Open-Label Randomized Controlled Study of Ciprofloxacin vs Rifaximin as Neutropenia Prophylaxis in Allogeneic Hematopoietic Stem Cell Transplantation.

Loss of microbiota diversity has been clearly associated with poor outcomes in the allogeneic hematopoietic stem cell transplantation setting. However, the choice of the optimal antibiotic prophylaxis during the pre-engraftment phase remains unclear. We designed a prospective randomized study to compare our standard-of-care neutropenia prophylaxis (ciprofloxacin) with rifaximin. We enrolled 38 consecutive adult patients who underwent allogeneic hematopoietic stem cell transplantation setting and were randomly assigned to receive ciprofloxacin (20 patients) or rifaximin (18 patients) at day -1. Pretransplant and transplant characteristics did not differ between groups. Cumulative incidence (CI) of acute graft-vs-host disease grade II to IV and moderate/severe chronic graft-vs-host disease was similar in both groups. With a median follow-up of 13.2 months (range, 6.8-30.2) in surviving patients, the 1-year CI of relapse was 20.8% in ciprofloxacin vs 17.8% in rifaximin (P = .616). Importantly, the 1-year CI of treatment-related mortality was significantly reduced in the ciprofloxacin group (10.2% vs 27.8%, P = .032), leading to higher 1-year overall survival (88.9% vs 74.6%, P = .038). In Cox-regression multivariate analysis, antibiotic prophylaxis remained the only predictor of overall survival, independently of donor type, disease risk index, and moderate/severe chronic graft-vs-host disease. Further studies are needed to assess the effects on microbiota diversity and confirm these outcomes.

Time-dependent fate of transplanted neural precursor cells in experimental autoimmune encephalomyelitis mice.

Transplanted Neural Precursor Cells (NPCs) are capable of long-distance migration inside the inflamed CNS, but exhibit limited myelinating capacities in animal models of Multiple Sclerosis (MS). Inflammation seems to be both beneficial for the recruitment and migration of NPCs and restrictive for their terminal differentiation. In the present study, a set of transplantation experiments was applied in order to investigate the migratory potential, the differentiation pattern and long-term survival of NPCs in Experimental Autoimmune Encephalomyelitis (EAE) mice, the animal model of MS. The in vitro differentiation potential of NPCs in the presence of either pro- (TNFa, INFγ) or anti- (TGFb) inflammatory cytokines was also analyzed. According to the in vivo results obtained, at the acute phase of EAE only a small fraction of transplanted NPCs succeed to differentiate, whereas at chronic phase most of them followed a differentiation process to glial cell lineage along white matter tracts. However, this differentiation was not fully completed, since 8 months after their transplantation a number of NPCs remained as pre-oligodendrocytes. Glial differentiation of NPCs was also found to be inhibited or promoted following their treatment with TNFa or TGFb respectively, in vitro. Our findings suggest that inflammation triggers migration whereas the anti-inflammatory component is a prerequisite for NPCs to follow glial differentiation thereby providing myelinating oligodendrocytes. It is speculated that the fine balance between the pro- and anti-inflammatory determinants in the CNS may be a key factor for transplanted NPCs to exhibit a better therapeutic effect in EAE and MS. This article is part of a Special Issue entitled "Interaction between repair, disease, & inflammation."

Inflammatory changes induced by transplanted neural precursor cells in a multiple sclerosis model.

Recent studies on neural precursor cell (NPC) transplantation in multiple sclerosis animal models reveal that these cells exert their therapeutic effect mainly because of immunomodulation rather than cell replacement. In this study intraventricularly transplanted NPCs in mice, induced experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis, improved the clinical symptoms and suppressed inflammation in the brain by enhancing the apoptosis of inflammatory cells. However, the same treatment failed to reduce significantly the inflammatory cells in the spinal cord, the pathology of which predominantly determines the clinical manifestation of experimental autoimmune encephalomyelitis. Our findings suggest that immunosuppression is rather a local phenomenon and thus, bystander neuroprotective mechanisms triggered by NPC intraventricular transplantation should be accountable for their therapeutic effect.