CD40 and rheumatoid arthritis: An open chromatin peak located upstream of CD40 and in contact with the promoter of the gene under synergistic stimuli overlapped with rs6074022, which is in tight LD (r2 = 0.9 in the East Asian, r2 = 0.95 in the European population) with an established RA risk SNP rs4810485 (Fig. 6e).