Bone marrow transplants for paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare clonal haematological disorder characterized by intravascular haemolysis and increased risk of th rombosis. PNH is associated with bone marrow failure syndromes including ap lastic anaemia, myelodysplasia and leukaemia. Bone marrow transplants are s ometimes used to treat PNH, but small series and reporting biases make asse ssment of transplant outcome difficult. The outcome of 57 consecutive allog eneic bone marrow transplants for PNH reported to the international Bone Ma rrow Transplant Registry (IBMTR) between 1978 and 1995 was analysed. The 2- year probability of survival in 48 recipients of HLA-identical sibling tran splants was 56% (95% confidence interval 49-63%). Two recipients of identic al twin transplants remain alive 8 and 12 years after treatment, One of sev en recipients of alternative donor allogeneic transplants is alive 5 years after transplant. The most common causes of treatment failure were graft fa ilure and infections, Our results indicate that bone marrow transplantion c an restore normal bone marrow function in about 50% of PNH patients.