[Post-transfusion HL-A alloimmunization in acute leukemia]

Patients with acute leukemia (AML and ALL) who received multiple transfusions of whole blood, platelets or granulocytes, may develop anti-HL-A immunization in spite of chemotherapy. The frequency of HL-A alloimmunization was studied in 21 patients with AML and in 11 children with ALL. Multispecific HL-A antibodies were detected in 10 patients with AML and in 8 with ALL. The presence of these antibodies was associated with febrile transfusion reactions and with immediate destruction of platelets or granulocytes. Selection of HL-A compatible donors eliminated those reactions and the platelet counts could be maintained at levels sufficient to avoid the risk of hemorrhage. It seems therefore warranted to transfuse exclusively HL-A compatible platelets or leukocytes, as soon as anti-HL-A immunization has been detected.