QUANTITATIVE AND FUNCTIONAL ASSESSMENT OF ANTI-RHD - A COMPARATIVE-STUDY OF NONINVASIVE METHODS IN ANTENATAL PREDICTION OF RH HEMOLYTIC-DISEASE

Study objective. To investigate if the prediction of hemolytic disease of the newborn (HDN) in infants of RhD immunized women has been impro ved by introduction of AutoAnalyzer quantitation and may be further im proved by the use of a functional assay. Methods. Manual antibody titr ation. AutoAnalyzer quantitation and chemiluminescence test (CLT) were compared by testing 42 sera from 38 RhD immunized mothers, The sera w ere also screened for the presence of monocyte-reactive antibodies whi ch have the potential to protect the unborn. Results. Among the 42 inf ants there were 19 unaffected by HDN and 23 affected by HDN. Manual ti tration correctly predicted the occurrence of HDN in 29/42 (69%). Auto Analyzer was correct in 28/42 (67%) and CLT showed correct predictions with 30/42 (71%). In babies born without signs of HDN. maternal monoc yte-reactive antibodies were found in 13/18 cases. The majority (9/13) were HLA class I-specific, the remaining four antibodies were either HLA class II or monocyte-specific. In affected HDN group, 8/16 monocyt e-reactive antibodies were HLA class Ii or monocyte-specific. Conclusi ons. AutoAnalyzer and CLT improve the ability to discriminate unaffect ed babies from those affected by RhD HDN. when compared to manual titr ation. A protocol for the laboratory management of RhD immunized women is proposed that includes these tests to further improve the predicti on of HDN. This study has also highlighted the need for more investiga tions into the protective role of monocyte-reactive antibodies in HDN.