Serum immunoglobulin and complement levels in tropical pulmonary eosinophilia, and their correlation with primary and their relapsing stages of the illness.

Serum concentrations of IgA, IgG, IgM, IgE, C3 and C4 complement components were estimated in 19 patients with tropical pulmonary eosinophilia (TPE). Thirteen of the patients presented during their first episode of TPE and 6 of them during a relapse of the disease. We found a remarkable elevation of serum IgE level in TPE, which is consistent with earlier reports. In contrast, there was a modest increase in IgM levels and unchanged or even lower levels in IgA and IgG immunoglobulin classes. There seemed to be a direct relationship between IgE level and degree of peripheral blood eosinophilia in TPE. The outstanding finding, however, was a nearly threefold higher mean serum IgE level in patients with relapsing disease as compared to that observed in patients during the primary attack. This is the first reported study of circulating complement components in TPE. A significant rise of serum C3 level was found in these patients; there was no similar elevation of serum C4 component.