Cortisol and loss of malaria immunity in human pregnancy.

The concentration of both total (bound to corticoid-binding-globulin plus free) and free cortisol was determined in sera from two groups of pregnant women in Tanzania. One group consisted of 152 pregnant women (57 nulliparas and 95 multiparas) exhibiting clinical malaria during pregnancy, and the other group comprised 527 pregnant women (105 nulliparas and 422 multiparas), who did not have a record of malaria during pregnancy. The serum concentration of total cortisol was significantly higher in women with clinical malaria than in women without recorded malaria, and this is true for both nulliparae and multiparae. Free cortisol fractions did not differ significantly between these groups. Indications were obtained that higher total cortisol levels cause loss of malaria immunity rather than being concomitant with malaria infection only. The data are compatible with those of a murine malaria model.