Association of intraleukocytic Plasmodium falciparum malaria pigment with disease severity, clinical manifestations, and prognosis in severe malaria

Abstract

Peripheral parasite density of Plasmodium falciparum is used as an indicator of malaria disease severity, but does not quantify central sequestration, which is important in the pathogenesis of severe disease. Malaria pigment, recognizable within the cytoplasm of phagocytic cells by light microscopy may represent a peripheral marker for parasite biomass. One hundred seventy-two index cases of severe malaria and 172 healthy age-, residence-, and ethnicity-matched controls with uncomplicated malaria in Bandiagara, Mali were analyzed prospectively for presence of malaria pigment. The presence of polymorphonuclear cell (PMN) and monocyte pigment was strongly associated with severe disease compared with uncomplicated malaria. Total PMN pigment burden in children with severe malaria was higher in those with cerebral manifestations and with combined cerebral manifestations and severe anemia (hemoglobin < or = 5 g/dL) but was not associated with hyperparasitemia (> 500,000 asexual forms/mm3). Additionally, pigmented PMNs/mm3 was associated with a fatal outcome in patients with severe malaria. This study validates the presence of malaria pigment in monocytes and neutrophils as a marker for disease severity, and demonstrates that pigmented neutrophils are associated with cerebral malaria and with death in children with severe malaria.