A higher frequency of CD4⁺CXCR5⁺ T follicular helper cells in patients with newly diagnosed IgA nephropathy.

The frequency of different subsets of CD4(+)CXCR5(+) TFH cells and the levels of serum cytokines were examined in 24 patients with newly diagnosed IgAN before and 8-12 weeks after treatment and in 12 healthy controls (HC). In comparison with HC, significantly higher percentages of CD4(+)CXCR5(+), CD4(+)CXCR5(+)ICOS(+), CD4(+)CXCR5(+)PD-1(+) TFH cells and higher levels of serum IL-17A, IFN-γ, IL-2, IL-10, IL-4 and IL-21 were detected in IgAN patients. The percentages of CD4(+)CXCR5(+) TFH cells were negatively correlated with the values of eGFR and CD4(+)CXCR5(+)PD-1(+) TFH cells were correlated positively with the levels of serum IL-21 and Gd-IgA1 as well as 24h urinary proteins. Treatment with prednisone significantly reduced the frequency of CD4(+)CXCR5(+) and CD4(+)CXCR5(+)PD-1(+) TFH cells and the levels of serum IL-21, but increased IL-4 and IL-10 in those patients. A higher frequency of CD4(+)CXCR5(+) TFH cells existed in patients with IgAN and may be associated with the development of IgAN.