Severe infections after single umbilical cord blood transplantation in adults with or without the co-infusion of CD34+ cells from a third-party donor: results of a multicenter study from the Grupo Español de Trasplante Hematopoyético ( GETH)

Background Umbilical cord blood transplantation ( CBT) is an established alternative source of stem cells in the setting of unrelated transplantation. When compared with other sources, single-unit CBT ( sCBT) is associated with a delayed hematologic recovery, which may lead to a higher infection-related mortality ( IRM). Co-infusion with the sCBT of CD34+ peripheral blood stem cells from a third-party donor ( TPD) ( sCBT + TPDCD34+) has been shown to markedly accelerate leukocyte recovery, potentially reducing the IRM. However, to our knowledge, no comparative studies have focused on severe infections and IRM with these 2 sCBT strategies. Methods A total of 148 consecutive sCBT (2000-2010, median follow-up 4.5 years) were included in a multicenter retrospective study to analyze the incidence and risk factors of IRM and severe viral and invasive fungal infections ( IFIs). Neutrophil engraftment occurred in 90% of sCBT ( n = 77) and 94% sCBT + TPDCD34+ ( n = 71) recipients at a median of 23 and 12 days post transplantation, respectively ( P < 0.01). Results The 4-year IRM was 24% and 20%, respectively ( P = 0.7), with no differences at day +30 (5% and 4%, respectively) and day +100 (10% and 8%, respectively). In multivariate analysis early status of the underlying malignancy, cytomegalovirus ( CMV)-seronegative recipient and high CD34+ cell content in the cord blood unit before cryostorage (≥1.4 × 105/kg) were protective of IRM. Among the causes of IRM, bacterial infections and IFIs were more common in sCBT (15% vs. 4%), while CMV disease and parasitic infections were more common in the sCBT + TPDCD34+ cohort (5% vs. 16%). Conclusion These data show that sCBT supported with TPDCD34+ cells results in much shorter periods of post-transplant leukopenia, but the short- and long-term rates of IRM were comparable to those of sCBT, presumably because immune recovery is equally delayed in both graft types. [ABSTRACT FROM AUTHOR]