Objective: We examined whether mononuclear cell purification of human blood could be done while minimizing contamination with RhD-positive red blood cells to treat hemolytic disease of the fetus/newborn that was caused by rhesus disease.
Study design: Whole blood from 16 individuals who tested rhesus positive was diluted and centrifuged over a Ficoll gradient. The cell pellet was incubated with red blood cell lysis buffer, divided into three samples, and analyzed for cell count, mononuclear cell yield, and RhD-positive red cell contamination by flow cytometry.
Results: Mean RhD-positive red cell contamination was 0.24% (range, 0%-1.9%). The average yield of mononuclear cells was 11.5% (range, 1.8%-23.6%). Through regression analysis, 34 to 180 mL of paternal whole blood would be necessary to achieve an antigen load that is sufficient for an HLA antibody response.
Conclusion: Purification of human blood is possible to produce reasonable mononuclear cell yields with minimal rhesus activity, which makes paternal leukocyte therapy a plausible treatment for severe rhesus alloimmunization.