Late cytomegalovirus pneumonia in adult allogeneic blood and marrow transplant recipients

Clinical significance of late CMV disease in adult patients who underwent allogeneic stem cell transplant

INTRODUCTION

Late cytomegalovirus (CMV) disease, which was defined as CMV disease occurring >100 days post-transplant, remains an important complication among allogeneic stem cell transplant recipients, even now that the prophylactic strategy using ganciclovir preemptive therapy has been established. Due to the recent expansion of donor sources and conditioning regimens, it is therefore appropriate to reevaluate the incidence, risk factors, and clinical impacts of late CMV disease.

METHODS

This study included the 1295 adult patients, who underwent transplant for the first time from 2008 to 2015, without underlying disease relapse or CMV disease within 100 days post-transplant. There were no restrictions on underlying diseases or transplant procedures.

RESULTS

During the median follow-up period of 48.4 months, 21 patients developed late CMV disease and the 5-year cumulative incidence of late CMV disease was 1.6%. By multivariate analysis, haploidentical related donor, adult T-cell leukemia lymphoma, and preemptive therapy before 100 days post-transplant were extracted as independent risk factors. Late CMV disease negatively affected transplant outcomes, and was identified as an independent risk factor for the non-relapse mortality rate (hazard ratio 3.83, p < 0.001) and overall survival rate (hazard ratio 4.01, p < 0.001). Although 17 of 21 patients with late CMV disease died, the main causes of death were not related to CMV, except in three patients with CMV pneumonia.

CONCLUSIONS

Although the incidence of late CMV disease is low in transplant recipients, this complication negatively affects clinical courses. Therefore, transplant recipients with these risk factors should be more carefully managed.

Hematopoietic stem cell donor vaccination with cytomegalovirus triplex augments frequencies of functional and durable cytomegalovirus-specific T cells in the recipient: A novel strategy to limit antiviral prophylaxis

To enhance protective cytomegalovirus (CMV)-specific T cells in immunosuppressed recipients of an allogeneic hematopoietic cell transplant (HCT), we evaluated post-HCT impact of vaccinating healthy HCT donors with Triplex. Triplex is a viral vectored recombinant vaccine expressing three immunodominant CMV antigens. The vector is modified vaccinia Ankara (MVA), an attenuated, non-replicating poxvirus derived from the vaccinia virus strain Ankara. It demonstrated tolerability and immunogenicity in healthy adults and HCT recipients, in whom it also reduced CMV reactivation. Here, we report feasibility, safety, and immunological outcomes of a pilot phase 1 trial (NCT03560752 at ClinicalTrials.gov) including 17 CMV-seropositive recipients who received an HCT from a matched related donor (MRD) vaccinated with 5.1 × 108 pfu/ml of Triplex before cell harvest (median 15, range 11-28 days). Donor and recipient pairs who committed to participation in the trial resulted in exceptional adherence to the protocol. Triplex was well-tolerated with limited adverse events in donors and recipients, who all engrafted with full donor chimerism. On day 28 post-HCT, levels of functional vaccinia- and CMV-specific CD137+ CD8+ T cells were significantly higher (p < .0001 and p = .0174, respectively) in recipients of Triplex vaccinated MRD than unvaccinated MRD (control cohort). Predominantly, central and effector memory CMV-specific T-cell responses continued to steadily expand through 1-year follow-up. CMV viremia requiring antivirals developed in three recipients (18%). In summary, this novel approach represents a promising strategy applicable to different HCT settings for limiting the use of antiviral prophylaxis, which can impair and delay CMV-specific immunity, leading to CMV reactivation requiring treatment.

Releasing the concept of HLA-allele specific peptide anchors in viral infections: A non-canonical naturally presented human cytomegalovirus-derived HLA-A*24:02 restricted peptide drives exquisite immunogenicity

T‐cell receptors possess the unique ability to survey and respond to their permanently modified ligands, self HLA‐I molecules bound to non‐self peptides of various origin. This highly specific immune function is impaired following hematopoietic stem cell transplantation (HSCT) for a timespan of several months needed for the maturation of T‐cells. Especially, the progression of HCMV disease in immunocompromised patients induces life‐threatening situations. Therefore, the need for a new immune system that delivers vital and potent CD8+ T‐cells carrying TCRs that recognize even one human cytomegalovirus (HCMV) peptide/HLA molecule and clear the viral infection long term becomes obvious. The transcription and translation of HCMV proteins in the lytic cycle is a precisely regulated cascade of processes, therefore, it is a highly sensitive challenge to adjust the exact time point of HCMV‐peptide recruitment over self‐peptides. We utilized soluble HLA technology in HCMV‐infected fibroblasts and sequenced naturally sHLA‐A*24:02 presented HCMV‐derived peptides. One peptide of 14 AAs length derived from the IE2 antigen induced the strongest T‐cell responses; this peptide can be detected with a low ranking score in general peptide prediction databanks. These results highlight the need for elaborate and HLA‐allele specific peptide selection.

Is hospital-acquired pneumonia different in transplant recipients?

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are serious complications in transplant patients. The aim of this review is to summarize the evidence regarding nosocomial pneumonia in transplant recipients, including HAP in non-ventilated patients and VAP, and to identify future directions for improvement.A comprehensive literature search in the PubMed/MEDLINE database was performed. Articles written in English and published between 1990 and November 2018 were included. HAP/VAP in transplant patients usually occurs early post-transplant, particularly during neutropenia in haematopoietic stem cell transplant recipients. Bacteria are the leading cause of nosocomial pneumonia for both immunocompetent and transplant recipients, being Gram negative organisms, and especially Pseudomonas aeruginosa, highly prevalent. Multidrug-resistant bacteria are of special concern. Pneumonia in the transplant setting may be caused by opportunistic pathogens, and the differential diagnosis needs to be extended to other non-infectious complications. The most relevant opportunistic pathogens are Aspergillus fumigatus, Pneumocystis jirovecii and cytomegalovirus. Nevertheless, they are an exceptional cause of nosocomial pneumonia, and usually occur in severely immunosuppressed patients not receiving antimicrobial prophylaxis. Performing bronchoalveolar lavage may improve the rate of aetiological diagnosis, leading to a change in therapeutic management and improved outcomes. The optimal length of antibiotic therapy for bacterial HAP/VAP has not been well defined, but it should perhaps be longer than in the general population. Mortality associated with HAP/VAP is high. HAP/VAP in transplant patients is frequent and is associated with increased mortality. There is room for improvement in gaining knowledge about the management of HAP/VAP in this population.

Prevention of Infections in Patients with Hematological Malignancies

Infection is a major complication of patients with hematological malignancies. Prophylaxis is a key element in the management of these patients, and is composed by two main components: infection control measures and antimicrobial chemoprophylaxis. Infection control measures are safe, but not always effective. Antimicrobial prophylaxis is usually effective but may increase resistance rates, toxicity, and cost. Therefore, a careful evaluation of the actual risk for infection, the pathogens that predominate in a particular setting, and the periods at risk are important in order to define the most appropriate strategy. In this chapter we review the most important parameters to assess the risk on an individual basis, and the evidences and recommendations supporting infection control measures and antimicrobial prophylaxis against bacteria, fungi, viruses, and parasites.

Modification of the HCMV-specific IFN-γ release test (QuantiFERON-CMV) and a novel proposal for its application

Human cytomegalovirus (HCMV) is universally distributed among humans without any adverse effects; however, it induces severe diseases in immunocompromised patients such as organ transplant recipients and AIDS patients. To manage these immunocompromised patients, an easy clinical examination for the monitoring of disease risk is required. In this study, we modified the interferon-γ (IFN-γ) release test (QuantiFERON^®-CMV) using HCMV immediate early-1 (IE-1) or pp65 whole proteins, or UV-inactivated HCMV particles as an antigen. The response of heparinized peripheral blood from healthy volunteers to the pp65 protein showed an obvious dose-dependent sigmoid curve, although no correlation was observed between results of this assay and an ELISPOT assay. The addition of pp65 to the blood samples at a final concentration of 1×10³ to 1×10⁵ pg/ml was found to be optimum. Using this assay, we observed a significant enhancement in cellular immunity in volunteers after the daily ingestion of yogurt for 8 weeks, which suggested a novel application of the assay in addition to monitoring HCMV infection risk. IFN-γ secretion from peripheral blood cells on HCMV-antigen stimulation differed significantly between individuals; therefore, the assay could not be normalized. Nevertheless, it was found to be particularly useful for observing fluctuations in cellular immune activity on an individual level.

CMV-specific immune reconstitution following allogeneic stem cell transplantation

Cytomegalovirus (CMV) remains a major contributor to morbidity and mortality following allogeneic haemopoietic stem cell transplant (HSCT) despite widespread use of viraemia monitoring and pre-emptive antiviral therapy. Uncontrolled viral replication occurs primarily in the first 100 d post transplant but this high risk period can extend to many months if immune recovery is delayed. The re-establishment of a functional population of cellular effectors is essential for control of virus replication and depends on recipient and donor serostatus, the stem cell source, degree of HLA matching and post-transplant factors such as CMV antigen exposure, presence of GVHD and ongoing use of immune suppression. A number of immune monitoring assays exist but have not yet become widely accessible for routine clinical use. Vaccination, adoptive transfer of CMV specific T cells and a number of graft engineering processes are being evaluated to enhance of CMV specific immune recovery post HSCT.

An overview of infectious complications after allogeneic hematopoietic stem cell transplantation

Infections are the most common and significant cause of mortality and morbidity after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The presence of neutropenia and mucosal damage are the leading risk factors in the early pre-engraftment phase. In the early post-engraftment phase, graft versus host disease (GvHD) induced infection risk is increased in addition to catheter related infections. In the late phase, in which reconstitution of cellular and humoral immunity continues, as well as the pathogens seen during the early post-engraftment phase, varicella-zoster virus and encapsulated bacterial infections due to impaired opsonization are observed. An appropriate vaccination schedule following the cessation of immunosuppressive treatment after transplantation, intravenous immunoglobulin administration, and antimicrobial prophylaxis with penicillin or macrolide antibiotics during immunosuppressive treatment for GvHD might decrease the risk of bacterial infections. Older age, severe mucositis due to toxicity of chemotherapy, gastrointestinal tract colonization, prolonged neutropenia, unrelated donor and cord blood originated transplantations, acute and chronic GvHD are among the most indicative clinical risk factors for invasive fungal infections. Mold-active anti-fungal prophylaxis is suggested regardless of the period of transplantation among high risk patients. The novel serological methods, including Aspergillus galactomannan antigen and beta-D-glucan detection and computed tomography are useful in surveillance. Infections due to adenovirus, influenza and respiratory syncytial virus are encountered in all phases after allo-HSCT, including pre-engraftment, early post-engraftment and late phases. Infections due to herpes simplex virus-1 and -2 are mostly seen during the pre-engraftment phase, whereas, infections due to cytomegalovirus and human herpes virus-6 are seen in the early post-engraftment phase and Epstein-Barr virus and varicella-zoster virus infections often after +100th day. In order to prevent mortality and morbidity of infections after allo-HSCT, the recipients should be carefully followed-up with appropriate prophylactic measures in the post-transplant period.

Pneumonia in the neutropenic cancer patient

PURPOSE OF REVIEW

Pneumonia is the leading cause of death among neutropenic cancer patients, particularly those with acute leukaemia. Even with empiric therapy, case fatality rates of neutropenic pneumonias remain unacceptably high. However, recent advances in the management of neutropenic pneumonia offer hope for improved outcomes in the cancer setting. This review summarizes recent literature regarding the clinical presentation, microbiologic trends, diagnostic advances and therapeutic recommendations for cancer-related neutropenic pneumonia.

RECENT FINDINGS

Although neutropenic patients acquire pathogens both in community and nosocomial settings, patients' obligate healthcare exposures result in the frequent identification of multidrug-resistant bacterial organisms on conventional culture-based assessment of respiratory secretions. Modern molecular techniques, including expanded use of galactomannan testing, have further facilitated identification of fungal pathogens, allowing for aggressive interventions that appear to improve patient outcomes. Multiple interested societies have issued updated guidelines for antibiotic therapy of suspected neutropenic pneumonia. The benefit of antibiotic medications may be further enhanced by agents that promote host responses to infection.

SUMMARY

Neutropenic cancer patients have numerous potential causes for pulmonary infiltrates and clinical deterioration, with lower respiratory tract infections among the most deadly. Early clinical suspicion, diagnosis and intervention for neutropenic pneumonia provide cancer patients' best hope for survival.

Valganciclovir for the prevention of complications of late cytomegalovirus infection after allogeneic hematopoietic cell transplantation: a randomized trial

BACKGROUND

Optimal prevention of late cytomegalovirus (CMV) disease is poorly defined.

OBJECTIVE

To compare valganciclovir prophylaxis with polymerase chain reaction-guided preemptive therapy.

DESIGN

Randomized, double-blind trial. (ClinicalTrials.gov: NCT00016068).

SETTING

Multicenter trial.

PATIENTS

184 recipients of hematopoietic cell transplantation (HCT) who were at high risk for late CMV disease (95 patients received valganciclovir and 89 received placebo).

INTERVENTION

6 months of valganciclovir (900 mg/d) or placebo. Patients with polymerase chain reaction positivity at 1000 copies/mL or greater or a 5-fold increase over baseline were treated with ganciclovir or valganciclovir (5 mg/kg or 900 mg twice daily, respectively).

MEASUREMENTS

The composite primary end point was death, CMV disease, or other invasive infections by 270 days after HCT. Secondary end points were CMV disease, CMV DNAemia, death, other infections, resource utilization, ganciclovir resistance, quality of life, immune reconstitution, and safety.

RESULTS

The primary composite outcome occurred in 20% of valganciclovir recipients versus 21% of placebo-preemptive therapy recipients (treatment difference, -0.01 [95% CI, -0.13 to 0.10]; P = 0.86). There was no difference in the primary end point or its components 640 days after HCT. The incidence of a CMV DNAemia level of 1000 copies/mL or greater or a 5-fold increase over baseline was reduced in the valganciclovir group (11% vs. 36%; P < 0.001). Neutropenia was not significantly different at the absolute neutrophil count of less than 0.5 × 109 cells/L (P = 0.57); however, more patients received hematopoietic growth factors in the valganciclovir group (25.3% vs. 12.4%; P = 0.026). No significant differences were seen in other secondary outcomes.

LIMITATION

Some high-risk patients were not included.

CONCLUSION

Valganciclovir prophylaxis was not superior in reducing the composite end point of CMV disease, invasive bacterial or fungal disease, or death when compared with polymerase chain reaction-guided preemptive therapy. Both strategies performed similarly with regard to most clinical outcomes.

PRIMARY FUNDING SOURCE

Roche Laboratories.

Donor-derived CMV-specific T cells reduce the requirement for CMV-directed pharmacotherapy after allogeneic stem cell transplantation

Infusion of CMV-specific T cells early posttransplant does not increase acute or chronic graft-versus-host disease. CMV-specific T cells early posttransplant reduce the need for pharmacotherapy without increased rates of CMV-related organ damage.

The significance of cytomegalovirus viremia at day 100 or more following allogeneic hematopoietic stem cell transplantation

We conducted a single-center retrospective review of patients who had received allogeneic hematopoietic stem cell transplantation (HSCT) between January 2003 and December 2007, to assess the incidence and risk factors for late CMV infection and evaluate its effects on outcomes. Twenty of 49 HSCT recipients (41%) developed CMV infection at day ≥ 100 after transplant. Univariable analysis showed that having a matched unrelated donor, having early CMV infection, having a diagnosis of lymphoma, and receipt of antithymocyte globulin were risks for developing late CMV. On multivariable analysis, the occurrence of CMV prior to day 100 and lymphoma conferred a significant risk for late CMV infection. Of the 20 patients with late CMV infection, two patients manifested CMV disease (10%). Despite the relatively low incidence of CMV disease, patients with late CMV infection had a 4.8-fold increased risk of death compared to patients without late CMV. Identifying patients at increased risk for developing late CMV infection may be important for prompting more intensive monitoring of infection late after HSCT, particularly because this manifestation of CMV is associated with poorer outcomes.

Cytomegalovirus-specific cytotoxic T lymphocytes can be efficiently expanded from granulocyte colony-stimulating factor-mobilized hemopoietic progenitor cell products ex vivo and safely transferred to stem cell transplantation recipients to facilitate immune reconstitution

Uncontrolled cytomegalovirus (CMV) reactivation after allogeneic hematopoietic stem cell transplantation causes significant morbidity and mortality. Adoptive transfer of CMV-specific cytotoxic T lymphocytes (CTLs) is a promising therapy to treat reactivation and prevent viral disease. In this article, we describe the generation of clinical-grade CMV-specific CTLs directly from granulocyte colony-stimulating factor-mobilized hemopoietic progenitor cell (G-HPC) products collected for transplantation. This method requires less than 2.5% of a typical G-HPC product to reproducibly expand CMV-specific CTLs ex vivo. Comparison of 11 CMV CTL lines generated from G-HPC products with 52 CMV CTL lines generated from nonmobilized peripheral blood revealed similar expansion kinetics and phenotype. G-HPC-derived CTLs produced IFN-γ after reexposure to CMVpp65 antigen and exhibited CMV-directed cytotoxicity but no alloreactivity against transplantation recipient-derived cells. Seven patients received CMV-specific CTL lines expanded from G-HPC products in a prophylactic adoptive immunotherapy phase I/II clinical trial. Use of G-HPC products will facilitate integration of CTL generation into established quality systems of transplantation centers and more rapid inclusion of T cell therapies into routine clinical care.

Prevention of Infections in Patients with Hematological Malignancies

Infection is a frequent complication and a leading cause of morbidity and mortality in patients with hematological malignancies. Problems associated with the management of infections in these patients include difficulties in early diagnosis because the clinical signs of infection are subtle, the low performance of diagnostic tests, and suboptimal response to treatment because recovery of host defenses is a key factor for resolution of infection. Preventing these infections relies on infection control measures and antimicrobial chemoprophylaxis. While infection control measures are safe (but not always effective), the use of antimicrobial agents for prophylaxis of infection is not devoid of problems. Its wide use may increase the possibility of the development of resistance, select for resistant organisms, and increase toxicity and cost. Therefore, any attempt to administer an antimicrobial agent should be accompanied by a reflection of the potential benefits and risks of prophylaxis.

Foscarnet in the management of cytomegalovirus infections in hematopoietic stem cell transplant patients

Despite significant advances in the day-to-day management of patients receiving hematopoietic stem cell transplantations, including the introduction of new antiviral drugs, cytomegalovirus (CMV) infection continues to be a major cause of morbidity and mortality. The aim of this article is to undertake a literature-based review of foscarnet in this therapeutic setting and to align current best-published evidence with recent recommendations presented at the European Conference on Infections in Leukaemia. Ganciclovir remains the mainstay of CMV infection/disease antiviral management protocols. However, approximately a third of patients develop severe neutropenia and others become resistant to ganciclovir, and thus, a reasonably large proportion of patients are not able to receive and/or continue with this medication. Foscarnet is a suitable option as both pre-emptive therapy or for the treatment of active disease in these patients. Randomized trials have demonstrated that foscarnet is equally effective when compared with ganciclovir for pre-emptive treatment of CMV infections: the outcome was comparable with ganciclovir in terms of control of antigenemia and survival rates. There is a paucity of information for its use in the prophylaxis of CMV, although preliminary data show that it was effective in some patients at high risk of CMV reactivation. The main adverse events associated with foscarnet are renal impairment, serum electrolyte and hemoglobin disturbances, seizures and local genital irritation/ulceration. Foscarnet is a well-established antiviral option in immunocompromised patients, and it is usually administered as a second-line option to ganciclovir. In patients receiving hematopoietic stem cell transplantation, it has proven efficacy when used pre-emptively to treat CMV reactivation, as an alternative to and also in combination with ganciclovir.

Pneumonia in allogeneic stem cell transplantation recipients: a multicenter prospective study

Pneumonia is a common cause of mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT) but updated and prospective information is partial. The aim of this nationwide prospective study is to determine the current epidemiology, etiology, and outcome of pneumonia in allo-HSCT recipients. From September-2003 to November-2005, 112 episodes in 427 consecutive allo-HSCT recipients were included (incidence 52.2 per 100 allo-HSCT/yr), and 72 of them (64.3%) were microbiologically defined pneumonia. Bacterial pneumonia (44.4%) was more frequent than fungal (29.2%) and viral pneumonia (19.4%). The most frequent microorganisms in each group were: Escherichia coli (n = 7, 8.9%), Streptococcus pneumoniae (n = 4, 5.0%), cytomegalovirus (n = 12, 15.4%), and Aspergillus spp. (n = 12, 15.4%). The development of pneumonia and chronic graft-versus-host disease (GVHD) was associated with increased mortality after allo-HSCT, and the probability of survival was significantly lower in patients that had at least one pneumonia episode (p < 0.01). Pneumonia development in the first 100 d after transplantation, fungal etiology, GVHD, acute respiratory failure, and septic shock were associated with increased mortality after pneumonia. Our results show that pneumonia remains a frequent infectious complication after allo-HSCT, contributing to significant mortality, and provide a large current experience with the incidence, etiology and outcome of pneumonia in these patients.

Cytomegalovirus in hematopoietic stem cell transplant recipients

This article examines the clinical manifestations of and risk factors for cytomegalovirus (CMV). Prevention of CMV infection and disease are also explored. Antiviral resistance and management of CMV are examined.

Choice of Immunosuppression Influences Cytomegalovirus DNAemia in Cynomolgus Monkey (Macaca fascicularis) Islet Allograft Recipients

This retrospective study reviews the results of our experience with the occurrence of CMV DNAemia in islet cell transplanted cynomolgus monkeys subjected to different immunosuppressive protocols, including induction treatment with thymoglobulin (TMG), with a combination of thymoglobulin and fludarabine (FLUD), with cyclophosphamide, or with daclizumab. CMV DNA in the peripheral blood (CMV DNAemia) of 47 monkeys was quantified by real-time PCR on a weekly to biweekly basis. As compared to other immunosuppressive regimens, and in association with greater decreases in WBC, lymphocyte, CD3+CD4+, and CD3+CD8+ lymphocyte counts, frequent CMV DNAemia occurred earlier (within the first month posttransplant), and was of greater severity and duration in recipients of TMG ± FLUD. Treatment of recipients with alternative induction agents that resulted in less dramatic reductions in WBC and lymphocyte counts, however, resulted in occurrence of CMV DNAemia after postoperative day 60. The frequency, average intensity, duration, and area under the curve (AUC) for CMV DNAemia in animals receiving TMG ± FLUD were 75–100%, 4.02 ± 1.75 copies/ng DNA, 23.0 ± 5.3 days, and 367.0 ± 121.1 days x copies/ng DNA, respectively; corresponding values in animals receiving other treatments (0–44%, 0.19 ± 0.10 copies/ng DNA, 0.5 ± 0.3 days, and 75.4 ± 40.2 days x copies/ng DNA, respectively) were significantly different. The value of WBC, T and B cells at the nadir of cell depletion greatly affects the occurrence of CMV DNAemia. No animals developed CMV DNAemia within the next 3 weeks when the lowest value of WBC, lymphocyte, CD3+, CD3+CD4+, CD3+CD8+, or CD20+ cells was above 4500, 1800, 300, 200, 150, or 300 cells/μl, respectively. Oral valganciclovir prophylaxis did not completely prevent the appearance of CMV DNAemia.

Cytomegalovirus in hematopoietic stem cell transplant recipients

This article examines the clinical manifestations of and risk factors for cytomegalovirus (CMV). Prevention of CMV infection and disease are also explored. Antiviral resistance and management of CMV are examined.

Cytomegalovirus-specific CD8(+) T cells targeting different HLA/peptide combinations correlate with protection but at different threshold frequencies

Cytomegalovirus (CMV) causes significant morbidity and mortality in patients after haematopoietic stem cell transplantation (HSCT). Due to limitations of current antiviral therapies, alternative approaches, involving transfer of donor-derived CMV-specific CD8(+) T cells, have been considered. Levels of such cells correlating with protection against CMV infection and disease have only been reported in patients expressing HLA-A*0201 and HLA-B*0702. This is despite an increasing number of reports describing cells targeting CMV peptides presented by other human leucocyte antigens (HLAs). Considering several frequent HLA alleles, our findings suggest that HLA-A*2402/pp65 (341-349)- and HLA-B*3501/pp65 (123-131)-specific CD8(+) T cells correlate with protection from CMV reactivation at significantly lower cell levels than HLA-A*0101/pp50 (245-253)- and HLA-A*0201/pp65 (495-503)-specific CD8(+) T cells, both in HSCT recipients post-transplant and in healthy CMV seropositive volunteers. This may result from a differing efficiency of the responses restricted by the two sets of HLA alleles. These findings add to the knowledge of immunodominance and differences in antigen processing that are coordinated in individuals with different HLA alleles and have direct implications for therapy and monitoring in patients.

Validation of a DNAemia cutoff for preemptive therapy of cytomegalovirus infection in adult hematopoietic stem cell transplant recipients

A randomized trial comparing a DNAemia cutoff of 10 000 copies per ml whole blood and first pp65 antigenemia positivity for initiation of preemptive therapy of human cytomegalovirus (HCMV) infection in adult hematopoietic stem cell transplant recipients was completed. DNAemia was chosen for cutoff definition since it is more automatable and standardizable than antigenemia, and more closely reflects the actual viral replication. The primary end point of the study was to compare the number of patients treated in the two arms. A total of 83 patients (42 in the DNAemia, and 41 in the antigenemia arm) were enrolled in the study. The incidence of HCMV infection, as detected by the relevant randomization assay (76% in the DNAemia versus 85% in the antigenemia arm), was comparable in the two arms, whereas the number of patients treated was significantly lower in the DNAemia arm (63 versus 80%, P=0.02). A single patient in the DNAemia arm suffered from biopsy-proven HCMV gastric disease diagnosed in the absence of detectable virus in blood. The incidence of graft-versus-host disease, and transplantation-related mortality did not differ between the two arms. In conclusion, our study shows that the use of a cutoff significantly reduces the number of patients requiring antiviral treatment, thus sparing unnecessary drug administration.

Surveillance of cytomegalovirus (CMV) DNAemia in pediatric allogeneic stem cell transplantation: incidence and outcome of CMV infection and disease

Cytomegalovirus (CMV) remains a serious problem after hematopoietic stem cell transplantation (HSCT). To investigate the incidence of CMV infection and outcome we retrospectively analyzed 70 consecutive pediatric allogeneic HSCTs monitored by CMV polymerase chain reaction (PCR), with at least 1-year follow-up or until death. All patients at risk for CMV infection (CMV-seropositive patients and CMV-seronegative recipients transplanted from CMV-seropositive donors) received hyperimmune anti-CMV globulins whereas in the group of HSCT patients with both donor and recipient CMV negativity, polyvalent immunoglobulins were given, both at a dose of 400 mg/kg. All patients received acyclovir at prophylactic doses for at least 6 months. Patients were monitored twice a week by CMV PCR. Patients with 2 positive results for CMV DNAemia received ganciclovir for 14 days and continued until 2 consecutive negative results were obtained. The incidence of CMV DNAemia was 12.8% (9/70) in the whole group, with significant higher risk for patients with CMV-seropositive recipient status, 8 out of 22 (36%), vs. patients with seronegative status, 1 out of 48 (2%) (P=0.0002). Three out of 9 patients with DNAemia developed CMV disease despite adequate preemptive treatment. The transplant-related mortality was higher in the CMV-seropositive recipient group (P=0.05). Age, use of hyperimmune anti-CMV globulins at a high dose, and the low incidence of graft-versus-host disease might be contributing factors to this low incidence.

Complications pulmonaires précoces des allogreffes de cellules souches hématopoïétiques

INTRODUCTION

Pneumonia is one of the main causes of mortality following allogenic stem cell transplantation, especially in the first months after the transplant has been performed.

STATE OF THE ART

Pneumonia is the most common infection occurring after transplant and the infection with the highest mortality. Following the classical, myeloablative approach to transplant, two thirds of the pneumonias that occur are of infectious origin. Their causes roughly follow the timing of the immune reconstitution, and may depend on the type of transplant, the match between donor and recipient, and, overall, the occurrence of graft-versus-host disease. Most bacterial pneumonias occur during the initial neutropenic phase. The 2nd and 3rd month post transplant are mainly complicated by viral pneumonia, especially respiratory virus and adenovirus pneumonia in deeply immunosuppressed patients. Preemptive and prophylactic strategies have considerably reduced the incidence of cytomegalovirus pneumonia. Pneumonia due to encapsulated bacteria, such as Haemophilus influenzae and Streptococcus pneumoniae, usually considered to be late infections, may actually be observed from the second month post-transplant.

PERSPECTIVES

The increasing use of reduced-intensity conditioning regimens has modified the time course of the main adverse events following transplantation, including the timing of the infectious pneumonias. The pneumonias that are specifically related to allogenic transplant are idiopathic interstitial pneumonia, bronchiolitis obliterans, and bronchiolitis obliterans organizing pneumonia, which are all considered to be pulmonary manifestations of graft-versus-host disease, and treated as such. Prophylaxis for many of these infectious pneumonias (i.e., P jiroveci, S pneumoniae, toxoplasmosis) are well standardized.

CONCLUSIONS

Much remains to be done to decrease the incidence of pneumonia in these patients and to understand their mechanisms.

Analysis of cytomegalovirus (CMV) viremia using the pp65 antigenemia assay, the amplicor CMV test, and a semi-quantitative polymerase chain reaction test after allogeneic marrow transplantation

A pp65 antigenemia assay for polymorphonuclear leukocytes (PMNLs) (CINAkit Rapid Antigenemia), and a qualitative polymerase chain reaction (PCR) test for plasma 'PCR-P qual' (Amplicor cytomegalovirus [CMV] test) were performed for 126 samples (blood and plasma) obtained from 18 bone marrow transplant patients, over a 9-month surveillance period. Among those samples, 92 were assayed with a semi-quantitative PCR test for PMNLs 'PCR-L quant.' The number of samples with a positive CMV test for antigenemia and PCR-P qual assays was 20.63% and 12.7%, respectively, whereas the PCR-L quant assay was positive in 48 of the 92 samples assayed (52.17%). The rates of concordance of the results of PCR-P qual and antigenemia, PCR-P qual and PCR-L quant, antigenemia and PCR-L quant were 92%, 65.2% and 66.8%, respectively. The analysis of the results for the 92 specimens tested by all 3 methods showed a rate of concordance of 63% among all methods. Good agreement (kappa=0.72) was found only between pp65 Ag and PCR-P qual assays. Clinical disease correlates with an antigenemia high viral load. Three patients had CMV disease despite preemptive therapy, and all of them had graft-versus-host-disease (GVHD). PMNLs-based assays are more efficient in monitoring CMV reactivation, but for high-risk patients with GVHD, more sensitive assays (real-time PCR) must be done.

Reduced dose of foscarnet as preemptive therapy for cytomegalovirus infection following reduced-intensity cord blood transplantation

Although foscarnet is a promising alternative for the treatment of cytomegalovirus (CMV) infection, its toxicity can be significant in patients with advanced age. We retrospectively reviewed medical records of 123 patients (median age of 55; range, 17-79) who received reduced-intensity cord blood transplantation (RI-CBT). Patients preemptively received reduced-dose foscarnet 30 mg/kg twice daily when CMV antigenemia exceeded 10/50,000. Sixty-three patients developed CMV antigenemia on a median of day 34, and 29 received foscarnet preemptively. The median level of CMV antigenemia at the initiation of foscarnet was 30. Median duration of foscarnet administration was 24 days. Adverse effects included electrolyte abnormalities (n=19), renal impairment (n=13), and skin eruption requiring discontinuation of foscarnet (n=1). Preemptive therapy of foscarnet was completed in 18 patients. Seven patients died during foscarnet use without developing CMV disease. The remaining 3 developed CMV enterocolitis 5, 14, and 17 days after initiation of foscarnet. All of them were successfully treated with ganciclovir or foscarnet. Reduced dose of foscarnet is beneficial to control CMV reactivation following RI-CBT; however, it has considerable toxicities in RI-CBT recipients with advanced age. Further studies are warranted to minimize toxicities and identify optimal dosages.

Chronic GvHD decreases antiviral immune responses in allogeneic BMT

Chronic graft-versus-host disease (cGvHD) is associated with functional immunodeficiency and an increased risk of opportunistic infections in allogeneic bone marrow transplantation (BMT). We used a parent to F1 model of allogeneic BMT to test the hypothesis that cGvHD leads to impaired antigen-specific antiviral immunity and compared BM transplant recipients with cGvHD to control groups of allogeneic BM transplant recipients without GvHD. Mice with and without cGvHD received a nonlethal dose of murine cytomegalovirus (MCMV) +100 days after transplantation. Recipients with cGvHD had more weight loss and higher viral loads in the spleen and liver. MCMV infection led to greater than 25-fold expansion of donor spleen-derived MCMV peptide-specific tetramer-positive CD8(+) T cells in blood of transplant recipients with and without cGvHD, but mice with cGvHD had far fewer antigen-specific T cells in peripheral tissues and secondary lymphoid organs. The immunosuppression associated with cGvHD was confirmed by vaccinating transplant recipients with and without cGvHD using a recombinant Listeria expressing MCMV early protein (Lm-MCMV). Secondary adoptive transfer of lymphocytes from donor mice with or without cGvHD into lymphopenic congenic recipients showed that cGvHD impaired tissue-specific homing of antigen-specific T cells. These results indicate that cGvHD causes an intrinsic immunosuppression and explain, in part, the functional immunodeficiency in allogeneic transplant recipients.

Bone marrow transplantation from a pediatric donor with a high frequency of cytomegalovirus-specific T-cells

A recent study reported that quantitation of cytomegalovirus (CMV)-specific CD8+ T lymphocytes in the graft and monitoring of these T cells might identify hematopoietic stem cell transplantation-recipients at the risk for progressive CMV infection. A 6-year-old girl underwent bone marrow transplantation from an HLA-identical sibling with a very high frequency of CMV specific tetramer-positive CD8+ T-cells. CMV-specific T-cell immunity was prospectively evaluated using a peptide (HLA-A2, NLVPMVATV). Tetramer assay showed that the frequency of CMV-specific CD8+ T cells of the donor in the peripheral blood was 5.3%, higher than average amongst young children. The frequency of CMV-specific CD8+ T cells of the donor in the graft was 3.7% of CD8+ T-cells. Before transplantation, the frequency of CMV specific CD8+ T cells of the recipient was 0.1% in the peripheral blood. Surprisingly, the frequency of CMV specific CD8+ T cells increased up to 30% of CD8+ T-cells at day 27 after transplantation. IFN-gamma enzyme-linked immunospot assay showed the recipient-T cells had strong responses to the A2-specific NLVPMVATV peptide. Although the phenotypic pattern of the CMV-specific T cells of the recipient was different from those of the donor before transplantation, the phenotype of the donor-derived cells retained their original phenotype in the recipient after transplantation. These finding suggested that active transferred immunity from the graft with a high frequency of CMV-specific CTL could induce a rapid reconstitution of CMV-specific T-cell mediated immunity in pediatric HLA-identical allogenetic bone marrow transplantation. The screening of peripheral blood using HLA-peptide tetramer staining might be beneficial to select donors.

Cellular immunotherapy for cytomegalovirus and HIV-1 infection

Current antiviral drugs do not fully reconstitute the specific antiviral immune control in chronically human immunodeficiency virus (HIV)-1-infected patients or in cytomegalovirus (CMV)-infected patients after hematopoietic stem cell transplantation. Therefore, immunotherapy in which the patient's immune system is manipulated to enhance antiviral immune responses has become a promising area of viral immunology research. In this review, an overview is provided on the cellular immunotherapy strategies that have been developed for HIV infection and CMV reactivation in immunocompromised patients. As an introduction, the mechanisms behind the cellular immune system and their importance for the development of a workable immunotherapy approach are discussed. Next, the focus is shifted to the immunopathogenesis of CMV and HIV-1 infections to correlate these findings with the concepts and ideas behind the viral-specific immunotherapies discussed. Current and future perspectives of active and passive cellular immunotherapy for the treatment of CMV and HIV-1 infections are reviewed. Finally, pitfalls and key issues with regard to the development of immunotherapy protocols that can be applied in a clinical setting are addressed.

New reporter cell line to evaluate the sequential emergence of multiple human cytomegalovirus mutations during in vitro drug exposure

We developed a new reporter cell line for human cytomegalovirus (HCMV) drug susceptibility testing. This cell line was obtained by incorporating the luciferase reporter gene under the control of an HCMV-specific promoter into the genome of astrocytoma cells (U373MG). We then used our reporter cell line to evaluate phenotypic changes conferred by the sequential emergence of HCMV UL54 and UL97 mutations following long-term drug exposure. The laboratory strain AD169 was passaged in the presence of increasing concentrations of ganciclovir (one viral line) or foscarnet (two viral lines). Resistant viruses were plaque purified at five different concentrations of ganciclovir and at three different concentrations of foscarnet. In addition to the previously described M460I and L595S UL97 mutations and the L545S and V812L UL54 mutations, exposition to ganciclovir (up to 3,000 microM) resulted in the selection of two unreported UL54 mutations (P829S and D879G). Passages in the presence of foscarnet (up to 3,000 microM) resulted in the selection of seven not previously described UL54 mutations (K500N, T552N, S585A, N757K, L802V, L926V, and L957F) in addition to the N408D mutation that has been associated with ganciclovir and cidofovir resistance. Long-term exposure of HCMV to either ganciclovir or foscarnet ultimately resulted in the selection of multiple UL54 mutations that conferred high levels of resistance to all approved HCMV DNA polymerase inhibitors, i.e., ganciclovir, cidofovir, and foscarnet. Emergence of each viral mutation conferred stepwise increases in drug 50% inhibitory concentrations that could be objectively measured with the new reporter cell assay.

Cytomegalovirus Infection in Patients with Lymphoma: An Important Cause of Morbidity and Mortality

BACKGROUND

Cytomegalovirus (CMV) antigenemia (CMV-A) and CMV disease (CMV-D), known causes of morbidity and mortality among patients with leukemia and recipients of hematopoietic stem cell transplantations, are described sporadically in patients with lymphoma. We sought to determine the risk factors and outcome of CMV-A and CMV-D among patients with lymphoma.

PATIENTS AND METHODS

We conducted a retrospective cohort study with such patients identified between 1997 and 2003 at The University of Texas M. D. Anderson Cancer Center. Seventy-one patients with 82 episodes of CMV-A and/or CMV-D (CMV-A in 38 episodes and CMV-D in 44 episodes) were studied.

RESULTS

Cytomegalovirus antigenemia and/or CMV-D were more common among patients with non-Hodgkin's lymphoma than among those with Hodgkin's disease (P = 0.01). Most CMV infectious episodes occurred in patients who had active (88%) and stage III/IV lymphoma (84%). Eleven of 65 patients (17%) with outcome data died with CMV-A and/or CMV-D. Death with CMV infection was more common among patients with CMV-D than among those with CMV-A (29% vs. 3%, respectively, P = 0.005). Predictors of death by univariate analysis included intensive care unit admission, mechanical ventilation, high antigenemia burden, relapse of CMV-A and/or CMV-D, and antiviral-associated toxicity (all P < 0.05). Multivariate analysis identified antiviral toxicity as the only independent predictor of death (P = 0.01).

CONCLUSION

In an era of intense and pleiotropic immunosuppressive therapy in patients with lymphoma, CMV-A and CMV-D are significant infections. Preventive strategies might be warranted for patients at risk.

Epidemiology of cytomegalovirus disease in solid organ and hematopoietic stem cell transplant recipients

PURPOSE

The novel and traditional risk factors for cytomegalovirus (CMV) infection and disease in solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, the current strategies for the prevention of CMV disease, the emerging syndrome of late-onset CMV disease, and the risk factors for antiviral drug resistance are described.

SUMMARY

The evolution of transplantation practices, the changes in the characteristics of donors and recipients, the introduction of novel immunosuppressive drugs, and the widespread use of antiviral drugs for CMV prevention have collectively influenced the natural history of CMV infection and disease in SOT and HSCT recipients. Strategies for CMV prevention with the use of antiviral drugs, whether as prophylaxis or as preemptive therapy, are effective in reducing the incidence of CMV disease in transplant recipients. However, late-onset CMV disease is now emerging as a serious problem. Donor and recipient CMV serostatus and other traditional risk factors for early-onset CMV disease appear to contribute to the occurrence of late-onset CMV disease during the first year after transplantation.

CONCLUSION

The epidemiology of CMV infection and disease has changed after transplantation. Strategies to prevent late-onset CMV disease include the prolonged use of antiviral prophylaxis, but this practice can lead to the emergence of antiviral drug resistance, which has been associated with high rates of morbidity and mortality.

Cidofovir for cytomegalovirus reactivation in pediatric patients after hematopoietic stem cell transplantation

BACKGROUND

Cidofovir (CDV) is a nucleotide analogue with broad antiviral activity. This drug has a very favorable pharmacokinetic profile that enables intermittent dosing, but the potential for nephrotoxicity has hitherto restricted its use in stem cell transplant recipients. Data on pediatric patients are limited.

OBJECTIVES

To report the efficacy and toxicity of CDV in a group of pediatric patients with cytomegalovirus (CMV) reactivation after allogeneic stem cell transplantation.

STUDY DESIGN

Prospective evaluation of safety and efficacy of CDV used pre-emptively for CMV reactivation in 10 out of 30 children who underwent allogeneic hematopoietic stem cell transplantation from January 2000 to December 2001. In all the patients but one, CDV was used as second-line therapy (after foscarnet or ganciclovir) of CMV reactivation.

RESULTS

Overall, 12 courses of CDV were administered with a median 5 doses per course, range 1-6 (two patients were treated twice). Considering the first CDV treatment episode, 8 out of 10 patients had positive CMV antigenemia assay when they started CDV. Five of eight antigenemic patients responded completely while three were switched to foscarnet or ganciclovir, respectively, due to increasing (one) or persistent CMV antigenemia (two). Overall, the therapy with CDV was well tolerated, but it was withdrawn in one patient due to a two-fold increase in the baseline creatinine level. This patient concurrently had a high tacrolimus blood level.

CONCLUSION

Safety is the major concern regarding the use of CDV but the adoption of probenicid, intravenous hydration and anti-emetic therapy improved its tolerability profile. Our data suggest that CDV has an acceptable toxicity and would deserve further controlled studies in the setting of pre-emptive therapy for CMV.

Clinical aspects of CMV infection after stem cell transplantation

Cytomegalovirus (CMV) infection is one of the most important infectious complications after stem cell transplantation (SCT). Major improvements in the management of CMV infection have been achieved during the last decade, including the introduction of safe blood product support for CMV-seronegative patients, the development of early pre-emptive antiviral therapy based on sensitive diagnostic tests, and antiviral prophylaxis. With the better control of CMV infection during the first 100 days after allogeneic SCT an increase in the incidence of CMV infection and disease after day 100 after transplantation was observed. New methods that allow for the reconstitution of CMV-specific immune responses such as adoptive T-cell therapy are promising tools that might help to improve the management of late CMV infection and disease.

Influence of cytomegalovirus (CMV) sero-positivity on CMV infection, lymphocyte recovery and non-CMV infections following T-cell-depleted allogeneic stem cell transplantation: a comparison between two T-cell depletion regimens

We compared the incidence and outcome of preemptively treated cytomegalovirus (CMV) infection, lymphocyte recovery and non-CMV infections between two different TCD modalities, one employing CD34+ selection and T-cell add-back (TCAB), preceded by Campath-1H in vivo (CD34+/TCAB group, n=29), and the other using grafts incubated with Campath-1H in vitro (Campath-1H in vitro group, n=32). The probabilities of CMV reactivation and recurrence were 67 and 83.6% in the CD34+/TCAB group and 42.9 and 20% in the Campath-1H group (P=0.07 and 0.02). Donor sero-positivity reduced CMV reactivation in the Campath-1H group, but not in the CD34+/TCAB group. The durations of positive PCR/antigenemia positivity and antiviral therapy were also significantly longer in the CD34+/TCAB group. However, only two patients developed CMV disease in each group. The mean absolute lymphocyte counts (x 10(9)/l) at 30 days (0.27 vs 0.4, P=0.03) and 100 days (0.77 vs 1.4, P=0.01) were significantly lower in the CD34+/TCAB group along with a higher incidence of non-CMV infections in CMV at-risk patients, but not in the CMV low-risk group. These findings suggest that the modality of TCD should be tailored according to the CMV risk status, and CMV sero-positive patients should receive a less extensively T-cell-depleted graft and a CMV sero-positive graft if possible.

Infectious complications and outcomes after allogeneic hematopoietic stem cell transplantation in Korea

We reviewed 242 allogeneic hematopoietic stem cell transplantation (HSCT) recipients retrospectively over a 2-year period (January 1998-December 1999) in order to analyze the characteristics and assess the outcomes of infectious complications in patients after HSCT in Korea. Bacteria were the major pathogens before engraftment, and viral and fungal infections predominated during the post-engraftment period. Varicella zoster virus was the most common viral pathogen after engraftment. Cytomegalovirus disease occurred mainly in the late-recovery phase. The frequency of mold infection was higher than that of yeast. There was a relatively high incidence of tuberculosis (3.0%) and Pneumocystis carinii pneumonia (6.5%). One case of death by measles confirmed by autopsy was also noted. Overall, cumulative mortality was 43% (104/242), and 59.6% of these deaths (62/104) were infection-related. Allogeneic HSCT recipients from unrelated donors were prone to infectious complication and higher mortality than those from matched sibling (17/39 (43.6%) vs 45/203 (22.2%), respectively; P<0.01; odd ratio 2.5; 95% confidence interval 1.2-5.1). As infection was the main post-HSCT complication in our data, more attention should be given to the management of infections in HSCT recipients.

Late cytomegalovirus disease with atypical presentation in renal transplant patients: Case reports

Cytomegalovirus (CMV) disease typically occurs 1 to 4 months (median 35 days) after solid organ transplantation. Recent reports documented that the natural history of CMV disease associated with solid organ transplantation has been modified as a result of the widespread use of potent immunosuppressents and antiviral prophylaxis. We herein report three pretransplant CMV seropositive recipients (with unknown donor status) who were diagnosed recently to display late and atypical CMV disease. Two men and one woman included two patients who presented with allograft dysfunction at 12 years and at 3 years after transplantation. Both patients showed increased serum creatinine approximately from baseline 200 to >400 micromol/L over 3 months in the absence of features of rejection or cyclosporine toxicity. A renal biopsy was refused by both patients. Two of the three patients presented with symptoms of enterocolitis (diarrhea, nausea, weight loss), which had persisted for more than 6 months. Other symptoms and signs of overt CMV disease (fever, leukopenia) were absent. None had pulmonary, hepatic, or other major organ involvement. In all patients IgG antibodies and CMV DNA by polymerase chain reaction were positive with negative IgM antibodies. The immunosuppressive regimen consisted of mycophenolate mofetil (MMF), steroids, and calcineurin inhibitors. The kidney function significantly improved in both patients with renal dysfunction. Gastrointestinal symptoms resolved completely with gradual weight gain. The recognition and early diagnosis of late atypical CMV disease in kidney transplant patients presenting with allograft dysfunction and/or other organ systems is important. The MMF has a red herring effect in our cases due to its GI side effects.

Recent advances in the prevention of CMV infection and disease after hematopoietic stem cell transplantation

Cytomegalovirus (CMV) remains an important pathogen in hematopoietic stem cell transplant (HCT) recipients in the current era of antiviral prophylaxis and preemptive therapy, despite the almost complete elimination of CMV disease during the first 3 months after transplantation. Pretransplant CMV serostatus of the donor and/or recipient remains an important risk factor for poor post-transplant outcome, especially in highly immunodeficient patients (e.g. recipients of ex vivo or in vivo T-cell depletion). Prevention of late CMV disease continues to be a challenge in selected high-risk populations, and indirect immunomodulatory effects of CMV (e.g. invasive bacterial and fungal infections) appear to contribute to the poor outcome. The risk of developing antiviral resistance remains low in most patients; however, in a setting of intense immunosuppression (e.g. after transplantation from a haploidentical donor) the incidence may be as high as 8%. Transfusion-transmitted CMV infection can be reduced by the provision of seronegative or leukocyte-depleted blood products; however, a small risk of 1-2% of CMV disease remains. Surveillance and preemptive therapy is effective in preventing transfusion-related CMV disease. The development of new drugs and immunologic strategies (adoptive transfer of CMV-specific T-cells and donor/recipient vaccination strategies) are important goals for the elimination of the negative impact of CMV in the HCT setting.

Cytomegalovirus antigenemia and outcome of patients treated with pre-emptive ganciclovir: retrospective analysis of 241 consecutive patients undergoing allogeneic hematopoietic stem cell transplantation

CMV disease remains a major infectious complication after allogeneic hematopoietic stem cell transplantation (HSCT). To investigate the relationship between CMV antigenemia, treatment with ganciclovir (GCV), and outcome, we retrospectively analyzed 241 consecutive patients at risk for CMV infection who underwent allogeneic HSCT. Antigenemia-guided pre-emptive strategy with GCV was used for all patients. CMV antigenemia developed in 169 patients (70.1%), and CMV disease in 18 patients (7.5%). Multivariate analysis showed that acute GVHD (grades II-IV) was the only risk factor for developing antigenemia, and acute GVHD and advanced age for CMV disease. GCV use, as well as acute GVHD and advanced age, significantly increased the risk for bacterial and fungal infection after engraftment. Those who developed CMV antigenemia had a poorer outcome than those who did not (log-rank, P=0.0269), although the development of CMV disease worsened the outcome with only borderline significance (log-rank, P=0.0526). In conclusion, detection of antigenemia proved to be a poor prognostic factor for HSCT patients, which may be attributed to a combination of factors, including CMV disease itself, the effect of treatment, and a host status that allows for reactivation of CMV. Optimal pre-emptive strategy needs to be determined.

Cytomegalovirus infection after bone marrow transplantation in children

Cytomegalovirus (CMV) is a well-known cause of disease occurring after bone marrow transplantation (BMT). The manifestations of CMV range from asymptomatic infection, defined as active CMV replication in the blood in the absence of clinical manifestations or organ failure abnormalities, to CMV disease, characterized by CMV infection with clinical symptoms or organ function abnormalities. Diagnostic procedures to assess the viral load have improved greatly with the increased use of antigenemia, CMV DNA, and immediate early-messenger RNA. Many conditions concur in determining the risk of developing CMV reactivation or disease after bone marrow transplant with serologic status of donor and recipient, type of bone marrow transplant, presence of graft-versus-host disease being the most studied. However, time and quality of immune reconstitution seems to be the pivotal factors. Pneumonia and gastrointestinal involvement are the most frequently documented clinical pictures with late-onset CMV reactivation or disease representing a new challenge. CMV prophylaxis or pre-emptive therapy adopted during the last few years in allogeneic BMT recipients has changed the natural history of the disease, reducing the risk of CMV disease, CMV-associated death, transplant-related mortality, and has prolonged the period at risk. Specific studies on children are lacking, however, the clinical pictures and features seems to be similar both in children and adults.

Pulmonary complications of solid organ and hematopoietic stem cell transplantation

The ability to successfully transplant solid organs and hematopoietic stem cells represents one of the landmark medical achievements of the twentieth century. Solid organ transplantation has emerged as the standard of care for select patients with severe vital organ dysfunction and hematopoietic stem cell transplantation has become an important treatment option for patients with a wide spectrum of nonmalignant and malignant hematologic disorders, genetic disorders, and solid tumors. Although advances in surgical techniques, immunosuppressive management, and prophylaxis and treatment of infectious diseases have made long-term survival an achievable goal, transplant recipients remain at high risk for developing a myriad of serious and often life-threatening complications. Paramount among these are pulmonary complications, which arise as a consequence of the immunosuppressed status of the recipient as well as from such factors as the initial surgical insult of organ transplantation, the chemotherapy and radiation conditioning regimens that precede hematopoietic stem cell transplantation, and alloimmune mechanisms mediating host-versus-graft and graft-versus-host responses. As the population of transplant recipients continues to grow and as their care progressively shifts from the university hospital to the community setting, knowledge of the pulmonary complications of transplantation is increasingly germane to the contemporary practice of pulmonary medicine.

Allogeneic T cells treated with amotosalen prevent lethal cytomegalovirus disease without producing graft-versus-host disease following bone marrow transplantation

Infusion of donor antiviral T cells can provide protective immunity for recipients of hemopoietic progenitor cell transplants, but may cause graft-vs-host disease (GVHD). Current methods of separating antiviral T cells from the alloreactive T cells that produce GVHD are neither routine nor rapid. In a model of lethal murine CMV (MCMV) infection following MHC-mismatched bone marrow transplantation, infusion of MCMV-immune donor lymphocytes pretreated with the DNA cross-linking compound amotosalen prevented MCMV lethality without producing GVHD. Although 95% of mice receiving 30 x 10(6) pretreated donor lymphocytes survived beyond day +100 without MCMV disease or GVHD, all mice receiving equivalent numbers of untreated lymphocytes rapidly died of GVHD. In vitro, amotosalen blocked T cell proliferation without suppressing MCMV peptide-induced IFN-gamma production by MCMV-primed CD8(+) T cells. In vivo, pretreated lymphocytes reduced hepatic MCMV load by 4-log(10) and promoted full hemopoietic chimerism. Amotosalen-treated, MCMV tetramer-positive memory (CD44(high)) CD8(+) T cells persisted to day +100 following infusion, and expressed IFN-gamma when presented with viral peptide. Pretreated T cells were effective at preventing MCMV lethality over a wide range of concentrations. Thus, amotosalen treatment rapidly eliminates the GVHD activity of polyclonal T cells, while preserving long-term antiviral and graft facilitation effects, and may be clinically useful for routine adoptive immunotherapy.

Adoptive immunotherapy for posttransplantation viral infections

Viral diseases are a major cause of morbidity and mortality after hemopoietic stem cell transplantation. Because viral complications in these patients are clearly associated with the lack of recovery of virus-specific cellular immune responses, reconstitution of the host with in vitro expanded cytotoxic T lymphocytes is a potential approach to prevent and treat these diseases. Initial clinical studies of cytomegalovirus and Epstein-Barr virus in human stem cell transplant patients have shown that adoptively transferred donor-derived virus-specific T cells may restore protective immunity and control established infections. Preclinical studies are evaluating this approach for other viruses while strategies for generating T cells specific for multiple viruses to provide broader protection are being evaluated in clinical trials. The use of genetically modified T cells or the use of newer suicide genes may result in improved safety and efficacy.

Infectious complications following nonmyeloablative allogeneic hematopoietic stem cell transplantation

Nonmyeloablative hematopoietic stem cell transplantation (NST) has been explored in hematological malignancies and solid tumors in an attempt to minimize treatment-related toxicity. Whether this approach is associated with reduced risk of infectious complications is unclear. The aim of the current study was to evaluate the infectious complications in a series of 32 consecutive adult patients who received NST at our institution. Peripheral blood stem cell grafts (n=30) or marrow grafts (n=2) were infused from human leukocyte antibody (HLA)-matched sibling (n=30), partially matched related (n=1), or unrelated (n=1) donors. Neutropenia developed in two-thirds of patients and lasted 16 days. Acute graft-versus-host disease (GVHD) grade II to IV was observed in 25% of patients, whereas 35% of patients had signs of extensive chronic GVHD. Twenty-two patients (69%) had at least one significant infectious episode. Bacteremia occurred in 19% of patients (n=5 gram-positive, n=1 gram-negative microorganisms). Cytomegalovirus (CMV) infection was observed in 10 out of 28 (36%) evaluable patients; 4 of these had recurrent or persistent CMV antigenemia requiring a second-line treatment, but eventually the viremia cleared. No patients experienced CMV disease. Fungal infections were documented in five (16%) patients, comprising invasive fungal infections in two cases and mucosal fungal infections in three. Four patients died of transplant-related causes, and three of these died before day +100. Infection was considered the primary cause of death in one patient (pulmonary aspergillosis) and contributed to death in another two. The actuarial probability of nonrelapse mortality at 100 days was 10% (95% confidence interval, 3-26%). Our preliminary results suggest that NST is associated to a low incidence of bacteremia or fungal and viral infections. Whether these findings would translate into an improved overall survival needs to be confirmed in larger prospective studies.

Incidence, risk factors, and mortality from pneumonia developing late after hematopoietic stem cell transplantation

The incidence, etiology, outcome, and risk factors for developing pneumonia late after hematopoietic stem cell transplantation (SCT) were investigated in 1359 patients transplanted in Seattle. A total of 341 patients (25% of the cohort) developed at least one pneumonic episode. No microbial or tissue diagnosis (ie clinical pneumonia) was established in 197 patients (58% of first pneumonia cases). Among the remaining 144 patients, established etiologies included 33 viral (10%), 31 bacterial (9%), 25 idiopathic pneumonia syndrome (IPS, 7%), 20 multiple organisms (6%), 19 fungal (6%), and 16 Pneumocystis carinii pneumonia (PCP) (5%). The overall cumulative incidence of first pneumonia at 4 years after discharge home was 31%. The cumulative incidences of pneumonia according to donor type at 1 and 4 years after discharge home were 13 and 18% (autologous/syngeneic), 22 and 34% (HLA-matched related), and 26 and 39% (mismatched related/unrelated), respectively. Multivariate analysis of factors associated with development of late pneumonia after allografting were increasing patient age (RR 0.5 for <20 years, 1.2 for >40 years, P=0.009), donor HLA-mismatch (RR 1.6 for unrelated/mismatched related, P=0.01), and chronic graft-versus-host disease (GVHD; RR 1.5, P=0.007). Our data suggest that extension of PCP prophylaxis may be beneficial in high-risk autograft recipients. Further study of long-term anti-infective prophylaxis based on patient risk factors after SCT appear warranted.