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Graft-versus-host disease (GVHD), one of the most common and serious complications after allogeneic stem cell transplantation, is mediated by allocative T cells. IL-6 mediates both pro- and anti-inflammatory effects and modulates T cell response through classical signaling and trans-signaling. We investigated the effects on the mTOR and JAK/STAT pathways after various types of IL-6 signaling for circulating T cells were derived from 31 allotransplant recipients 90 days post-transplant. Cells were stimulated with IL-6 alone, hyper-IL-6 (trans-signaling), IL-6+IL-6 receptor (IL-6R; classical + trans-signaling) and IL-6+IL-6R+soluble gp130-Fc (classical signaling), and flow cytometry was used to investigate the effects on phosphorylation of AKT (Thr308), mTOR (Ser2442), STAT3 (Ser727) and STAT3 (Tyr705). CD3+CD4+ and CD3+C8+ T cells responded to classical and trans IL-6 stimulation with increased STAT3 (Tyr705) phosphorylation; these responses were generally stronger for CD3+CD4+ cells. STAT3 (Tyr705) responses were stronger for patients with previous acute GVHD; CD3+CD4+ cells from GVHD patients showed an additional STAT3 (Ser727) response, whereas patients without acute GVHD showed additional mTOR (Ser2448) responses. Furthermore, treatment with antithymocyte globulin as a part of GVHD prophylaxis was associated with generally weaker STAT3 (Tyr705) responses and altered STAT3 (Ser727) responsiveness of CD3+CD4+ cells together with increased mTOR (Ser2448) responses for the CD3+CD8+ cells. Thus, early post-transplant CD3+CD4+ and CD3+ CD8+ T cell subsets differ in their IL-6 responsiveness; this responsiveness is modulated by antithymocyte globulin and differs between patients with and without previous acute GVHD. These observations suggest that allotransplant recipients will be heterogeneous with regard to the effects of post-transplant IL-6 targeting. [ABSTRACT FROM AUTHOR]

• The type of nutritional support seems to have relatively minor effects on the post-transplant metabolomic profile. • The metabolic profile of patients treated with standard-care nutritional support indicates an insufficient calorie intake compared with patients treated with individualized enteral nutritional support. Patients undergoing allogeneic stem cell transplantation usually require nutritional support. There is no consensus on whether enteral support through tube feeding should be preferred. A recent randomized study could not detect any difference between enteral and parenteral feeding with regard to post-transplant outcomes, whereas 2 retrospective studies described an association between enteral feeding and a favorable post-transplant outcome. We compared pre- and post-transplant plasma metabolomic profiles for 10 patients receiving mainly enteral nutritional support and 10 patients receiving mainly parenteral support. Samples were collected before conditioning and 3 weeks post-transplant; 824 metabolites were analyzed using mass spectrometry. The pretransplant metabolite profiles showed a significant overlap between the 2 groups. Post-transplant samples for both patient groups showed an increase of secondary bile acids and endocannabinoids, whereas reduced levels were seen for food preservatives, plasmalogens, and retinol metabolites. The main post-transplant differences between the groups were decreased levels of fatty acids and markers of mitochondrial activation in the control group, indicating that these patients had insufficient energy intake. A significant effect was also seen for heme/bilirubin metabolism for the parenteral support. To conclude, allotransplant recipients showed altered metabolic profiles early after transplantation; this was mainly due to the conditioning/transplantation/reconstitution, whereas the type of nutritional support had minor effects. [ABSTRACT FROM AUTHOR]

Steroid refractory acute graft-versus-host-disease of the gut is a serious complication associated with high mortality after allogeneic stem cell transplantation. Treatment options are limited and not predictably effective. We describe the treatment of steroid-refractory acute graft-versus-host-disease with vedolizumab, an antibody directed against integrin α4β7, in 6 patients. All patients responded, and 4 of 6 patients are alive with a median follow-up of 10 months. [ABSTRACT FROM AUTHOR]