Primary refractoriness to platelet transfusion caused by Nak a antibody alone

BACKGROUND AND OBJECTIVES: Anti-Nak(a), a platelet-specific antibody, occasionally causes platelet-transfusion refractoriness (PTR) together with human leucocyte antigen (HLA) antibodies. Anti-Nak(a) usually appears after frequent platelet transfusions or pregnancy. We report the first case of PTR caused by anti-Nak(a) alone. MATERIALS AND METHODS: A 19-year-old male patient with testicular tumour showed PTR when receiving his first transfusion of platelets. Screening for platelet antigens and platelet antibodies revealed that he had type I CD36 (Nak(a)) deficiency and that anti-Nak(a), but not anti-HLA, was present before he received his first transfusion. RESULTS: The transfusion of Nak(a)-negative, but HLA non-selected, platelets was effective in raising the platelet count. CONCLUSION: Clinically significant Nak(a) antibody was present as naturally occurring antibody in a platelet glycoprotein IV (CD36)-negative non-transfused male patient.