Rare “P-null” Phenotype – Two Case Reports from Western India

Abstract

The null phenotype in the P1PK blood group, known as “p,” is extremely rare in the world. Such individuals lack the three high-incidence antigens P, P1, and Pk. Individuals of p phenotype spontaneously form anti-PP1PK isoantibody in the serum which is also known as anti-Tja against the missing antigens. We present the two cases of p phenotype with naturally occurring anti-PP1PK isoantibodies in an infant and a young female. Serological tests, including alloantibodies screening and identification, were conducted to demonstrate the phenotype in the P1PK blood group. Both cases were serologically confirmed by higher reference laboratory in India. A well-planned patient blood management strategy can manage the repeated transfusion needs of rare blood group patients. As one of the cases is a young female, monitoring the titer of anti-PP1PK and early initiation of medical intervention are essential after her pregnancy.

Keywords

• anti-pp1pk
• p-null phenotype
• patient blood management
• rare blood group