Influence of mid-trimester amniotic fluid on endogenous and lipopolysaccharide-mediated responses of mononuclear lymphoid cells.

PROBLEM  We evaluated the influence of amniotic fluid (AF) on immune mediator production by mononuclear leukocytes. METHOD OF STUDY  Thirty mid-gestation AFs were incubated with peripheral blood mononuclear cells (PBMCs) in the presence or absence of lipopolysaccharide (LPS). Supernatants were tested for interleukin (IL) - 6, 10, 12, 23, tumor necrosis factor-α (TNF-α) and monocyte chemotactic protein (MCP)-1. RESULTS  Endogenous mediator production was minimal or non-detectable. AF stimulated endogenous MCP-1, IL-6 and TNF-α release. In the presence of LPS, production of MCP-1 and IL-10 by PBMCs was enhanced eight- to ninefold by AF. Release of IL-6 and IL-23 was enhanced less than twofold by the addition of AF while TNF-α production was unchanged. AF-stimulated mediator production was similar irrespective of pregnancy outcome. CONCLUSION  Selective AF stimulation of LPS-mediated MCP-1 and IL-10 release may be a mechanism to promote antibody production and the influx of phagocytic cells to engulf pathogens while downregulating the production of pro-inflammatory cytokines.