(P-TS-107) Role of a Single Blood Donor in Multiple Allergic Transfusion Reactions

Background/Case Studies: Allergic transfusion reactions (ATRs) are the most common type of transfusion reaction in the United States. As they recur in some recipients, ATRs are believed to be driven predominantly by recipient-specific factors and rarely attributed to donor-specific factors. Our hospital-based blood donation center identified a donor implicated in multiple ATRs after anaphylactic transfusion reactions were identified in two separate recipients. This study investigated if any shared recipient-specific factors could potentially explain the multiple ATRs from blood products from this donor.

Study

Design/Methods: The implicated donor’s donation and medical history were reviewed and additional blood testing for chronic urticaria index, anti-basophil antibodies, and monoclonal serum proteins were conducted with donor consent. A case-control study of all unique blood product transfusions from this donor was conducted to compare recipient age, gender, ABO minor mismatch, allergy history, and medication history (within 7 days prior to transfusion) between those who experienced an ATR (case) versus those who did not (control). Fisher’s exact and t-test were used to compare recipient features between cases and controls and a p-value< 0.05 was considered significant. This study was approved by the local institutional review board.

Results/Findings: The implicated blood donor was an A+ female with a clinical history of chronic urticaria, vancomycin allergy (rash), and clindamycin allergy (rash) that predated all blood donations. Additional blood testing revealed a normal chronic urticaria index of 3.7 (normal < 10), normal serum IgG/IgM/IgA levels, no monoclonal serum protein (including IgD or IgE), and no anti-basophil antibodies. Of 67 unique blood product transfusions from this donor, there were 18 (27%) cases (Figure). Only two cases (11%) had any previous ATRs. Cases were slightly younger (mean age 54.1 vs 62.5 yrs; p=0.17) and more female (39% vs 27%; p=0.37) than controls. Cases had significantly lower rates of vancomycin within the 7 days prior to transfusion than controls (22% vs 53%; p=0.03) and there was no difference in rates of clindamycin within the 7 days prior to transfusion (0% vs 4%; p=1). There was no difference in blood product ABO minor mismatch rates between cases and controls (11% vs 6%; p=0.61). There was no common allergy or other medication found across the 18 cases.

Conclusions: A single blood donor had a 27% ATR rate with a range of reaction severities. No shared recipient-specific factors were associated with these ATRs and additional testing failed to identify a donor-specific cause. This study highlights how ATRs can be donor-specific and there may be a role for systematic reporting of severe/anaphylactic ATRs back to blood collectors for donor investigation.