Platelet hypersensitivity in acute malaria (Plasmodium falciparum) infection in man.

During acute malaria infection, platelets in human platelet-rich plasma re hypersensitive to the addition of ADP between 1.0 micro M and 5.0 micro M, or adrenaline 0.11 micro M as aggregating agents. The mean maximum aggregation amplitude (as % of light transmission) obtained from 8 subjects in response to added ADP (1.0 micro M) , 39.8 +/- 27 (1SD), was significantly greater than the value in 6 controls (5.2 +/- 6.7 (1SD); t = 3,51 P less than 0.005). A similar pattern of response was obtained with higher ADP concentrations (2,4, 4.5 or 5.0 micro M) in 22 patients and 20 control subjects (89.9 +/- 14.9 % vs 77.8 +/- 16.5% (1SD) t = 2,45, P less than 0.02). Addition to 4.5 microM ADP to patient PRP usually evoked only a single aggregation wave (fused primary and secondary waves) while the typical primary and secondary wave pattern was usually obtained from controls. Mean plasma B-thromboglobulin (BTG) concentration in 7 patients (208.3 +/0 15.6 ng/ml) was significantly higher than the value in 6 control subjects (59.2 +/- 15.7 ng/ml; t=13.44, P less than 0.002).