Naturally occurring anti‐Kpa in an infant with recurrent bacterial infection: A case report and review of the literature

Naturally occurring anti‐Kpa antibody is extremely rare and was first reported in 1957, named after the first producer ‘Penney’. However, the subsequent anti‐Kpa reports presented were all anti‐Kpa due to isoimmunization. Individuals with severe bacterial infections particularly Gram‐negative bacteria are known to be capable of producing cross‐reactive antibodies against Kell blood group system. However, such uncommon antibodies like anti‐Kpa can be easily missed in routine pre‐transfusion testing unless the panel cells containing low incidence antigen are used for antibody screening. Here, we report a case of naturally occurring anti‐Kpa antibody, identified incidentally during pre‐transfusion testing of a 12‐month‐old female infant with the diagnosis of Niemann–Pick disease and recurrent bacterial (Escherichia coli) infection.