Application of monocyte monolayer assay on hemolytic disease of fetus and newborn caused by IgG anti-M

Abstract

Objective To elucidate the prediction ability of monocyte monolayer assay(MMA) used in hemolytic disease of fetus and newborn(HDFN) caused by IgG anti-M. Methods Plasma from eight pregnant women containing IgG anti-M were collected, and were divided into two groups(4 cases with HDFN, with severe clinical symptoms such as fetal hydrops, and 4 cases without HDFN) according to the clinical outcomes. M antigen positive cells were sensitized with dithiothreitol(DTT) treated plasma from eight pregnant women respectively. MMA was performed by coincubation with monocytes and sensitized M cells, along with negative and positive control set up. T-test was conducted to compare the difference in phagocytic efficiency between two groups. Results The phagocytic efficiency in group with HDFN were 15.37%, 13.05%, 9.17% and 24.50% respectively, with the mean value of 15.52%, while the group without HDFN were 8.74%, 11.07%, 5.12% and 6.23% respectively, with the mean value of 7.79%.There was no significant difference in phagocytic efficiency between two groups(P>0.05). The mean values of both groups were not significantly different from the negative control(P>0.05), but both were significantly lower than positive control(P<0.05). Conclusion The low phagocytic efficiency couldn’t convince that the MMA is an effective predictor for the HDFN caused by IgG anti-M, indicating that another mechanism might be responsible for it rather than monocyte phagocytosis. The assessment of the peak systolic velocity in middle cerebral artery of the fetal should be considered in the management for pregnant women who produce IgG anti-M to estimate the situation of fetal anemia.

Keywords

• monocyte monolayer assay(mma)
• igg anti-m
• hemolytic disease of fetus and newborn(hdfn)