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).


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.
Williamson
Lorna M
LM
Department of Haematology, University of Cambridge, and NHS Blood and Transplant, Long Road, Cambridge, United Kingdom. lorna.williamson@nbs.nhs.uk
Stainsby
Dorothy
D
Jones
Hilary
H
Love
Elizabeth
E
Chapman
Catherine E
CE
Navarrete
Cristina
C
Lucas
Geoff
G
Beatty
Cynthia
C
Casbard
Angela
A
Cohen
Hannah
H
D016824:Antigens, Human Platelet / Q000276:immunology; D006086:Graft vs Host Disease / Q000209:etiology*; D006801:Humans; D007108:Immune Tolerance; D047589:Leukocyte Reduction Procedures; D011693:Purpura / Q000209:etiology*; D065227:Transfusion Reaction
D016824:Antigens, Human Platelet