Children with high levels of IgM at enrolment were associated with a 53% [95% confidence interval (CI), 0.25 to 0.89] reduction in the risk of clinical malaria (fever plus >5000 parasites/μl) compared to children with low levels of IgM after adjusting for confounders (age and location of residence) (Table 1 and Fig. 5D). This evidence concerns the gene CD40LG and malaria.