Complement receptor 1 in autoimmune disorders

Complement receptor 1 (CR1) has gained much attention in recent years. The reason is manifold. Growing understanding on this protein has facilitated insight into the pathophysiology of autoimmune disorders. CR1, a polymorphic protein, is important as a complement regulatory protein, as well as a vehicle for immune complex clearance. Functional and clinical significance of CR1 polymorphism is a continuously revealing area in complement research. The levels of CR1 are altered in autoimmune disorders like rheumatoid arthritis, glomerulonephritis and systemic lupus erythematosus. This envisages CR1 as a potential prognostic marker for such diseases. Lower levels of erythrocyte CR1 are observed in patients suffering from the above diseases. This partially explains the tissue injury and inflammatory manifestations in patients suffering from these disorders. The benevolent role of CR1 in autoimmune and inflammatory disorders and propagation of disease manifestations due to its deficiency are further established with the therapeutic success of recombinant soluble CR1 in inflammatory and autoimmune disorders. This review is a brief and update account of CR1 and its importance in autoimmune disorders.