Research articleT follicular helper cell-mediated IL-21 production suppresses FOXP3 expression of T follicular regulatory-like cells in diffuse large B cell lymphoma patients
Introduction
Interleukin (IL)-21 is a pleiotropic cytokine belonging to the IL-2 family [1]. The IL-21 receptor is a heterodimer comprised of the IL-21R chain and the common γ (γc) chain, and signals via JAK1/JAK3 to mediate STAT3, STAT1, and STAT5 phosphorylation [2]. IL-21 is produced by activated T follicular helper (Tfh) cells, T helper (Th)17 cells, natural killer T (NKT) cells, and CD8 T cells, and can act on a variety of immune cells to perform diverse effector functions [3], [4], [5]. In germinal center, Tfh-mediated IL-21 promotes the proliferation, immunoglobulin production, and plasma cell differentiation of B cells [6]. IL-21 is also involved in the differentiation, proliferation, and cytokine production of Th17 and Tfh cells [7], [8]. TGF-β promotes Treg differentiation, but in the presence of either IL-21 or IL-6, Th17 differentiation is favored. Additionally, IL-21 inhibits IL-2 production and decreases Treg viability [9]. In tumor, IL-21 potently enhances the survival and cytotoxicity of CD8 T cells, NK cells, and NKT cells [5], [10]. On the other hand, IL-21 increases the production of IL-10, a regulatory cytokine, in Th1, Th17, and B cells [11], [12]. IL-21 acts in opposition to GM-CSF and limits the number of conventional dendritic cells via STAT3-dependent and BIM-dependent induction of apoptosis [13].
Diffuse large B cell lymphoma (DLBCL) is an aggressive B cell lymphoma currently treated via a standard R-CHOP (anti-CD20 rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) regimen [14], [15]. Heterogeneous response to R-CHOP is observed in DLBCL patients, with complete remission in some patients and partial remission in others. A subset of patients may develop relapsed disease following remission, which is harder to manage [16]. In addition, prediction of patient response is not yet possible, further complicating the treatment process. These difficulties are present, largely due to a lack of understanding in the complex interactions between various cellular and molecular mechanisms involved in the pathogenesis of DLBCL.
Several DLBCL cell lines are shown to express IL-21R, and upon receiving IL-21, a proapoptotic pathway involving the phosphorylation of STAT3 and upregulation of c-Myc is activated, resulting in the death of DLBCL but not healthy B cells [17]. However, the CXCR5+ circulating CD4 T cells, which normally express higher IL-21 than CXCR5- circulating CD4 T cells and are regarded as the peripheral counterpart of germinal center T follicular helper cells (Tfh) [18], expressed lower IL-21 and higher IL-10 in DLBCL patients than in healthy controls, and promoted primary DLBCL survival via IL-10-mediated effects [19]. We later showed that in DLBCL patients, a significantly higher proportion of CXCR5+ CD4 T cells expressed Foxp3, similar to the T follicular regulatory (Tfr) cells. This Tfr-like subset existed at even higher frequency in the tumor, and supported the proliferation of autologous CD19+ tumor cells. The effect of IL-21 on the regulation of Tfr cells remains unclear, and is investigated in this study.
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Study participants
Twenty-seven subjects with de novo presentation of primary DLBCL and twenty-seven healthy subjects were included in this study. The patients presented stage III DLBCL at diagnosis, based on the Ann Arbor Classification System [20]. The patient group and the control group each included 15 females and 12 males between 40 and 70 years of age. All participants gave written informed consent. Ethical approval was obtained from the Ethics Committee of the First Affiliated Hospital of Xiamen University
Circulating CD25+CXCR5+CD4+ Tfr-like cells presented high Bcl-6, low Blimp-1, and high Foxp3 expression
Peripheral blood mononuclear cells (PBMCs) and tumor-infiltrating lymphocytes (TILs) were harvested from twenty-seven patients with newly diagnosed, untreated DLBCL. We previously showed that the Tfr cells were characterized by CD4+CD25+CXCR5+ surface marker expression [21]. Here, we sorted circulating CD4 T cells into CD25+CXCR5+, CD25−CXCR5+, and CXCR5− fractions (Fig. 1A). Compared to healthy subjects, DLBCL patients presented higher frequencies of CD25+CXCR5+ CD4 T cells and lower
Discussion
In the current investigation, we demonstrated that the Tfh cells (CXCR5+CD4+ T cells) could be separated into the CD25+CXCR5+ subset (Tfr-like) and the CD25−CXCR5+ subset (CD25− Tfh), which were different in the expression of transcription factors and cytokines. The Tfr-like cells (CD25+CXCR5+CD4+) presented slightly higher Blimp-1 and significantly higher Foxp3 than the CD25− Tfh cells (CD25−CXCR5+CD4+). The cytokine expression was also distinctive in each subset. Most of the previous studies
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This work was supported by National Natural Science Foundation of China (No.81770126; No.81800163; No.81800196), and Foundation of health and family planning Commission of in Fujian Province of China (2017-2-99).
References (27)
- et al.
IL-2 family cytokines: New insights into the complex roles of IL-2 as a broad regulator of T helper cell differentiation
Curr. Opin. Immunol.
(2011) - et al.
IL-21 is produced by Th17 cells and drives IL-17 production in a STAT3-dependent manner
J. Biol. Chem.
(2007) - et al.
IL-21 inhibits T cell IL-2 production and impairs Treg homeostasis
Blood
(2012) - et al.
The role of IL-21 in immunity and cancer
Cancer Lett.
(2015) - et al.
IL-21/anti-Tim1/CD40 ligand promotes B10 activity in vitro and alleviates bone loss in experimental periodontitis in vivo
Biochim. Biophys. Acta Mol. Basis Dis.
(2017) - et al.
The cytokines IL-21 and GM-CSF have opposing regulatory roles in the apoptosis of conventional dendritic cells
Immunity
(2013) - et al.
Novel IL-21 signaling pathway up-regulates c-Myc and induces apoptosis of diffuse large B-cell lymphomas
Blood
(2010) - et al.
Circulating CXCR5+CD4+ T cells assist in the survival and growth of primary diffuse large B cell lymphoma cells through interleukin 10 pathway
Exp. Cell Res.
(2017) - et al.
The prevalence and function of CD4+CXCR5+Foxp3+ follicular regulatory T cells in diffuse large B cell lymphoma
Int. Immunopharmacol.
(2018) - et al.
Human circulating PD-1+CXCR3-CXCR5+ memory Tfh cells are highly functional and correlate with broadly neutralizing HIV antibody responses
Immunity
(2013)
Blood relatives of follicular helper T cells
Immunity
Interleukin-21: basic biology and implications for cancer and autoimmunity
Annu. Rev. Immunol.
IL-21 is produced by NKT cells and modulates NKT cell activation and cytokine production
J. Immunol.
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These authors contributed equally to this work.