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Background. Pre-emptive therapy with valganciclovir (VGCV) has become the standard therapy for preventing cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (HSCT). The effectiveness of low-dose VGCV (900 mg per day) has been shown to be equal to that of standard-dose VGCV (900 mg twice daily); however, individualized optimal dosing and toxicity of VGCV have not been reported. Methods. We conducted a retrospective study to evaluate the optimal dose of VGCV as pre-emptive therapy for preventing CMV infection by comparing the frequency of adverse events (AEs) and clinical efficacy in a low-dose VGCV group with those in a standard-dose VGCV group. Thirty-eight patients who were administered VGCV because of CMV antigenemia after HSCT were analyzed. Results. Neutropenia (standard-dose group: 33%, low-dose group: 15%, P = 0.26) and thrombocytopenia (standard-dose group: 39%, low-dose group: 15%, P = 0.14) were frequent AEs of VGCV, and a significantly higher frequency of overall AEs was detected in the standard-dose group than in the low-dose group (P < 0.01). In comparison of dosage based on weight, dosage of VGCV >27 mg/kg was closely related to onset of AEs (P = 0.04). Conclusions. Low-dose VGCV was not inferior in clinical efficacy, including clearance rate of CMV antigenemia and incidence of consequent CMV disease, to standard-dose VGCV as was previously reported. Initial low-dose VGCV for pre-emptive CMV therapy markedly reduces hematologic toxicity and has clinical efficacy equivalent to that of standard-dose VGCV. It is therefore reasonable for patients, except for noticeably overweight patients, to be given initial low-dose VGCV. [ABSTRACT FROM AUTHOR]

Background Intestinal microbial ecology is actively regulated by Paneth cell-derived antimicrobial peptides, α-defensins. Graft-versus-host disease ( GVHD) is a major complication of allogeneic hematopoietic stem cell transplantation ( SCT). We previously demonstrated that Paneth cells are targeted by GVHD, and their expression of antimicrobial peptide α-defensins is impaired, leading to a loss of physiological diversity among the microflora and development of bloodstream infection. Herein, we evaluated whether fecal levels of α-defensins could be surrogate marker of intestinal dysbiosis. Methods We directly measured α-defensin cryptdin-1 (Crp1) in fecal pellets of mice with GVHD by using a novel enzyme-linked immunosorbent assay. Results Fecal levels of Crp1 were significantly decreased in mice with GVHD but unchanged in mice without GVHD after SCT. These were correlated with intestinal flora diversity. Conclusion We demonstrate a link between reduced secretion of Paneth cell α-defensins and dysbiosis of intestinal flora in GVHD. Fecal levels of α-defensins could be surrogate markers for intestinal microbial homeostasis. [ABSTRACT FROM AUTHOR]

Background Reactivation of hepatitis B virus ( HBV) infection, reverse seroconversion ( RS), is a serious complication after allogeneic stem cell transplantation (allo HSCT). We previously conducted a post-transplant hepatitis B vaccine intervention trial and demonstrated the vaccine efficacy in preventing HBV- RS. This report is an update of the hepatitis B vaccine study. Methods In this trial, 21 patients were enrolled and received a standard 3-dose regimen of hepatitis B vaccine after discontinuation of immunosuppressants, whereas 25 transplant recipients with previous HBV infection did not receive the vaccine and served as controls. Results None of the 21 patients in the vaccine group developed HBV- RS and 12 controls developed HBV- RS in median follow-up periods of 60 months (range 13-245). HBV vaccine resulted in a positive value of hepatitis B surface antibody ( HBsAb) titer in 9 patients, while HBsAb remained negative in 12 patients. Presence of a high titer of HBsAb before vaccination was associated with conversion into HBsAb positivity after vaccination. Conclusion These results demonstrated the long-term effects of HBV vaccine for preventing HBV- RS after allo HSCT. Of note, no HBV- RS occurred, even in patients who did not achieve conversion into HBsAb positivity after vaccination. [ABSTRACT FROM AUTHOR]