Immunologic studies of human schistosomiasis. I. Clinical and immunological findings in acute and chronic schistosomiasis.

Sera and ascitic fluid of 26 patients with acute and chronic schistosomiasis were studied for the presence of circulating immune complexes (CIC's), IgG, IgM, IgA, complement C3 and C4, as well as their correlation with the clinical manifestations of the disease. Serum levels of CIC's and IgG were significantly increased in patients with acute S. mansoni and S. haematobium infections and in patients with chronic schistosomiasis. Serum IgA levels were evaluated in 20% of patients with S. mansoni infection, 67% with S. haematobium infections and in 100% of chronically infected patients. Complement C3 levels were normal in all patients. Ascitic fluid analysis revealed the presence of IgG, IgM, IgA, C3 and C4 and high concentrations of CIC's. A significant positive correlation was demonstrated to occur between serum CIC's and IgG, as well as between the serum and ascitic fluid levels of CIC's of chronic patients. These findings also correlated with the degree and severity of the clinical syndrome.