Higher Anti-A/B isoagglutinin titers of IgG class, but not of IgM, are associated with increased red blood cell transfusion requirements in bone marrow transplantation with major ABO-mismatch.

BACKGROUND: Major ABO mismatch between donor and recipient in bone marrow transplantation (BMT) may cause hemolysis, delayed red blood cell (RBC) engraftment and pure red cell aplasia (PRCA), which result in increased transfusion needs. High pretransplant anti-A/B antibody titers have been associated with increased risk of PRCA. Herein, we studied the impact of anti-A/B titers on transfusion needs after BMT with major ABO mismatch. METHODS: We reviewed the medical charts of 27 patients who underwent to BMT with major ABO mismatch and categorized them into two groups according to anti-A/B titers of IgG (≤16 and ≥32). We recorded the number of RBC and platelet units transfused in the first 180 days after transplantation. We also evaluated the impact of anti-A/B titers on overall survival. RESULTS: Patients with anti-A/B titer ≥32 of IgG class required more RBC transfusion than patients with titer ≤16 (6.60±4.55 vs 21.29±14.68; P=.03). Anti-A/B of IgM class had no impact on both RBC and platelet transfusion needs. Anti-A/B titers had no impact on overall survival. CONCLUSION: Higher titers of anti-A/B antibodies of IgG class, but not of IgM, are associated with a higher demand for RBC transfusion.