[Complement regulatory proteins CR 1, MCP, DAF, and MACIF levels in patients with Behçet's disease].

We previously reported that serum complements in patients with Behçet's disease were extremely low just before the ocular attack. On the other hand, C3a and C5a levels, which have anaphylactic activity and chemotactic activity for polymorphonuclear leucocytes, were higher just before the ocular attack than at the time of the ocular attack, and there was negative correlation between C3a/C5a and CH50. In this report, we evaluated complement regulatory proteins. The results of low levels of C3b/C4b receptor (CR1) and membrane cofactor protein (MCP), and low tendency of decay accelerating factor (DAF) and membrane attack complex inhibition factor (MACIF) suggested that the function of complement regulatory proteins in patients with Behçet's disease decreases as a whole. But mean levels of both CH50 and ACH50 were significantly higher than in the controls. Although it is unclear which is the cause and which is the result, we suppose the function of complement production works excessively and these phenomena are caused by making up for the lack of complement regulatory proteins.