Cord colitis syndrome in cord-blood stem-cell transplantation.

BACKGROUND Diarrhea is a frequent complication of hematopoietic stem-cell transplantation (HSCT). Important causes of diarrhea after HSCT include acute graft-versus-host disease (GVHD), infections, and medications. After the transplantation and engraftment of hematopoietic stem cells from umbilical-cord blood, we observed a new syndrome of culture-negative, antibiotic-responsive diarrhea not attributable to any known cause. METHODS We conducted a retrospective cohort study of all patients undergoing cord-blood HSCT at our center between March 2003 and March 2010. The cord colitis syndrome was defined as a persistent diarrheal illness in such patients that was not due to acute GVHD, viral or bacterial infection, or another identifiable cause. Clinical and histopathological features of patients meeting the case definition were further analyzed. RESULTS Among 104 patients who underwent cord-blood HSCT at our center, the cord colitis syndrome developed in 11 (10.6%). The 1-year Kaplan-Meier cumulative probability of meeting the case definition for the syndrome was 0.16. The median time to onset after transplantation was 131 days (range, 88 to 314). All patients had a response to a 10-to-14-day course of empirical therapy with metronidazole, alone or in combination with a fluoroquinolone. Five of the 11 patients (45%) had recurrent diarrhea shortly after discontinuation of antibiotics, and all patients who had a relapse had a response to reinitiation of antibiotic therapy. On histologic examination, all patients with the cord colitis syndrome had chronic active colitis, with granulomatous inflammation present in 7 of 11 patients (64%). CONCLUSIONS The cord colitis syndrome is clinically and histopathologically distinct from acute GVHD and other causes of diarrhea in patients who have undergone cord-blood HSCT and is relatively common in this patient population. The syndrome should be considered in such patients who have diarrhea that is not attributable to other causes.