A Retrospective Study of Red Cell Maternal Antibodies by Chemiluminescence

Abstract

Plasma samples from 109 patients with maternal IgG alloantibodies were investigated using a chemiluminescence (CL) assay, a functional test, to predict which antibodies were clinically significant. The CL assay was able to distinguish between those patients who were unaffected or mildly affected requiring only phototherapy, and those patients with moderate or severe haemolytic disease of the fetus or newborn (HDN) requiring transfusion therapy. The CL result was compared with the anti-D quantification result, the number of IgG molecules bound per red cell and, in 80% of the cases, the monocyte monolayer assay. If mothers carrying Rh-negative fetuses were ignored, then the CL assay correctly predicted the outcome for 93.4% of all cases (including those other than D), while the AutoAnalyzer and monocyte assay predicted correctly 92.7% (of the anti-D patients) and 81.5%, respectively. Greater than 80% of patients with severe or moderate HDN had both IgG1 + IgG3 subclasses in the maternal plasma, while those infants who were unaffected or only mildly affected had a greater chance of having IgG1 only (44%) in the maternal plasma, IgG3 only (27%) or both subclasses (29%).

IgG1 and IgG3 anti‐D in maternal serum and on the RBCs of infants suffering from HDN: relationship with the severity of the disease

“…Several investigators have tried to establish a relationship between the severity of HDN and antibody subclass composition. Some authors 16‐19 have shown that it is mainly IgG1 antibody that causes severe HDN, whereas others have suggested that severe HDN occurs most often when both D‐specific IgG1 and D‐specific IgG3 are present in the maternal serum 20‐23 . Therefore, the respective contributions of IgG1 anti‐D and IgG3 anti‐D to the pathogenesis of HDN remain unclear.…”