Narrow-Band Ultraviolet B Phototherapy Ameliorates Acute Graft-Versus-Host Disease of the Intestine by Expansion of Regulatory T Cells.

Narrowband ultraviolet B (NB-UVB) has been widely used in dermatological phototherapy. As for the application of NB-UVB phototherapy to graft-versus-host disease (GVHD), we previously reported that it was highly efficacious for cutaneous lesions of acute GVHD (aGVHD) and that expansion of regulatory T (Treg) cells induced by NB-UVB might be one of the mechanisms. In order to examine whether NB-UVB irradiation through expansion of Treg cells is effective for the treatment of not only cutaneous aGVHD but also aGVHD of inner organs such as the intestine or liver, we conducted experiments in which a murine lethal aGVHD model, characterized by severe involvement of the intestine, was irradiated with NB-UVB. We found that NB-UVB irradiation improved the clinical score and survival rate. The pathological score of aGVHD was improved in all affected organs: intestine, liver, and skin. In the serum of mice irradiated with NB-UVB, the levels of Treg cells-associated cytokines such as transforming growth factor beta (TGFß) and interleukin-10 (IL-10) were elevated. The numbers of infiltrating Treg cells in inflamed tissue of the intestine and those in spleen were increased in mice treated with NB-UVB. This is the first report demonstrating that NB-UVB phototherapy has the ability to ameliorate intestinal aGVHD through the expansion of Treg cells.

Efficacy of Enteral Supplementation Enriched with Glutamine, Fiber, and Oligosaccharide on Mucosal Injury following Hematopoietic Stem Cell Transplantation.

The combination of glutamine, fiber and oligosaccharides (GFO) is thought to be beneficial for alleviating gastrointestinal mucosal damage caused by chemotherapy. A commercial enteral supplementation product (GFO) enriched with these 3 components is available in Japan. We performed a retrospective study to test whether oral GFO decreased the severity of mucosal injury following hematopoietic stem cell transplantation (HSCT). Of 44 HSCT patients, 22 received GFO and 22 did not. Severity of diarrhea/mucositis, overall survival, weight loss, febrile illness/documented infection, intravenous hyperalimentation days/hospital days, engraftment, acute and chronic GVHD, and cumulative incidence of relapse were studied. Sex, age, performance status, diagnosis, disease status, and treatment variables were similar in both groups. There were fewer days of diarrhea grade 3-4 in patients receiving GFO than in those who did not (0.86 vs. 3.27 days); the same was true for days of mucositis grade 3-4 (3.86 vs. 6.00 days). Survival at day 100 was 100% in the GFO group, but only 77.3% for the patients not receiving GFO (p = 0.0091, log-rank test). Weight loss and the number of days of intravenous hyperalimentation were better in the GFO group (p < 0.001 and p = 0.0014, respectively). Although not significant, less gut bacterial translocation with Enterococcus species developed in the GFO group (p = 0.0728) than in the non-GFO group. Other outcomes were not affected. To the best of our knowledge, this is the first comparative clinical study of GFO supplementation to alleviate mucosal injury after allo-HSCT. We conclude that glutamine, fiber and oligosaccharide supplementation is an effective supportive therapy to decrease the severity of mucosal damage in HSCT.

Narrowband ultraviolet B phototherapy ameliorates acute graft-versus-host disease by a mechanism involving in vivo expansion of CD4+CD25+Foxp3+ regulatory T cells.

Narrowband ultraviolet B phototherapy (NB-UVB) is a therapeutic alternative for haematopoietic stem cell transplantation-related skin graft-versus-host disease (GVHD). The beneficial effects of this intervention may be induced by direct irradiation of inflammatory cells in the skin; however, the putative involvement of indirect effects on systemic immunity has not been elucidated. To address this issue, 11 acute skin GVHD patients refractory to standard corticosteroid treatment and with no gut/liver involvement were treated with NB-UVB irradiation. The median number of treatments was 10 times, with a mean cumulative exposure of 6.36 J/cm(2). No other immunosuppressive therapy was initiated during irradiation. Eight patients achieved an objective complete response, two had a partial response, and one showed no change. None of the patients experienced progressive skin GVHD or newly diagnosed gut/liver GVHD. NB-UVB was well tolerated, with no patients discontinuing irradiation due to toxicity. We additionally demonstrated by flow cytometry that NB-UVB irradiation induces the increment of the proportion of regulatory T cell (Tregs) in patients' peripheral blood. These results suggest that NB-UVB may exert beneficial effects on steroid-refractory skin GVHD through the expansion of Tregs.