Metabolism of IgM in the tropical splenomegaly syndrome

IgM metabolism was studied in five patients with the tropical splenomegaly syndrome and in five controls. The half-life and turnover time of I¹²⁵ IgM was similar in the two groups. We conclude that the raised serum IgM levels found in patients with the tropical splenomegaly syndrome are not due to decreased IgM catabolism but are due to increased IgM production.