Complement and C1q binding substances in otitis media.

Complement activation, as shown by increased amounts of complexes composed of C1r-C1s-C1 IA, and abnormal complexes of C1r-C1s were demonstrated in serum from patients with acute pneumococcal and chronic otitis media, serous or mucoid respectively. C1q binding substances were shown in middle ear effusions and in sera from patients with chronic serous otitis media. Presence of immune complexes and/or bacterial products capable of binding c1q results in formation of C1r-C1s-C1 IA complexes and may also cause the generation of C1r-C1s complexes. Such a dissociation of the C1 component will compromise the important opsonic function of the classical pathway.