OCCURRENCE OF ALLOGENEIC HLA AND NON-HLA ANTIBODIES AFTER TRANSFUSIONOF PRESTORAGE FILTERED PLATELETS AND RED-BLOOD-CELLS - A PROSPECTIVE-STUDY

The incidence and consequences of HLA and non-HLA immunization were ev aluated in 229 patients with aplastic thrombocytopenia. All patients w ere transfused with prestorage filtered red blood cells and platelets. On admission, 29 patients presented with HLA antibodies due to prior immunization by pregnancy and/or blood transfusions. Of the 200 patien ts showing no detectable HLA antibodies on admission, 164 could be eva luated. HLA antibodies developed in 2.7% (3 of 112) of the patients wi th a negative risk history of prior immunization. The occurrence of HL A antibodies in patients with a history of previous pregnancies or pri or non-leukocyte-depleted blood transfusions (risk history positive) w as 31% (16 of 52). Of the total of 48 patients who were or became allo immunized, 92% (44 of 48) had a positive risk history. Ten patients wi th broad multispecific HLA antibodies with a panel reactivity (PRA) of greater than 70% required transfusions with HLA-matched platelets. Pa tients with HLA antibodies with lower PRA could be supported by random donor platelets. Two patients developed platelet-specific antibodies, causing transfusion refractoriness that necessitated selecting platel ets by the absence of a platelet-specific antigen. Using prestorage le ukocyte depletion of red cells and platelets with less than 5 x 10(6) residual leukocytes. 95% of the patients, including patients with a pr evious risk history or with HLA antibodies with low PRA, can be suppor ted with random donor transfusions for the entire duration of their th rombocytopenic periods. (C) 1995 by The American Society of Hematology .