CFHR4 and Behcet disease: Functional annotation of biological processes revealed that proteins highly expressed in the mild BD group were enriched in immune response (C1QA, ECM1, IGHV1‐3, TUBB, APOA2, IGHV2‐26, IGKV1D‐33, IGHV1‐18, C3, IGLL5, IGLV1‐51, ADAMTS13, IGKV1‐27, IGLV6‐57, CFHR4, C1RL, LCP1, A2M, PF4, LTF), protein activation cascade (C3, C1QA, CFHR4, FGG, C1RL, FBLN1, A2M), and immune effector response (C3, C1QA, IGLL5, IGHV1‐3, CFHR4, TUBB, C1RL, APOA2, LCP1, IGHV2‐26, A2M, IGHV1‐18).