Elevated IgG and decreased complement component C3 and factor B in B-thalassaemia major.

Serum immunoglobulins, complements C3 and C4 and factor B were assayed in the sera of children with B-thalassaemia major, siblings and matched controls in an attempt to resolve the controversy surrounding the conflicting results reported in the literature. Significantly elevated IgG and decreased C3 and factor B levels were observed in thalassaemic patients who also had a high incidence of HBS hepatitis and other infections. The controversial results probably reflect differences in the incidence of infection, and the presence of circulating immune complexes due to blood transfusions, in the various communities. The alterations in immunoglobulin and complement levels represent a secondary rather than a primary immune disorder.