[Circulating immune complexes and anti-mite specific IgG antibody in status asthmatics--effects of methylprednisolone...

Serial changes of circulating immune complexes and anti-mite specific IgG antibody in the peripheral blood were measured eight times in six status asthmatics treated with high doses of methylprednisolone (MPS). Circulating immune complexes decreased to normal levels three hours after MPS administration. By contrast, anti-mite specific IgG antibody increased to beyond the normal range 14 days after MPS administration. Serum levels of IgE and allergen specific IgG4 antibody did not show any significant changes. In vitro experiments, circulating immune complexes in the sampled sera were decreased by an absorption test with anti-mite specific IgG antibody, and increased by reaction with an adequate volume of mite allergen. These facts indicate that circulating immune complexes are an anti-complementary factor working on the complement system, as previously reported, and that mite allergen and anti-mite IgG antibody relate to their conformation in status asthmatics. Clinically, MPS might possess an inhibitory effects on the formation of immune complexes and/or accelerate complement-dependent solubilization of antigen-antibody complexes, so that anti-mite specific IgG antibody increased markedly in the peripheral blood.