Lymphocyte mitogenic factor in sera from patients with falciparum malaria

To test for the presence of a lymphocyte mitogenic factor in malaria, sera were obtained from 10 patients with malaria (9 with falciparum and one with vivax), and 10 noninfected controls. The sera from the malarial patients caused an increased blastogenesis in mouse splenic lymphocyte cultures and inhibited hemagglutination between lipid-A-coated erythrocytes and lipid-A antibodies. None of the sera were positive using the limulus amebocyte lysate test. These results could be interpreted to demonstrate that patients with falciparum malaria have a circulating mitogen which cross-reacts with endotoxin. However, alternate explanations must be considered, including an hypothesis that antiglobulins and/or immune complexes in the sera of malarious patients both caused the blastogenesis of mouse spleen cells and inhibited hemagglutination to lipid-A antibodies.