T follicular helper cells (TFH cells) provides a helper function to B cells. It is one of the most important subsets of effector T cells in lymphoid tissues. The features of TFH cells include chemokine receptor expression (CXCR5), location/migration (B cell follicles), and function (B cell help). TFH cells produce a "helper" cytokine-IL-21, which can stimulate B cells to differentiate into Ab-forming cells through IL-21R. Dysregulation of TFH cell function likely contributes to the pathogenesis of immune-related diseases. In this article, the discovery of CXCR5 and TFH cells, origin of TFH cells, cytokines related with TFH cell function, migration and location of TFH effector cells and memory cells as well as dysregulation of TFH cell function and related diseases were reviewed.
Humans ; Interleukins ; immunology ; Receptors, CXCR5 ; immunology ; T-Lymphocytes, Helper-Inducer ; immunology

OBJECTIVE: To explore the relation of circulating follicular helper T cell (c Tfh) changes with B cell dysfunction in MDS patients. METHODS: 20 patients diagnosed as MDS from Auguct 2015 to October 2017 were enrolled in MDS group, and 20 healthy valuntears matching in age and sex were enrolled in healthy control (HC) group. The perepheral blood in 2 groups were collected, the mononuclear cells (PBMC) from which were isolated by densily gradient contrifugation, at the same time, the serum left in isolation process was reserved for further study. The flow cytometry was used to detect the ratio of cTfh such as CD4CXCR5 T cells and its subset CD4CXCR5ICOS T cells, CD4CXCR5PD-1 T cells in PBMC, as well as the ratio of plasmablast CD19CD20CD38 B cells. The ELISA was used to detect the concentration of IgA, IgM and IgG. The differences in ratio of cTfh cells and plasmablast B cells, as well as the concentration of IgA, IgM and IgG between MDS and HC groups were compared, at the same time, the correlation of cTfh cell ratio with the plasmablast B cell ratio and the concentration of IgA, IgM and IgG in MDS patient was analyzed. RESULTS: The ratio of CD4CXCR5T, CD4CXCR5ICOST cells and CD19CD20CD38B cells and the concentration of IgA, IgM and IgG decreased in MDS patients, while the ratio of CD4CXCR5PD-1T cells increased in MDS patients. The ratio of CD4CXCR5T cells, CD4CXCR5ICOST cells positively correlated with the ratio of CD19CD20CD38B cells, as well as with the concentration of IgA, IgM and IgG in MDS patients. However, the ratio of CD4CXCR5PD-1T cells negatively correlated with the ratio of CD19CD20CD38B cells, as well as with the concentration of IgA, IgM and IgG. CONCLUSION The ratio of circulating Tfh cells and their subsets showed significant changes, that correlate with B cell dysfunction in MDS patients.
B-Lymphocytes ; Humans ; Interleukins ; Leukocytes, Mononuclear ; Myelodysplastic Syndromes ; Plasma Cells ; Receptors, CXCR5 ; T-Lymphocytes, Helper-Inducer

OBJECTIVE: To study the role of follicular helper T (Tfh) cells and galactose-deficient IgA1 (Gd-IgA1) in the pathogenesis of childhood Henoch-Schönlein purpura (HSP) and the correlation between them. METHODS: A total of 36 children with newly-diagnosed HSP were enrolled. They were divided into two groups: HSP nephritis (HSPN) group with 11 children and non-HSPN group with 25 children according to the presence or absence of HSPN. Another 15 children who underwent physical examination at the outpatient service were enrolled as the healthy control group. Flow cytometry was used to measure the proportion of Tfh cells (CD4CXCR5ICOS) in peripheral blood. ELISA was used to measure the levels of interleukin-21 (IL-21) and interleukin-6 (IL-6) in peripheral blood and the serum levels of IgA1 and Gd-IgA1. A Pearson correlation analysis was used to investigate the correlation of serum Gd-IgA1 concentration with Tfh cells and related factors expression in the children with HSP. RESULTS: Both the HSPN and non-HSPN groups had significantly higher proportion of Tfh cells and expression levels of IL-21 and IL-6 in peripheral blood than the healthy control group (P<0.05). The HSPN group had significant increases in the above indices compared with the non-HSPN group (P<0.05). Both the HSPN and non-HSPN groups had significantly higher serum levels of IgA1 and Gd-IgA1 than the healthy control group (P<0.05). The HSPN group had significantly higher serum levels of IgA1 and Gd-IgA1 than the non-HSPN group (P<0.05). In the children with HSP, serum Gd-IgA1 level was positively correlated with Tfh cells proportion and IL-21 and IL-6 levels (P<0.05). CONCLUSIONS Tfh cells and related cytokines and serum Gd-IgA1 are involved in the development of HSP/HSPN. Tfh cells may mediate the increased production of Gd-IgA1.
Child ; Galactose ; Humans ; Immunoglobulin A ; Purpura, Schoenlein-Henoch ; Receptors, CXCR5 ; T-Lymphocytes, Helper-Inducer

Epilepsy is a common, chronic neurological disorder that has been associated with impaired neurodevelopment and immunity. The chemokine receptor CXCR5 is involved in seizures via an unknown mechanism. Here, we first determined the expression pattern and distribution of the CXCR5 gene in the mouse brain during different stages of development and the brain tissue of patients with epilepsy. Subsequently, we found that the knockdown of CXCR5 increased the susceptibility of mice to pentylenetetrazol- and kainic acid-induced seizures, whereas CXCR5 overexpression had the opposite effect. CXCR5 knockdown in mouse embryos via viral vector electrotransfer negatively influenced the motility and multipolar-to-bipolar transition of migratory neurons. Using a human-derived induced an in vitro multipotential stem cell neurodevelopmental model, we determined that CXCR5 regulates neuronal migration and polarization by stabilizing the actin cytoskeleton during various stages of neurodevelopment. Electrophysiological experiments demonstrated that the knockdown of CXCR5 induced neuronal hyperexcitability, resulting in an increased number of seizures. Finally, our results suggested that CXCR5 deficiency triggers seizure-related electrical activity through a previously unknown mechanism, namely, the disruption of neuronal polarity.
Animals ; Humans ; Mice ; Actin Cytoskeleton/metabolism* ; Actins/metabolism* ; Epilepsy/metabolism* ; Neurons/metabolism* ; Receptors, CXCR5/metabolism* ; Seizures/metabolism*

How follicular T-helper (Tfh) cells develop is incompletely understood. We find that, upon antigen exposure in vivo, both naïve and antigen-experienced T cells sequentially upregulate CXCR5 and Bcl6 within the first 24 h, relocate to the T-B border, and give rise to phenotypic Bcl6(+)CXCR5(+) Tfh cells before the first cell division. CXCR5 upregulation is more dependent on ICOS costimulation than that of Bcl6, and early Bcl6 induction requires T-cell expression of CXCR5 and, presumably, relocation toward the follicle. This early and rapid upregulation of CXCR5 and Bcl6 depends on IL-6 produced by radiation-resistant cells. These results suggest that a Bcl6(hi)CXCR5(hi) phenotype does not automatically define a Tfh lineage but might reflect a state of antigen exposure and non-commitment to terminal effector fates and that niches in the T-B border and/or the follicle are important for optimal Bcl6 induction and maintenance.
Animals ; CD40 Ligand ; metabolism ; Cell Differentiation ; physiology ; DNA-Binding Proteins ; metabolism ; Inducible T-Cell Co-Stimulator Protein ; metabolism ; Interleukin-6 ; metabolism ; Mice ; Proto-Oncogene Proteins c-bcl-6 ; Receptors, CXCR5 ; metabolism ; T-Lymphocytes, Helper-Inducer ; metabolism

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.
Antiviral Agents/therapeutic use* ; DNA, Viral ; Guanine/analogs & derivatives* ; Hepatitis B Surface Antigens ; Hepatitis B e Antigens ; Hepatitis B virus/genetics* ; Hepatitis B, Chronic ; Humans ; Programmed Cell Death 1 Receptor ; Receptors, CXCR5/analysis* ; T-Lymphocytes

OBJECTIVETo study the alterations of follicular T helper cells (CD4(+)CXCR5(+)Tfh cells, Tfh) on circulating T lymphocytes in children with asthma, and to study the expression of transcription regulatory factors BCL-6 and BLIMP-1 mRNA.

METHODSSixty-four children with asthma and 25 healthy controls were enrolled in this study. On the basis of the disease, the children with asthma were classified into acute phase group (n=36) and remission phase group (n=28). The flow cytometry was used to detect the proportion of CD4(+)CXCR5(+)Tfh cells on CD4(+)T lymphocytes. Real-time PCR was performed to detect the levels of BCL-6 mRNA and BLIMP-1 mRNA. The double -antibody Sandwich ELISA was used to detect plasma concentrations of total IgE, IL-2, IL-6 and IL-21.

RESULTSThe proportion of CD4(+)CXCR5(+)Tfh cells was significantly higher in the acute group than in the control group and the remission group (P<0.05). Transcription levels of BCL-6 mRNA were significantly higher, while the inhibitory factors BLIMP-1 mRNA was significantly lower in the acute group than in the remission group and control group (P<0.05). The plasma concentration of IL-6 in the acute group increased significantly compared with the control group (P<0.05). Plasma concentrations of total IgE and IL-21 increased significantly, in contrast, plasma IL-2 concentration decreased significantly in the acute group, compared with the control group and the remission group (P<0.05). Correlation analysis showed that both IL-21 and IL-6 concentrations were positively correlated with the proportion of CD4(+)CXCR5(+)Tfh cells (r=0.76, r=0.46 respectively; P<0.05), while IL-2 level was negatively correlated with the proportion of Tfh cells (r=-0.68, P<0.05).

CONCLUSIONSThe abnormal proportion of CD4(+)CXCR5(+)Tfh cells might be involved in the immunological pathogenesis of acute asthma in children. The increased expression of BCL-6 mRNA and decreased expression of BLIMP-1 mRNA as well as the alterations of plasma total IgE, cytokines IL-2, IL-6 and IL-21 in microenvironment might be account for the increased proportion of CD4(+)CXCR5(+)Tfh cells in children with acute asthma.

Asthma ; immunology ; Child ; Child, Preschool ; DNA-Binding Proteins ; genetics ; Female ; Humans ; Immunoglobulin E ; blood ; Infant ; Interleukins ; blood ; Male ; Positive Regulatory Domain I-Binding Factor 1 ; Proto-Oncogene Proteins c-bcl-6 ; RNA, Messenger ; analysis ; Receptors, CXCR5 ; analysis ; Repressor Proteins ; genetics ; T-Lymphocytes, Helper-Inducer ; immunology