As for CD14+ monocytes, although no significant changes were revealed in the expression of TIM-3, PD-1, and PD-L1 in the three groups, the expression of PD-L2 significantly reduced in patients with BD compared with HCs (24.90 ± 10.84 vs. 36.74 ± 14.29, P = 0.029, Fig. 3 and Table 3), but not in patients with MD. This evidence concerns the gene PDCD1 and Behcet disease.