Cd83, a member of the immunoglobulin (Ig) superfamily, is expressed in membrane-bound (mCD83) and soluble (sCD83) forms. It is expressed on mature dendritic cells (DCs), activated B cells, T cells, and other immune cells [1,2,3]. Cd83 is involved in regulating immune responses, including the differentiation of T and B lymphocytes, and is crucial for maintaining the balance between tolerance and inflammation [2]. It also plays a role in DC maturation, activation, and homeostasis [3].

In immune thrombocytopenia (ITP), ITP patients show higher CD83 expression. Down-regulation of DC-CD83 inhibits CD4+ T cell proliferation, while over-expression promotes it. siRNA-CD83 can reverse Th1/Th2 and Th17/Tregs polarization, indicating CD83's important role in ITP pathogenesis [4]. In uveitis, CD83+ B cells, the main source of sCD83, alleviate symptoms by inhibiting DCs through sCD83, suggesting their potential therapeutic role [5]. Soluble CD83 can also modulate human-monocyte-derived macrophages toward an alternative phenotype, function, and metabolism, with potential as a new therapeutic agent for inflammatory conditions [6].

In conclusion, Cd83 is a key regulatory molecule in the immune system. Its functions in immune response regulation, as revealed through studies in disease models like ITP and uveitis, highlight its potential importance in understanding and treating autoimmune and inflammatory diseases.