Using mean plus 3 SD of US controls samples, 11, 57 and 17% of malaria-infected Cameroonians had IgM Ab to MSP1, MSP2 and MSP3, respectively; 15 and 30% had IgM Ab to HRP2-A and HRP2-B, with the highest MFI values for these antigens reaching only 4930 and 3823 MFI. This evidence concerns the gene CD40LG and malaria.