Application of noninvasive phagocytic cellular assays using autologous monocytes to assess red cell alloantibodies in sickle cell patients

We investigated red cell (RBC) alloantibodies in 125 sickle cell anemia (SCA) patients using tube indirect antiglobulin test (PEG, LISS or enzyme) and gel centrifugation test (LISS or enzyme). Prediction of clinical significance of alloantibodies was evaluated by the monocyte monolayer assay (MMA) and the chemiluminescence test (CLT) using autologous monocytes. The alloimmunization rate was 20.8% and the gel test detected a higher number of alloantibodies than the tube test (26 v 21, p=0.02). We observed 58.3% and 69.2% positive MMA and CLT results, respectively. Eighteen (69.2%) antibodies exhibited clinical relevance, 14 (58.3%) antibodies reacted by both MMA and CLT, while 4 (15.4%) antibodies reacted only by CLT. In conclusion, the application of phagocytic cellular assays using autologous monocytes defined clinical significance of about 70% of RBC alloantibodies detected in SCA patients. The data also suggest that the CLT may be more valuable than the MMA as a noninvasive test for predicting hemolysis after transfusion of incompatible blood in SCA patients.