Contrasting functions of IgG and IgE antimalarial antibodies in uncomplicated and severe Plasmodium falciparum malaria

Plasmodial infection results in a significant elevation of the blood concen trations of immunoglobulins including IgE. Two well-characterized groups of adult Thai patients with either uncomplicated or severe Plasmodium falcipa rum malaria were studied over a period of four weeks. The mean parasitemias were approximately three-fold higher in patients with severe malaria than in those with uncomplicated disease. The mean concentrations of both total IgG and IgG antiplasmodial antibodies tended to be highest in the group wit h uncomplicated disease while total IgE and IgE antibodies were higher in t he group with severe disease. The IgE antibodies detected in approximately 65% of the patients were positively correlated to parasitemia. These result s suggest that antiplasmodial IgG antibodies are involved in reducing the s everity of P. falciparum malaria, while IgE antibodies may contribute to th e pathogenesis of this infection.