Respiratory virus infections in transplant recipients after reduced-intensity conditioning with Campath-1H: high incidence but low mortality

High-dose alemtuzumab and cyclosporine vs tacrolimus, methotrexate, and sirolimus for chronic graft-versus-host disease prevention

ABSTRACT

Chronic graft-versus-host disease (cGVHD) remains a significant problem for patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although in vivo lymphodepletion for cGVHD prophylaxis has been explored in the myeloablative setting, its effects after reduced-intensity conditioning (RIC) are not well described. Patients (N = 83) with hematologic malignancies underwent targeted lymphodepletion chemotherapy followed by a RIC allo-HSCT using peripheral blood stem cells from unrelated donors. Patients were randomized to 2 GVHD prophylaxis arms: alemtuzumab and cyclosporine (AC; n = 44) or tacrolimus, methotrexate, and sirolimus (TMS; n = 39), with the primary end point of cumulative incidence of severe cGVHD. The incidence of severe cGVHD was lower with AC vs TMS prophylaxis at 1- and 5-years (0% vs 10.3% and 4.5% vs 28.5%; overall, P = .0002), as well as any grade (P = .003) and moderate-severe (P < .0001) cGVHD. AC was associated with higher rates of grade 3 to 4 infections (P = .02) and relapse (52% vs 21%; P = .003) with no difference in 5-year GVHD-free-, relapse-free-, or overall survival. AC severely depleted naïve T-cell reconstitution, resulting in reduced T-cell receptor repertoire diversity, smaller populations of CD4Treg and CD8Tscm, but a higher ratio of Treg to naïve T-cells at 6 months. In summary, an alemtuzumab-based regimen successfully reduced the rate and severity of cGVHD after RIC allo-HSCT and resulted in a distinct immunomodulatory profile, which may have reduced cGVHD incidence and severity. However, increased infections and relapse resulted in a lack of survival benefit after long-term follow-up. This trial was registered at www.ClinicalTrials.gov as #NCT00520130.

Outcome of Human Parainfluenza Virus infection in allogeneic stem cell transplantation recipients: possible impact of ribavirin therapy

BACKGROUND

This retrospective study focused on analyzing community-acquired respiratory virus (CARV) infections, in particular human parainfluenza virus (hPIV) after allogeneic stem cell transplant (allo-SCT) in adults recipients. It aimed to assess the impact of ribavirin treatment, clinical characteristics, and risk factors associated with lower respiratory tract disease (LRTD) progression and all-cause mortality.

PATIENTS AND METHODS

The study included 230 allo-SCT recipients diagnosed with hPIV between December 2013 and June 2023. Risk factors for the development of LRTD, disease severity, and mortality were analyzed. Ribavirin treatment was administered at physician discretion in 61 out of 230 cases (27%).

RESULTS

Risk factors for LRTD progression in multivariate analysis were corticosteroids > 30 mg/day (Odds ratio (OR) 3.5, 95% Confidence Interval (C.I.) 1.3-9.4, p = 0.013), fever at the time of hPIV detection (OR 3.89, 95% C.I. 1.84-8.2, p < 0.001), and absolute lymphocyte count (ALC) < 0.2 × 109/L (OR 4.1, 95% C.I. 1.42-11.9, p = 0.009). In addition, the study found that ribavirin therapy significantly reduced progression to LRTD [OR 0.19, 95% C.I. 0.05-0.75, p = 0.018]. Co-infections (OR 5.7, 95% C.I. 1.4-23.5, p = 0.015) and ALC < 0.2 × 109/L (OR 17.7, 95% C.I. 3.6-87.1, p < 0.001) were independently associated with higher day + 100 after hPIV detection all-cause mortality. There were no significant differences in all-cause mortality and infectious mortality at day + 100 between the treated and untreated groups.

CONCLUSION

ALC, corticosteroids, and fever increased the risk for progression to LRTD while ribavirin decreased the risk. However, mortality was associated with ALC and co-infections. This study supports further research of ribavirin therapy for hPIV in the allo-HSCT setting.

Respiratory Syncytial Virus Infections in Recipients of Bone Marrow Transplants: A Systematic Review and Meta-Analysis

Human Respiratory Syncytial Virus (RSV) is a common cause of respiratory tract infections. Usually associated with infants and children, an increasing amount of evidence suggests that RSV can cause substantial morbidity and mortality in immunocompromised individuals, including recipients of bone marrow transplantation (BMT). The present systematic review was therefore designed in accordance with the PRISMA guidelines to collect available evidence about RSV infections in BMT recipients. Three medical databases (PubMed, Embase, and MedRxiv) were therefore searched for eligible observational studies published up to 30 September 2023 and collected cases were pooled in a random-effects model. Heterogeneity was assessed using I2 statistics. Reporting bias was assessed by means of funnel plots and regression analysis. Overall, 30 studies were retrieved, including 20,067 BMT cases and 821 RSV infection episodes. Of them, 351 were lower respiratory tract infections, and a total of 78 RSV-related deaths were collected. A pooled attack rate of 5.40% (95% confidence interval [95%CI] 3.81 to 7.60) was identified, with a corresponding incidence rate of 14.77 cases per 1000 person-years (95%CI 9.43 to 20.11), and a case fatality ratio (CFR) of 7.28% (95%CI 4.94 to 10.60). Attack rates were higher in adults (8.49%, 95%CI 5.16 to 13.67) than in children (4.79%, 95%CI 3.05 to 7.45), with similar CFR (5.99%, 95%CI 2.31 to 14.63 vs. 5.85%, 95%CI 3.35 to 10.02). By assuming RSV attack rates as a reference group, influenza (RR 0.518; 95%CI 0.446 to 0.601), adenovirus (RR 0.679, 95%CI 0.553 to 0.830), and human metapneumovirus (RR 0.536, 95%CI 0.438 to 0.655) were associated with a substantially reduced risk for developing corresponding respiratory infection. Despite the heterogeneous settings and the uneven proportion of adult and pediatric cases, our study has identified high attack rates and a substantial CFR of RSV in recipients of BMT, stressing the importance of specifically tailored preventive strategies and the need for effective treatment options.

American Society of Transplantation and Cellular Therapy Series: #7 - Management of Respiratory Syncytial Virus Infections in Hematopoietic Cell Transplant Recipients

The Practice Guidelines Committee of the American Society of Transplantation and Cellular Therapy (ASTCT) partnered with its Transplant Infectious Disease Special Interest Group (TID-SIG) to update the 2009 compendium-style infectious disease guidelines for hematopoietic cell transplantation (HCT). A new approach was adopted to better serve clinical providers by publishing each standalone topic in the infectious disease series in a concise format of frequently asked questions (FAQ), tables, and figures. Experts in HCT and infectious diseases identified FAQs and then provided answers based on the strength of the recommendation and the level of supporting evidence. In the seventh guideline in the series, we focus on the respiratory syncytial virus (RSV) with FAQs addressing epidemiology, clinical diagnosis, prophylaxis, and treatment. Special consideration was given to RSV in pediatric, cord blood, haploidentical, and T cell-depleted HCT and chimeric antigen receptor T cell therapy recipients, as well as to identify future research directions.

Incidence and impact of community respiratory viral infections in post-transplant cyclophosphamide-based graft-versus-host disease prophylaxis and haploidentical stem cell transplantation

Community respiratory viral infections (CRVIs) are associated with pulmonary function impairment, alloimmune lung syndromes and inferior survival in human leucocyte antigen (HLA)-matched allogeneic haematopoietic stem cell transplant (HCT) recipients. Although the incidence of viral infections in HLA-haploidentical HCT recipients who receive post-transplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis is reportedly increased, there are insufficient data describing the incidence of CRVIs and the impact of donor source and PTCy on transplant outcomes. Analysing patients receiving their first HCT between 2012 and 2017 for acute myeloid leukaemia, acute lymphoblastic leukaemia and myelodysplastic syndromes, we describe comparative outcomes between matched sibling transplants receiving either calcineurin-based GVHD prophylaxis (SibCNI, N = 1605) or PTCy (SibCy, N = 403), and related haploidentical transplants receiving PTCy (HaploCy, N = 757). The incidence of CRVIs was higher for patients receiving PTCy, regardless of donor type. Patients in the HaploCy cohort who developed a CRVI by day +180 had both a higher risk of treatment-related mortality [hazard ratio (HR) 2⋅14, 99% confidence interval (CI) 1⋅13-4⋅07; P = 0⋅002] and inferior 2-year overall survival (HR 1⋅65, 99% CI 1⋅11-2⋅43; P = 0⋅001) compared to SibCNI with no CRVI. This finding justifies further research into long-term antiviral immune recovery, as well as development of preventive and treatment strategies to improve long-term outcomes in such patients.

Treatment of infections in cancer patients: an update from the neutropenia, infection and myelosuppression study group of the Multinational Association for Supportive Care in Cancer (MASCC)

INTRODUCTION

Patients with hematological and advanced solid malignancies have acquired immune dysfunction, often exacerbated by treatment, posing a significant risk for the development of infections. This review evaluates the utility of current clinical and treatment guidelines, in the setting of management of infections in cancer patients.

AREAS COVERED

These include causes of infection in cancer patients, management of patients with high-risk and low-risk febrile neutropenia, management of low-risk patients in an outpatient setting, the role of granulocyte colony-stimulating factor (G-CSF) in the prevention and treatment of neutropenia-related infections, management of lung infections in various clinical settings, and emerging challenges surrounding the risk of infection in cancer patients treated with novel treatments. The literature search was performed by accessing PubMed and other databases, focusing on published clinical trials of relevant anti-cancer agents and diseases, primarily covering the recent past, but also including several key studies published during the last decade and, somewhat earlier in a few cases.

EXPERT REVIEW

Notwithstanding the promise of gene therapy/gene editing in hematological malignancies and some types of solid cancers, innovations introduced in clinical practice include more discerning clinical management such as the generalized use of biosimilar formulations of G-CSF and the implementation of novel, innovative immunotherapies.

Respiratory syncytial virus in hematopoietic cell transplant recipients and patients with hematologic malignancies

In the USA and other western nations, respiratory syncytial virus is one of the most commonly encountered respiratory viruses among patients who have been diagnosed with a hematologic malignancy or who have undergone a stem cell transplant. Multiple studies have been performed to evaluate the complications associated with respiratory syncytial virus infections. Other studies have evaluated therapeutic agents and strategies in which these agents can be used. There have also been numerous reports of outbreaks in bone marrow transplant units and oncology wards, where infection control measures have been invaluable in controlling the spread of disease. However, despite these novel approaches, respiratory syncytial virus continues to be potentially fatal in immunocompromised populations. In this review, we discuss the incidence of respiratory syncytial viral infections, risk factors associated with progression from upper respiratory tract infection to lower respiratory tract infection, other complications and outcomes (including mortality), management strategies, and prevention strategies in patients with a hematologic malignancy and in hematopoietic cell transplant recipients.

Pulmonary Impairment after Respiratory Viral Infections Is Associated with High Mortality in Allogeneic Hematopoietic Cell Transplant Recipients

Pulmonary impairment predicts increased mortality in many settings, and respiratory viral infection (RVI) causes considerable morbidity and mortality in allogeneic hematopoietic cell transplant recipients (allo-HCT). We hypothesized that pulmonary impairment after RVI, defined as a decline of forced expiratory volume in 1 second values by ≥10%, may identify allo-HCT recipients at high risk for mortality. We studied all allo-HCT recipients at our institution who had RVI with respiratory syncytial virus, parainfluenza virus, or influenza from 2004 to 2013 and had pre-RVI and post-RVI pulmonary function tests. We used competing risk regression models to identify risk factors for 2-year nonrelapse mortality (NRM) as the primary outcome after RVI and relapse-related mortality as a competing risk. From 223 eligible patients, pulmonary impairment after RVI was associated with over a 3-fold increase in 2-year NRM (pulmonary impairment, 25.3%; no impairment, 7.4%; univariate subhazard ratio [SHR], 3.9; 95% confidence interval [CI], 1.9 to 8.1; P < .001). After adjusting for age and systemic steroid use, pulmonary impairment after RVI was still associated with increased 2-year NRM (SHR, 3.3 [95% CI, 1.6 to 6.9]; P = .002). After adjustment for race and graft-versus-host disease (GVHD) prophylaxis, chronic GVHD at the time of RVI (odds ratio [OR], 2.8 [95% CI, 1.4 to 5.4]; p = .003) and lymphopenia (OR, 2.2 [95% CI, 1.1 to 4.2]; P = .02) were associated with increased odds of pulmonary impairment, whereas use of nonmyeloablative conditioning was associated with reduced odds of pulmonary impairment (OR, .4 [95% CI, .2 to .8]; P = .006). In allo-HCT recipients with RVIs, pulmonary impairment after RVI is associated with high NRM at 2years.

Viral Respiratory Tract Infections in Allogeneic Hematopoietic Stem Cell Transplantation Recipients in the Era of Molecular Testing

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Rhinovirus caused the majority of vRTI episodes in first 100 days following transplantation.

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Progression to lower respiratory tract infection was seen in 30% of patients with vRTI.

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vRTI in first 100 days after transplantation is associated with morbidity (ie, ICU admission).

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All of the deaths in our study cohort occurred in patients who acquired vRTI within 30 days of transplantation.

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Previous autologous transplantation is a significant risk factor for vRTI.

Viral respiratory tract infection (vRTI) is a significant cause of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed to assess the epidemiologic characteristics, risk factors, and outcomes of vRTI occurring in the period from conditioning to 100 days after allo-HSCT in the era of molecular testing. This study was a retrospective record review of patients who underwent allo-HSCT at Royal Melbourne Hospital between January 2010 and December 2015. Symptomatic patients were tested using respiratory multiplex polymerase chain reaction (PCR). Logistic regression and Kaplan-Meier analysis were used to identify risk factors for vRTI and the risk of death or intensive care unit (ICU) admission, respectively. A total of 382 patients were reviewed, and 65 episodes of vRTI were identified in 56 patients (14.7%). Rhinovirus accounted for the majority of infections (69.2%). The majority of episodes presented initially with upper respiratory tract infection (58.5%), with 28.9% of them progressing to lower respiratory tract infection. Eleven episodes (16.9%) were associated with ICU admission. There were no deaths directly due to vRTI. Previous autologous HSCT was associated with an increased risk of vRTI (odds ratio, 2.1; 95% confidence interval, 1.0 to 4.1). The risks of death (P = .47) or ICU admission (P = .65) were not significantly different by vRTI status. vRTI is common in the first 100 days after allo-HSCT and is associated with ICU admission.

Human Parainfluenza Virus Type 3 Infections in Patients with Hematopoietic Stem Cell Transplants: the Mode of Nosocomial Infections and Prognosis

There have been a few prospective and comprehensive surveillance studies on the respiratory viral infections (RVIs) among patients undergoing hematopoietic stem cell transplantation (HSCT). A 2-year prospective cohort surveillance study of symptomatic and asymptomatic RVIs was performed in hospitalized HSCT patients. Oropharyngeal (OP) swab samples were serially collected each week from 1 week before and up to 100 days after HSCT and were tested for virus isolation with cell culture-based viral isolation (CC-based VI) and a multiplex PCR (MPCR). A total of 2,747 OP swab samples were collected from 250 HSCT patients (268 HSCT procedures). Among these patients, 79 had RVIs (CC-based VI, n = 63; MPCR, n = 17). The parainfluenza virus type 3 (PIV3) accounted for 71% (57/80) of the cases of RVIs. Some PIV3 infections were asymptomatic and involved a longer virus-shedding period. The PIV3 was often cultured from samples taken before the onset of a respiratory disease. The PIV3 infections were attributed to the transmission of nosocomial infections. PIV3 infections before engraftment will more likely result in the development of lower respiratory tract infections and worse outcomes. A real-time monitoring of respiratory viral infections in the HSCT ward among patients with or without respiratory symptoms is required for the prevention of nosocomial RVIs, especially of PIV3 infections.

Impact of Alemtuzumab Scheduling on Graft-versus-Host Disease after Unrelated Donor Fludarabine and Melphalan Allografts

Alemtuzumab conditioning is highly effective at reducing the incidence of acute and chronic graft versus host disease (GVHD) in reduced intensity fludarabine and melphalan transplantation with ciclosporin monotherapy. Less frequent and lower dose scheduling may be used with sibling donors but an optimal regimen for matched unrelated donors has not been defined. In this retrospective observational study of 313 patients, the incidence and severity of GVHD was compared in patients receiving the standard 100mg regimen (20mg on day -7 to -3), 60mg (30mg day -4 and -2) or 50mg (10mg on day -7 to -3). Patients treated with 100mg, 60mg or 50mg developed acute GVHD grade I-IV with an incidence of 74%, 65% and 64%, respectively, while 36%, 32% and 41% developed chronic GHVD. An excess of severe acute grade III/IV GVHD was observed in the 50mg cohort (15% vs. 2-6%; p = 0.016). The relative risk of severe acute grade GVHD remained more than three-fold higher in the 50mg cohort, compared with 100mg, after adjustment for differences in age, gender mismatch, CMV risk and diagnosis (p = 0.030). The findings indicate that 60mg doses of alemtuzumab is comparable to 100mg but lower dosing may increase the risk of severe grade GVHD.

Viral Pneumonia in Patients with Hematologic Malignancy or Hematopoietic Stem Cell Transplantation

Viral pneumonias in patients with hematologic malignancies and recipients of hematopoietic stem cell transplantation cause significant morbidity and mortality. Advances in diagnostic techniques have enabled rapid identification of respiratory viral pathogens from upper and lower respiratory tract samples. Lymphopenia, myeloablative and T-cell depleting chemotherapy, graft-versus-host disease, and other factors increase the risk of developing life-threatening viral pneumonia. Chest imaging is often nonspecific but may aid in diagnoses. Bronchoscopy with bronchoalveolar lavage is recommended in those at high risk for viral pneumonia who have new infiltrates on chest imaging.

DAS181 for Treatment of Parainfluenza Virus Infections in Hematopoietic Stem Cell Transplant Recipients at a Single Center

Parainfluenza virus (PIV) causes severe respiratory infections in hematopoietic stem cell transplant (HSCT) recipients. Currently, no effective therapies are available. DAS181 is a novel antiviral agent that inhibits attachment of PIV to respiratory cells, but clinical data on the use of DAS181 for PIV infection are limited to case reports. We report the clinical manifestations and outcomes of 16 HSCT recipients who received DAS181 daily for the treatment of PIV infection through a compassionate-use protocol or a single-arm clinical trial. Of the 16 patients (clinical trial: 9; compassionate use: 7), 13 were allogeneic HSCT recipients and 8 had graft-versus-host disease. PIV types were 3 (n = 7), 4 (n = 5), 1 (n = 3), and type 3 and 4 coinfection (n = 1). Fourteen patients had pneumonia. All patients presented with cough, 14 had dyspnea, 11 had hypoxia, and 8 had a fever. Patients received 5 to 10 days of treatment. Nine patients (56%) had a complete clinical response after DAS181 therapy and 4 (25%) had a partial response. The 3 patients without a clinical response had coinfections with other pathogens. Of the 7 patients with virologic and spirometric data, 5 had >1-log reduction in nasopharyngeal swab PIV viral load and 4 had improved forced expiratory volumes by the end of treatment. Three patients (19%) died within 30 days and 2 of these deaths were related to PIV infection. Our data suggest that DAS181 may be an effective therapy for PIV pneumonia in HSCT recipients. Randomized placebo-controlled trials are needed to better evaluate its efficacy.

Parainfluenza virus infections in hematopoietic cell transplant recipients and hematologic malignancy patients: A systematic review

Parainfluenza viral infections are increasingly recognized as common causes of morbidity and mortality in cancer patients, particularly in hematopoietic cell transplant (HCT) recipients and hematologic malignancy (HM) patients because of their immunocompromised status and susceptibility to lower respiratory tract infections. Advances in diagnostic methods, including polymerase chain reaction, have led to increased identification and awareness of these infections. Lack of consensus on clinically significant endpoints and the small number of patients affected in each cancer institution every year make it difficult to assess the efficacy of new or available antiviral drugs. In this systematic review, we summarized data from all published studies on parainfluenza virus infections in HM patients and HCT recipients, focusing on incidence, risk factors, long-term outcomes, mortality, prevention, and management with available or new investigational agents. Vaccines against these viruses are lacking; thus, infection control measures remain the mainstay for preventing nosocomial spread. A multi-institutional collaborative effort is recommended to standardize and validate clinical endpoints for PIV infections, which will be essential for determining efficacy of future vaccine and antiviral therapies.

Unrelated donor hematopoietic stem cell transplantation for the treatment of non-malignant genetic diseases: An alemtuzumab based regimen is associated with cure of clinical disease; earlier clearance of alemtuzumab may be associated with graft rejection

Hematopoietic stem cell transplantation (HSCT) with matched unrelated donors (MUD), offers potentially curative therapy for patients with non-malignant genetic diseases. In this pilot study conducted from 2006 to 2014, we report the outcomes of 15 patients with non-malignant genetic diseases who received a myeloablative regimen with a reduced cyclophosphamide dose, adjunctive serotherapy and MUD HSCT [intravenous alemtuzumab (52 mg/m(2) ), busulfan (16 mg/kg), fludarabine (140mg/m(2) ), and cyclophosphamide (105 mg/kg)]. Graft-versus-host-disease (GVHD) prophylaxis consisted of tacrolimus/cyclosporine and methylprednisolone. Median (range) time to neutrophil engraftment (>500 cells/µL) and platelet engraftment (>20,000/mm(3) ) were 15 (12-28) and 25 (17-30) days, respectively. At a median follow-up of 2 (0.2-5.4) years, the overall survival (OS) was 93.3% (95% CI: 0.61-0.99) and disease-free survival (DFS) was 73.3% (95% CI: 0.44-0.89). Among this small sample, earlier alemtuzumab clearance was significantly associated with graft rejection (P = 0.047), earlier PHA response (P = 0.009) and a trend toward earlier recovery of recent thymic emigrants (RTE) (P = 0.06). This regimen was associated with durable donor engraftment and relatively low rates of regimen related toxicity (RRT); future alemtuzumab pharmacokinetic studies may improve outcomes, by allowing targeted alemtuzumab clearance to reduce graft rejection and promote more rapid immune reconstitution.

A comparative study of reduced dose alemtuzumab in matched unrelated donor and related donor reduced intensity transplants

In vivo T cell depletion with 100 mg alemtuzumab prevents graft-versus-host disease (GVHD) in reduced intensity conditioned transplants but is associated with delayed immune reconstitution, a higher risk of infection and relapse. De-escalation studies have shown that a reduced dose of 30 mg is as effective as 100 mg in preventing GVHD in matched related donor (MRD) transplants. Dose reduction in matched unrelated donor (MUD) transplants is feasible but the comparative efficacy of alemtuzumab in this setting is not known and opinions vary widely concerning the optimal level of GVHD prophylaxis that should be achieved. Through retrospective analysis we made an objective comparison of MUD transplants receiving an empirically reduced dose of 60 mg, with MRD transplants receiving a 30 mg dose. We observed proportionate levels of alemtuzumab according to dose but an inverse relationship with body surface area particularly in MRD transplants. MUD transplants experienced more acute and chronic GVHD, higher T cell chimerism, more sustained use of ciclosporin and less need for donor lymphocyte infusion than MRD transplants. Thus, doubling the dose of alemtuzumab to 60 mg did not provide equivalent prevention of GVHD after MUD transplant although there was no difference in non-relapse mortality or survival compared with MRD transplants.

Pneumonia in the immunocompromised host

PURPOSE OF REVIEW

Novel treatment modalities for previously fatal diseases, including newer chemotherapeutic and biologic agents and the expansion of the indications for solid organ and stem cell transplantation, have resulted in prolonged patient survival and a significant increase in the population of immunocompromised hosts (ICHs).

RECENT FINDINGS

This review discusses the increasing spectrum of opportunistic infections in the ICH, the general approach for early diagnosis and treatment of pulmonary infections in this population, and the current and novel diagnostic modalities available to establish a rapid and specific microbiologic diagnosis, focusing on recent controversies and advances.

SUMMARY

Early diagnosis and prompt initiation of effective therapy for infection help reduce morbidity in ICHs. Advances in diagnostic assays using nonculture-based methods, such as nucleic acid amplification, may allow for earlier targeted therapy. Invasive procedures including bronchoscopy and biopsy remain essential and should be vigorously pursued in ICHs given the broad differential diagnosis of possible pulmonary pathogens in this population, and the need to establish a specific diagnosis to allow accurate targeted therapy.

Parainfluenza virus type 3 Ab in allogeneic hematopoietic cell transplant recipients: factors influencing post-transplant Ab titers and associated outcomes

Parainfluenza virus type 3 (PIV-3) can cause severe respiratory illness among hematopoietic cell transplantation (HCT) recipients. Factors associated with PIV-3-specific Ab level, and the association between PIV-3 Ab levels and clinical outcomes in HCT recipients who acquire PIV-3 infection, are unknown. We evaluated PIV-3-specific hemagglutination inhibition Ab levels and clinical outcomes among 172 patients with PIV-3 infection following HCT. In a multivariable linear regression model, high post-transplantation Ab levels were independently associated with higher pre-transplantation recipient titer (mean difference 0.38 (95% confidence interval (CI), 0.26, 0.50), P<0.001). Significant associations between pre-HCT Ab titers in both patients and donors and occurrence of lower respiratory tract disease (LRD) after HCT were not observed. In conclusion, low pre-transplantation titers are associated with low Ab levels after HCT. The relationship between PIV-3 Ab levels and outcomes remain uncertain. Further study is needed to prospectively evaluate the dynamics of PIV-3-specific Ab responses and the relative contribution of PIV-3-specific Ab to protection from infection acquisition and progression to LRD.

Outcomes of hematopoietic cell transplantation in adult patients with acquired aplastic anemia using intermediate-dose alemtuzumab-based conditioning

Graft-versus-host disease (GVHD) has no therapeutic benefit after hematopoietic cell transplantation (HCT) for patients with acquired aplastic anemia (AA), and its prevention is highly desirable. We designed a conditioning regimen using an intermediate dose of alemtuzumab (50 to 60 mg) and describe our institutional experience of 41 patients who underwent HCT for AA. The median age at HCT was 37 years (range, 17 to 59). The conditioning regimen was high-dose cyclophosphamide (n = 9) or fludarabine based (n = 32). Additional GVHD prophylaxis was with cyclosporine. With a median follow-up of 3.6 years, overall survival at 3 years was 85%. Survival in patients <40 years and ≥40 years was 96% and 67%, respectively (P = .04). Graft failure occurred in 4 (10%) patients; 2 primary and 2 secondary. The cumulative incidences of acute (grades 1 to 2) and chronic GVHD were 27% and 15%, respectively. No patients developed grade 3 to 4 acute GVHD or severe chronic GVHD. The following viral complications were frequent: cytomegalovirus reactivation (79%), herpes simplex (18%), varicella zoster (25%), and BK virus hemorrhagic cystitis (8%). The majority of patients had no significant long-term health issues. This intermediate-dose alemtuzumab-based conditioning regimen results in excellent survival with a favorable impact on GVHD and long-term health outcomes, but close monitoring for viral complications is important.

Low-dose serotherapy improves early immune reconstitution after cord blood transplantation for primary immunodeficiencies

Cord blood transplantation (CBT) is curative for many primary immunodeficiencies (PIDs) but is associated with risks of viral infection and graft-versus-host disease (GvHD). Serotherapy reduces GvHD but potentially increases the risk of viral infection by delaying immune reconstitution. Because many PID patients have pre-existing viral infections, the optimal dose of serotherapy is unclear. We performed a retrospective analysis in 34 consecutive PID patients undergoing CBT and compared immune reconstitution, viral infection, GvHD, mortality, and long-term immune function between high-dose (n = 11) and low-dose (n = 9) serotherapy. Serotherapy dose had no effect on neutrophil engraftment. Median CD3⁺ engraftment occurred at 92.5 and 97 days for high- and low-dose serotherapy, respectively. The low-dose serotherapy group had higher CD3⁺, CD4⁺, and early thymic emigrant counts at 4 months compared with the high-dose group. GvHD severity and number of viral infections did not differ between serotherapy doses. Survival from the transplantation process was 90.9% for high-dose and 100% for low-dose groups. In conclusion, low-dose serotherapy enhanced T cell reconstitution and thymopoiesis during the first year after CBT with no increase in GvHD.

Low-dose alemtuzumab vs. standard policy for prevention of graft-versus-host disease in unrelated and related allogeneic stem cell transplantation-a matched pair analysis

Antibody-mediated in vivo T cell depletion is common prior to unrelated (URD) or mismatched allogeneic stem cell transplantation (alloSCT) and optional in HLA-identical sibling (FAM) alloSCT. While anti-thymocyte globulin (ATG) is the current standard, alemtuzumab is an alternative. The optimal dose of alemtuzumab has not been defined. This retrospective analysis compares low-dose alemtuzumab with ATG in URD alloSCT and with no antibody in FAM alloSCT. Twenty-eight patients treated with alemtuzumab (10 mg; HLA mismatch, 20 mg) were matched to 28 patients who have either received ATG (URD) or no antibody (noAB) according to disease, disease stage, age, transplant type and risk state. Both groups were compared for engraftment, outcome, disease-free (DFS) and overall survival (OS), graft-versus-host disease (GvHD), freedom from GvHD (ffGvHD) and transplant-related mortality (TRM). No significant differences were found between the groups for leukocyte engraftment, GvHD, ffGvHD, TRM, DFS and OS. There was a trend for reduction of cGvHD by alemtuzumab (p = 0.05). A transplant-type stratified subanalysis consolidated equivalency of alemtuzumab and ATG in URD-SCT and indicates possible superiority of low-dose alemtuzumab compared to noAB in FAM-SCT. Low-dose alemtuzumab, as part of conditioning regimen prior to alloSCT, is safe and comparable to standard ATG. Prospective trials, particularly comparing alemtuzumab vs. noAB in FAM alloSCT, should be conducted.

Current management of parainfluenza pneumonitis in immunocompromised patients: a review

Parainfluenza viruses (PIV) are common respiratory viruses that belong to the Paramyxoviridae family. PIV infection can lead to a wide variety of clinical syndromes ranging from mild upper respiratory illness to severe pneumonia. Severe disease can be seen in elderly or chronically ill persons and may be fatal in persons with compromised immune systems, particularly children with severe combined immunodeficiency disease syndrome and hematopathic stem cell transplant recipients. At present, there are no licensed antiviral agents for the treatment of PIV infection. Aerosolized or systemic ribavirin in combination with intravenous gamma globulin has been reported in small, uncontrolled series and case reports of immunocompromised patients. A number of agents show antiviral activity in vitro and in animals, but none are currently approved for human use.

Human parainfluenza virus infection after hematopoietic stem cell transplantation: risk factors, management, mortality, and changes over time

Human parainfluenza viruses (HPIVs) are uncommon, yet high-risk pathogens after hematopoietic stem cell transplant (HCT). We evaluated 5178 pediatric and adult patients undergoing HCT between 1974 and 2010 to determine the incidence, risk factors, response to treatment, and outcome of HPIV infection as well as any change in frequency or character of HPIV infection over time. HPIV was identified in 173 patients (3.3%); type 3 was most common (66%). HPIV involved upper respiratory tract infection (URTI; 57%), lower respiratory tract infection (LRTI; 9%), and both areas of the respiratory tract (34%), at a median of 62 days after transplantation. In more recent years, HPIV has occurred later after HCT, whereas the proportion with nosocomial infection and mortality decreased. Over the last decade, HPIV was more common in older patients and in those receiving reduced intensity conditioning (RIC). RIC was a significant risk factor for later (beyond day +30). HPIV infections, and this association was strongest in patients with URTI. HCT using a matched unrelated donor (MURD), mismatched related donor (MMRD), age 10 to 19 years, and graft-versus-host disease (GVHD) were all risk factors for HPIV infections. LRTI, early (<30 days), age 10 to 19 years, MMRD, steroid use, and coinfection with other pathogens were risk factors for mortality. The survival of patients with LRTI, especially very early infections, was poor regardless of ribavirin treatment. HPIV incidence remains low, but may have delayed onset associated with RIC regimens and improving survival. Effective prophylaxis and treatment for HPIV are needed.

Respiratory viral infections in hematopoietic stem cell and solid organ transplant recipients

Respiratory viral infections (RVIs) are common causes of mild illness in immunocompetent children and adults with rare occurrences of significant morbidity or mortality. Complications are more common in the very young, very old, and those with underlying lung diseases. However, RVIs are increasingly recognized as a cause of morbidity and mortality in recipients of hematopoietic stem cell transplants (HSCT) and solid organ transplants (SOTs). Diagnostic techniques for respiratory syncytial virus (RSV), parainfluenza, influenza, and adenovirus have been clinically available for decades, and these infections are known to cause serious disease in transplant recipients. Modern molecular technology has now made it possible to detect other RVIs including human metapneumovirus, coronavirus, and bocavirus, and the role of these viruses in causing serious disease in transplant recipients is still being worked out. This article reviews the current information regarding epidemiology, pathogenesis, clinical presentation, diagnosis, and treatment of these infections, as well as the aspects of clinical significance of RVIs unique to HSCT or SOT.

Perspective: emerging challenges in the treatment of influenza and parainfluenza in transplant patients

Influenza, respiratory synctial virus, and parainfluenza are common respiratory infections in immunocompromised transplant recipients, causing significant morbidity and mortality in this patient population. This paper focuses on influenza and parainfluenza virus infections in transplant patients with emphasis on the pandemic 2009 H1N1 influenza infection. Current antiviral treatment recommendations for influenza and parainfluenza in immunocompromised patients as well as novel investigational therapeutic approaches currently being tested in the clinic are discussed. In addition to the morbidity and mortality caused by these viruses, the development of multidrug resistance leading to transmission of resistant viruses is of great public health concern. The development of effective new therapies for influenza and parainfluenza in these high-risk patients is needed with randomized placebo-controlled studies to assess their clinical utility.

Management of RSV infections in adult recipients of hematopoietic stem cell transplantation

Respiratory syncytial virus (RSV) is a common cause of seasonal respiratory viral infection in patients who have undergone hematopoietic stem cell transplantation. RSV usually presents as an upper respiratory tract infection in this patient population but may progress rapidly to lower respiratory tract infection. Available therapies that have been used for the treatment of RSV infections are limited to ribavirin, intravenous immunoglobulin, and palivizumab. The use of aerosolized ribavirin, alone or in combination with either palivizumab or intravenous immunoglobulin, remains controversial. In this comprehensive review, we present and discuss the available literature on management of RSV infections in adult hematopoietic stem cell transplantation recipients with a focus on therapeutic modalities and outcomes.

Symptomatic parainfluenza virus infections in children undergoing hematopoietic stem cell transplantation

Parainfluenza virus (PIV) infections cause significant mortality in adults undergoing hematopoietic stem cell transplantation (HSCT). Children are more prone to PIV infections than adults; however, data on the epidemiology of these infections in children undergoing HSCT are limited. This study examined the incidence of symptomatic PIV infections, risk factors for lower respiratory tract infection (LRTI), and the impact on mortality after pediatric HSCT. A total of 1028 children who underwent HSCT between 1995 and 2009 were studied. PIV infections were detected in 46 of the 738 patients tested for respiratory infection (6.2%). PIV infection was the most common symptomatic respiratory viral infection in this population. On multivariate logistic regression analysis, receipt of an allogeneic transplant (P < .0001) and total body irradiation-based conditioning (P < .0001) were associated with increased risk of acquiring symptomatic PIV infection. Of the 46 HSCT patients with PIV infection, 18 (39%) had an LRTI. LRTI was associated with PIV infection in the first 100 days post-HSCT (P = .006), use of steroids (P = .035), and absolute leukocyte count (ALC) <100 cells/μL at the onset of infection (P < .0001). An ALC of <500 cells/μL was associated with prolonged viral shedding (P = .045). Six (13%) HSCT patients died of PIV infection. Mortality was associated with African-American ethnicity (P = .013), LRTI (P = .002), use of steroids (P < .0001), mechanical ventilation (P < .0001), and ALC <100 cells/μL at the onset of infection (P = .01). PIV infection causes significant morbidity and mortality in children undergoing HSCT.

A parainfluenza-3 outbreak in a SCT unit: sepsis with multi-organ failure and multiple co-pathogens are associated with increased mortality

The estimated frequency of parainfluenza virus 3 (PIV-3) infections following haematopoietic SCT (HSCT) is 2–7%, whereas reported mortality ranges from 18 to 33%. We report a retrospective outcome analysis following an outbreak of PIV-3 infection in our transplant unit. A total of 16 HSCT patients developed PIV-3 infection. All patients had upper respiratory tract infection, whereas lower respiratory tract infection occurred in 8 patients. Overall, 13 patients were treated with aerosolised Ribavirin (2 g t.d.s. for 5 days) and i.v. Ig (0.5 g/kg) as per standard protocol. One patient refused treatment, whereas two patients with full immune reconstitution were not treated. Overall mortality was 62.5%. Sepsis with multi-organ failure and the presence of pulmonary co-pathogens were both significantly associated with PIV-3-related mortality. Our series confirms that high mortality is associated with PIV-3 infection in HSCT recipients. In patients who develop PIV-3 infection, despite strict enforcement of infection control policies, the best strategy might be careful risk assessment, with effective broad-spectrum anti-microbials in those who are at risk of secondary infection.

Antithymocyte globulins and chronic graft-vs-host disease after myeloablative allogeneic stem cell transplantation from HLA-matched unrelated donors: a report from the Sociéte Française de Greffe de Moelle et de Thérapie Cellulaire

This retrospective report assessed the impact of rabbit antithymocyte globulins (ATG), incorporated within a standard myeloablative conditioning regimen prior to allogeneic stem cell transplantation (allo-SCT) using human leukocyte antigen-matched unrelated donors (HLA-MUD), on the incidence of acute and chronic graft-vs-host disease (GVHD). In this series of leukemia patients, 120 patients (70%) did not receive ATG ('no-ATG' group), whereas 51 patients received ATG ('ATG' group). With a median follow-up of 30.3 months, the cumulative incidence of grade 3-4 acute GVHD was 36% in the no-ATG group and 20% in the ATG group (P = 0.11). The cumulative incidence of extensive chronic GVHD was significantly lower in the ATG group as compared to the no-ATG group (4 vs 32%, respectively; P = 0.0017). In multivariate analysis, the absence of use of ATG was the strongest parameter associated with an increased risk of extensive chronic GVHD (relative risk) = 7.14, 95% CI: 1.7-33.3, P = 0.008). At 2 years, the probability of nonrelapse mortality, relapse, overall and leukemia-free survivals was not significantly different between the no-ATG and ATG groups. We conclude that the addition of ATG to GVHD prophylaxis resulted in decreased incidence of extensive chronic GVHD without an increase in relapse or nonrelapse mortality, and without compromising survival after myeloablative allo-SCT from HLA-MUD.

Respiratory syncytial virus and other respiratory viruses in the setting of bone marrow transplantation

PURPOSE OF REVIEW

Several epidemiologic studies have enhanced our understanding of the impact of respiratory viruses on bone marrow transplant recipients.

RECENT FINDINGS

Respiratory viral infections occur frequently following stem cell transplantation but present atypically. Many patients have asymptomatic infections. There is a growing armamentarium of antiviral agents currently under development, although prospective studies in transplant patients are needed.

SUMMARY

Respiratory viral infections occur frequently after hematopoietic stem cell transplant. Newer agents may prove useful in the prevention and treatment of respiratory viral infections in this population.

An observational study of once weekly intravenous ganciclovir as CMV prophylaxis in heavily pre-treated chronic lymphocytic leukemia patients receiving subcutaneous alemtuzumab

Fifteen consecutive resistant/relapsed chronic lymphocytic leukemia (CLL) patients (median age: 65 years) received alemtuzumab for 16 consecutive weeks. All patients had negative CMV anti genemia at baseline. Five patients received oral acyclovir 800 mg twice a day for CMV prophylaxis and 10 patients got intravenous (iv) ganciclovir 7.5 mg/kg once a week. A total of five CMV reactivations occurred, four in the acyclovir and one in the ganciclovir prophylaxis group. Alemtuzumab was then discontinued and all patients were treated with iv ganciclovir 7.5 mg/kg per day. All patients achieved negative CMV anti genemia after a median of 15 days of therapy. Weekly iv ganciclovir prophylaxis and alemtuzumab treatment were then restarted without any further CMV reactivations. In conclusion, weekly iv ganciclovir appears feasible and effective in preventing CMV reactivation and disease in this setting of high-risk immunocompromised patients, allowing an easier management of a therapy otherwise difficult to be routinely used.

Immune deficits in allogeneic hematopoietic stem cell transplant (HSCT) recipients

Immune deficits account for the high frequency of life threatening bacterial, viral, and fungal opportunistic infections seen in allogeneic HSCT recipients. Despite advances in infectious disease management, the integrity of host defenses remains the mainstay of defense. The intensity of the preparative regimen, degree of HLA matching, source of stem cells (marrow, blood, or cord), extent of T-cell depletion, and immunosuppressive therapy are some of the factors that impact the kinetics, characteristics, and quality of immune reconstitution. Graft-versus-host disease and its prophylaxis or treatment produce a host environment that is particularly vulnerable to infections. Mucosal disruption and prolonged severe neutropenia usually confine their impact to the early course of transplant. After initial engraftment, HSCT recipients remain at great risk for opportunistic infections and this is related to prolonged and severe T-lymphocyte dysfunction of a complex multifactorial nature. B cell dysfunction is less problematic clinically, but includes deficiencies of immunoglobulin subclasses and impaired ability to mount a vaccine response. Advances in understanding of these immune deficits have resulted in successful strategies including revaccination, growth factors, thymic protection, and adoptive cellular therapy with antigen-specific cells.

Alemtuzumab markedly reduces chronic GVHD without affecting overall survival in reduced-intensity conditioning sibling allo-SCT for adults with AML

By retrospective analysis of 88 patients from the British Society of Blood and Marrow Transplantation registry, we investigated the effect of in vivo T-cell depletion in HLA-identical sibling reduced-intensity conditioning (RIC) allografts for adult AML by comparing patients who received alemtuzumab with those without alemtuzumab conditioning. Both groups were equivalent for age, sex, karyotype and disease status at transplant. With a median follow-up of 27 months (3-72 months) and 48 months (7-72 months), the 2- and 5-year overall survival, with or without alemtuzumab, is 60 and 60% (P=0.80) and 61 and 53%, respectively (P=0.85). The 2-year non-relapse mortality is 12% with alemtuzumab, and 17% without alemtuzumab (P=0.49). The 2-year relapse rate is 35% with alemtuzumab compared with 19% without alemtuzumab (P=0.28). Grades II-IV acute GVHD occurred in 22% (8/37) without alemtuzumab compared with 14% (7/51) given alemtuzumab (P=0.25). Extensive chronic GVHD occurred in 47% (14/30) not given alemtuzumab compared with 4% (2/45) who were given alemtuzumab (P=0.001). Among evaluable patients, the risk of infections was higher in those treated with alemtuzumab compared with those not treated with alemtuzumab (79 vs 57%, respectively, P=0.02). In conclusion, alemtuzumab has a beneficial effect by reducing chronic GVHD without affecting overall survival. Further studies are warranted before alemtuzumab can be recommended as standard in RIC allografts for AML.

The challenge of respiratory virus infections in hematopoietic cell transplant recipients

Respiratory virus infections in hematopoietic cell transplant (HCT) recipients are a major cause of morbidity and mortality. While respiratory syncytial virus (RSV), human metapneumovirus, parainfluenzaviruses, and influenza viruses are well known for their potential to cause fatal pneumonia, information has only recently emerged regarding the significance of the newly discovered viruses, such as human coronaviruses NL63 and HKU1, and human bocavirus. Lymphopenia seems to be the most important risk factor for progression to lower respiratory tract disease. Airflow obstruction is another complication of respiratory virus infections after HCT, and data to date indicate this complication may occur following parainfluenza virus and RSV infection. Infection control procedures are key for prevention. Unfortunately, there are no randomized treatment studies, which make the interpretation of the literature on interventions difficult. This article reviews the spectrum of pathogens, epidemiology, risk factors and clinical manifestations of infection, as well as recent advances in diagnostic and clinical management.

Successful treatment of parainfluenza virus 3 pneumonia with oral ribavirin and methylprednisolone in a bone marrow transplant recipient

We report a case of severe parainfluenza (PIV) 3 pneumonia in a hematopoietic stem cell transplant recipient that was successfully treated with oral ribavirin and methylprednisolone. A 42-year-old woman diagnosed with acute myelogenous leukemia (FAB M5a) in first complete remission underwent allogeneic bone marrow transplantation from an HLA-matched unrelated donor in May 2006. In July 2007, she developed PIV3 pneumonia. Her respiratory status progressively worsened and she required O(2) inhalation at 6 L/min. After an informed consent was obtained, oral ribavirin was initiated (16 mg/kg per day) for 1 week on July 31. By day 3 of treatment, the high-grade fever had disappeared. However, it recurred after ribavirin was discontinued. In addition, the patient's hypoxia continued to worsen, requiring O(2) inhalation at 9 L/min. To suppress the inflammatory reaction in the lung caused by PIV3 pneumonia, intravenous methylprednisolone (1,000 mg once a day for 3 days) was started along with high-dose oral ribavirin (16 mg/kg per day) on August 11. The patient showed dramatic clinical improvement, and oxygen inhalation was discontinued on September 3. Our case suggests that with concomitant effective anti-viral treatment, corticosteroids may suppress host inflammatory or immune reactions that lead to respiratory failure.

Respiratory viruses other than influenza virus: impact and therapeutic advances

Though several antivirals have been developed and marketed to treat influenza virus infections, the development of antiviral agents with clinical activity against other respiratory viruses has been more problematic. Here we review the epidemiology of respiratory viral infections in immunocompetent and immunocompromised hosts, examine the evidence surrounding the currently available antivirals for respiratory viral infections other than influenza, highlight those that are in the pipeline, and discuss the hurdles for development of such agents.

Graft-versus-host disease following marrow transplantation for aplastic anemia: different impact of two GVHD prevention strategies

Prevention of GVHD is one of the most desirable goals of BMT in aplastic anemia (AA). We reviewed the medical records of 24 consecutive patients treated with BMT for acquired AA using two different GVHD prevention strategies. Ten patients were given alemtuzumab-based GVHD prophylaxis (50-60 mg in three divided doses on days -8, -7 and -6), and 14 patients were given conventional GVHD prophylaxis with calcineurin inhibitors plus MTX before the introduction of the alemtuzumab-based protocols. The incidence of acute, chronic and 'serious GVHD' was significantly reduced in alemtuzumab-treated patients compared to conventionally treated patients [11 vs 64% (P=0.03), 0 vs 78% (P=0.002) and 0 vs 57% (P=0.007), respectively]. Engraftment time and rates of graft failure appeared similar in the two groups. A significantly higher proportion of alemtuzumab-treated patients developed CMV reactivation compared to control patients (83 vs 12%; P=0.03); none developed CMV disease. The rates of other infectious complications did not appear significantly different. Our data suggest that 50-60 mg of alemtuzumab given according to the current schedule significantly reduces the risk of GVHD without increasing the risk of graft failure or serious infections.

Clonal gammopathies following alemtuzumab-based reduced intensity conditioning haematopoietic stem cell transplantation: association with chronic graft-versus-host disease and improved overall survival

The presence of clonal gammopathies (CG) has been reported following both conventional myeloablative and autologous haematopoietic stem cell transplantation (HSCT). We monitored the occurrence of CG in a cohort of patients with myeloid malignancies receiving FBC (fludarabine-busulphan-alemtuzumab)-based reduced intensity conditioned (RIC) HSCT, and assessed its correlation with infections, graft-versus-host disease (GvHD) and survival. Serial serum protein electrophoresis was analysed in a total of 138 patients and CG were detected in 49 patients (36%). The predominant Ig isotype was IgG (82%). There was no difference in the incidence of viral infections between patient groups. However, patients with gammopathies were more likely to have had prior chronic GvHD (OR 2.7, 95% CI 1.3-5.5, P<0.001). On multivariate analysis, the only factors that were found to influence overall survival (OS) were presence of gammopathies, which was associated with an improved OS (OR 0.35 95% CI 0.14-0.86, P=0.02) as well as disease stage, patients with advanced disease having a higher risk of death (OR 2.20 95% CI 1.18-4.11, P=0.02). Disease stage was the only variable that influenced relapse incidence on multivariate analysis (OR 4.22 95% CI 1.82-9.78, P<0.01). Clonal gammopathies are a frequent but benign occurrence following alemtuzumab-based RIC HSCT, and their appearance may define a group of patients with a favourable overall outcome.

Immune reconstitution after allogeneic stem cell transplantation with reduced-intensity conditioning regimens

Reduced-intensity conditioning (RIC) regimens have been increasingly used as an alternative to conventional myeloablative conditioning (MAC) regimens for elderly patients, for patients medically infirm to qualify for conventional allogeneic stem cell transplantation (SCT), and for disorders in which traditional MAC-SCT are associated with high rates of non-relapse mortality. One of the theoretical advantages of RIC-SCT is that it might lend to better immune reconstitution after transplantation due to less damage of the thymus, allowing regeneration of naive T cells derived from prethymic donor stem cells, and due to the proliferation of immunologically competent host T cells that survive the conditioning regimen. Although limited, studies comparing immune recovery following RIC and MAC-SCT have been insightful. One of the main difficulties of these studies is the current spectrum of RIC protocols, which vary considerably in myeloablative and immunosuppressive potential, resulting in apparently contradictory findings. In spite of this, most reports have shown significant quantitative and/or qualitative differences in T- and B-cell reconstitution after RIC-SCT in comparison with conventional SCT. This paper will review current knowledge of immune reconstitution following RIC-SCT.

EBV-related disease following haematopoietic stem cell transplantation with reduced intensity conditioning

The use of reduced intensity regimens has decreased early mortality following stem cell transplantation. However, the increased immunosuppression following these protocols results in profound and often prolonged lymphopenia, resulting in an increased incidence of viral reactivation. We and others have observed a high incidence of EBV viraemia and post-transplant lymphoproliferative disease (PTLD) following reduced-intensity conditioning regimens, reflecting the delayed recovery of EBV-specific immunity after such transplants. The clinical and histological features at presentation are similar to that seen after conventional intensity conditioning. Given the increasing use of reduced intensity conditioning (RIC) transplants, we review the risk factors for EBV related disease following transplantation with RIC, the potential for pre-emptive therapy of PTLD based on monitoring EBV viraemia and management options in such patients.

Allogeneic transplantation for myelodysplastic syndrome (MDS)

Haematopoietic stem cell transplantation (HSCT) remains the only curative option for patients with myelodysplastic syndrome (MDS). Developing conditioning regimens with low toxicity, at the same time as preserving an effective graft versus tumour response, is pivotal to expanding the scope for allogeneic transplantation in older patients with MDS. With the introduction of reduced intensity conditioned regimens, transplant centres worldwide are able to offer allogeneic HSCT to a much larger cohort of patients. Graft versus host disease (GvHD) remains a significant cause of morbidity and mortality, however with the use of T-cell depletion, centres have been able to utilise volunteer unrelated donors with an increasing degree of HLA disparity. The graft versus dysplasia effect resulting from allogeneic HSCT and the infusion of donor leukocytes has led to a greater understanding of the immunological mechanisms that govern outcome following transplantation in MDS.

Assessment of disseminated adenovirus infections using quantitative plasma PCR in adult allogeneic stem cell transplant recipients receiving reduced intensity or myeloablative conditioning

OBJECTIVES

Disseminated adenovirus (AdV) infections following allogeneic stem cell transplantation (allo-SCT) are increasingly recognised, particularly in children. This study evaluated the clinical relevance of disseminated AdV infections in adult allo-SCT recipients, after different conditioning regimens.

METHODS

In a cohort of 107 adult allo-SCT recipients, receiving either reduced intensity conditioning (RIC, n = 48) or myeloablative conditioning (MAC, n = 59), AdV DNA levels in plasma were determined retrospectively at 1, 3 and 6 months following transplantation. Results of this screening regimen were compared with a cohort of 58 paediatric allo-SCT recipients, in whom AdV DNA load was monitored prospectively, as part of a pre-emptive treatment strategy. In positive cases, the course of AdV DNA load and clinical outcome were assessed.

RESULTS

AdV DNA levels > or =1000 copies/mL were detected in five adults (4.7%) and eight children (13.8%). Screening for AdV viraemia at 1, 3 and 6 months would have detected seven of eight paediatric patients. One adult, receiving MAC, died with disseminated AdV disease and in four (three RIC and one MAC) AdV viraemia was transient without clinical symptoms specifically attributable to AdV. Seven paediatric patients with AdV viraemia were pre-emptively treated with ribavirin or cidofovir and in three of them disseminated AdV infection was related to a fatal outcome.

CONCLUSIONS

Disseminated AdV infections following allo-SCT was a rare event in the adults and cause morbidity in a minority of these patients. In four of five adult patients, spontaneous clearance of AdV viraemia occurred. Results did not differ between the conditioning regimens that were applied in the adult cohort.

Viral respiratory tract infections in transplant patients: epidemiology, recognition and management

Viral respiratory tract infections (RTIs) are common causes of mild illness in immunocompetent children and adults, with occasional significant morbidity or mortality in the very young, very old or infirm. However, recipients of solid organ transplants (SOT) or haematopoietic stem cell transplants (HSCT) are at markedly increased risk for significant morbidity or mortality from these infections. The infections are generally acquired by transmission of large respiratory droplets and can be nosocomial in origin with many documented outbreaks on specialised transplant units. Typically, the infections begin as upper RTIs, with cough or rhinorrhoea predominating. Many will resolve at this stage, but more immunocompromised patients, typically closer in time to their SOT or HSCT, may develop progressive infection to lower RTI or pneumonia. The most common RTI pathogens are influenza viruses, parainfluenza viruses and respiratory syncytial viruses. Newer polymerase chain reaction-based diagnostic strategies are more sensitive than previous assays, and allow rapid and accurate diagnoses of these infections. These newer assays may also detect emerging pathogens of significance, one of which is human metapneumovirus. While diagnostic techniques have advanced significantly in the past decade, well established and effective specific treatments for these infections remain elusive. The epidemiology, clinical presentation, diagnosis and treatment of the common viral RTIs in SOT or HSCT recipients are reviewed, and recommendations presented based on a thorough review of recent literature.

Antiviral prophylaxis in patients with haematological malignancies and solid tumours: Guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Oncology (DGHO)

Morbidity and mortality in patients with malignancies are increased by viral infections. These mostly are reactivations of asymptomatic latent infections. They primarily concern clinical entities associated with the reactivation of herpes viruses, such as varicella zoster virus (VZV) and cytomegalovirus (CMV). Respiratory tract infections caused by influenza, parainfluenza or respiratory syncytial virus (RSV) are less common. Since reactivation of latent infections has major clinical impact, antiviral prophylaxis is an attractive approach for patients expecting immunosuppression. The main risk factor for clinically relevant reactivation is profound disruption of cellular immune response. Duration and severity of chemotherapy induced neutropenia are of lesser importance. The risk of viral complications rises significantly in the presence of sustained suppression of T-cell function, e.g. in recipients of allogeneic stem cell transplants or of alemtuzumab (Campath-1H) antibody therapy. The objective of this guideline is to review the basis of prophylactic strategies and to provide recommendations for clinicians treating patients with haematological malignancies and solid tumors.