To evaluate the efficacy of long-term prophylaxis with ultra-low-dose acyclovir against varicella-zoster virus (VZV) reactivation, we analyzed the records of 242 Japanese adult patients who underwent allogeneic hematopoietic stem cell transplantation for the first time from 1995 to 2006 at our hospital. We started long-term oral acyclovir at 200 mg/day in July 2001. Acyclovir was continued until the end of immunosuppressive therapy and at least 1 year after transplantation. Sixty-six patients developed VZV reactivation at a median of 248 days after HSCT, with a cumulative incidence of 34.7%. Only one breakthrough reactivation occurred during long-term acyclovir, which responded well to therapeutic dose of valacyclovir. The use of long-term acyclovir was the only independent determinant that significantly decreased the overall incidence of VZV reactivation (20% vs. 50%, P < 0.0001). With this prophylaxis, visceral dissemination and serious complications other than post-herpetic neuralgia was completely eliminated, and thereby need for hospitalization was significantly reduced (21% vs. 71%, P 5 0.0034). Fifteen of the 57 patients who discontinued acyclovir developed VZV reactivation, with a cumulative incidence of 32.1%. VZV reactivation following discontinuation tended to occur in patients who were receiving immunosuppressive therapy at the cessation of acyclovir. These findings suggested that long-term prophylaxis of ultra-low-dose acyclovir resulted in a successful prevention of severe VZV-related symptoms and death, with a significantly decreased overall incidence of VZV reactivation. Prolongation of prophylactic acyclovir on profound immunosuppression might be important for thorough suppression of VZV reactivation. Am. J. Hematol. 83:472-476, 2008. V

Key Points• Detection of multiple HY-Abs at 3 months post-F→M HCT predicts cGVHD incidence, severity, and nonrelapse mortality.• Patients with a high HY score may be good candidates for cGVHD prevention trials, especially those targeting allogeneic B cells.Allogeneic antibodies against minor histocompatibility antigens encoded on the Y chromosome (HY-Abs) develop after hematopoietic cell transplant (HCT) of male recipients with female donors (F→M). However, the temporal association between HY-Ab development and chronic graft-versus-host disease (cGVHD) has yet to be elucidated. We studied 136 adult F→M HCT patients, with plasma prospectively collected through 3 years posttransplant, and measured immunoglobulin G against 6 H-Y antigens. Multiple HY-Abs were frequently detected beginning at 3 months posttransplant: 78 (57%) of F→M patients were seropositive for at least 1 of the 6 HY-Abs, and 3-month seropositivity for each HYAb was associated with a persistent seropositive response throughout the posttransplant follow-up period (P < .001 in each). There were no associations between pretransplant features and 3-month overall HY-Ab development. Detection of multiple HY-Abs at 3 months (represented by HY score) was significantly associated with an increased risk of cGVHD (P < .0001) and nonrelapse mortality (P < .01). Compared to clinical factors alone, the addition of HY score to clinical factors improved the predictive potential of cGVHD (P < .01). Monitoring HY-Ab development thus stratifies cGVHD risk in F→M HCT patients and may support preemptive prophylaxis therapy for cGVHD beginning at 3 months posttransplant. (Blood. 2015;125(20):3193-3201)

H-Y antigens are a group of minor histocompatibility antigens encoded on the Y-chromosome with homologous H-X antigens on the X-chromosome. The disparate regions of the H-Y antigens are highly immunogenic and play an important role in understanding human alloimmunity. In this review, we investigate the history of H-Y antigen discovery along with their critical contributions in transplantation and pregnancy. In hematopoietic cell transplantation, male recipients with female donors who become seropositive for B-cell responses as H-Y antibodies following transplantation have increased rates of chronic graft-versus-host disease and decreased rates of relapse. Conversely, female patients who receive male kidney allografts are more likely than other gender combinations to develop H-Y antibodies and reject their allografts. Finally, in the setting of pregnancy, mothers who initially gave birth to boys are more likely to have subsequent pregnancy complications, including miscarriages, in association with H-Y antibody development. H-Y antigens continue to serve as a model for alloimmunity in new clinical scenarios. Our development of more sensitive antibody detection and next-generation DNA sequencing promises to further advance our understanding and better predict the clinical consequences of alloimmunity.

Cyclosporine A (CsA) is the mainstay of pharmacologic prevention of acute graft‐versus‐host disease (GVHD). We previously reported that continuous infusion of CsA with a target blood level between 250 and 400 ng/ml significantly increased the incidence of acute GVHD compared to twice‐daily infusion with a target trough level between 150 and 300 ng/ml. Thus, we raised the target level of CsA continuous infusion to 450–550 ng/ml. We treated 33 patients with the higher target level (CsA500) and compared the efficacy and toxicity with those in the 33 historical control patients (CsA300 group). Other transplantation procedures were not changed. The patients' characteristics were equivalent. The average CsA concentration was adjusted around 500 ng/ml and the actual daily dose was maintained at the initial dose (CsA 3mg/kg/day). Toxicities were equivalently observed among the two groups. The incidence of grades II–IV acute GVHD was significantly lower in the CsA500 group (27 vs. 52%, P = 0.033). The target level of CsA was identified as an independent significant risk factor for grades II–IV acute GVHD (P = 0.039), adjusted for the presence of HLA mismatch. The incidence of chronic GVHD was also decreased in the CsA500 group (47 vs. 73%, P = 0.016). We conclude that the toxicity of the continuous CsA infusion with a target level of 450–550 ng/ml is acceptable and the efficacy to prevent acute GVHD is significant. A larger comparative study is warranted to confirm these findings. Am. J. Hematol., 2008. © 2007 Wiley‐Liss, Inc.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare skin-tropic hematological malignancy of uncertain pathogenesis and poor prognosis. We examined 118 BPDCN cases for cytomorphology, MYC locus rearrangement, and MYC expression. Sixty-two (53%) and 41 (35%) cases showed the classic and immunoblastoid cytomorphology, respectively. Forty-one (38%) MYCBPDCN (positive for rearrangement and expression) and 59 (54%) MYCBPDCN (both negative) cases were identified. Immunoblastoid cytomorphology was significantly associated with MYCBPDCN. All examined MYCBPDCNs were negative for MYB/MYBL1 rearrangement (0/36). Clinically, MYCBPDCN showed older onset, poorer outcome, and localized skin tumors more commonly than MYCBPDCN. MYC was demonstrated by expression profiling as one of the clearest discriminators between CAL-1 (MYCBPDCN) and PMDC05 (MYCBPDCN) cell lines, and its shRNA knockdown suppressed CAL-1 viability. Inhibitors for bromodomain and extra-terminal protein (BETis), and aurora kinases (AKis) inhibited CAL-1 growth more effectively than PMDC05. We further showed that a BCL2 inhibitor was effective in both CAL-1 and PMDC05, indicating that this inhibitor can be used to treat MYCBPDCN, to which BETis and AKis are probably less effective. Our data will provide a rationale for the development of new treatment strategies for patients with BPDCN, in accordance with precision medicine.

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The impact of the conditioning intensity and TBI on acute GVHD (aGVHD) is still a matter of debate. We analyzed 6848 adult recipients who received allogeneic hematopoietic cell transplants (HCT) between 2006 and 2011 in Japan. The subjects were divided into groups who had received myeloablative conditioning (MAC) or reduced-intensity conditioning (RIC), either with or without TBI. There was a significant difference in the incidence of aGVHD 2-4 among the different conditioning types: 39% in TBI-MAC, 35% in TBI-RIC and 32% in both no-TBI MAC and no-TBI-RIC (P o 0.001). In a multivariate analysis, TBI-MAC, but not no-TBI MAC, was significantly associated with an increased risk of aGVHD 2-4 (hazard ratio (HR) 1.33, P o 0.01), whereas TBI-RIC was associated with an increased risk of GVHD 3-4 (HR 1.36, P = 0.048). TBI-MAC and TBI-RIC were significantly associated with skin and gastrointestinal aGVHD. Subgroup analyses demonstrated that not only TBI-MAC, but also TBI-RIC, was significantly associated with aGVHD 2-4 in older patients. Furthermore, high-dose TBI only had an adverse impact on aGVHD 2-4 in HLA-matched HCT. Impacts of intensity and TBI on aGVHD differ by patient backgrounds, and this difference should be considered to establish a risk-adapted strategy for the prevention of aGVHD.

Secondary failure of platelet recovery (SFPR), a late decrease in the platelet count after primary platelet recovery that is not due to relapse or graft rejection, occasionally occurs after allogeneic hematopoietic stem cell transplantation (HSCT). The risk factors and impact of SFPR on transplantation outcomes are not well known in the clinical setting. Therefore, we retrospectively evaluated 184 adult patients who underwent their first allogeneic HSCT and achieved primary platelet recovery. The cumulative incidence of SFPR, defined as a decrease in the platelet count to below 20,000/µL for more than 7 days, was 12.2% at 3 years, with a median onset of 81 days (range, 39 to 729) after HSCT. Among patients who developed SFPR (n = 23), 19 (82.6%) showed recovery to a sustained platelet count of more than 20,000/µL without transfusion support, and the median duration of SFPR was 23 days (range, 7 to 1048 days). A multivariate analysis showed that in vivo T cell depletion (hazard ratio [HR], 6.92; 95% confidence interval [CI], 2.31 to 20.7; P < .001), grades II to IV acute graft-versus-host disease (HR, 3.99; 95% CI, 1.52 to 10.5; P = .005), and the use of ganciclovir or valganciclovir (HR, 2.86; 95% CI, 1.05 to 7.77; P = .039) were associated with an increased risk for SFPR. The occurrence of SFPR as a time-dependent covariate was significantly associated with inferior overall survival (HR, 2.29; 95% CI, 1.18 to 4.46; P = .015) in a multivariate analysis. These findings may help to improve the management and treatment strategy for SFPR.