Utility of cross-matched platelet transfusions in patients with hypoproliferative thrombocytopenia: a systematic review.

Background: Multiply transfused hypoproliferative thrombocytopenic (HT) patients with alloimmune transfusion refractoriness require specially selected platelets (PLTs). Cross-matching apheresis PLTs is a popular support option, avoiding requirements for large panels of typed donors for HLA-based selection. We undertook a systematic review of the utility of various cross-matching techniques on mortality reduction, prevention of hemorrhage, alloimmunization and refractoriness, and improvement in PLT utilization or count increments.

Study Design And Methods: A systematic review to December 2012 was conducted of MEDLINE, EMBASE, and Cochrane databases along with a bibliographic search of pertinent references.

Results: Of 146 retrieved citations, 20 met inclusion criteria. Eleven more were chosen from bibliographies, describing 29 unique cohorts. All but five enrolled transfusion-refractory, predominantly alloimmunized patients. Cross-match impact on mortality and hemorrhage could not be assessed from these studies. Two studies demonstrated durable corrected count increments and/or breadth of alloimmunization throughout cross-match support; none addressed development or persistence of refractoriness. In alloimmunized refractory patients and nonrefractory cohorts with greater than 25% alloimmunization, higher increments were seen with cross-match-compatible PLTs than incompatible or un-cross-matched units. In two nonrefractory, nonalloimmunized cohorts, the lack of utility of cross-match was reflected by test sensitivity of less than 20%. Comparison of cross-matched PLT success with that of HLA-identical units revealed inferior success rates for the former in one study and equivalent rates in another. No trend was observed regarding relative utility of the various commonly employed techniques.

Conclusion: Cross-matched PLTs are useful in increasing PLT counts in alloimmunized, transfusion-refractory HT patients, but data about their impact on hemorrhage and mortality are lacking.