HLA Class I and HLA Class II Antibodies in Whole Blood Donors and a Lookback on Recipients of Their Blood Components.

Introduction: Transfusion-related acute lung injury (TRALI) in recent years has become the leading cause of transfusion associated mortality. All transfusable blood components (and rarely IVIG) have been implicated in TRALI. However, plasma and single donor platelet products amount for the majority of cases. (Blood Products Advisory Committee 89^th Meeting - April 27, 2007) Although the mechanism of pathogenesis is not fully known, 45 % to 60% of cases are reported to be associated with Neutrophil-Specific Antibodies (NSA) found in the donor. Less commonly, antibodies to HLA Class I and HLA Class II antigens have been implicated. Pregnancy is known to result in development of Leucocyte antibodies and HLA antibodies. (

Material and Methods: At our institution, a three month (May to July 2008) retrospective review was conducted on all whole blood donors screened by the ELISA test (DONORSCREEN-HLA Class I and Class II by GTI Diagnostics @ Waukesha, WI) performed on the Quick Biotest machine. The OD for the donors as well as the cut offs were reviewed for each run. A total number of 4056 whole blood donations collected at our blood center were tested for HLA Class I and HLA Class II antibodies by this method. The Whole Blood Donors met the criteria established by AABB and FDA standards. A look back was conducted on the final disposition of the components prepared from the donors that tested positive for either HLA Class I or HLA Class II antibodies or both HLA Class I and HLA Class II antibodies. We relied on existing reporting systems in place in our institution for reporting of transfusion reaction.

Results: Of the 4056 whole blood donors there were tested, 231 (5.84%) donors of which 231 (97.47%) females and 6 (2.53%) males tested positive for HLA Class I antibodies and 198 (4.93%) donors tested positive for HLA Class II antibodies of which 186 (93.94%) were females and 14 (7.07%) were males. A total number of 52 (1.28%) donors tested positive for both HLA Class I and HLA Class II antibodies of which 51 (1.26%) were females and only 1 (0.02%) was male. From the HLA Class I positive donors, 217 packed RBCs, 176 platelets and 14 plasma components were transfused. From the HLA Class II positive donors, 183 packed RBCs, 153 platelets and 11 plasma components were transfused. All of the components were irradiated. The packed RBCs and plasma were transfused via Fenwal Sepacell Leukocyte Reduction Filters. The platelets were pooled and transfused via Fenwal Sepacell PLS-10A Leukocyte Reduction Y Administration Set. The platelets were issued for transfusion within two days of donation in most instances. The patients who received plasma from the HLA positive donors did not receive IVIG treatment. The plasma that was processed from these whole blood donors that tested positive for either HLA Class I or HLA Class II antibodies were pooled with other plasma products from other whole blood donors. There were no transfusion reactions attributable to TRALI that were reported in any of the patients that received packed RBCs, platelets or plasma from these donors. There were 48 transfusion reactions reported for the same period of time that this review was conducted. All of the reported transfusion reactions were also reviewed. There were no reported cases of transfusion reactions or clinical symptoms attributable to TRALI in any of the patients that received components processed from these donors or in the patients that had reported transfusion reactions. The patients at our institution may not reflect the general patient population of other institutions, as most of our patients are immunosuppressed. This retrospective review was conducted to correlate the reported transfusion reactions with components that were transfused from HLA immunized donors. The presence of antibodies to HLA Class I or HLA Class II may not reflect the incidence of TRALI in cancer patients.