BACKGROUND CD40 ligand (CD40L) deficiency is a rare X linked immunodeficiency disorder leading to recurrent bacterial infection, with cryptosporidial enteritis and subsequent hepatic cirrhosis. Bone marrow transplantation offers the only cure.

OBJECTIVE To analyse retrospectively the outcome of bone marrow transplantation for this condition in one centre.

DESIGN A retrospective case note analysis was performed, identifying all patients with CD40L deficiency who had undergone bone marrow transplantation between May 1988 and December 2000. Details of pre-existing infection, pretransplantation immunological and infective data, transplant procedure (particularly donor type and HLA match), conditioning regimen, and marrow manipulation were analysed. Post-transplantation data including infective episodes, engraftment details, immune function, complications, and outcome were recorded.

RESULTS Eight boys (age 1–14 years, median 5.75) had transplants. Six received T cell depleted unrelated donor marrow. Four survive and have normal immune function. Six had previous Pneumocystis carinii pneumonia and three had histological liver damage. Survival was associated with younger age at transplantation and normal liver histology.

CONCLUSIONS Bone marrow transplantation can be curative in CD40L deficiency. Better outcome is associated with younger age at transplantation and normal liver histology.