Seasonal changes in cell mediated immune responses to soluble Plasmodium falciparum antigens in children with haemoglobin AA and haemoglobin AS.

In this longitudinal study peripheral blood mononuclear cells (PBMC) were obtained before and during the malaria season from healthy HbAA and HbAS children. Cells were compared for proliferation in response to stimulation by soluble Plasmodium falciparum antigens (SPAg) or purified derivative of tuberculin (PPD). The lymphoproliferative responses to SPAg of the paired PBMC samples showed 2 distinct seasonal changes in relation to the haemoglobin phenotype. In HbAA children, the lymphoproliferative responses to SPAg were suppressed during the malaria season. In contrast, they were enhanced in HbAS children during the malaria season. No distinct seasonal change in the response to PPD was found in relation to the haemoglobin phenotype. The study points to the role of the sickle cell trait in modulating the cellular immune responses to falciparum malaria.