The use of a potential novel tool in virtual crossmatching for platelet transfusion in platelet refractoriness.
OBJECTIVE
Transfusion support for immune-mediated platelet refractoriness (PR) is clinically challenging, technically laborious and costly. The development of 'EpHLA/EpVix software' has been used successfully to select kidney donors. Here, we sought to evaluate this new software as a tool for platelet virtual crossmatch (VxM).


METHODS
This is a prospective study from 2007 to 2014 of PR patients in a tertiary hospital. Platelet components selected by HLAMatchmaker program were crossmatched by EpHLA/EpVix, anti-human globulin complement-dependent lymphocytotoxicity test (AHG-CDC), flow cytometry platelet crossmatch (FCxM) and then compared. Effectiveness of platelet components transfused was evaluated by CCI.


RESULTS
Ninety-seven crossmatched platelet transfusions for 27 patients were enrolled. Partial matches were analysed for 75 transfusions by the 3 methods, and 22% showed discrepant results among the assays. After further analysis, data showed that all divergent cases could be explained by HPA alloimmunization, prozone effect (FCxM), low sensitivity of AHG-CDC and possible interference in FCxM/AHG-CDC assays. Notably, sensitivity and specificity of VxM analysis was excellent (100%). Satisfactory CCI counts were obtained for the majority (22/30) of the transfusions.


CONCLUSIONS
The new EpHLA/EpVix method showed to be effective, feasible and fast for VxM at no cost and able to minimize labour on donor identification. However, platelet crossmatching may be a necessary step because EpHLA/EpVix does not formally exclude HPA alloimmunization.
Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue (INCTS), Campinas, Brazil.
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CB
Bub
Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue (INCTS), Campinas, Brazil.
A C
AC
Gonçalez
Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue (INCTS), Campinas, Brazil.
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ML
Barjas-Castro
Immunogenetics and Molecular Biology Laboratory, Federal University of Piauí, Teresina, Brazil.
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LC
Sousa
Immunogenetics and Molecular Biology Laboratory, Federal University of Piauí, Teresina, Brazil.
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SJ
do Monte
Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue (INCTS), Campinas, Brazil.
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V
Castro
D000293:Adolescent; D000328:Adult; D000368:Aged; D001788:Blood Grouping and Crossmatching / Q000379:methods*; D002675:Child, Preschool; D046148:Donor Selection / Q000379:methods*; D005260:Female; D006650:Histocompatibility Testing / Q000379:methods*; D006801:Humans; D007223:Infant; D016030:Kidney Transplantation / Q000379:methods; D008875:Middle Aged; D017713:Platelet Transfusion / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012984:Software
alloimmunization; crossmatch; platelet antigens; platelet refractoriness