Autoimmune diseases and infections exhibit broad sharing of genetic risk variants across conditions.72 Genes in which the direction of effect was concordant between EBV DNA positivity and autoimmune disease risk, including RSBN1, SLAMF7, CTLA4, EOMES, CD86, TP63, TRAF3, CLEC16A, and IKZF3, converged on pathways governing B-cell differentiation, germinal-center dynamics,73 NF-κB signaling,74 T cell effector function, and antigen presentation. Here, CTLA4 is linked to infection.