The platelet alloantibody and importance of compatible HPA-2b in patients receiving multiple platelets.

8 HPA-2b antibodies were detected in the serum of 163 patients administered platelet concentrates at more than 100 units. When the patients showed HPA-2b antibody in the serum administered incompatible HLA-matched platelets by MPHA (mixed passive haemagglutination) test cross-match, no increase could be detected in the mean 24-hour post-transfusion CPI (corrected platelet increment). 900 Japanese plateletpheresis donors were examined using HPA-2b antibody at our laboratory and 687 of whom were typed as HPA-2b antigen negative. The mean 24-hour post-transfusion CPI of HLA-matched platelets typed as HPA-2b antigen negative and HPA-2b antigen positive were 0.91±0.74 and -0.15±0.35, respectively. Efficiency was 72.2% and 0% (p<0.0001), respectively.