Objectives: To evaluate the treatment effect of recombinant interferon-alpha2a (rIFN-alpha2a) on complement activation and regulation in MS patients.
Material and methods: Plasma levels of the complement activation products C3bc and terminal complement complex (TCC) and serum levels of the complement regulatory proteins, complement receptor 1, CR1 (CD35) and the membrane inhibitor of reactive lysis, protectin (CD59), were determined by enzyme-linked immunosorbent assay (ELISA) in MS patients treated with IFN-alpha2a (14 patients) or placebo (7 patients).
Results: The level of soluble CD35 decreased while the level of TCC and to a lesser degree C3bc increased in the IFN-alpha2a 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 the initial phase of rIFN-alpha2a treatment. This could partly be due to a concomitant reduction in soluble CD35.