Next-generation sequencing of the hypervariable V3 region of the 16s rRNA gene isolated from serial stool specimens collected from 31 patients receiving allogeneic stem cell transplantation (SCT) was performed to elucidate variations in the composition of the intestinal microbiome in the course of allogeneic SCT. Metagenomic analysis was complemented by strain-specific enterococcal PCR and indirect assessment of bacterial load by liquid chromatography-tandem mass spectrometry of urinary indoxyl sulfate. At the time of admission, patients showed a predominance of commensal bacteria. After transplantation, a relative shift toward enterococci was observed, which was more pronounced under antibiotic prophylaxis and treatment of neutropenic infections. The shift was particularly prominent in patients that developed subsequently or suffered from active gastrointestinal (GI) graft-versus-host disease (GVHD). The mean proportion of enterococci in post-transplant stool specimens was 21% in patients who did not develop GI GVHD as compared with 46% in those that subsequently developed GI GVHD and 74% at the time of active GVHD. Enterococcal PCR confirmed predominance of Enterococcus faecium or both E. faecium and Enterococcus faecalis in these specimens. As a consequence of the loss of bacterial diversity, mean urinary indoxyl sulfate levels dropped from 42.5 ± 11 µmol/L to 11.8 ± 2.8 µmol/L in all post-transplant samples and to 3.5 ± 3 µmol/L in samples from patients with active GVHD. Our study reveals major microbiome shifts in the course of allogeneic SCT that occur in the period of antibiotic treatment but are more prominent in association with GI GVHD. Our data indicate early microbiome shifts and a loss of diversity of the intestinal microbiome that may affect intestinal inflammation in the setting of allogeneic SCT.

Chronic graft versus host disease (cGVHD) is the most frequent long-term complication after allogeneic stem cell transplantation (allo-SCT) and results in impaired quality of life and increased long-term morbidity and mortality. We analyzed 243 patients with cGVHD, documented according to the 2005 revised National Institutes of Health consensus criteria, to identify risk factors for the occurrence of cGVHD and outcomes for the patients with cGVHD. Patients without evidence of cGVHD (n = 147) were used as controls. Performing univariate and multivariate Cox regression analyses, we identified prior acute GVHD grades III or IV (hazard ratio [HR], 2.01; P = .005), use of peripheral blood stem cell graft (HR, 2.10; P = .03), and HLA-mismatched allo-SCT from unrelated donor (HR, 1.57; P = .02) as independent risk factors for cGVHD. Performing Kaplan-Meier analyses, progressive compared with de novo and quiescent onset of cGVHD and a platelet count of less than 100/nL compared with more than 100/nL at the time of cGVHD onset were associated with a significantly increased cumulative incidence of transplantation-related mortality (TRM) and significantly decreased overall survival. Furthermore, we found a significantly higher incidence of TRM in patients with severe cGVHD compared with patients without cGVHD (58% versus 11%, P < .0001). However, in subgroup analysis, patients with severe cGVHD and involvement of the lung, liver, or gastrointestinal (GI) tract had a 6.5-fold significantly higher incidence of TRM (72%), whereas patients with severe cGVHD lacking lung, liver, or GI involvement had only a 2.8-fold significantly higher incidence of TRM (31%) compared with patients without cGVHD (11%; P < .0001 and P = .03). Patients without lung, liver, or GI involvement did not have a significantly different TRM compared with patients with moderate cGVHD (31% versus 25%, P = .52). In conclusion, we confirm prior known risk factors for the occurrence of cGVHD and subsequent mortality and we provide evidence that the presence of lung, liver, or GI involvement in patients with severe cGVHD defines a subgroup with high mortality after allo-SCT; however, in the absence of these risk factors, the outcome appears not to be impaired compared with moderate cGVHD.

Induction of indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme in tryptophan degradation along the kynurenine pathway, acts as a potent immunoregulatory loop. To address its role in human allogeneic stem cell transplantation, we measured major tryptophan metabolites, such as quinolinic acid and kynurenine, in serial urine specimens from 51 patients by liquid chromatography-tandem mass spectrometry. Samples were collected between admission and day 90 after transplantation, and metabolite levels were correlated with early clinical events and outcome. In selected patients, IDO gene expression was assessed by quantitative RT-PCR in intestinal biopsies. Surviving patients had significantly lower metabolite levels on days 28, 42, and 90, respectively, compared with patients dying of GVHD and associated complications (n = 10). Kynurenine levels were directly correlated with severity and clinical course of GVHD: Mean urinary quinolinic acid levels were 4.5 ± 0.3 μmol/mmol creatinine in the absence of acute GVHD, 8.0 ± 1.1 μmol/mmol creatinine for GVHD grade 1 or 2, and 13.5 ± 2.7 μmol/mmol creatinine for GVHD grade 3 or 4 (P < .001), respectively. GVHD-dependent induction of IDO was further suggested by increased expression of IDO mRNA in intestinal biopsies from patients with severe GVHD. Our data indicate reactive release of kynurenines in GVHD-associated inflammation.

In this retrospective analysis, 30 patients with acute GVHD (aGVHD) and 32 patients with chronic GVHD (cGVHD) treated with extracorporeal photopheresis (ECP) performed by the COBE Spectra System were evaluated. After 3 months of ECP treatment, a CR and PR were observed in 9 (30%) and 6 (20%) patients with aGVHD and in 2 (6%) and 12 (38%) patients with cGVHD. In 16 (53%) patients with aGVHD and 9 (28%) with cGVHD ECP treatment was already stopped after 3 months. One (3%) patient with aGVHD and 7 (22%) patients with cGVHD received new additional immunosuppressive therapy started during the first 3 months of ECP treatment and were classified as 'nonresponder' with regard to ECP. Of these patients a PR was achieved in one patient with aGVHD and in three patients with cGVHD. Steroids could be tapered by X50 in 83% of patients with aGVHD and in 29% of patients with cGVHD after 3 months of ECP treatment. Patients with aGVHD achieving a CR or PR showed a significant improved OS after allo-SCT (P ¼ 0.019). ECP is associated with significant response rates and successful reduction of steroids in patients with GVHD.

Purpose: Limited data are available on immunologic responses to primary pandemic H1N1 (2009) vaccination in recipients of allogeneic hematopoietic stem cell transplantation (HSCT) recipients. In 2009 serologic responses to either pandemic H1N1 (2009) vaccine (n = 36)