New allergies after cord blood transplantation

Umbilical cord blood transplantation (CBT) is an effective treatment for benign and malignant diseases. Late effects of CBT are not well described in the literature. In the present study, we present our experience of new-onset allergies in long-term survivors after CBT.

After an initial patient had a severe peanut allergic reaction after CBT, all CBT patients were prospectively followed for new allergy development. Fifty patients received CBT between March 2006 and June 2011.

The median follow-up after CBT was 447 days (range, 12-2022). At the time of analysis, 30 patients were alive, with 3-year survival of 55.5%; median follow-up of surviving patients was 910 days (range, 68-2022). The allergic syndrome developed in five patients, with the cumulative incidence of new allergies at 2 years of 18.4% (95% confidence interval, 10.8-26). The median time to onset of new allergy after transplantation was 298 days (range, 250-809).

Allergy development has been linked to a delayed maturation of the immune system in several studies. We present the first case series of patients who had new allergies after CBT. Further study of this novel complication as well as counseling of patients after CBT would be important.