Autoimmune neurologic diseases
Anti Acetylcholine receptor antibody is produced with the help of C-X-Chemokine Receptor 5 (CXCR5)-positive follicular helper T cells (Tfh) in myasthenia gravis (MG). CXCR5, which is also expressed on B cells, is important for homing to lymphoid organs. Here, we analyzed the alteration of Tfh phenotype in MG and production of Interleukin (IL)-21 by peripheral Tfh in MG and healthy controls (HC), and the effect of IL-21 on B and Tfh cells.
We analyzed phenotypes of peripheral blood T cells from MG before and after treatments and IL-21 production of Tfh. Effect by IL-21 on B and Tfh cells was analyzed. These analyses were mainly performed by flow cytometry.
Total frequency of CXCR5+ cells in Th cells were elevated in MG, additionally Inducible T-cell co-stimulator (ICOS) were upregulated on Tfh cells compared with HC. Immunotherapy reduced the frequency of CXCR5+ and ICOShighCXCR5+ in Th cells in parallel with their clinical improvement. The production of IL-21 by Tfh upon a stimulation from MG patients was about nine times as high as that from HC. Interestingly, IL-21 improved B cell survival and maintained CXCR5 expression on B and Tfh cells.
Activated CXCR5+ Th cells were significantly higher in MG and immunotherapy corrects this alternation. IL-21 production by Tfh cells, its maintenance of CXCR5 on B and Tfh cells may promote Tfh-B interaction in lymphoid organs in MG.