The activation of neutrophils was studied in preeclampsia (n = 10) and eclampsia (n = 20) compared to normotensive controls (n = 10) and nonpregnant essential hypertensives (n = 10). Plasma elastase levels were raised in preeclampsia (0.53 +/- 0.32 microgram/mL, P < .002) and eclampsia (1.26 +/- 0.8 microgram/mL, P < .001) respectively compared to normal pregnancies (0.032 +/- 0.009 microgram/mL). The plasma elastases were more elevated in eclamptic cases compared to essential hypertensive (0.53 +/- 0.27 microgram/mL; P = .01) patients. We analyzed the correlation among elastase values, systolic (SBP), mean blood pressures (MBP), endothelin-1 (ET-1) levels and sera cytotoxicity (as measured by fura-2 release from human umbilical venous endothelial cell culture) in eclamptic cases. SBP and MBP were significantly correlated with plasma elastase levels in preeclampsia (r = 0.67, 0.63, respectively; P < .03) and eclampsia (r = 0.49, 0.49, respectively; P < .02). ET-1 levels were correlated with SBP (P = .003) and MBP (P = .001) and corresponding elastase levels (r = 0.606, P < .003) in eclamptic patients. Doses of 10, 25, and 50 pmol/mL of ET-1 increased elastase release in human neutrophil cultures dose and time dependently. Cytotoxicity of eclamptic sera correlated (P < .001) to the corresponding plasma elastase values. Therefore, this study suggests that neutrophil activation and ET-1 induced neutrophil activation occurs in this disease.