Racial disparity in membrane response to infectious stimuli: a possible explanation for observed differences in the incidence of prematurity. Community Award Paper.

Abstract

This study compares the immune responsiveness of amniochorionic membranes (AC) derived from African American (AA) and white (C) women to an infectious stimulus ex vivo. AC derived from AA and C women were placed in an organ explant culture for 48 hours and then stimulated with endotoxin. Enzyme-linked immunosorbent assay measured the concentration of matrix metalloproteinase 9 (MMP9), tumor necrosis factor-alpha (TNF-alpha), and soluble TNF receptors (sTNFR1 and sTNFR2) in culture media from stimulated and unstimulated AC. The C group produced 8-fold more TNF-alpha after stimulation than did the AA group. Both soluble receptor (R1 and R2) production increased in the C group and decreased in the AA group after stimulation. Although the C group-derived membranes produced more MMP9 at rest, a 6-fold increase in MMP9 concentration was seen in the AA group-derived membranes after stimulation. No change in MMP9 concentration was seen after stimulation of the C group-derived membranes. Although the C group produced more TNF, they also produce higher sTNFRs, which may serve a protective role. The increased MMP9 release by the AA group may be suggestive of the greater risk of premature rupture of membranes in the AA group.