Abstract
Introduction/Objective
Human platelets (PLTs) do not express any Rh system antigens; however, PLT concentrates can be contaminated with small amounts of red blood cells (RBCs), which may induce alloimmunization when transfused to Rh(D)-negative individuals. RhIG has been utilized to prevent Rh(D) alloantibody development following transfusion of Rh mismatched PLTs.
RhIG is manufactured using pooled plasma of healthy Rh(D)-negative donors, with the most common Rh haplotype being ce; treated subjects are exposed to Rh (D)-positive RBCs, with the most common Rh haplotype of donors being DCe. In this report, we detail our experiences with recipients of Rh mismatched apheresis PLTs who were noted to develop anti-D + anti-C post-RhIG administration.
Methods
Retrospective review was conducted of all Rh mismatched PLTs between December, 2018 and May, 2019 at our facility (Yale-New Haven Hospital, New Haven, CT). Inclusion in the study required: Rh(D)-negative donor receiving one or more Rh(D)-positive apheresis PLTs, Receiving RhIG, >1 antibody screen following RhIG administration demonstrating antibodies other than anti-D
Results
Our retrospective review identified 8 unique recipients of Rh mismatched apheresis PLTs who acquired anti- C, in addition to the expected anti-D, following administration of RhIG. The product (Rhophylac) was administered in all cases intravenously at a dose of 1500 IU (300 mcg) within 72 hours following Rh mismatched PLTs. In all patients, routine screening following RhIG simultaneously detected anti-D and anti-C 1-3 days after administration of Rh mismatched PLTs/RhIG, the antibody screen remained positive for a range of 27-167 days for both antibodies.
Conclusion
Based on this case series, which represented entirely men and older women, and coupled with emerging evidence about the extremely low likelihood of D-alloimmunization following Rh mismatched apheresis PLTs,2,3,6 we have changed our practice, limiting immunoprophylaxis for Rh mismatched platelets exclusively to women of reproductive age.
The blood bank and apheresis communities should be aware that passive transfer of non-D antibodies is possible when RhIG is dosed and could account for newly-detected non-D alloimmunization events. This phenomenon is another compelling reason to limit RhIG exposure to cases where it is only absolutely clinically necessary.7
Association Between Biomarkers of Ovarian Reserve and Infertility Among Older Women of Reproductive Age
