RA patient–derived PD-1–expressing B cells had higher expression of CD86 and CD80 compared with their PD-1– counterparts under normoxic (P = 0.0026, P = 0.001, respectively) and hypoxic (P = 0.0015, P < 0.0001, respectively) conditions (Figure 5D). Here, CD86 is linked to rheumatoid arthritis.