Overexpression of CXCR5 in CD4+ T cells of SLE patients caused by excessive SETD3.

The peripheral blood of systemic lupus erythematosus patients showed an increased expression of CXCR5 positive T cells. However, the molecular mechanism of the abnormal expression of CXCR5 in SLE CD4+ T cells remains unclear. The present study demonstrated that the levels of H3K4me3 and H3K36me3 in CXCR5 promoter were significantly higher in SLE patients than those in healthy controls. Furthermore, the expression of SETD3 was upregulated in SLE CD4+ T cells as compared to the healthy controls. Excessive SETD3 increased the level of H3K4me3 and H3K36me3 and promoted the expression of CXCR5. These data strongly suggested that SETD3 plays a major role in the regulation of CXCR5 expression and the progression of SLE.