The utility of a monocyte monolayer assay in the assessment of intravenous immunoglobulin-associated hemolysis.

Background Hemolysis following the administration of intravenous immunoglobulin (IVIG) is an important adverse event (AE). While the monocyte monolayer assay (MMA) has been used to predict in vivo hemolysis when serologically incompatible blood may be transfused, it has also been shown to correlate with IVIG-associated hemolysis. In this study, the MMA was examined for its utility in assessing the risk of hemolysis after IVIG. Study Design and Methods Forty-two non-blood group O patients receiving high-dose IVIG (>= 2 g/kg) were examined using an autologous and allogeneic MMA. Hemolysis was defined by a drop in hemoglobin of >= 1 g/L, a positive direct antiglobulin test (DAT) and eluate, and a decrease in haptoglobin or increase in lactate dehydrogenase and/or reticulocytes. Results Forty-two patients provided 50 assessable postinfusion samples, with hemolysis observed in 20 (40%) of cases. Autologous MMA using post-IVIG red blood cells significantly correlated with clinical outcomes when compared to allogeneic MMA (P= .0320 vs .5806,ttest). No significant difference in receiver operating characteristics was observed when comparing autologous MMA testing against DAT for the diagnosis of IVIG-associated hemolysis. However, when using samples collected 5 to 10 days after receipt of high-dose IVIG, the autologous MMA had higher sensitivity than the DAT. Conclusion MMA testing with autologous monocytes collected 5 to 10 days after receipt of high-dose IVIG can be used for the diagnosis of IVIG-associated hemolysis and may be of particular value in cases in which the Day 5 to 10 DAT is negative.