The expression levels of IL-21 and IgA in AP patients increased. The ratio of CXCR5+IL-21+ cells in peripheral blood of AP patients (n=14) and HCs (n=7) were detected by flow cytometry and the expression levels of IL-21, IgA and IgM were detected by CBA in AP patients (n=35) and HCs (n=20). A. Representative flow cytometry figure of the ratio of CXCR5+IL-21+ cells in CD3, CD4 double positive cells; B-E. Statistical analysis of: B. The ratio of CXCR5+IL-21+ cells in CD3, CD4 double positive cells; C. Expression levels of plasma IL-21 (MFI); D. Expression levels of plasma IgA (MFI); E. expression levels of plasma IgM (MFI); Results are expressed as mean ± SEM, NS: no significant difference, *, P < 0.05; **, P < 0.01; ***, P < 0.001, ****, P < 0.0001.