Key Points• For good immune reconstitution and fewer viral reactivations, thymoglobulin should be omitted in cord blood transplants.• Because omission of thymoglobulin is associated with higher acute GVHD rates, further improvement of outcome may require individualized dosing.In vivo T-cell depletion might contribute to the delayed immune reconstitution observed after unrelated umbilical cord blood transplantation (UCBT). We studied the impact of early, late, and no antithymocyte globulin (ATG) on immune reconstitution and outcome. One hundred twenty seven children receiving UCBT in London or Utrecht were divided into 3 groups: early ATG (days 29 to 25; n 5 33), late ATG (days 25 to 0; n 5 48), and no ATG (n 5 46). The no-ATG group received mycophenolate mofetile 1 cyclosporin A as graft-versus-host disease (GVHD) prophylaxis, while the ATG groups received cyclosporin A 1 prednisone. End points studied were survival, immune recovery, infections, and GVHD. The probability of survival was similar in all groups: no ATG, 71% 6 8%; early ATG, 68% 6 9%; and late ATG, 61% 6 7%. CD3 1 , CD4 1 , and CD4 1-naive T-cell counts were significantly higher (P < .001) in the no-ATG group at 1, 2, 3, 6, and 12 months post-UCBT. In the no-ATG group, significantly fewer viral reactivations (P 5 .021) were noted. A higher probability of severe acute GVHD (aGVHD; 31%) was found in the no-ATG group compared with 18% (P 5 .018) for early-ATG and 5% (P < .001) for late-ATG groups. This was not associated with more chronic GVHD (cGVHD). (Blood. 2014;123(1):126-132)

Busulfan (Bu) is used as a myeloablative agent in conditioning regimens before allogeneic hematopoietic cell transplantation (allo-HCT). In line with strategies explored in adults, patient outcomes may be optimized by replacing cyclophosphamide (Cy) with or without melphalan (Mel) with fludarabine (Flu). We compared outcomes in 2 consecutive cohorts of HCT recipients with a nonmalignant HCT indication, a myeloid malignancy, or a lymphoid malignancy with a contraindication for total body irradiation (TBI). Between 2009 and 2012, 64 children received Flu + Bu at a target dose of 80-95 mg·h/L, and between 2005 and 2008, 50 children received Bu targeted to 74-80 mg·h/L + Cy. In the latter group, Mel was added for patients with myeloid malignancy (n = 12). Possible confounding effects of calendar time were studied in 69 patients receiving a myeloablative dose of TBI between 2005 and 2012. Estimated 2-year survival and event-free survival were 82% and 78%, respectively, in the FluBu arm and 78% and 72%, respectively, in the BuCy (Mel) arm (P = not significant). Compared with the BuCy (Mel) arm, less toxicity was noted in the FluBu arm, with lower rates of acute (noninfectious) lung injury (16% versus 36%; P = .007), veno-occlusive disease (3% versus 28%; P = .003), chronic graft-versus-host disease (9% versus 26%; P = .047), adenovirus infection (3% versus 32%; P = .001), and human herpesvirus 6 infection reactivation (21% versus 44%; P = .005). Furthermore, the median duration of neutropenia was shorter in the FluBu arm (11 days versus 22 days; P < .001), and the patients in this arm required fewer transfusions. Our data indicate that Flu (160 mg/m(2)) with targeted myeloablative Bu (90 mg·h/L) is less toxic than and equally effective as BuCy (Mel) in patients with similar indications for allo-HCT.

This study was aimed at finding predictors of invasive fungal infection (IFI) after pediatric allogeneic hematopoietic SCT (HSCT). All children who received allogeneic HSCT in the Wilhelmina Children's Hospital Utrecht between 2004 and 2012 were included. HSCT data were prospectively collected. Patients were retrospectively classified into high-or low-risk groups for developing IFI using criteria based on available literature. Predictors for the occurrence of IFI were analyzed using Cox regression models. We used logistic regression models to analyze the association between other HSCT-related complications and IFI. Secondary outcomes were overall survival and treatment-related mortality (TRM). Two-hundred nine patients were included in the analysis; median age was 6.6 years. The cumulative incidence of IFI was 12%. In patients classified as 'low risk' (n ¼ 75), only 5.3% developed IFI (odds ratio (OR): 0.325; P ¼ 0.047). In multivariate analysis, a predictor for the occurrence of IFI was an a priori determined HSCT TRM risk 420% (based on EBMT-risk score). Post-HSCT, the administration of high-dose steroids was associated with IFI (OR: 4.458; P ¼ 0.010). Patients who developed IFI showed an increased risk of TRM (OR: 3.773; P ¼ 0.004). These results confirm that risk group stratification should guide intensity of monitoring for IFI and use of antifungal prophylaxis.

Acute graft-versus-host disease (aGVHD) can be triggered by inflammatory conditions, including infections and mucositis. We investigated the association between PCR positivity for gastrointestinal (GI) viruses in stool before hematopoietic cell transplantation (HCT) and intestinal aGVHD using Cox proportional hazard models. We included 48 consecutive HCT patients (28 with malignancies and 20 with nonmalignancies) without GI symptoms before HCT. Fifteen patients were GI virus positive: 9 adenovirus, 3 norovirus, 2 parechovirus, and 1 astrovirus. Overall survival was 58% ± 8%. The cumulative incidence of aGVHD grade 2 to 4 was 43% ± 8% (n = 18) after a median of 47 days (range, 14 to 140). In univariate analysis, GI virus PCR positivity was the only predictor for aGVHD (P = .008): within the group of GI virus PCR-positive patients, the cumulative incidence of aGVHD 2 to 4 was 70% ± 12% versus 29 ± 8% in the PCR-negative group (P = .004). In conclusion, GI virus PCR positivity before HCT predicted development of intestinal aGVHD. These results may ultimately affect monitoring, aGVHD prophylaxis, and treatment, as well as rescheduling of elective HCTs.

Outcome of 333 children with acute myeloid leukaemia relapsing after a first allogeneic haematopoietic stem cell transplantation was analyzed. Four-year probability of overall survival (4y-pOS) was 14%. 4y-pOS for 122 children receiving a second haematopoietic stem cell transplantation was 31% and 3% for those that did not (P = <0Á0001). Achievement of a subsequent remission impacted survival (P = <0Á0001). For patients receiving a second transplant survival with or without achieving a subsequent remission was comparable. Graft source (bone marrow vs. peripheral blood stem cells, P = 0Á046) and donor choice (matched family vs. matched unrelated donor, P = 0Á029) positively impacted survival after relapse. Disease recurrence and non-relapse mortality at four years reached 45% and 22%.

Introduction In vivo T-cell-depletion generated by the use of Thymoglobulin (ATG) within the conditioning regimen might contribute to the delayed immune-reconstitution observed after unrelated umbilical cord blood transplantation (UCBT). We studied the impact of early, late and no ATG on immune reconstitution and clinical outcome. Methods 127 Children receiving an unrelated UCBT in London or Utrecht between 2006 and 2011 were included and divided in 3 groups: late ATG (day -5 to 0, n=48), early ATG (day -9 to -5, n= 33) and no ATG(n=46). The no ATG group received MMF and CsA as GVHD prophylaxis, while the ATG groups both received CSA and prednison as prohylaxis, Endpoints studied were survival, early and late immune-recovery, infections and GvHD. Subset analysis CD3+, CD4+ and CD4+naïve, B and NK cell numbers were prospectively measured during post-transplant follow-up at 1, 2, 3, 6 and 12 months post-UCBT. Results The probability of survival was not significantly different between the groups: 71% +/- 8% (no ATG), 68% +/- 9% (early ATG) and 61% +/- 7% (late ATG). There were no significant differences in engraftment and primary or secondary graft failure. Immune reconstitution as defined by CD3+, CD4+ and CD4+ naïve T-cell counts were significantly higher (p<0.001) in the no ATG group at 1, 2, 3, 6, and 12 months post-UCBT with a log more T cells than in the ATG groups. The median CD3+ T-cell count in the no ATG group at 1, 2, 3, 6 and 12 months post UCBT was 340 x10e6/L, 720 x 10e6/L, 535 x 10e6/L, 940 ± 194 x 10e6/L, and 1860 x 10e6/L respectively. In the no ATG group significantly less viral reactivations (p=0.021) were noted. A higher probability (p<0,001) of severe acute GvHD (31%+/-9%) was found in the no ATG group compared to 18% +/- 9% for the early ATG and 5% +/-4% for the late ATGgroup. This was not associated with a higher probability of chronic GvHD or non-infectious lung injury in the no ATG group. Conclusion Cord blood transplantation without Thymoglobulin (ATG), in the context of MMF and CsA post-transplant prophylaxis, is associated with higher GVHD risk but with a surprisingly good immune reconstitution and with an engraftment and survival similar to the groups with ATG. The findings of improved immune-reconstitution, associated with lower viral reactivations, albeit at the cost of increased rates of acute GvHD (but not chronic GvHD), suggest that omitting ATG in cord blood transplantation may be important to prevent viral reactivations, especially in those at high risk for these. Disclosures: No relevant conflicts of interest to declare.