Maternal serum and amniotic fluid levels of macrophage inhibitory cytokine 1 in Down syndrome and chromosomally normal pregnancies

Objectives To measure maternal serum and amniotic fluid levels of macrophage inhibitory cytokine‐1 (MIC‐1) in Down syndrome and normal pregnancies, assessing the utility of MIC‐1 as a prenatal marker of Down syndrome. Methods Stored serum from 64 Down syndrome and 399 control pregnancies, collected at 8 to 17 weeks of pregnancy, and stored amniotic fluid from 17 Down syndrome and 53 controls, collected at 15 to 19 weeks of pregnancy, were retrieved for analysis. MIC‐1 was measured using an established in‐house ELISA, blinded to sample type. Results In maternal serum, MIC‐1 levels are not altered in Down syndrome in either the first or second trimester. Levels, expressed as median (95% CI) multiples of the median (MoM), in the Down syndrome cases and controls were 1.07 (0.9–1.1) MoM and 1.0 (0.95–1.03) MoM respectively. In amniotic fluid, MIC‐1 levels were significantly decreased compared to controls, 0.52 (0.44–0.64) MoM versus 1.0 (0.85–1.08) MoM (p < 0.0001). Conclusion MIC‐1 is decreased in amniotic fluid but not in maternal serum in Down syndrome pregnancies. MIC‐1 will not be useful as a prenatal marker of Down syndrome. Copyright © 2004 John Wiley & Sons, Ltd.