Lack of association of severe preeclampsia with maternal and fetal mutant alleles for tumor necrosis factor alpha and lymphotoxin alpha genes and plasma tumor necrosis factor alpha levels

OBJECTIVE: The purpose of this study was to determine whether the increased frequency of mutant alleles of the gene for tumor necrosis factor alpha an d elevated maternal and fetal plasma levels of tumor necrosis factor a were associated with severe preeclampsia. STUDY DESIGN: We performed a prospective cross-sectional study involving 11 2 patients with severe preeclampsia matched for gestational age with 106 no rmotensive pregnant women. Deoxyribonucleic acid for restriction fragment l ength polymorphism analysis was extracted from maternal and fetal blood. Tw o mutations associated with the gene for tumor necrosis factor a were assay ed by polymerase chain reaction. Poly polymerase chain reaction products we re digested with the restriction enzyme Ncol and then fractionated by gel e lectrophoresis. Genotypic frequencies were calculated. Maternal and fetal p lasma tumor necrosis factor a levels were assayed by the dual monoclonal an tibody sandwich enzyme-linked immunosorbent assay technique. The chi (2) te st, the Fisher exact test, the Student t test, and the Mann-Whitney test we re performed to calculate statistical significance. RESULTS: The differences in the genotypic frequencies of the two loci were not significant in either maternal or fetal samples between control women a nd women with pregnancies complicated by severe preeclampsia. There was no statistical difference in median maternal plasma levels of tumor necrosis f actor ct between control subjects (0.0 pg/mL) and patients with severe pree clampsia (2.5 pg/mL; P=.36): Unexpectedly, fetal plasma tumor necrosis fact or cc levels were found to be significantly elevated in control women (18.4 pg/mL) relative to women with severe preeclampsia (9.1 pg/mL; P <.0001). CONCLUSION: Neither the genotypic frequencies for tumor necrosis factor <al pha> mutant alleles nor maternal tumor necrosis factor a plasma levels were increased in patients with severe preeclampsia. (Am J Obstet Gynecol 2001; 184:1273-7).