Yuko Ishihara

Antibiotic prophylaxis in hematopoietic stem cell transplantation. A meta-analysis of randomized controlled trials.

OBJECTIVES We performed a meta-analysis to evaluate the impact of systemic antibiotic prophylaxis in hematopoietic stem cell transplantation (HSCT) recipients. METHODS We collected reports from PubMed, the Cochrane Library, EMBASE, CINAHL, and Web of Science, along with references cited therein. We included prospective, randomized studies on systemic antibiotic prophylaxis in HSCT recipients. RESULTS Seventeen trials with 1453 autologous and allogeneic HSCT recipients were included. Systemic antibiotic prophylaxis was compared with placebo or no prophylaxis in 10 trials and with non-absorbable antibiotics in two trials. Systemic antibiotics other than fluoroquinolones were evaluated in five of these 12 trials. Four trials evaluated the effect of the addition of antibiotics for gram-positive bacteria to fluoroquinolones. One trial compared two different systemic antibiotic regimens: fluoroquinolones versus trimethoprim-sulfamethoxazole. As a result, systemic antibiotic prophylaxis reduced the incidence of febrile episodes (OR 0.16; 95%CI 0.09-0.30), clinically or microbiologically documented infection (OR 0.38; 95%CI 0.22-0.63) and bacteremia (OR 0.31; 95%CI 0.16-0.59) without significantly affecting all-cause mortality or infection-related mortality. CONCLUSIONS Systemic antibiotic prophylaxis successfully reduced the incidence of infection. However, there was no significant impact on mortality. The clinical benefits of prophylaxis with fluoroquinolones were inconclusive because of the small number of clinical trials evaluated.

Prophylactic role of long-term ultra-low-dose acyclovir for varicella zoster virus disease after allogeneic hematopoietic stem cell transplantation §

OBJECTIVES To evaluate the prophylactic role of long-term ultra-low-dose acyclovir for varicella zoster virus (VZV) disease after allogeneic hematopoietic stem cell transplantation (HSCT). METHODS We evaluated 141 patients who were planned to receive acyclovir at 200mg/day until the end of immunosuppressive therapy and for at least 1 year after HSCT in our center between June 2007 and June 2012. RESULTS The cumulative incidence of VZV disease after HSCT was 4.5% at 1 year and 18.3% at 2 years. Protocol violation was the only independent significant factor that increased the incidence of VZV disease (hazard ratio (HR) 7.50, 95% confidence interval (CI) 3.60-15.63). Excluding patients with protocol violation, the discontinuation of acyclovir was the only significant factor for the development of VZV disease (HR 5.90, 95% CI 1.56-22.37). Six patients experienced breakthrough VZV disease, but four of these six had not taken acyclovir for several weeks before breakthrough VZV disease. On the other hand, the cumulative incidence of VZV disease after the cessation of acyclovir was 28.4% at 1 year and 38.0% at 2 years. The proportion of disseminated VZV disease was only 7% and no patient died directly of VZV disease. CONCLUSIONS This study shows that long-term ultra-low-dose acyclovir appears to be effective for preventing VZV disease, especially disseminated VZV disease, after allogeneic HSCT. We recommend continuing acyclovir until the end of immunosuppressive therapy and for at least 1 year after HSCT, but additional strategies such as the administration of varicella vaccine may be needed to eradicate VZV disease.

Low-dose acyclovir prophylaxis for the prevention of herpes simplex virus disease after allogeneic hematopoietic stem cell transplantation

Currently, acyclovir (ACV) at 1000 mg/day is widely used as prophylaxis in the early phase of hematopoietic stem cell transplant (HSCT) in Japan. However, low‐dose ACV (200 mg/day) has been shown to prevent varicella zoster virus reactivation in the middle and late phases of HSCT.

Prediction of transplant-related complications by C-reactive protein levels before hematopoietic SCT.

Various biomarkers have been investigated with regard to their ability to predict the outcome of allogeneic hematopoietic SCT (HSCT). In this study, we retrospectively reviewed 90 recipients who received HSCT between 2007 and 2011 in our institution, and evaluated the predictive value of the baseline serum C-reactive protein (CRP) levels just before the initiation of conditioning for transplant-related complications after allogeneic HSCT. A receiver-operating characteristic curve revealed that the baseline serum CRP levels had an excellent predictive value for non-relapse mortality (NRM), with an area under the curve of 0.83. The sensitivity and specificity for NRM were 80% and 87%, respectively, with a cutoff of 0.6 mg/dL. With this cutoff value, multivariate analyses revealed that a higher baseline CRP level was an independent risk factor for NRM (HR 6.21, P<0.01), grade III–IV acute GVHD (HR 3.91, P=0.03) and poor overall survival (HR 3.27, P=0.0018). On the other hand, the baseline CRP level did not predict infectious events. These findings suggested that CRP levels before conditioning may be a useful predictive biomarker for poor survival.

Risk factors for pre‐ and post‐engraftment bloodstream infections after allogeneic hematopoietic stem cell transplantation

Bloodstream infections (BSI) are frequently observed after allogeneic hematopoietic stem cell transplant (HSCT), and could cause morbidity and mortality.

Evaluation of the validity of preemptive therapy against cytomegalovirus disease based on antigenemia assay with a cutoff of 20 positive cells per two slides.

Background Preemptive therapy with ganciclovir (GCV) based on the results of a cytomegalovirus (CMV) antigenemia assay is a standard strategy for preventing CMV disease after allogeneic hematopoietic cell transplantation (HCT). However, the appropriate threshold of antigenemia-positive cells for deciding when to start GCV remains unclear. Patients This retrospective study included 80 recipients who received HCT from an alternative donor between 2007 and 2011. In 2009, we switched the threshold from 3 (3A group, n=24) to 20 (20A group, n=56) antigenemia-positive cells per two slides for preemptive therapy after HCT from an alternative donor. Results Early CMV disease within 100 days after HCT was observed in one patient in the 20A group. Antiviral agents including GCV, val-GCV, and foscarnet were given in 17 (71%) and 36 (64%) patients in the 3A and 20A groups, respectively (p=0.23). In 13 (23%) patients in the 20A group, the initiation of preemptive therapy was avoided because of the change in the cutoff value for CMV antigenemia. However, the total dose of GCV was not different between the two groups. The use of steroid was significantly associated with CMV antigenemia of at least 20 positive cells among patients with low-level antigenemia at the first detection. Conclusion The increased threshold up to 20 positive cells for starting preemptive therapy was not associated with a significant increase in CMV disease, but the total dose of GCV was not reduced and there was one early CMV disease in the 20A group. We should explore how to identify patients who are at high risk for increased antigenemia among patients with low-level antigenemia, but at least, preemptive therapy should not be withheld in patients who are already receiving systemic steroid.

Long-Term Persistence of Limited HTLV-I Tax-specific Cytotoxic T Cell Clones in a Patient with Adult T Cell Leukemia/Lymphoma after Allogeneic Stem Cell Transplantation

PurposeAdult T cell leukemia/lymphoma (ATL) is a highly aggressive malignancy of T cells caused by human T cell lymphotropic virus type 1 (HTLV-1). Recent clinical studies have suggested that allogeneic stem cell transplantation (HSCT) improves the clinical course of ATL by harnessing a graft-versus-ATL effect, and that donor-derived HTLV-1 Tax-specific CD8+ cytotoxic T cells (CTLs) contribute to the graft-versus-ATL effect after HSCT. However, little is known about the immunological characteristics of Tax-specific CTLs in ATL patients who underwent HSCT.MethodsWe serially analyzed frequencies, differentiation, functions and clonal dynamics of Tax-specific CTLs in paired samples of peripheral blood (PB) and bone marrow (BM) from an ATL patient after HSCT at the single-cell level. We used flowcytometric and single-cell T cell receptor (TCR) repertoire analysis methods without culture steps.ResultsDonor-derived Tax-specific CTLs effectively suppressed HTLV-1 replication in both PB and BM at least during chronic graft-versus-host disease after HSCT. Furthermore, Tax-specific CTLs had comparable properties between BM and PB, except for preferential accumulation in BM rather than PB. Tax-specific CTLs persistently existed as less-differentiated CD45RA-CCR7- effector memory CTLs based on predominant phenotypes of CD27+, CD28+/− and CD57+/−. Our approach using single-cell TCR repertoire analysis method showed highly restricted oligoclonal responses of Tax-specific CTLs, and TCR BV7- or BV30- expressing two predominant CTL clones persistently existed and maintained strong cytotoxic activities against HTLV-1 in both PB and BM over three years after HSCT.ConclusionsThese findings about Tax-specific CTLs provide insights into future directions for studies on immunotherapy against ATL.

Single-cell T-cell receptor-β analysis of HLA-A*2402-restricted CMV- pp65-specific cytotoxic T-cells in allogeneic hematopoietic SCT

Cellular immunity is important for the control of CMV infection after allogeneic hematopoietic cell transplantation (Allo-HCT). However, the actual in vivo dynamics of CMV-specific cytotoxic T cell (CMV-CTL) clones are still unclear. We conducted clone monitoring of tetramer+ CMV-CTLs in HLA-A*2402-positive donor–patient pairs, using a direct single-cell analysis that enabled the simultaneous identification and quantification of CTL clones. Clone dynamics were assessed in three cases with or without CMV reactivation. In Case-1 without CMV reactivation, despite the long-term use of systemic steroid, dominant clones of Donor-1 persisted and remained dominant. The CMV-CTLs at 1 year after Allo-HCT included a high proportion of CD45RA+CCR7− effector and CD27−CD57+mature T cells. On the other hand, in Cases-2 and -3 with CMV reactivation, novel clones appeared and became dominant during the follow-up. Their CMV-CTLs included more CD27+ immature T cells at 1 year after Allo-HCT. With regard to clonotypes, HLA-A*2402-restricted CMV-CTLs tended to select BV7 and BJ1-1 genes for complementarity-determining region 3 (CDR3) of T-cell receptor (TCR)-β. Specific amino-acid sequences of CDR3 of TCR-β were found in each case. Patterns of clone reconstitution and phenotype would be different according to CMV reactivation. In vivo clone monitoring of CMV-CTLs could provide insight into the mechanism of immunological reconstitution following Allo-HCT.

The safety and efficacy of acute graft-versus-host disease prophylaxis with a higher target blood concentration of cyclosporine around 500 ng/mL

Cyclosporine (CsA) is the most widely used immunosuppressive agent for the prevention of acute graft‐versus‐host disease (GVHD). In a previous report, the incidence of acute GVHD was decreased by increasing the target blood concentration of CsA during a continuous infusion from 300 to 500 ng/mL without excessive toxicities. To confirm these results, we retrospectively analyzed 69 patients who received a continuous infusion of CsA at a higher target CsA level between 450 and 550 ng/mL (CsA500 group) and compared the clinical outcome with 29 patients who received CsA with a lower target concentration between 250 and 350 ng/mL (CsA300 group). The target concentration was determined based on the status of background diseases. Multivariate analysis revealed that the incidence of grade III‐IV acute GVHD was significantly lower in the CsA500 group, although the incidence of grade II‐IV acute GVHD was not different. Toxicities were equivalently observed between the two groups. Concomitant administration of voriconazole or itraconazole and higher hematocrit were identified as independent significant factors for higher concentration/dose ratio of CsA. The average dose of CsA to maintain CsA level around 500 ng/mL was higher compared with the previous study (3.4 mg/kg vs. 2.7 mg/kg at three wk), probably due to the difference in measuring method of CsA concentration. We conclude that continuous infusion of CsA with a target level between 450 and 550 ng/mL is a feasible and effective GVHD prophylaxis, but caution should be paid for the difference in measuring method.

High Incidence of Afebrile Bloodstream Infection Detected by Surveillance Blood Culture in Patients on Corticosteroid Therapy after Allogeneic Hematopoietic Stem Cell Transplantation.

Bloodstream infections (BSI) are still important complications after allogeneic hematopoietic stem cell transplantation (allo-SCT). Patients who are receiving corticosteroid therapy can develop BSI without fever. The utility of surveillance blood cultures in these situations is controversial. We retrospectively analyzed 74 patients who received a corticosteroid consisting of ≥.5 mg/kg prednisolone or equivalent after allo-SCT. In principle, we performed surveillance blood culture weekly for these patients. Sixteen patients (21.6%) developed definite BSI. In a multivariate analysis, a myeloablative conditioning regimen, high-risk disease status at allo-SCT, and the presence of a central venous catheter at the initiation of corticosteroid therapy were identified as independent significant risk factors for the development of definite BSI. At the first definite BSI episode, 7 patients (46.7%) were afebrile and diagnosed by surveillance blood culture. However, 6 of these 7 afebrile patients showed various signs that could be attributed to infection at the time of positive blood culture. In conclusion, patients receiving corticosteroid therapy after allo-SCT frequently develop afebrile BSI. Although surveillance blood culture might be beneficial in these situations, it also seems important to not miss the signs of BSI, even when patients are afebrile.