Distinct pattern of class and subclass antibodies in immune complexes of children with cerebral malaria and severe malarial anaemia.

Plasmodium falciparum infection can lead to deadly complications such as severe malaria-associated anaemia (SMA) and cerebral malaria (CM). Children with severe malaria have elevated levels of circulating immune complexes (ICs). To further investigate the quantitative differences in antibody class/subclass components of ICs in SMA and CM, we enrolled 75 children with SMA and 32 children with CM from hospitals in western Kenya and matched them to 74 and 52 control children, respectively, with uncomplicated symptomatic malaria. Total IgG IC levels were always elevated in children with malaria upon enrollment, but children with CM had the highest levels of any group. Conditional logistic regression showed a borderline association between IgG4-containing IC levels and increased risk of SMA (OR = 3.11, 95% CI 1.01-9.56, P = 0.05). Total IgG ICs (OR = 2.84, 95% CI 1.08-7.46, P = 0.03) and IgE-containing ICs (OR = 6.82, OR 1.88-24.73, P < or = 0.01) were associated with increased risk of CM. These results point to differences in the contribution of the different antibody class and subclass components of ICs to the pathogenesis of SMA and CM and give insight into potential mechanisms of disease.