IS THERE A CRITICAL GESTATIONAL-AGE IN NEUTROPHIL SUPEROXIDE PRODUCTION ACTIVITY

We studied superoxide (O-2(-)) production in neutrophils from 78 normal pregnant women at 7 to 39 weeks' gestation to determine whether there is a critical gestational age in O-2(-) production activity of maternal neutrophils. The O-2(-) production was measured by determining the rate of superoxide dismutase-inhibitable reduction of ferricytochrome c at 550 to 540 nm. A scattergram of neutrophil O-2(-) production value versus gestational age was analyzed using the least median of squares regression, leading to a statistical stratification in which the median values of O-2(-) production for outlying and nonoutlying points were 6.60 nmol/10(6) cells and 2.72 nmol/10(6) cells, respectively. All of the outlying points were concentrated at 19 to 22 gestational weeks. There was the significant difference in FMLP-induced O-2(-) production in neutrophils of nonpregnant subjects when incubated with the sera from 10 cases (selected among 60 cases with nonoutlying points) (3.86 +/- 0.77 nmol/10(6) cells) compared with 5 cases with outlying points (5.62 +/- 1.19 nmol/10(6) cells) (P < .05). These results suggest that during the normal course of pregnancy, the production of O-2(-) from the function of circulating neutrophils can be dissociated from such neutrophil functions as adherence, chemotaxis, and phagocytosis. (C) 1995 by The American Society of Hematology.