Transfusion management in two patients with anti-f antibodies - A case report and review of the literature.

The anti-f antibody is rarely encountered in the immunohematology laboratory. It is against the compound antigen "ce" or "f." The "f-"antigen is only expressed when both c and e alleles are present in the cis position on the same haplotype. Anti-f is a clinically significant antibody that can cause hemolytic transfusion reaction and hemolytic disease in fetuses and newborns. Herein, we report two cases of anti-f antibodies in a 12-year-old boy with a background of bicytopenia and in an 82-year-old male patient with non-Hodgkin lymphoma. In the first case, it was an allo-anti-f associated with a warm type of autoantibody, and the second patient was suspected to have auto-anti-f. The direct antiglobulin test was positive in both cases. Both patients were transfused with c-antigen-negative compatible red cell units without any adverse reactions. This report highlighted the fact that units negative for the c-antigen are a more conservative choice for transfusion than units negative for the e-antigen as both c- and e-antigen-negative units are extremely difficult to find in the general population.