Synergistic effect of DDT and its metabolites in lipopolysaccharide‐mediated TNF‐α production is inhibited by progesterone in peripheral blood mononuclear cells

Increased TNF‐α levels have been associated with adverse pregnancy outcomes. Lipopolysaccharide (LPS), 1,1,1‐trichloro‐2,2‐bis‐(chlorophenyl)ethane (DDT), 1,1‐bis‐(chlorophenyl)‐2,2‐dichloroethene (DDE), and 1,1‐dichloro‐2,2‐bis(chlorophenyl)ethane (DDD) induce TNF‐α release in peripheral blood mononuclear cells (PBMC). Conversely, progesterone (P4) inhibits TNF‐α secretion. Pregnant women in malaria endemic areas may be co‐exposure to these compounds. Thus, this study was to investigate the synergistic effect of LPS and these pesticides in PBMC and to assess P4 influence on this synergy. Cultured PBMC were exposed to each pesticide in the presence of LPS, P4, or their combination. TNF‐α was measured by ELISA. All pesticides enhanced TNF‐α synthesis in PBMC. Co‐exposure with LPS synergizes TNF‐α production, which is blocked by progesterone. These results indicate that these organochlorines act synergistically with LPS to induce TNF‐α secretion in PBMC. This effect is blocked by P4.