen, Zhang, Xie, Chen, Li, Zheng, Chai, Wang, Zang and He.)

Severe burn injury causes local and systemic immune responses that can persist up to months, and can lead to systemic inflammatory response syndrome, organ damage and long-term sequalae such as hypertrophic scarring. To prevent these pathological conditions, a better understanding of the underlying mechanisms is essential. In this longitudinal study, we analyzed the temporal peripheral blood immune profile of 20 burn wound patients admitted to the intensive care by flow cytometry and secretome profiling, and compared this to data from 20 healthy subjects. The patient cohort showed signs of systemic inflammation and persistently high levels of pro-inflammatory soluble mediators, such as IL-6, IL-8, MCP-1, MIP-1β, and MIP-3α, were measured. Using both unsupervised and supervised flow cytometry techniques, we observed a continuous release of neutrophils and monocytes into the blood for at least 39 days. Increased numbers of immature neutrophils were present in peripheral blood in the first three weeks after injury (0.1-2.8 × 10 6 /ml after burn vs. 5 × 10 3 /ml in healthy controls). Total lymphocyte numbers did not increase, but numbers of effector T cells as well as regulatory T cells were increased from the second week onward. Within the CD4 + T cell population, elevated numbers of CCR4 + CCR6 - and CCR4 + CCR6 + cells were found. Altogether, these data reveal that severe burn injury induced a persistent innate inflammatory response, including a release of immature neutrophils, and shifts in the T cell composition toward an overall more pro-inflammatory phenotype, thereby continuing systemic inflammation and increasing the risk of secondary complications., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Mulder, Vlig, Boekema, Stoop, Pijpe, van Zuijlen, de Jong, van Cranenbroek, Joosten, Koenen and Ulrich.)

B cells are important pathogenic players in multiple sclerosis (MS), but their exact role is not known. We have previously demonstrated that B cells from cerebrospinal fluid (CSF) of MS patients can activate T cells that specifically recognize antigenic determinants (idiotopes) from their B cell receptors (BCRs). The aim of this study was to evaluate whether in silico prediction models could identify antigenic idiotopes of immunoglobulin heavy-chain variable (IGHV) transcriptomes in MS patients. We utilized a previously assembled dataset of CSF IGHV repertoires from MS patients. To guide selection of potential antigenic idiotopes, we used in silico predicted HLA-DR affinity, endosomal processing, as well as transcript frequency from nine MS patients. Idiotopes with predicted low affinity and low likelihood of cathepsins cleavage were inert controls. Peripheral blood mononuclear cells from these patients were stimulated with the selected idiotope peptides in presence of anti-CD40 for 12 h. T cells were then labeled for activation status with anti-CD154 antibodies and CD3 + CD4 + T cells phenotyped as memory (CD45RO + ) or naïve (CD45RO - ), with potential for brain migration (CXCR3 and/or CCR6 expression). Anti-CD14 and -CD8 were utilized to exclude monocytes and CD8 + T cells. Unstimulated cells or insulin peptides were negative controls, and EBNA-1 peptides or CD3/CD28 beads were positive controls. The mean proportion of responding memory CD4 + T cells from all nine MS patients was significantly higher for idiotope peptides with predicted high HLA-DR affinity and high likelihood of cathepsin cleavage, than toward predicted inert peptides. Responses were mainly observed toward peptides affiliated with the CDR3 region. Activated memory CD4 + T cells expressed the chemokine receptor CCR6, affiliated with a Th17 phenotype and allowing passage into the central nervous system (CNS). This in vitro study suggests that that antigenic properties of BCR idiotopes can be identified in silico using HLA affinity and endosomal processing predictions. It further indicates that MS patients have a memory T cell repertoire capable of recognizing frequent BCR idiotopes found in endogenous CSF, and that these T cells express chemokine receptors allowing them to reach the CSF B cells expressing these idiotopes., (Copyright © 2020 Høglund, Bremel, Homan, Torsetnes, Lossius and Holmøy.)

IL-11 + CD4 + cells accumulate in the cerebrospinal fluid of patients with early relapsing-remitting multiple sclerosis (MS) and in active brain MS lesions. Mouse studies have confirmed a causal role of IL-11 in the exacerbation of relapsing-remitting experimental autoimmune encephalomyelitis (RREAE). Administration of IL-11 at the time of clinical onset of RREAE induced an acute exacerbation and increased clinical scores, which persisted during the entire course of the disease. IL-11 increased the numbers of spinal cord inflammatory foci, as well as the numbers of peripheral and CNS-infiltrating IL-17 + CD4 + cells and IL-17A serum levels. Ag recall assays revealed that IL-11 induces IL-17A + , GM-CSF + , and IL-21 + CD4 + myelin Ag-reactive cells. Passive transfer of these encephalitogenic CD4 + T cells induced severe RREAE with IL-17A + CCR6 + CD4 + and B cell accumulation within the CNS. Furthermore, passive transfer of nonmanipulated CNS-derived mononuclear cells from mice with RREAE after a single dose of IL-11 induced severe RREAE with increased accumulation of IL-17A + and CCR6 + CD4 + cells within the CNS. These results suggest that IL-11 might serve as a biomarker of early autoimmune response and a selective therapeutic target for patients with early relapsing-remitting MS., (Copyright © 2019 by The American Association of Immunologists, Inc.)

Chemokines and their receptors have been proposed to play important roles in tumor progression and metastasis. To investigate their roles in the progression of primary and metastatic malignant liver tumors and their prognosis, we compared expression profiles of CXCL12/CXCR4, CCL20/CCR6, and CCL21/CCR7 in hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM). Immunohistochemistry was used to analyze the expression levels of the chemokine/chemokine receptor pairs in 29 HCC and 11 CRLM specimens and adjacent non-cancerous tissues, and correlations with clinicopathological variables and overall survival were determined. CCL20/CCR6 expression was higher in HCC than in adjacent non-cancerous tissues. High CCR6 expression in HCC was negatively associated with 5-year survival rate and was an independent prognostic factor for overall survival of HCC patients, whereas differences were not observed between CRLM and adjacent tissues. Furthermore, significantly higher expression of CCL21/CCR7 was found in CRLM than in HCC. In summary, the CCL20/CCR6 axis was elevated in HCC but not in CRLM, whereas the CCL21/CCR7 axis was elevated in CRLM but not in HCC.

Current researches have determined the significance of C-C chemokine receptor (CCR)6 expression as either a marker of T helper cells (Th) or an effector and regulator of T cell function. However, the roles of CCR6 in the pathogenesis of immune thrombocytopenia (ITP) are unclear. In this study, we aimed to investigate the phenotype and functional characteristics of circulating CCR6 + T cells in blood from chronic ITP patients and healthy controls. We found that the frequency of CCR6 + CD4 + cells was higher in ITP patients than in healthy controls. Anti-CD3/anti-CD28 stimulation induced rapid expansion of CCR6 + CD4 + cells in ITP patients. CCR6 + CD4 + cells had a phenotype of activated cells and predominantly expressed CD45RO. Forkhead box protein P3 (FoxP3) and CD25-positive cells were exclusively detected within the CCR6 + CD4 + cells. In ITP patients, CCR6 + regulatory T cells (T reg ) were decreased and positively correlated with platelet counts and transforming growth factor (TGF)-β plasma levels. In contrast to CCR6 - counterparts, CCR6 + CD4 + cells produced higher levels of interleukin (IL)-17A. The frequency of CCR6 + Th17 was higher in ITP patients and positively correlated with IL-17A levels in supernatant. Most importantly, CCR6 + CD4 + cell subpopulations, but not CCR6 - CD4 + , were closely correlated to treatment response of ITP patients. These findings suggest that circulating CCR6 + CD4 + cells in ITP patients have characteristics of activated memory Th17 phenotype and could be used to monitor disease activity and treatment response., (© 2018 British Society for Immunology.)

Background Human β-defensins (hBD2 and hBD3) are small cationic antimicrobial peptides of innate immune system which can act as a barrier against the majority of pathogens, contributing to the host immune defence. Objective The aim of study is to determine whether hBD2 and hBD3 play a role in development and proliferation of human effector CD4 T cells or not. Furthermore, if enhanced proliferation is observed in the presence of hBD2 and hBD3, these data will demonstrate whether chemokine receptor type 6 (CCR6) is required to be present for this activity to occur. Methods In this study, we examined the effect of hBD2 and hBD3 on CD4+ T cell proliferation in CCR6+ and CCR6- T cells through co-culture of peripheral blood mononuclear cells with anti-CD3 and anti-CD28 stimulation in the presence or absence of hBD2 and hBD3. Proliferation was assessed using flow cytometry. Results It was demonstrated that, co-culture with hBD2 and hBD3 led to up-regulation of CD4+ T cell proliferation after 72 h whereas, CD4+ T cell proliferation was suppressed after 96 h. On the other hand, CCR6- and CCR6+ T cell proliferation was up-regulated after 72 h. But, CCR6+ only was down-regulated in the second cycle in the presence of hBD3. In contrast, after 96 h CCR6+ and CCR6- T cell proliferation was decreased. Conclusion Collectively, our data indicated that hBD2 and hBD3 play a positive and negative regulatory role in development and proliferation of human effector CD4+ T cells which is essential for optimal adaptive immune responses and the control of immunopathology.

The profound deficiency of Th17 cells contributes to HIV disease progression. The mechanisms of their perturbation remain unclear. Recently, CCR6 + CD95 + CD4 + naïve T cells (CCR6 + CD95 + CD4 + T NA ), identified as pre-committed Th17 precursors, were recognized as a subpopulation of CD4 + T cells with stem cell properties. Following phenotypical identification, we evaluated their level in patients during chronic HIV infection and following antiretroviral therapy (ART) using flow cytometry. The levels of CCR6 + CD95 + CD4 + T NA were decreased during chronic HIV infection and correlated with CD4 + T cell counts. Immunological responders harbored higher frequency of CCR6 + CD95 + CD4 + T NA , which was associated with CD4/CD8 T cell ratio. Immunological non-responders with lower frequency of CCR6 + CD95 + CD4 + T NA failed to exhibit a correlation between CCR6 + CD95 + CD4 + T NA and CCR6 + CD95 + CD4 + T CM , and displayed elevated ratio of CCR6 + CD95 + CD4 + T CM /T NA . The number of CCR6 + CD95 + CD4 + T NA was increased following early ART. These findings shed light on the importance of targeting pre-committed Th17 precursors that enhance immune reconstitution., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease that is characterized by the presence of different autoantibodies such as rheumatoid factor (RF) and anti-citrullinated protein antibodies. CD4T cells expressing CXCR5, referred as follicular helper T cells (Tfh), collaborate with B cells to produce antibodies. Differential expression of CXCR3 and CCR6 within CD4 + CXCR5 + T cells defines three mayor subsets: CXCR3 + CCR6 - (Tfh1), CXCR3 - CCR6 - (Tfh2) and CXCR3 - CCR6 + (Tfh17). The aim of the study was to assess whether there is an association between the percentage of these cells and RA and whether there is a correlation with disease activity., Material and Methods: Twenty-four RA patients, 22 healthy controls (HC) and 16 undifferentiated arthritis (UA) patients were included. Percentage of CD4 + CXCR5 + T cells and their subsets were analyzed by flow cytometry., Results: No differences were found in the percentages of CD4 + CXCR5 + T cells in the comparison of RA vs HC or RA vs UA patients. Tfh1, Tfh2 and Tfh17 subsets showed no differences either. There was no correlation between CD4 + CXCR5 + T cells, Tfh1, Tfh2 and Tfh17, and Disease Activity Score in twenty-eight joints (DAS28) or erythrocyte sedimentation rate. Surprisingly, there was a positive correlation between Tfh17 cells and C-reactive protein. Finally, there was no correlation between CD4 + CXCR5 + T cells, or their subsets, and anti-mutated citrullinated vimentin, or between the cells and RF., Conclusion: There were no differences between the percentages of CD4 + CXCR5 + T cells and their subsets in peripheral blood of RA patients and the percentages of cells in the control groups. This finding does not rule out a pathogenic role of these cells in the development and activity of RA., (Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.)

Recruitment of leukocytes by chemokines and chemokine receptors to CNS plays a crucial role in the induction of inflammatory response in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). In the present study, chemokine and chemokine receptors involved in trafficking of lymphocytes to the CNS were measured in HAM/TSP patients, HTLV-1 asymptomatic carriers (ACs), and healthy controls. The PVL, CCR6, and CXCR3 mRNA expression, and CXCL9 and CXCL10 protein levels were measured in all subjects. The PVL of HAM/TSP patients was higher than that of ACs (P = 0.02). CCR6 expression was higher in HAM/TSP patients and in ACs compared to the healthy controls (P = 0.005 and P = 0.04, respectively). A significant difference was observed in CCR6 expression when a combination of HAM/TSP patients and ACs were compared to the healthy individuals (P = 0.005). Furthermore, there was a significantly lower CXCR3 expression between HAM/TSP and control groups (P = 0.001), and between the ACs and healthy controls (P = 0.001). However, the increased CXCR3 expression in ACs compared to HAM/TSP patients was not significant. Furthermore, the CXCL10 protein levels in HAM/TSP patients was higher than in controls (P = 0.012), and CXCL9 protein levels was also higher in the HAM/TSP and ACs groups than in the controls (P = 0.001 and P = 0.004, respectively). In conclusion, it seems that decreased expression of CXCR3 and higher expression of CCR6 were associated with HTLV-1 infection, what indicate that these alterations may favor virus dissemination but not disease manifestation., (© 2017 Wiley Periodicals, Inc.)

Experimental autoimmune uveitis (EAU), in which CD4 + Th1 and/or Th17 cells are immunopathogenic, mimics various clinical features of noninfectious uveitis in humans. The impact of bromodomain extraterminal (BET) inhibitors on Th17 cell function was studied in a mouse model of EAU in vivo and in mouse and human Th17 cells in vitro. Two BET inhibitors (GSK151 and JQ1) were able to ameliorate the progression of inflammation in EAU and in mouse CD4 + T cells in vitro, downregulating levels of Th17 cells. Additionally, the uveitogenic capacity of Th17 cells to transfer EAU was abrogated by BET inhibitors in an adoptive transfer model. In human CD4 + T cells, a 5-d exposure to BET inhibitors was accompanied by a significant downregulation of Th17-associated genes IL-17A, IL-22, and retinoic acid-related orphan receptor γt. However, in vitro, the inhibitors had no effect on already polarized Th17 cells. The key finding is that, in response to BET inhibitors, Th17-enriched cultures developed a regulatory phenotype, upregulated FOXP3 expression and IL-10 secretion, and lost pathogenicity in vivo. We conclude that BET targeting of Th17 cells is a potential therapeutic opportunity for a wide range of inflammatory and autoimmune diseases, including uveitis., (Copyright © 2017 by The American Association of Immunologists, Inc.)

Objectives: The objective of this article is to investigate the contribution of colon and blood CD4 T-cell subsets expressing the chemokine receptor CCR6 to HIV persistence during antiretroviral therapy., Design: Matched sigmoid biopsies and blood samples (n = 13) as well as leukapheresis (n = 20) were collected from chronically HIV-infected individuals receiving antiretroviral therapy. Subsets of CD4 T cells with distinct differentiation/polarization profiles were identified using surface markers as follows: memory (TM, CD45RA), central memory (TCM; CD45RACCR7), effector (TEM/TM; CD45RACCR7), Th17 (CCR6CCR4), Th1Th17 (CCR6CXCR3), Th1 (CCR6CXCR3), and Th2 (CCR6CCR4)., Methods: We used polychromatic flow cytometry for cell sorting, nested real-time PCR for HIV DNA quantification, ELISA and flow cytometry for HIV p24 quantification. HIV reactivation was induced by TCR triggering in the presence/absence of all-trans retinoic acid., Results: Compared with blood, the frequency of CCR6 TM was higher in the colon. In both colon and blood compartments, CCR6 TM were significantly enriched in HIV DNA when compared with their CCR6 counterparts (n = 13). In blood, integrated HIV DNA levels were significantly enriched in CCR6 versus CCR6 TCM of four of five individuals and CCR6 versus CCR6 TEM of three of five individuals. Among blood TCM, Th17 and Th1Th17 contributed the most to the pool of cells harboring integrated HIV DNA despite their reduced frequency compared with Th2, which were infected the least. HIV reactivation was induced by TCR triggering and/or retinoic acid exposure at higher levels in CCR6 versus CCR6 TM, TCM, and TEM., Conclusion: CCR6 is a marker for colon and blood CD4 T cells enriched for replication-competent HIV DNA. Novel eradication strategies should target HIV persistence in CCR6CD4 T cells from various anatomic sites.

Background: Th17 cells are permissive to HIV-1 infection and their depletion from the gut of infected individuals leads to microbial translocation, a major cause for non-AIDS co-morbidities. Most recent evidence supports the contribution of long-lived Th17 cells to HIV persistence during antiretroviral therapy (ART). However, the identity of long-lived Th17 cells remains unknown., Results: Here, we performed an in-depth transcriptional and functional characterization of four distinct Th17 subsets and investigated their contribution to HIV reservoir persistence during ART. In addition to the previously characterized CCR6(+)CCR4(+) (Th17) and CCR6(+)CXCR3(+) (Th1Th17) subsets, we reveal the existence of two novel CCR6(+) subsets, lacking (double negative, CCR6(+)DN) or co-expressing CXCR3 and CCR4 (double positive, CCR6(+)DP). The four subsets shared multiple Th17-polarization markers, a fraction of cells proliferated in response to C. albicans, and exhibited lineage commitment and plasticity when cultured under Th17 and Th1 conditions, respectively. Of note, fractions of CCR6(+)DN and Th17 demonstrated stable Th17-lineage commitment under Th1-polarization conditions. Among the four subsets, CCR6(+)DN expressed a unique transcriptional signature indicative of early Th17 development (IL-17F, STAT3), lymph-node homing (CCR7, CD62L), follicular help (CXCR5, BCL6, ASCL2), and self-renewal (LEFI, MYC, TERC). Cross sectional and longitudinal studies demonstrated that CCR6(+)DN cells were the most predominant CCR6(+) subset in the blood before and after ART initiation; high frequencies of these cells were similarly observed in inguinal lymph nodes of individuals receiving long-term ART. Importantly, replication competent HIV was isolated from CCR6(+)DN of ART-treated individuals., Conclusions: Together, these results provide new insights into the functional heterogeneity of Th17-polarized CCR6(+)CD4(+) T-cells and support the major contribution of CCR6(+)DN cells to HIV persistence during ART.

Lymph nodes (LNs) contain innate-like lymphocytes that survey the subcapsular sinus (SCS) and associated macrophages for pathogen entry. The factors promoting this surveillance behavior have not been defined. Here, we report that IL7R(hi)Ccr6(+) lymphocytes in mouse LNs rapidly produce IL17 upon bacterial and fungal challenge. We show that these innate-like lymphocytes are mostly LN resident. Ccr6 is required for their accumulation near the SCS and for efficient IL17 induction. Migration into the SCS intrinsically requires S1pr1, whereas movement from the sinus into the parenchyma involves the integrin LFA1 and its ligand ICAM1. CD169, a sialic acid-binding lectin, helps retain the cells within the sinus, preventing their loss in lymph flow. These findings establish a role for Ccr6 in augmenting innate-like lymphocyte responses to lymph-borne pathogens, and they define requirements for cell movement between parenchyma and SCS in what we speculate is a program of immune surveillance that helps achieve LN barrier immunity., Competing Interests: The authors declare that no competing interests exist.

Background: CCR6 expression is deregulated in some human malignancies and may be involved in the tumor progression. The aim of the present study was to determine the CCR6 expression in gastric cancer (GC) and to clarify its clinical significance., Methods: We used western blotting to examine CCR6 protein expression in GC tissues and matched adjacent non-tumor tissues. Immunohistochemistry was performed on a large cohort of 372 postoperative GC samples. Chi-square test, Kaplan-Meier analysis and Cox regression model were used to analyze the data., Results: Upregulated CCR6 protein expression was observed in the GC tissues by western blotting compared with the adjacent non-cancerous gastric tissues. High CCR6 expression was detected in 56.5 % (210/372) samples and significantly associated with the extracapsular extension of the tumor, tumor relapse and poor overall survival in GC (P < 0.001). Further analysis demonstrated that the CCR6 expression level stratified the patient outcome in stage II, stage III, T3/4, N positive and poorly differentiated/undifferentiated tumor subgroups. The Cox regression analysis showed that high expression of CCR6 was an independent prognostic factor for GC patients., Conclusions: CCR6 expression may be a novel biomarker for predicting clinical outcomes for GC patients.

Background: HIV latent infection can be established in vitro by treating resting CD4 T cells with chemokines that bind to chemokine receptors (CKR), CCR7, CXCR3, and CCR6, highly expressed on T cells., Objective: To determine if CKR identify CD4 T cells enriched for HIV in HIV-infected individuals receiving suppressive antiretroviral therapy (ART)., Design: A cross-sectional study of CKR expression and HIV persistence in blood from HIV-infected individuals on suppressive ART for more than 3 years (n = 48). A subset of 20 individuals underwent leukapheresis and sorting of specific CD4 T-cell subsets., Methods: We used flow cytometry to quantify CCR5, CCR6, CXCR3, and CXCR5 expression on CD4 T cells. HIV persistence was quantified using real-time Polymerase Chain Reaction to detect total, integrated HIV DNA, 2-long terminal repeat circles and cell-associated unspliced (CA-US) HIV RNA in total CD4 T cells from blood or sorted T-cell subsets. Associations between CKR and HIV persistence in CD4 T cells in blood were determined using regression models and adjusted for current and nadir CD4 T-cell counts., Results: The frequency of cells harbouring integrated HIV DNA was inversely associated with current CD4 T-cell count and positively associated with CCR5+ CD4 T cells, CXCR3+CCR6+ and CXCR3+CCR6- expression on total memory CD4 T cells (P < 0.001, 0.048, 0.015, and 0.016, respectively). CXCR3+CCR6+ CM CD4 T cells contained the highest amount of integrated HIV DNA and lowest ratio of CA-US HIV RNA to DNA compared to all T-cell subsets examined., Conclusion: CXCR3 and CCR6 coexpression defines a subset of CD4 T cells that are preferentially enriched for HIV DNA in HIV-infected individuals on ART.

Systemic lupus erythematosus (SLE) is a complex and potentially fatal autoimmune disorder. Although Th17 cells are thought to be central mediators of SLE, mechanisms underlying their counter regulation remain largely unknown. To help define this, we studied the function of the newly defined Stat3-dependent Th17-specific regulatory T cells (Treg17). Treg-specific deletion of Stat3 was achieved by generating Foxp3(Cre) × Stat3(fl/fl) mice and SLE was induced by intraperitoneal injection of pristane. Lack of Treg17 cells in these mice caused selectively enhanced peritoneal Th17 inflammation. Importantly, Treg17 deficiency also resulted in aggravated pulmonary vasculitis with increased percentages of Th17 cells and significantly higher mortality. Similarly, 4 and 9 months after pristane injection, analysis of renal and systemic immunity showed overshooting Th17 responses in the absence of Treg17 cells, associated with the aggravation of lupus nephritis. Expression of the Th17 characteristic trafficking receptor CCR6 was strikingly reduced on Tregs of Foxp3(Cre) × Stat3(fl/fl) mice, resulting in impaired renal Treg infiltration. Thus, Stat3-induced Treg17 cells are novel antiinflammatory mediators of SLE. One mechanism enabling Treg17 cells to target pathogenic Th17 responses is shared expression of the chemokine receptor CCR6., (Copyright © 2015 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Background: Different serotypes of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis have been shown to induce differential dendritic cell (DC) responses. This study investigates whether cytokine and CC-chemokine receptor (CCR) production by DCs stimulated with different serotypes of A. actinomycetemcomitans or P. gingivalis is Toll-like receptor 2 (TLR2) and/or TLR4 dependent., Methods: DCs were obtained from healthy individuals and primed at a multiplicity of infection (MOI) of 10(2) with different A. actinomycetemcomitans or P. gingivalis serotypes in the presence or absence of anti-TLR2 or anti-TLR4 blocking antibodies. TLR2 and TLR4 expression, CCR5 and CCR6 expression, and interleukin (IL)-1β, IL-10, IL-12, and IL-23 expression and secretion were quantified by flow cytometry, real-time reverse-transcription polymerase chain reaction, and enzyme-linked immunosorbent assay., Results: When DCs were stimulated with serotype b of A. actinomycetemcomitans or serotype K1 of P. gingivalis, higher levels of TLR2 or TLR4, respectively, were detected compared to DCs stimulated with the other serotypes. Similarly, higher levels of cytokines and CCRs were detected in serotype b- or serotype K1-primed DCs compared to the others, and these increased levels positively correlated with levels of TLR2 or TLR4. When TLR2 signaling was blocked using a specific anti-TLR2 monoclonal antibody, serotype b-induced cytokine and CCR expression was inhibited; when TLR4 signaling was blocked, serotype K1-induced response was inhibited., Conclusions: These results demonstrate that the variability of secretion of cytokines and expression of CCRs detected in DCs stimulated with different serotypes of A. actinomycetemcomitans or P. gingivalis is TLR2 or TLR4 dependent, respectively.

Background: Interleukin (IL)-17A and Th17 cells are critically involved in T cell-mediated synovial inflammation. Besides IL-17A, Th17 cells produce IL-22. Recently, Th22 cells were discovered, which produce IL-22 in the absence of IL-17. However, it remains unclear whether IL-22 and Th22 cells contribute to T cell-mediated synovial inflammation. Therefore, we examined the potential of IL-22 and Th22 cells to induce synovial inflammation and whether IL-22 is required for T cell-mediated experimental arthritis., Methods: Peripheral and synovial Th17 and Th22 cells were identified and sorted from patients with rheumatoid arthritis (RA). Co-culture experiments of these primary T cell populations with RA synovial fibroblasts (RASF) were performed. The in vivo IL-22 contribution to synovial inflammation was investigated by inducing T cell-mediated arthritis in IL-22 deficient mice and wild-type mice., Results: Peripheral Th17 and Th22 cell populations were increased in patients with RA and present in RA synovial fluid. In T cell-RASF co-cultures, IL-22 in the presence of IL-17A had limited effects on IL-6, IL-8, matrix metalloproteinase-1 (MMP-1) and MMP-3 production. Furthermore, primary peripheral blood and synovial Th17 cells were more potent in the induction of these factors by RASF compared with Th22 cells. In line with this, similar synovial inflammation and disease severity was found between IL-22 deficient and wild-type mice in T cell-mediated experimental arthritis., Conclusions: These findings show that IL-17A/Th17 cell-mediated synovial inflammation is independent of IL-22 and Th22 cells. This implies that targeting IL-17A/Th17 cells, rather than IL-22/Th22 cells, should be the focus for treatment of T cell-mediated synovial inflammation.

Background: The role of programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) in persistent HBV infection is controversial. Increasing PD-1 and PD-L1 expression has been found in hepatitis B patients during immune clearance phase, but not in HBV-tolerant patients. We investigated PD-1 and PD-L1 expression and inflammation in chronic hepatitis B., Methods: Twenty patients with chronic hepatitis B participated in this study. Fifteen patients were in the immune clearance phase, and 5 were in the immune inactive phase. Circulating HBV-specific T cells were analyzed by flow cytometric detection of major histocompatibility complex (MHC) class I peptide complexes, known as pentamers. Intra-hepatic PD-1 and PD-L1 expressions were analyzed by immunostaining., Results: The frequency of pentamers, including core 18-27 (1.88%+/-0.36%), env 335-343 (1.85%+/-0.37%), and pol 575-583 (1.56%+/-0.29%) was 8.30-, 7.71- and 8.48-fold greater during immune clearance phase than those during the immune inactive phase. In addition, more than 70% of circulating pentamers were PD-1 positive. During immune clearance phase, the numbers of intra-hepatic PD-1 and PD-L1 positive cells were 108+/-23/HPF and 97+/-20/HPF respectively, in contrast, there was a paucity of PD-1 and PD-L1 positive cells in the immune inactive phase. The numbers of intra-hepatic PD-1 and PD-L1 positive cells were positively correlated with serum alanine aminotransferase and the number of intra-hepatic CD8+ T cells. Immunofluorescence showed that almost all of the intra-hepatic CD8+ T cells were PD-1 and CCR6 positive. These cells aggregated around macrophage inflammatory protein-3 alpha (MIP3alpha) positive cells and mixed with PD-L1 positive cells., Conclusions: PD-1 and PD-L1 expressions were significantly correlated with inflammation. CCR6 and PD-1 co-expressed in the same cells; these cells were increased both in circulation and the inflamed liver and aggregated around MIP3alpha positive cells. The mixture of CCR6 and PD-1, MIP3alpha and PD-L1 positive cells created immune response compartments which played an important role in specific immune response in HBV immune clearance.

Background: Systemic lupus erythematosus (SLE) is associated with a numerical and functional reduction of peripheral blood (PB) invariant natural killer T (iNKT) cells. Limited information exists on the role of iNKT cells in the pathogenesis of lupus erythematosus., Objective: To investigate the frequency and phenotype of iNKT cells in PB and dermal infiltrates from patients with SLE, subacute-cutaneous lupus erythematosus (SCLE) and discoid lupus erythematosus (DLE)., Methods: PB was obtained from 23 SLE, 6 SCLE, and 11 DLE patients, and from 30 healthy controls. iNKT cell frequency and CCR4/CCR6 surface expression were assessed by flow cytometry. The frequency and phenotype of skin infiltrating Vα24(+)Vβ11(+) iNKT cells were investigated by immunofluorescence in lesional biopsies from 20 patients, unaffected skin from 3 patients, and from 6 healthy controls., Results: Lupus erythematosus patients displayed significantly lower percentages of circulating CD3(+)6B11(+) iNKT cells compared to healthy controls. Whereas CCR6 expression on iNKT cells was enhanced in active SLE patients regardless of cutaneous involvement compared to healthy controls, CCR4 was exclusively increased in patients with active cutaneous lesions. Furthermore, iNKT cells were significantly enriched in lesional skin of SLE and DLE patients, but not in unaffected skin of lupus patients. The majority of lesional iNKT cells expressed IFN-γ and CCR4., Conclusion: The deficiency in circulating iNKT cells in cutaneous lupus erythematosus is associated with an increase of iNKT cells at the site of cutaneous inflammation. These data underscore the importance of analyzing iNKT cells not only in PB, but also in the target tissues., (Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Background: Discoid lupus erythematosus (DLE) is a cutaneous autoimmune inflammatory disease in which the role of conventional dendritic cells (cDCs) in skin damage has not been evaluated., Objective: To evaluate the involvement of cDCs in DLE pathogenesis., Material & Methods: Skin biopsies from 42 patients with DLE were embedded in paraffin or placed in culture. The dermis was separated and cell suspensions were characterized by flow cytometry., Results: We found an increase in cDCs with inflammatory characteristics in the skin of DLE patients, compared with control skins. Interestingly, cDCs from the DLE patients expressed low levels of the inhibitory molecule PD-L1 and showed a high expression of CCR6, which correlated with disease activity. Increased cellular death was observed in the skin of DLE patients compared with control skin and remarkably we found that damage-associated molecular patterns could be responsible for CCR6 expression on cDCs in the skin., Conclusions: Our results indicate the presence of pathogenic CCR6+ cDCs in the skin lesions of DLE patients, which could result from in situ phenotypic changes.

Background: Arthroscopic anterior cruciate ligament (ACL) reconstruction with allograft may vary in instrumented laxity compared with autograft. T helper (Th) cells (CCR4+CCR6+Th) and regulatory T (Treg) cells are important in the early stage of immunologic reactions. It is unknown whether the ratio of CCR4+CCR6+Th to Treg is imbalanced and if it correlates with early postoperative laxity after ACL allograft reconstruction. We investigated the ratio and functional influence between these cells and the correlation with postoperative anterior knee laxity., Methods: In 40 patients who experienced unilateral arthroscopy-assisted ACL reconstruction, the ACL graft was an allograft in 20 patients and autograft in 20 patients. Maximum manual anterior tibiofemoral laxity measurements were performed with arthrometry testing. The phenotypes of CCR4+CCR6+Th and Treg cells of peripheral blood and synovial fluid from the two patient groups were determined by flow cytometry. The functionality of isolated Treg cells and effector T cells was quantified in (3)H-thymidine proliferation assays., Results: Both CCR4+CCR6+Th and Treg cells were significantly increased in the synovial fluid in the allograft group and were correlated with anterior knee laxity. The ratio of CCR4+CCR6+Th to Treg cells in the synovial fluid was positively correlated with laxity. Synovial CD4+CD25+ Treg cells displayed an increased suppressive capacity compared with blood CD4+CD25+ Treg cells. Activated responder T cells from the synovial fluid were less susceptible to CD4+CD25+ T cell-mediated suppression than were responder cells from blood., Conclusions: The ratio of CCR4+CCR6+Th to Treg cells in the synovial fluid was correlated with anterior laxity after ACL allograft reconstruction.

Recent studies have demonstrated that the chemokine CCL20 and its receptor CCR6 may be involved in tumorigenesis, tumor progression and metastatic spread of various human malignancies. The aim of this study was to investigate the clinicopathological significance and prognostic value of CCL20 and CCR6 expression in human malignant glioma. CCL20 and CCR6 expression in human gliomas and nonneoplastic brain tissues was measured by immunohistochemistry. The association of CCL20 and CCR6 expression with clinicopathological factors or prognosis in glioma patients was statistically analyzed. The expression levels of CCL20 and CCR6 proteins were both up-regulated in glioma tissues. There was a significantly positive correlation between the expression of the two markers (r = 0.88; P < 0.001). In addition, the overexpressions of CCL20 and CCR6 were both detected in high-grade glioma tissues compared with those in low-grade tissues and increased with ascending tumor World Health Organization (WHO) grades (P = 0.006 and 0.008, respectively). The increased expressions of CCL20 and CCR6 proteins were also significantly correlated with low Karnofsky performance score (both P = 0.01). Moreover, univariate analysis found that CCL20 expression (P = 0.002), CCR6 expression (P = 0.002) and CCL20/CCR6 co-expression (P < 0.001) were all significantly associated with poor prognosis. In particular, glioma patients with CCL20/CCR6 co-expression have the shortest overall survival. Multivariate analysis further identified the expression levels of CCL20 and CCR6 to be independent prognostic factors. Our data suggest for the first time that CCL20 and CCR6 might play an important role in the regulation of aggressiveness in human gliomas. The up-regulation of CCL20 and CCR6 might be closely associated with poor clinical outcome of patients with gliomas.

Effector memory T (T(EM)) cells are a subpopulation of memory T cells that express receptors mediating migration to inflamed tissues and produce various cytokines. Effector memory T-helper (Th)17 (Th17(EM)) cells are thought to be essential for inflammation in Th17-mediated diseases, but have not been studied in detail. To identify superior surface markers to isolate a homogeneous population of Th17(EM) cells from peripheral blood, CD4(+) T cells were isolated from the peripheral blood of healthy donors based on the expression of CCR7, CCR6 and CD146 using six-color flow cytometry. After 4days of culture in the presence of anti-CD3/28 beads, intracellular cytokines were determined by flow cytometric analysis. To investigate the relevance of Th17(EM) cells in Th17-mediated disease, the frequencies of T(EM) -cell subsets in psoriasis were quantified using six-color flow cytometry. An enzyme-linked immunosorbent assay was performed to confirm the interleukin (IL)-17-producing capacity of T(EM) -cell subsets from the peripheral blood of a patient with psoriasis. CCR6(+) CD146(+) T(EM) (CD4(+) CD45RA(-) CCR7(-)) cells had a greater capacity to produce IL-17 than CCR6(+) CD146(-) or CCR6(-) CD146(+) T(EM) cells. Although the percentage of CCR6(+) CD146(+) cells in T(EM) cells was not significantly different between patients with psoriasis and controls, three of eight patients had a higher percentage of CCR6(+) CD146(+) T(EM) cells than the mean +5 standard deviations of the controls. Coexpression of CCR6 and CD146 is a useful marker for Th17(EM) cells. Increasing the number of CCR6(+) CD146(+) Th17(EM) cells in peripheral blood may facilitate estimation of systemic Th17-cell activity in Th17-mediated diseases., (© 2012 Japanese Dermatological Association.)

Interleukin 17A-secreting T-helper 17 (Th17) cells are pathogenic in inflammatory kidney diseases, but their intrarenal regulation is poorly understood. In order to better define Th17 cell dynamics during interstitial inflammation, we utilized the mouse unilateral ureteral obstruction model to analyze inflammatory cell subtypes by multicolor flow cytometry and cell sorting and by effects on in vitro-generated Th17 cells. Interleukin 17A expression localized to CCR6(+)CCR4(+/-)CD4(+) T-cells and progressively increased in obstructed kidneys. The number of CCR6(+)CD4(+) T-cells increased over 10-fold by 72 h, were enriched for interleukin 17A production, and were highly proliferative based on in vivo bromodeoxyuridine incorporation. Secreted products of leukocytes isolated from obstructed kidneys enhanced the interleukin 17A production of in vitro-generated Th17 cells. This Th17-enhancing activity was identified as interleukin-1 produced by renal dendritic cells and monocytes. The in vivo validity of these findings was confirmed in mice lacking the interleulin-1 receptor and in mice treated with a recombinant interleukin-1 receptor antagonist, each of which exhibited reduced intrarenal Th17 activity compared with control mice. Thus, the inflamed kidney accumulates CCR6(+) Th17 cells that undergo activation and proliferation. Production of interleukin 1 family cytokines by resident dendritic cells and infiltrating monocytes enhances intrarenal Th17 activation in acute kidney injury.

Background and Aim: A new subset of Treg cells, CD4(+) CD69(+) CD25(-) T cells, has been identified in mice. Herein, we aimed to identify this subset of T cells and to evaluate its function in patients with hepatocellular carcinoma (HCC)., Methods: We detected CD4(+) CD69(+) CD25(-) T cells and its expression of CCR6 and transforming growth factor-β1 (TGF-β1) in peripheral blood of 91 HCC patients, 38 chronic hepatitis patients and 34 healthy donors by flow cytometry. CD4(+) CD69(+) CD25(-) T cells in HCC tissues were also analyzed., Results: CD4(+) CD69(+) CD25(-) T cells were significantly increased in peripheral blood of HCC patients compared with healthy persons and chronic hepatitis patients (8.74% ± 0.42% vs 4.55% ± 0.33% and 5.15% ± 0.36%, P < 0.0001). The percentage of peripheral CD4(+) CD69(+) CD25(-) T cells was significantly higher in HCC patients with Tumor Node Metastasis (TNM) stage III plus IV (P < 0.05). Patients with large tumor size and tumor vascular invasion were inclined to obtain high percentage of CD4(+) CD69(+) CD25(-) T cells (P < 0.05). The frequency of membrane-bound TGF-β1 positive cells in CD4(+) CD69(+) CD25(-) T cells from HCC patients was higher than that from the other two groups (P < 0.0001). A considerable proportion of CD4(+) CD69(+) CD25(-) T cells were present in HCC tissues, which has significant correlation with tumor size and TNM stage. Few CD4(+) CD69(+) CD25(-) T cells express CCR6 both in peripheral blood and tumor tissues from HCC patients., Conclusions: Increased CD4(+) CD69(+) CD25(-) T cells in HCC patients are significantly correlated with tumor size, vascular invasion and TNM stage. Thus, increased CD4(+) CD69(+) CD25(-) T cells exert a critical role in HCC progression and might be a clinically aggressive phenotype of HCC., (© 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.)

Alpha-1-antitrypsin (AAT) is the primary circulating serine protease inhibitor, and is known to exert potent anti-inflammatory effects and to inhibit the progression of several autoimmune diseases. In this study, transgenic mice that over-express surfactant-driven human (h)AAT on the C57BL/6 background were evaluated for resistance to MOG-35-55 peptide-induced experimental autoimmune encephalomyelitis (EAE), compared to WT C57BL/6 control mice. According to the results, sustained levels of circulating hAAT profoundly inhibited induction of clinical signs, inflammatory lesions and demyelination observed in WT mice with EAE, concomitant with enhanced levels of CD4+FoxP3+ Treg cells, reduced secretion of MOG peptide-induced pro-inflammatory cytokines, IL-17, IL-1β & IL-6, diminished expression of caspase-1 and enhanced expression of CCR6. These results implicate hAAT as a potent immunoregulatory agent worthy of further investigation as a potential therapy in human autoimmune diseases including multiple sclerosis.

Background: Leukocyte depletion at the time of transplantation with alemtuzumab (Campath-1H) has been demonstrated to be a potential strategy for reducing long-term exposure to immunosuppressive drugs. Although the impact of alemtuzumab treatment on the immune system has been explored, the effects of long-term immunosuppressive therapy in alemtuzumab-treated patients still need to be elucidated., Methods: T-regulatory cells and Th1/Th17 responses were assessed by flow cytometry and real-time polymerase chain reaction more than 4 years after transplantation in 10 kidney recipients treated with alemtuzumab induction. Seven patients were converted to sirolimus monotherapy at 12 months posttransplant, whereas the remaining three patients with history of graft rejection were treated with sirolimus and mycophenolate mofetil. In addition, we sorted and expanded interleukin (IL)-17A-producing CCR6CD4 T cells and assessed their susceptibility to suppression by regulatory T (Treg) cells in in vitro suppression tests., Results: Three years of mammalian target of rapamycin inhibitor monotherapy correlates with an increase in the number of IL-17A producing cells, compared with patients treated with sirolimus and mycophenolate mofetil. In these patients, IL-17A expression was compensated for by an increase in Treg cell frequency and number. In addition, we demonstrated that both proliferation and cytokine production by Th17 cells can be effectively regulated by Treg cells., Conclusions: Our results demonstrate that history of rejection and long-term maintenance immunosuppression has an impact on the number of circulating Treg and Th17 cells. However, more importantly, we have shown that Treg cells can effectively regulate Th17cells both in vitro and in vivo.

Background: Dendritic cells are professional antigen presenting cells that mediate the response to inhaled allergens. In animal models, the induction and maintenance of allergic airway inflammation is primarily a function of myeloid dendritic cells, whereas the tolerization to inhaled allergens is likely a function of plasmacytoid dendritic cells., Objective: To investigate changes in sputum myeloid and plasmacytoid dendritic cells after allergen inhalation in subjects with asthma. Also, the number of myeloid and plasmacytoid dendritic cells expressing both CCR6 and 7 and their chemokine ligands macrophage inflammatory protein (MIP)-3alpha and 3beta were measured in sputum supernatants., Methods: Sputum was induced from 12 dual-responder subjects with allergic asthma before and 7 hours, 24 hours, and 72 hours after inhalation of diluent and allergen. Dendritic cells were enumerated via flow cytometry and the chemokines by using ELISAs., Results: The number of sputum myeloid dendritic cells was significantly higher 24 hours after allergen challenge compared with diluent. Similarly, sputum plasmacytoid dendritic cells increased significantly at 24 hours after allergen challenge. Also, a significant increase in CCR6(+) myeloid dendritic cells numbers occurred 72 hours after allergen challenge. In contrast, CCR7(+) myeloid dendritic cells, as well as the number of CCR6(+) and CCR7(+) plasmacytoid dendritic cells, were not different between challenges. Finally, allergen challenge increased sputum levels of MIP-3alpha, but not MIP-3beta, compared with baseline., Conclusions: Both myeloid and plasmacytoid dendritic cells increase in the sputum of subjects with asthma after allergen challenge, suggesting that both subsets are involved in the pathogenesis of allergen responses in asthma., (Copyright 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Although a notable amount of CCL20 is detectable in the synovial fluid of human rheumatoid arthritis (RA), its role in the pathogenesis of RA remains to be determined. IL-1beta vigorously induced the production of CCL20 from FLSs of human RA and the production of CCL20 induced by TNF-alpha was partially attributed to a trace amount of IL-1beta induced by TNF-alpha. Although IL-6 failed to induce CCL20, TNF-alpha-induced IL-6 enhanced the production of CCL20 in an autocrine/paracrine manner. To determine the role of CCL20 and its sole receptor CCR6 in the recruitment of mononuclear cells (MNCs) into the inflamed joint of RA, conditioned medium of IL-1beta-stimulated FLSs was used in migration assays. The conditioned medium significantly recruited CCR6(+) MNCs in a CCL20-dependent manner. The production of CCL20 induced by TNF-alpha and IL-1beta was modified by helper-T-cell-derived cytokines. Interestingly, CCL20 enhanced the production of IL-6 coordinately with the stimulation of IL-17 but not with that of IFN-gamma. These findings imply FLSs stimulated by proinflammatory cytokines recruit CCR6(+) MNCs including IL-17-producing-helper T cells into the inflamed joint, leading to the enhancement of the production of CCL20, which chemokine and IL-17 coordinately induce proinflammatory cytokines.

Pustulosis palmaris et plantaris (PPP) is a tonsil-related disease; tonsillectomy is somewhat effective in treating the condition. However, the aetiological association between the tonsils and PPP has not yet been elucidated fully. Recently, some chemokines and chemokine receptors, including CC chemokine receptor (CCR) 4, CCR6 and CX chemokine receptor (CXCR) 3, have been reported to play important roles in the development of psoriasis, a disease related closely to PPP. In this study, we found that CCR6 expression on both tonsillar and peripheral blood T cells was up-regulated more intensively in PPP patients than in non-PPP patients (P < 0.001 for both), but CCR4 and CXCR3 expressions were not. In vitro stimulation with alpha-streptococcal antigen enhanced CCR6 expression significantly on tonsillar T cells in PPP patients (P < 0.05), but this was not observed in non-PPP patients. The chemotactic response of tonsillar T cells to the CCR6 ligand CC chemokine ligand (CCL) 20 was significantly higher in PPP patients than in non-PPP patients (P < 0.05). The percentage of CCR6-positive peripheral blood T cells decreased after tonsillectomy in PPP patients (P < 0.01); this decrease correlated with an improvement of skin lesions (P < 0.05, r = -0.63). The numbers of CCR6-positive cells and the expression of CCL20 were increased significantly in pathological lesions compared with non-pathological lesions in PPP skin (P < 0.01, P < 0.05 respectively). These results suggest that a novel immune response to alpha-streptococci may enhance CCR6 expression on T cells in tonsils and that CCR6-positive T cells may move to peripheral blood circulation, resulting in recruitment to target skin lesions expressing CCL20 in PPP patients. This may be one of the key roles in pathogenesis of the tonsil-related disease PPP.

In early HIV-1 infection, Vdelta1 T lymphocytes are increased in peripheral blood and this is related to chemokine receptor expression, chemokine response, and recirculation. Herein we show that, at variance with healthy donors, in HIV-1-infected patients ex vivo-isolated Vdelta1 T cells display cytoplasmic interferon-gamma (IFN-gamma). Interestingly, these cells coexpress cytoplasmic interleukin-17 (IL-17), and bear the CD27 surface marker of the memory T-cell subset. Vdelta1 T cells, isolated from either patients or healthy donors, can proliferate and produce IFN-gamma and IL-17 in response to Candida albicans in vitro, whereas Vdelta2 T cells respond with proliferation and IFN-gamma/IL-17 production to mycobacterial or phosphate antigens. These IFN-gamma/IL-17 double-producer gammadelta T cells express the Th17 RORC and the Th1 TXB21 transcription factors and bear the CCR7 homing receptor and the CD161 molecule that are involved in gammadelta T-cell transendothelial migration. Moreover, Vdelta1 T cells responding to C albicans express the chemokine receptors CCR4 and CCR6. This specifically equipped circulating memory gammadelta T-cell population might play an important role in the control of HIV-1 spreading and in the defense against opportunistic infections, possibly contributing to compensate for the impairment of CD4(+) T cells.