Varicella-zoster reactivation after allogeneic stem cell transplantation without routine prophylaxis--the incidence remains high

Systematic Literature Review on the Incidence of Herpes Zoster in Populations at Increased Risk of Disease in the EU/EEA, Switzerland, and the UK

INTRODUCTION

Older adults and patients with underlying conditions such as immunocompromised (IC) populations (e.g., due to medical conditions or immunosuppressive medication) are at increased risk for herpes zoster (HZ). The first HZ recombinant vaccine for IC patients was approved in 2020. Limited evidence exists to inform decision-makers on HZ incidence in high-risk patients in Europe. This systematic literature review (SLR) assessed HZ incidence across 14 high-risk populations in the European Union/European Economic Area, Switzerland, and the United Kingdom.

METHODS

An SLR (Embase, Medline, 2002-2022, observational studies) was performed to identify HZ incidence (i.e., primary outcomes: rate or cumulative; secondary: relative incidence) in type 1 and 2 diabetes mellitus (DM); chronic obstructive pulmonary disease and asthma; depression; rheumatic disorders (RD); multiple sclerosis (MS); inflammatory bowel diseases (IBD); psoriasis; lupus; human immunodeficiency virus (HIV); solid organ transplantation (SOT); solid organ malignancy (SOM); hematologic malignancy (HM); and stem cell transplantation (SCT).

RESULTS

Of 776 unique records screened, 59 studies were included (24 reported incidence rate per 1000 person-years; two, cumulative incidence per 1000 persons; and 33, relative incidence). The highest incidence rates were reported for SOT (12.1-78.8) and SCT (37.2-56.1); HM (2.9-32.0); RD (0.41-21.5); lupus (11.0-16.5); IC mixed population (11.3-15.5); HIV/AIDS (11.8-13.0); chronic respiratory diseases (4.7-11.4); SOM (8.8-11.0); IBD (7.0-10.8); DM (4.3-9.4); depression (7.2-7.6); MS (5.7-6.3); and psoriasis (5.3-6.1). In many high-risk populations, HZ incidence was higher for older age groups, women, and some treatments.

CONCLUSIONS

The HZ incidence rate in Europe increased with age and varied across high-risk populations, with high rates for solid organ and stem cell transplants, cancer, and rheumatoid arthritis. Most studies were retrospective with methodological differences affecting generalizability and comparability. Future studies should stratify data by IC population, age, sex, severity, medication, and study timeframe.

Low-dose acyclovir for prophylaxis of varicella-zoster virus reactivation after hematopoietic stem cell transplantation in children

BACKGROUND

Varicella-zoster virus (VZV) reactivation is a serious complication of hematopoietic stem cell transplantation (HSCT). Although low-dose acyclovir can prevent VZV reactivation after HSCT in adults, the efficacy of a dose of acyclovir lower than the recommended dose, such as 60-80 mg/kg/day in children, is unclear. In this study, we aimed to evaluate the incidence of VZV reactivation after HSCT during and after low-dose acyclovir administration for preventing VZV reactivation in children.

METHODS

This single-center retrospective study included children aged ≤15 years who received oral acyclovir (at 15 mg/kg/day) to prevent VZV reactivation after HSCT. We examined the cumulative incidence of VZV reactivation after HSCT, during and after prophylactic acyclovir administration.

RESULTS

Fifty-three eligible patients were included in this study, of whom 37 underwent allogeneic HSCT. The median duration of prophylactic acyclovir therapy was 264 days (range: 69-1140 days). VZV reactivation occurred in 13 patients (24.5%, 95% confidence interval [CI]: 14.9-37.6). The cumulative incidence of VZV reactivation 1 and 2 years after HSCT was 6.26% (95% CI: 1.60-15.5) and 20.9% (95% CI: 10.3-34.0), respectively. While only one patient developed VZV reactivation during the administration of prophylactic acyclovir, the cumulative incidence of VZV reactivation increased to 24.2% (95% CI: 12.5-38.0) 1 year after the cessation of acyclovir.

CONCLUSION

Low-dose acyclovir (15 mg/kg/day) could be effective for preventing VZV reactivation after HSCT in children because VZV reactivation seldom occurs during the administration of 15 mg/kg/day acyclovir.

A Simple-to-Perform ifn-γ mRNA Gene Expression Assay on Whole Blood Accurately Appraises Varicella Zoster Virus-Specific Cell-Mediated Immunity After Allogeneic Hematopoietic Stem Cell Transplantation

Herpes zoster, which is due to the reactivation of Varicella zoster virus (VZV), is a leading cause of morbidity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). While cell-mediated immunity (CMI) is critical to inhibiting VZV reactivation, CMI is not routinely assessed due to a lack of reliable tests. In this study, we aimed to evaluate VZV-specific CMI among allo-HSCT recipients (n = 60) and healthy individuals (HI, n = 17) through a panel of three immune functional assays after ex vivo stimulation by VZV antigen: quantification of (i) IFN-γ release in the supernatants, (ii) T-cell proliferation after a 7-day stimulation of peripheral blood mononuclear cells (PBMC), and (iii) measurement of the ifn-γ mRNA gene expression level after 24 h of stimulation of a whole-blood sample. VZV responsiveness was defined according to IFN-γ release from VZV-stimulated PBMC. Upon VZV stimulation, we found that allo-HSCT recipients at a median time of 6 [5-8] months post-transplant had lower IFN-γ release (median [IQR], 0.34 [0.12–8.56] vs. 409.5 [143.9–910.2] pg/ml, P <.0001) and fewer proliferating T cells (0.05 [0.01–0.57] % vs. 8.74 [3.12–15.05] %, P <.0001) than HI. A subset of allo-HSCT recipients (VZV-responders, n = 15/57, 26%) distinguished themselves from VZV-non-responders (n = 42/57, 74%; missing data, n = 3) by higher IFN-γ release (80.45 [54.3–312.8] vs. 0.22 [0.12–0.42] pg/ml, P <.0001) and T-cell proliferation (2.22 [1.18–7.56] % vs. 0.002 [0.001–0.11] %, P <.0001), suggesting recovery of VZV-specific CMI. Interestingly, VZV responders had a significant fold increase in ifn-γ gene expression, whereas ifn-γ mRNA was not detected in whole blood of VZV-non-responders (P <.0001). This study is the first to suggest that measurement of ifn-γ gene expression in 24-h-stimulated whole blood could be an accurate test of VZV-specific CMI. The routine use of this immune functional assay to guide antiviral prophylaxis at an individual level remains to be evaluated.

High Incidence of Herpes Zoster After Cord Blood Hematopoietic Cell Transplant Despite Longer Duration of Antiviral Prophylaxis

BACKGROUND

Cord blood transplant (CBT) recipients have a high incidence of herpes zoster (HZ) in the context of short-term peritransplant antiviral prophylaxis. In 2009, international guidelines recommended HZ prophylaxis for at least 1 year after hematopoietic cell transplant. The impact of longer-term antiviral prophylaxis on HZ incidence after CBT is unknown.

METHODS

We retrospectively analyzed varicella zoster virus (VZV)-seropositive CBT recipients who were transplanted between 2006 and 2016. We abstracted HZ events and other variables for up to 5 years post-CBT. We calculated the cumulative incidence of HZ and used Cox proportional hazards regression to identify variables associated with HZ.

RESULTS

The study cohort consisted of 227 patients. Among 1-year survivors, 91% were still receiving prophylaxis, for a median duration of 20.6 months. HZ occurred in 44 patients (19%) at a median of 23.6 months. The cumulative incidence of HZ by 1 year after CBT was 1.8% (95% confidence interval [CI], .1%-4%), but increased to 26% (95% CI, 19%-33%) by 5 years. In a multivariable analysis, acute graft-vs-host disease was associated with increased risk, whereas antiviral prophylaxis was associated with reduced risk for HZ (adjusted hazard ratio, 0.19 [95% CI, .09-.4]). There was no association between CD4+ T-cell counts at 1 year post-CBT and subsequent risk for HZ.

CONCLUSIONS

We found a high incidence of HZ after CBT despite antiviral prophylaxis for > 1 year. Based on these findings, we suggest longer duration of prophylaxis for HZ after CBT. Compliance with antiviral prophylaxis, VZV-specific immune monitoring, and vaccination to mitigate HZ after CBT also require further study.

Varicella Zoster Virus Infection in Children with Autologous Hematopoietic Cell Transplantation: A Retrospective, Single-Center Study in Korea

Although long-term antiviral prophylaxis is recommended to prevent varicella zoster virus (VZV) infection in seropositive recipients of allogeneic and autologous (auto-) hematopoietic cell transplantation (HCT), studies of VZV infections in pediatric auto-HCT recipients are rare. This study aimed to investigate the incidence and characteristics of VZV infection in pediatric auto-HCT recipients and explore the risk factors of VZV infection and its effect on survival outcomes. This study included all pediatric patients who underwent auto-HCT at Samsung Medical Center, Seoul, Korea, between January 1998 and December 2013. Before 2006, short-term acyclovir prophylaxis was provided until neutrophil engraftment; thereafter, routine prophylaxis was not provided. Patients who developed either herpes zoster or chickenpox within 2 years from transplantation were identified, and a chart review was performed. A total of 413 recipients and 698 auto-HCTs were included. Sixty-one episodes of VZV infections were identified in 54 patients. Fourteen cases of VZV infection (23%; 14 of 61) occurred within 30 days after auto-HCT. The cumulative incidence of the first episode of VZV infection at 2 years after transplantation was 14% (95% confidence interval [CI], 7.9% to 22.8%) in all recipients and 9% (95% CI, 1.0 to 26.6) in VZV-seronegative patients. Notably, the VZV infection rate increased with age and the VZV infection rate in patients age 15 to 19 years was almost three times higher than in patients age 0 to 4 years (28% versus 10%; P = .003). However, there was no difference in the VZV infection rate between recipients of single auto-HCT and recipients of tandem auto-HCT. Two patients died of disseminated VZV infection. VZV infection is a considerable risk in auto-HCT recipients with or without short-term prophylaxis. Universal antiviral prophylaxis might be considered, particularly in older children, regardless of VZV serologic results. To our knowledge, this is the largest study of VZV infection in pediatric auto-HCT recipients reported to date.

Long-Term Follow-Up of a Pilot Study Using Placenta-Derived Decidua Stromal Cells for Severe Acute Graft-versus-Host Disease

There is a need for effective therapy with few side effects for severe acute graft-versus-host disease (GVHD). The placenta protects the fetus from the mother's haploidentical immune system during pregnancy. We found that maternal stromal cells from the fetal membrane, so-called decidua stromal cells (DSCs), are more immunosuppressive than other sources of stromal cells. We prospectively treated 21 patients (median age, 49 years; range, 1.6 to 72 years) for grade II-IV acute GVHD. All 21 patients had biopsy-proven gastrointestinal GVHD. The majority of patients were either steroid-refractory or had progressive GVHD, 11 patients after >7 days or with progression after 3 days, and 10 were refractory to steroids after >3 days. We used an improved protocol in which DSCs were thawed and infused in a buffer with 5% human albumin. DSCs were given at a median dose of 1.2 (range, 0.9 to 2.9) × 10⁶ cells/kg body weight with a median of 2 (range, 1 to 6) doses, given 1 week apart. The median viability of thawed DSCs was 93% (range, 69% to 100%), and the median cell passage number was 4 (range, 2 to 4). Complete resolution of GVHD was seen in 11 patients, with a partial response in the other 10. The cumulative incidence of chronic GVHD was 52%. GVHD was mild in 6 patients, moderate in 4 patients, and severe in 1 patient based on National Institutes of Health chronic GVHD severity scoring. Nine patients died, including 3 from relapse and 1 each from acute GVHD and septicemia, Zygomycetes infection, liver insufficiency, cerebral hemorrhage, multiple organ failure, and chronic GVHD with obstructive bronchiolitis. Four-year transplantation-related mortality was 28.6%, and overall survival was 57%. Survival was similar (P = .33) to that for all 293 patients who underwent allogeneic hematopoietic cell transplantation during the same period (2012 to 2015), with 66% overall survival. DSC infusion is a novel therapy for acute GVHD grade II-IV, and a randomized trial is currently underway (ClinicalTrials.gov NCT02172937).

Severe Herpes Zoster Requiring Intravenous Antiviral Treatment in Allogeneic Hematopoietic Cell Transplantation Recipients on Standard Acyclovir Prophylaxis

Allogeneic hematopoietic cell transplantation (HCT) recipients are at increased risk for varicella zoster virus (VZV) reactivation and associated complications. The incidence, timing, and risk factors for severe herpes zoster (HZ) are not well described in the era of acyclovir (ACV) prophylaxis. We performed a retrospective cohort study of all patients who underwent first allogeneic HCT between October 2006 and December 2015 at our institution. Patients were followed until December 2017 for the development of severe HZ, defined as necessitating administration of i.v. antiviral medication. Out of 2163 patients who underwent allogeneic HCT, 22 (1.0%) developed severe HZ at a rate of 1 per 228 person-years, including dermatomal/multidermatomal disease (n = 5), disseminated skin disease (n = 5), HZ ophthalmicus (n = 4), meningitis/encephalitis (n = 4), pneumonia (n = 2), viremia (n = 1), and erythema multiforme (n = 1). Severe HZ infection occurred in a bimodal distribution during the early peri-HCT period and at 12 to 24 months post-HCT (median, 12.7 months). Twelve patients (54.5%) were compliant with ACV prophylaxis at the time of HZ diagnosis. Eleven patients (50%) died during the study period, only 2 of whom (9.1%) with active VZV infection. Mortality was higher in patients on immunosuppressive therapy (62.5% versus 16.7%; P = .045) and with concurrent graft-versus-host disease (75.0% versus 35.7%; P= .044). These data suggest that severe HZ remains an important consideration despite ACV prophylaxis.

Visceral disseminated varicella zoster virus infection with brachial plexus neuritis detected by fluorodeoxyglucose positron emission tomography and computed tomography

Varicella zoster virus (VZV) infection sometimes result in visceral disseminated VZV infection (VD-VZV), which is a fulminant disease featured by abdominal pain and the absence of skin lesions, particularly occurs in the immunosuppressive patients. Brachial plexus neuritis (BPN) is another rare type of VZV infection usually appears without blisters. Few diagnostic images of both VD-VZV and BPN-VZV have been reported. A 25-year-old woman receiving allogeneic hematopoietic stem cell transplantation (HSCT) for acute myeloid leukemia. Unexplained severe pain in the left upper extremity followed by severe stomachache, liver dysfunction and unconsciousness appeared on day 344 post-HSCT. Computed tomography (CT) showed left brachial plexus hypertrophy and edematous changes to the hepatoduodenal ligament, fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased uptake in both lesions. Intravenous acyclovir therapy was started and successfully resolved all symptoms. Several days later, blisters appeared all over the body and positive VZV DNA from blood using polymerase chain reaction test was obtained. FDG-PET and CT may offer supportive findings for detecting or diagnosing blister-less VZV infectious diseases.

Approach to skin and soft tissue infections in non-HIV immunocompromised hosts

PURPOSE OF REVIEW

Skin and soft tissue infections are frequent contributors to morbidity and mortality in the immunocompromised host. This article reviews the changing epidemiology and clinical manifestations of the most common cutaneous pathogens in non-HIV immunocompromised hosts, including patients with solid organ transplants, stem cell transplants, solid tumors, hematologic malignancies, and receiving chronic immunosuppressive therapy for inflammatory disorders.

RECENT FINDINGS

Defects in the innate or adaptive immune response can predispose the immunocompromised host to certain cutaneous infections in a predictive fashion. Cutaneous lesions in patients with neutrophil defects are commonly due to bacteria, Candida, or invasive molds. Skin lesions in patients with cellular or humoral immunodeficiencies can be due to encapsulated bacteria, Nocardia, mycobacteria, endemic fungal infections, herpesviruses, or parasites. Skin lesions may reflect primary inoculation or, more commonly, disseminated infection. Tissue samples for microscopy, culture, and histopathology are critical to making an accurate diagnosis given the nonspecific and heterogeneous appearance of these skin lesions due to a blunted immune response.

SUMMARY

As the population of non-HIV immunosuppressed hosts expands with advances in medical therapies, the frequency and variety of cutaneous diseases in these hosts will increase.

Studies with herpes zoster vaccines in immune compromised patients

INTRODUCTION

The active component of the herpes zoster vaccine (ZVL), licensed for people ≥50 years of age, is a live attenuated varicella-zoster virus. ZVL is contraindicated for immune compromised individuals, with limited regard to the degree of immunosuppression. Areas covered: This review evaluates phase I and II and observational studies for ZVL, and published reports of the off-label use of ZVL, for conditions and therapies for which investigators considered the risk-benefit for using ZVL to be favorable. It also discusses exploratory trials of ZVL for additional immune compromising conditions, and summarizes clinical guidelines from many countries and professional societies that are based upon recent investigations. Studies in immune compromised patients of investigational vaccines that do not contain live virus are reviewed. Expert commentary: It is likely that past and ongoing research with ZVL will define immune compromising diseases and/or therapies for which the risk-benefit for using ZVL vaccine is favorable. The main variables to consider in this assessment in immune compromised patients are safety, immunogenicity, protection against herpes zoster, and persistence of protection. Vaccination against herpes zoster prior to suppressing immunity is an important clinical strategy, although efficacy of this approach has not been evaluated in a clinical trial.

Varicella-Zoster Virus Gastritis: Case Report and Review of the Literature

We report varicella-zoster virus (VZV) gastritis in a 70-year-old woman postchemotherapy for lymphoma, presenting with abdominal pain, vomiting, and delirium without rash. A gastric biopsy demonstrated viral inclusions but posed a diagnostic challenge as immunohistochemistry for cytomegalovirus and herpes simplex virus were negative, and VZV immunohistochemistry was not available. The patient developed a vesicular rash 7 days after her symptoms began. Molecular testing of the gastric biopsy and a skin swab both confirmed VZV infection. She also had probable involvement of her liver and pancreas based on imaging and serum chemistry, and possible central nervous system involvement. She recovered with appropriate antiviral therapy but later developed a postherpetic neuralgia, and chronic intrahepatic biliary strictures; liver biopsy demonstrated a cholangiopathy of uncertain etiology. A literature review of the pathogenesis, epidemiology and sequelae of VZV infection is included.

Antiviral prophylaxis for preventing herpes zoster in hematopoietic stem cell transplant recipients: A systematic review and meta-analysis

The optimal duration of prophylaxis for the varicella-zoster virus following hematopoietic stem cell transplantation (HSCT) remains unclear. The purpose of this study was to systematically review the available literature to determine the optimal duration of antiviral prophylaxis for preventing herpes zoster (HZ) in allogeneic and autologous HSCT recipients. The MEDLINE and EMBASE databases were searched to identify relevant studies. The relative risk (RR) of HZ was calculated using fixed effects or random effects models depending on heterogeneity across the included studies. We analyzed six observational studies comprising a total of 3420 patients. In all HSCT recipients, the overall incidence of HZ in the prophylaxis group and the control group was 7.8% and 25.6%, respectively, with a pooled RR of 0.31 (95% CI, 0.26-0.37). The incidence of HZ in the subgroup wherein prophylaxis was given for at least 1 year and in the subgroup wherein prophylaxis was given for less than 1 year was 2.1% and 15.4%, respectively, with a pooled RR of 0.23 (95% CI, 0.04-1.39). Taken together, our results demonstrate that antiviral prophylaxis can significantly reduce HZ in HSCT recipients, and suggests that long-term prophylaxis given for at least 1 year may be recommended for better preventive effects.

Neurologic Complications after Allogeneic Hematopoietic Stem Cell Transplantation

Neurologic complications after hematopoietic stem cell transplantation are frequently life-threatening, and their clinical management can be highly challenging. A wide spectrum of causative factors-including drug-related toxicities; infections sustained by virus, bacteria, or invasive molds; metabolic encephalopathy; cerebrovascular disorders; immune-mediated disorders; and disease recurrence-may lead to potentially lethal complications. Moreover, given that some neurologic complications are not uncommonly diagnosed post mortem, their overall incidence is likely to be underestimated. Their prompt recognition and timely treatment are of paramount importance to reduce the risk for transplantation-related death.

Zoster prophylaxis after allogeneic hematopoietic cell transplantation using acyclovir/valacyclovir followed by vaccination

Varicella zoster virus (VZV) disease (usually cutaneous zoster) occurs frequently after hematopoietic cell transplantation (HCT), and postherpetic neuralgia (PHN) results in poor quality of life. The optimal prophylaxis of VZV disease/PHN has not been established. At our center, before 2008, VZV prophylaxis consisted of ∼1 year of post-HCT acyclovir/valacyclovir ("old strategy"), whereas post-2008 prophylaxis consisted of 2 years of acyclovir/valacyclovir followed by immunization using varicella vaccine ("new strategy"). We performed a retrospective study comparing the cumulative incidence of VZV disease and PHN among patients who completed the old strategy (n = 153) vs the new strategy (n = 125). Patients who completed the old strategy had a significantly higher cumulative incidence of VZV disease (33% vs 17% at 5 years, P ≤ .01) and PHN (8% vs 0% at 5 years, P = .02). In conclusion, VZV prophylaxis with 2 years of acyclovir/valacyclovir followed by vaccination appears to result in a low incidence of VZV disease and may eliminate PHN.

Predicting risk factors for varicella zoster virus infection and postherpetic neuralgia after hematopoietic cell transplantation using ordered logistic regression analysis

To identify risk factors for varicella zoster virus (VZV) infection and postherpetic neuralgia (PHN) after hematopoietic cell transplantation (HCT), we conducted a retrospective chart review of 163 consecutive patients who underwent HCT between November 2004 and July 2014. Overall, the male/female (M/F) ratio was 80/83, median age at HCT was 54 (range 15-69) years, and autologous/allogeneic HCT (auto/allo-HCT) ratio was 71/92. Forty-four patients [M/F, 25/19; median age, 57 (range: 16-68) years; auto/allo-HCT, 26/18] developed VZV infection after HCT. All cases were successfully treated with acyclovir (ACV) or valacyclovir, and there was no VZV-related death. Nine (20%) of the 44 patients [M/F, 5/4; median age, 58 (range: 21-63) years; auto/allo-HCT, 7/2] developed PHN after resolution of zoster. Multivariate ordered logistic analysis identified receiving immunosuppressive therapy at the cessation of ACV [odds ratio (OR) = 74.53; 95% confidence interval (CI) = 6.99-794.32; P = 0.0004] as a risk factor for VZV infection and PHN in allo-HCT recipients. However, in auto-HCT recipients, only advanced age was identified as a risk factor (OR = 1.06, 95% CI = 1.002-1.127, P = 0.0429). Our findings indicate receiving immunosuppressive therapy at the cessation of ACV is a significant risk factor for allo-HCT recipients, while advanced age is a significant risk factor for auto-HCT recipients.

Brincidofovir treatment of acyclovir-resistant disseminated varicella zoster virus infection in an immunocompromised host

Brincidofovir (BCV) is a broad-spectrum antiviral agent active in vitro against double-stranded DNA viruses including herpesviruses, adenoviruses, polyomaviruses, and poxviruses. We report successful BCV use in management of disseminated acyclovir- and cidofovir-resistant varicella zoster virus in an immunocompromised hematopoietic stem cell transplant patient with chronic graft-versus-host disease who was intolerant to foscarnet.

Disseminated herpes zoster infection initially presenting with abdominal pain in patients with lymphoma undergoing conventional chemotherapy: A report of three cases

Visceral disseminated varicella zoster virus (VZV) disease has a high mortality rate, and occurs in immunocompromised hosts, mostly subsequent to allogeneic stem cell transplantation. Only a few cases of this disease that onset during conventional chemotherapy in patients with lymphoma have been reported. The present study reports the cases of 3 patients with disseminated and visceral VZV infection undergoing treatment for follicular lymphoma, diffuse large B-cell lymphoma and peripheral T-cell lymphoma, not otherwise specified. All 3 patients presented with initial symptoms of abdominal pain, and 2 patients demonstrated syndrome of inappropriate antidiuretic hormone and hepatitis. All patients developed widespread cutaneous dissemination, and all had a low cluster of differentiation 4 cell count or lymphocyte count at the time of VZV diagnosis and at least 4 month prior. With intravenous systemic acyclovir therapy (Cases 1 and 3, 1500 mg/day; Case 2, 750 mg/day), the patients achieved complete recovery by day 14 of therapy. Visceral disseminated VZV infection is not limited to patients undergoing stem cell transplantation, and may present with abdominal pain with or without skin eruption. Visceral infection may take a poor clinical course, therefore, in patients with prolonged duration of low lymphocyte count and/or long-term use of steroids, the prophylactic use of acyclovir may be considered.

Mesenchymal Stromal Cells and Viral Infection

Mesenchymal Stromal Cells (MSCs) are a subset of nonhematopoietic adult stem cells, readily isolated from various tissues and easily culture-expanded ex vivo. Intensive studies of the immune modulation and tissue regeneration over the past few years have demonstrated the great potential of MSCs for the prevention and treatment of steroid-resistant acute graft-versus-host disease (GvHD), immune-related disorders, and viral diseases. In immunocompromised individuals, the immunomodulatory activities of MSCs have raised safety concerns regarding the greater risk of primary viral infection and viral reactivation, which is a major cause of mortality after allogeneic transplantation. Moreover, high susceptibilities of MSCs to viral infections in vitro could reflect the destructive outcomes that might impair the clinical efficacy of MSCs infusion. However, the interplay between MSCs and virus is like a double-edge sword, and it also provides beneficial effects such as allowing the proliferation and function of antiviral specific effector cells instead of suppressing them, serving as an ideal tool for study of viral pathogenesis, and protecting hosts against viral challenge by using the antimicrobial activity. Here, we therefore review favorable and unfavorable consequences of MSCs and virus interaction with the highlight of safety and efficacy for applying MSCs as cell therapy.

A Japanese single-hospital observational trial with a retrospective case-control analysis of varicella zoster virus reactivation after autologous peripheral blood stem cell transplantation

BACKGROUND

Varicella zoster virus (VZV) reactivation following hematopoietic stem cell transplantation (SCT) is common. To help reduce its incidence and to identify predictive factors for VZV reactivation after autologous SCT (auto-SCT), we conducted a retrospective analysis in patients with hematologic malignancy at our hospital.

METHODS

We conducted a single-hospital observational trial with a retrospective case-control analysis of post-auto-SCT VZV reactivation in patients with malignant lymphoma (ML) and multiple myeloma (MM) between January 2001 and December 2010, in the Department of Hematology at our hospital. First, we analyzed the cumulative incidence of VZV reactivation during the post-SCT period. Second, we conducted a case-control analysis to identify the risk factors for VZV reactivation within 1 year after SCT. Univariate analyses were performed using Fisher's exact test for categorical variables. A multivariable model and logistic regression were used to assess the risk factors for VZV reactivation.

RESULTS

We included 97 patients in this study. The median duration of follow-up was 1027 days. Forty-two patients experienced VZV reactivation after SCT, while 29 (69.0%) experienced reactivation within 1 year after SCT. The cumulative incidence was 30.7% at 1 year and 51.2% for the total observation period. Multivariate analysis showed that engraftment after day 10 was an independent risk factor for VZV reactivation (P = 0.03).

CONCLUSIONS

Our study showed a high incidence of VZV reactivation in the first year after auto-SCT in ML and MM patients. Patients with delayed engraftment are at high risk for VZV reactivation and should be considered for prolonged VZV prophylaxis.

VZV encephalitis following successful treatment of CMV infection in a patient with kidney transplant

A 73-year-old woman with a history of deceased donor kidney transplantation and a recent cytomegalovirus (CMV) infection, presented to the emergency department with an altered mental status. She was found to have varicella zoster virus VZV encephalitis based on cerebrospinal fluid analysis and was treated successfully with intravenous valaciclovir with an improvement in her mental status. A review of the literature shows very few case reports on patients with kidney transplantation developing VZV encephalitis. A few case reports and studies report an association between CMV and VZV infection. In these patients, CMV infection can cause a marked decline in immunity and this predisposes them to other infections. Such associations have also been reported between other types of virus infections from the Herpesviridae family. The risk of disseminated VZV infection increases in the presence of CMV infection.