Interferon-alpha 2a effects on complement activation and regulation in MS patients

Objectives - To evaluate the treatment effect of recombinant interferon-alp ha 2a (rIFN-alpha 2a) on complement activation and regulation in MS patient s, Material and methods - Plasma levels of the complement activation produc ts C3bc and terminal complement complex (TCC) and serum levels of the compl ement regulatory proteins, complement receptor 1, CR1 (CD35) and the membra ne inhibitor of reactive lysis, protectin (CD59), were determined by enzyme -linked immunosorbent assay (ELISA) in MS patients treated with TFN-alpha 2 a (14 patients) or placebo (7 patients). Results - The level of soluble CD3 5 decreased while the level of TCC and to a lesser degree C3bc increased in the IFN-alpha 2a treated patients during the initial part of the treatment . There was also a concomitant reduction of leukocytes in the same patients . Conclusions - The results indicate that complement is activated during th e initial phase of rIFN-alpha 2a treatment. This could partly be due to a c oncomitant reduction in soluble CD35.