ABSTRACTThe serum levels of the four immunoglobulins, IgG, IgA, IgM and IgE, in Guatemalan onchocerciasis patients were determined quantitatively using a laser immunoassay system or radioimmunosorbent test.The IgG and IgE levels in Guatemalan onchocerciasis patients positive forOnchocerca volvulus microfilariaewere significantly higher than the levels in Guatemalan controls negative formicrofilariaeand in healthy Japanese controls. But, no differences in the levels of IgA and IgM were obtained between the Guatemalan onchocerciasis patient group and the two control groups.