The impact of universal leukodepletion of the blood supply on hemovigilance reports of posttransfusion purpura and transfusion-associated graft-versus-host disease.

Background: The pathogenesis of posttransfusion purpura (PTP) and transfusion-associated graft-versus-host disease (TA-GVHD) involves patient exposure to donor platelets (PLTs) and T lymphocytes, respectively, which are removed during blood component leukodepletion (LD).

Study Design And Methods: Reports of PTP and TA-GVHD to the UK hemovigilance scheme Serious Hazards of Transfusion (SHOT) from 1996 to 2005 were compared before and after implementation of universal LD during 1999.

Results: There were 45 reports of PTP, with a mean of 10.3 per year before universal LD and 2.3 per year afterward (p < 0.001). All patients had received red cells, but before universal LD, only 1 of 31 (3%) cases had also received PLTs, compared to 8 of 14 (57%) afterward (p < 0.001). Thirty-four cases (76%) had human platelet antigen (HPA)-1a antibodies, whereas 11 had antibodies to other HPA specificities, only 1 of which occurred after LD. Two cases reported before LD also had heparin-dependent PLT antibodies. There were 13 reports of TA-GVHD, all fatal, of which only 2 cases of undiagnosed immunodeficiency met current UK criteria for irradiated components. Eight others had one or more risk factors: B-cell malignancy (6), steroids (1), fresh blood (1), and donor-recipient HLA haplotype share (4). Eleven cases were due to non-LD and 2 to LD components (p < 0.001). No cases have been reported since 2001. In an additional 405 cases, nonirradiated components were transfused in error to high-risk recipients, mainly on fludarabine, but none developed TA-GVHD.

Conclusions: These findings suggest that universal LD has further reduced the already low risk of TA-GVHD in immunocompetent recipients and has altered the profile of PTP cases.