Polymorphonuclear leucocyte elastase in Plasmodium falciparum malaria

Abstract

Sixty-one patients with falciparum malaria were studied prospectively to determine the plasma concentrations of the lysosomal proteinase, polymorphonuclear leucocyte elastase (PMN-elastase) and their relationship to disease severity. The patients were divided into 3 groups; severe (parasitaemia >5%) or vital organ dysfunction (n = 23), moderate (parasitaemia 1%–5% without complications) (n = 15), and mild (parasitaemia 2 × SD above normal) in all patients with severe malaria and were above 100 ng/ml in 86·6% and 65% of the moderately severe and mild patients respectively. PMN-elastase levels during the first 3 hospital days were significantly higher in severe malaria compared with the other 2 groups (P = < 0·001–0·013). The levels decreased as the patients became afebrile and aparasitaemic. Admission plasma concentrations of PMN-elastase correlated directly with bilirubin (r_s = 0·50, P < 0·001), serum glutamic oxalacetic transaminase (r_s = 0·54, P0·001), parasite count (r_s = 0·62, P < 0·001), blood urea nitrogen (r_s = 0·54, P < 0.001) and inversely with antithrombin III activity (r_s = 0·54, P < 0·001) and the platelet count (r_s = 0·58, P < 0·001). Polymorphonuclear leucocyte activation may contribute to the pathogenesis of severe malaria.