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Ex vivo expanded CD4+ CD25 high CD127 − T regulatory cells (Tregs) are recognized as a promising candidate for immunosuppressive therapy in humans. However, due to the plasticity of Tregs lineage and artificial environment present during ex vivo expansion, Tregs easily lose suppressive activity. Here, we followed expanding CD4 + CD25 high CD127 − Tregs and their naive (CD45RA + ) and memory-like (CD45RA − ) subsets in order to establish the best conditions of the expansion. We found that, regardless of the phenotype sorted, expanding Tregs were undergoing changes resembling homeostatic proliferation and transformed into effector memory-like cells which produced not only suppressive interleukin-10 (IL-10) but also IL-6, IL-17, and interferon-γ (IFN-γ). With the time ex vivo, Tregs were losing the expression of FoxP3 and suppressive activity both when stimulated and when at rest. The only variable that helped preserve suppressive abilities of Tregs was the limitation of the time of ex vivo cultures to 2 weeks only. According to our study, the highest number of highly suppressive Tregs could be yielded with CD4 + CD25 high CD127 − Tregs cultured no longer than 2 weeks. Thorough quality check, preferentially with the assessment of FoxP3 expression and IFN-γ suppression assay, should be applied to assess suppressive activity of the cells.

In this multicenter study, we assessed the use of palifermin (recombinant human-keratinocyte growth factor 1) in the prevention of oral mucositis (OM) and acute GvHD (aGvHD) induced by a hematopoietic stem cell transplant (HSCT). Fifty-three patients with hematological diseases received three doses of palifermin (60 lg/kg once daily i.v.) pre-and post-conditioning regimens (total six doses). A retrospective control group of 53 transplant patients received no palifermin. There was a significant reduction in the incidence of OM of WHO (World Health Organization) grades 1-4 (58 vs 94%, Po0.001), 3-4 (13 vs 43%, Po0.001) and the median duration of OM (4 vs 9 days, Po0.001) in the palifermin group compared to the control group. The incidence of analgesics (32 vs 75.5%, Po0.001), opioid analgesics (24 vs 64%, Po0.001) and total parenteral nutrition (11 vs 45%, Po0.001) was also significantly reduced. The analysis of distribution of affected organs revealed that aGvHD was less prevalent in the palifermin group (P ¼ 0.036). There was no significant difference in the onset of any OM after HSCT, time to engraftment and length of hospitalization between groups. The drug was generally well tolerated and safe. Our results suggest that the use of palifermin reduces OM and probably aGvHD after HSCT, but a randomized trial is needed.

Composition of the gut microbiota seems to influence early complications of allogeneic hematopoietic cell transplantation (HCT) such as bacterial infections and acute graft-versus-host disease (GVHD). In this study, we assessed the impact of colonization with multidrug-resistant bacteria (MDRB) prior to HCT and the use of antibiotics against anaerobic bacteria on the outcomes of HCT. We retrospectively analyzed the data of 120 patients who underwent HCT for hematologic disorders between 2012 and 2014. Fifty-one (42.5%) patients were colonized with MDRB and 39 (32.5%) had infections caused by MDRB. Prior colonization was significantly correlated with MDRB infections (P < 0.001), especially bacteremia (P = 0.038). A higher incidence of MDRB infections was observed in patients with acute (P = 0.014) or chronic (P = 0.002) GVHD and in patients aged > 40 years (P = 0.002). Colonization had a negative impact on overall survival (OS) after HCT (64 vs. 47% at 24 months; P = 0.034) and infection-associated mortality (P < 0.001). Use of metronidazole was correlated with an increased incidence of acute GVHD (P < 0.001) and lower OS (P = 0.002). Patients colonized with MDRB are more susceptible to life-threatening infections. Colonization with virulent flora is the most probable source of neutropenic infection; therefore, information about prior positive colonization should be crucial for the selection of empiric antibiotic therapy. The use of metronidazole, affecting the biodiversity of the intestinal microbiome, seems to have a significant impact on OS and acute GVHD.