THE EFFECT OF LYMPHOCYTOTOXIC ANTIBODY REACTIVITY ON THE RESULTS OF SINGLE ANTIGEN MISMATCHED PLATELET TRANSFUSIONS TO ALLOIMMUNIZED PATIENTS

Despite selection strategies that attempt to maximize the platelet don or pool, significant numbers of alloimmunized patients have few if any available donors. Although the number of potential donors increases w hen one antigen mismatched platelet transfusions (OAMPT) are considere d, transfusions from such donors are often cited to fail to produce sa tisfactory platelet count increments. The presence of lymphocytotoxic antibody (LCTAB) correlates well with responsiveness to random donor p latelet transfusions and serves as a good serologic screen for the dia gnosis of alloimmunization. We therefore reviewed the results of OAMPT to alloimmunized patients and assessed the relationship between LCTAB levels in the recipient and posttransfusion platelet count increments . We noted an unexpectedly high percentage of good responses in our pa tient population: 73% of all OAMPT to recipients with LCTAB <60% react ive, resulted in successful increments. In recipients with LCTAB great er than or equal to 60%, 58% of all transfusions were still successful , Despite a statistically significant inverse relationship between the level of LCTAB and the response of OAMPT to alloimmunized patients, 5 8% to 73% of recipients will have a satisfactory platelet recovery pos ttransfusion. These data support extending donor searches for alloimmu nized patients to include any single mismatch particularly if a recipi ent's LCTAB has lower reactivity. (C) 1996 by The American Society of Hematology.