FLOW CYTOMETRIC QUANTITATION OF SERUM ANTI-D IN PREGNANCY

Background: The major cause of fetal hemolytic disease is maternal imm unization to D in D-incompatible pregnancies. To prevent complications , D-incompatible pregnancies are monitored for the level of maternal a nti-D. At present, the monitoring of anti-D levels is performed by the indirect antiglobulin test complemented by quantitation by the techni que used in an automated antibody detection and quantitation instrumen t. Study Design and Methods: Flow cytometry was used to quantitatively determine the level of anti-D in serum and to analyze the IgG subclas s distribution and the presence of IgM anti-D in these samples. The re sults were compared to the indirect antiglobulin test titer and to the results obtained by the technique used in an automated antibody detec tion and quantitation instrument. Results: Flow cytometry allowed sens itive and accurate determinations of anti-D levels with low interassay and intra-assay variability, both for serum samples and standard curv es. Conclusion: Flow cytometry is a simple, rapid, and reliable method for determining the serum levels of D antibodies and their Ig subclas s distribution. It is therefore well suited for the monitoring of wome n during D-incompatible pregnancies.