Outcome of unrelated umbilical cord blood transplantation in 88 patients with primary immunodeficiency in Japan

We report the results of umbilical cord blood transplantation (UCBT) performed in 88 patients with primary immunodeficiency (PID) between 1998 and 2008 in Japan; severe combined immunodeficiency (SCID, n=40), Wiskott-Aldrich syndrome (WAS, n=23), chronic granulomatous disease (n=7), severe congenital neutropaenia (SCN, n=5) and other immunodeficiencies (n=13). Five-year overall survival (5-year OS) for all patients was 69% [95% confidence interval (CI), 57-78%], and was 71% and 82% for SCID and WAS, respectively. The main cause of death before day 100 was infection (17/19), while that after day 100 was graft-versus-host disease (GVHD) (5/7). Using multivariate analyses, pre-transplant infection, no conditioning, ≥2 human leucocyte antigen (HLA) mismatches or diagnosis other than SCID, SCN or WAS were all associated with poor prognosis. Reduced-intensity conditioning was associated with decreased overall mortality compared with myeloablative therapy. The cumulative incidence of grade 2-4 acute GVHD at day 100 was 28% (95% CI, 19-38%), and that of chronic GVHD at day 180 was 13% (95% CI, 7-23%). We conclude that UCBT should be considered for PID patients without an HLA-matched sibling. The control of pre-transplant infection and selection of HLA-matched donors will lead to a better outcome.