CD28 and immune system disorder: Of the 91 eQTL genes that colocalized with immune diseases and could be tested in the Open Targets Platform, we found nine (tier 1: BLK, CD28, PIM3, PTGIR, and TNFRSF9 and tier 2: ERAP2, NDUFS1, TNFRSF1A, and TYK2; Figure 5A) that were already targeted by known drugs and were either used in clinical practice or undergoing clinical trials.