[New possibilities in diagnosing hemolytic disease of newborn infants].

Abstract

The diagnosis and management of HDN relies on measurement of maternal anti-D, amniotic fluid analysis and fetal blood sampling by chordiocentesis. However, amniocentesis and chordiocentesis have substantial risks of fetomaternal hemorrhage and subsequent increase in maternal anti-D. In addition to quantitation the functional activity of maternal anti-D has been determined by measuring the interaction of red blood cells sensitized by maternal serum in monocyte-monolayer assays. We assessed the functional activity of anti-D by titration of the sensitized red blood cells using selected sera with rheumatoid factor (RF) as human anti-IgG. First experiments using monoclonal anti-D showed a good correlation between erythrophagocytosis and RF titers. The bilirubin-protein ratio in amniotic fluid may be of great value in predicting the severity of HDN, as shown in 94 cases with severe and 39 cases with moderate disease. Amniotic fluid analysis is complicated by the presence of hemoglobin; we developed a computer program to solve this problem. To improve the serological diagnosis of ABO incompatibility, we measured IgG-anti-A, B in 1,392 maternal and newborn sera applying a sensitive gel test with Coombs serum. Furthermore, we determined the hemolytic activity of anti-A, B by microscopic observation of the morphological changes of red blood cells.