Parasite antigen-specific interleukin-10 and antibody responses predict accelerated parasite clearance in Plasmodium falciparum malaria

Using strict inclusion criteria, we conducted a hospital-based, case-contro l study in which 100 Gabonese children with severe Plasmodium falciparum ma laria were matched for age, gender and provenance with 100 children present ing with mild malaria. Parasite antigen-specific cellular and humoral immun ological responses were measured and compared with post-treatment parasite clearance times in each group, Significantly faster parasite clearance time s were associated with in vitro production of IL-10 by acute-phase peripher al blood mononuclear cells (PBMC) in response to both liver and asexual sta ge parasite antigens, but not with proliferative, IFN-gamma, or TNF respons es to the same antigens. In addition, in those children with mild malaria, higher levels of acute-phase antibody responses to liver stage antigen-1 (L SA-1) were associated with faster parasite clearance times, and were correl ated with the presence of IL-10 responses to the same antigen. No such asso ciations were found for IL-10 or antibody responses to a range of asexual b lood stage antigens. Those with severe malaria had significantly lower leve ls of anti-LSA-1 antibodies compared to their counterparts with mild malari a. In conclusion, the results of this study suggest that parasite antigen-s pecific IL-10-mediated antibody responses may play a role in the control of asexual stage parasite multiplication in P. falciparum malaria.