CD4 and rheumatoid arthritis: Since the RA-associated SNP (rs189352) has been reported in a SE of the UBASH3A locus [7], we also assessed the expression of UBASH3A and its regulatory mechanism in CD4+ T cells, and found that UBASH3A expression was indeed downregulated in RA CD4+ T cells, presumably due to dysfunction of the UBASH3A SE.