Detection of Epstein–Barr virus DNA in peripheral blood is associated with the development of bronchiolitis obliterans syndrome after lung transplantation

Screening and Management of PTLD

Posttransplant lymphoproliferative disorder (PTLD) represents a heterogeneous group of lymphoproliferative diseases occurring in the setting of immunosuppression following hematopoietic stem cells transplant and solid organ transplantation. Despite its overall low incidence, PTLD is a serious complication following transplantation, with a mortality rate as high as 50% in transplant recipients. Therefore, it is important to establish for each transplant recipient a personalized risk evaluation for the development of PTLD based on the determination of Epstein-Barr virus serostatus and viral load following the initiation of immunosuppression. Due to the dynamic progression of PTLD, reflected in the diverse pathological features, different therapeutic approaches have been used to treat this disorder. Moreover, new therapeutic strategies based on the administration of virus-specific cytotoxic T cells have been developed. In this review, we summarize the available data on screening and treatment to suggest a strategy to identify transplant recipients at a higher risk for PTLD development and to review the current therapeutic options for PTLD.

Evaluation of host cellular responses to Epstein-Barr virus (EBV) in adult lung transplant patients with EBV-associated diseases

Epstein-Barr virus (EBV) reactivation is commonly observed in lung transplant recipients (LTRs). However, cellular immune responses to EBV in adult LTRs have not been well described. We aimed to study CD4/CD8 ratio, EBV-specific T cells polyfunctional responses and phenotypic changes in natural killer (NK) cells in adult LTRs presenting with EBV-associated diseases. The CD4/CD8 ratio was significantly decreased in LTRs with EBV DNAemia compared with LTRs without EBV DNAemia and healthy controls (HCs). Stimulation with EBV lytic antigen BZLF1 peptide pools induced significant individual and polyfunctional responses from CD8+ CD69+ T cells. Frequencies of CD8+ CD69+ T cells expressing CD107a were significantly higher in LTRs without EBV DNAemia than in LTRs with DNAemia. Frequencies of CD8+ CD69+ T cells concurrently expressing CD107a, IFN-γ, and TNF-α were significantly greater in LTRs with and without EBV DNAemia than in HCs. Finally, BZLF1 induced significantly higher frequencies of CD8+ CD69+ T cells expressing CD107a and IFN-γ in LTRs without EBV DNAemia when compared with EBNA3B. Frequency of more differentiated CD56dim CD16pos NK cells was significantly decreased in LTRs with EBV DNAemia and PTLD compared with HCs. In conclusion, we noted the presence of significant changes in circulating cellular immune responses to EBV in adult LTRs.

Community-Acquired Respiratory Viruses Post-Lung Transplant

Survival in lung transplant recipients (LTRs) lags behind heart, liver, and kidney transplant, in part due to the direct and indirect effects of infection. LTRs have increased susceptibility to infection due to the combination of a graft continually exposed to the outside world, multiple mechanisms for impaired mucus clearance, and immunosuppression. Community-acquired respiratory viral infections (CARVs) are common in LTRs. Picornaviruses have roughly 40% cumulative incidence followed by respiratory syncytial virus and coronaviruses. Although single-center retrospective and prospective series implicate CARV in rejection and mortality, conclusive evidence for and well-defined mechanistic links to long-term outcome are lacking. Treatment of viral infections can be challenging except for influenza. Future studies are needed to develop better treatments and clarify the links between CARV and long-term outcomes.

Human cytomegalovirus multiple-strain infections and viral population diversity in haematopoietic stem cell transplant recipients analysed by high-throughput sequencing

Human cytomegalovirus (HCMV) is an important opportunistic pathogen in allogeneic haematopoietic stem cell transplant (HSCT) recipients. High-throughput sequencing of target-enriched libraries was performed to characterise the diversity of HCMV strains present in this high-risk group. Forty-four HCMV-DNA-positive plasma specimens (median viral input load 321 IU per library) collected at defined time points from 23 HSCT recipients within 80 days of transplantation were sequenced. The genotype distribution for 12 hypervariable HCMV genes and the number of HCMV strains present (i.e. single- vs. multiple-strain infection) were determined for 29 samples from 16 recipients. Multiple-strain infection was observed in seven of these 16 recipients, and five of these seven recipients had the donor (D)/recipient (R) HCMV-serostatus combination D + R + . A very broad range of genotypes was detected, with an intrahost composition that was generally stable over time. Multiple-strain infection was not associated with particular virological or clinical features, such as altered levels or duration of antigenaemia, development of acute graft-versus-host disease or increased mortality. In conclusion, despite relatively low viral plasma loads, a high frequency of multiple-strain HCMV infection and a high strain complexity were demonstrated in systematically collected clinical samples from this cohort early after HSCT. However, robust evaluation of the pathogenic role of intrahost viral diversity and multiple-strain infection will require studies enrolling larger numbers of recipients.

Viruses and atypical bacteria in the respiratory tract of immunocompromised and immunocompetent patients with airway infection

Respiratory tract infections (RTI) can take a serious course under immunosuppression. Data on the impact of the underlying pathogens are still controversial. Samples from the upper (n = 322) and lower RT (n = 169) were collected from 136 children and 355 adults; 225 among them have been immunocompromised patients. Exclusion criteria were presence of relevant cultivable microorganisms, C-reactive protein > 20 mg/dl, or procalcitonin > 2.0 ng/ml. Samples were tested by PCR for the presence of herpesviruses (HSV-1/-2; VZV; CMV; HHV6; EBV), adenoviruses, bocaviruses, entero-/rhinoviruses (HRV), parechoviruses, coronaviruses, influenza viruses (IV), parainfluenza viruses as well as for pneumoviruses (HMPV and RSV), and atypical bacteria (Mycoplasma pneumoniae, M.p.; Chlamydia pneumoniae, C.p.). Viral/bacterial genome equivalents were detected in more than two-thirds of specimens. Under immunosuppression, herpesviruses (EBV 30.9%/14.6%, p < 0.001; CMV 19.6%/7.9%, p < 0.001; HSV-1: 14.2%/7.1%, p = 0.012) were frequently observed, mainly through their reactivation in adults. Immunocompromised adults tended to present a higher RSV prevalence (6.4%/2.4%, p = 0.078). Immunocompetent patients were more frequently tested positive for IV (15.0%/5.8%, p = 0.001) and M.p. (6.4%/0.4%, p < 0.001), probably biased due to the influenza pandemic of 2009 and an M.p. epidemic in 2011. About 41.8% of samples were positive for a single pathogen, and among them EBV (19.9%) was most prevalent followed by HRV (18.2%) and IV (16.6%). HSV-2 and C.p. were not found. Marked seasonal effects were observed for HRV, IV, and RSV. Differences in pathogen prevalence were demonstrated between immunocompetent and immunocompromised patients. The exact contribution of some herpesviruses to the development of RTI remains unclear.

A Mini-Review of Adverse Lung Transplant Outcomes Associated With Respiratory Viruses

Due to their overall immunocompromised state, lung transplant recipients (LTRs) are at increased risk for the development of viral respiratory infections compared to the general population. Such respiratory infections often lead to poor transplant outcomes. We performed a systematic review of the last 30 years of medical literature to summarize the impact of specific respiratory viruses on LTRs. After screening 2,150 articles for potential inclusion, 39 manuscripts were chosen for final review. We found evidence for an association of respiratory viruses including respiratory syncytial virus (RSV), parainfluenza virus, and influenza viruses with increased morbidity following transplant. Through the literature search, we also documented associations of RSV and adenovirus infections with increased mortality among LTRs. We posit that the medical literature supports aggressive surveillance for respiratory viruses among this population.

Quantification of Torque Teno Virus and Epstein-Barr Virus Is of Limited Value for Predicting the Net State of Immunosuppression After Lung Transplantation

Background

Major hurdles for survival after lung transplantation are rejections and infectious complications. Adequate methods for monitoring immune suppression status are lacking. Here, we evaluated quantification of torque teno virus (TTV) and Epstein-Barr virus (EBV) as biomarkers for defining the net state of immunosuppression in lung-transplanted patients.

Methods

This prospective single-center study included 98 patients followed for 2 years after transplantation. Bacterial infections, fungal infections, viral respiratory infections (VRTI), cytomegalovirus (CMV) viremia, and acute rejections, as well as TTV and EBV levels, were monitored.

Results

The levels of torque teno virus DNA increased rapidly after transplantation, likely due to immunosuppressive treatment. A modest increase in levels of Epstein-Barr virus DNA was also observed after transplantation. There were no associations between either TTV or EBV and infectious events or acute rejection, respectively, during follow-up. When Tacrolimus was the main immunosuppressive treatment, TTV DNA levels were significantly elevated 6–24 months after transplantation as compared with Cyclosporine treatment.

Conclusions

Although replication of TTV, but not EBV, appears to reflect the functionality of the immune system, depending on the type of immunosuppressive treatment, quantification of TTV or EBV as biomarkers has limited potential for defining the net state of immune suppression.

Role of mTOR inhibitors for the control of viral infection in solid organ transplant recipients

Appropriate post-transplant immunosuppressive regimens that avoid acute rejection, while reducing risk of viral reactivation, have been sought, but remain a chimera. Recent evidence suggesting potential regulatory and antiviral effects of mammalian target of rapamycin inhibitors (mTORi) is of great interest. Although the concept of an immunosuppressive drug with antiviral properties is not new, little effort has been made to put the evidence together to assess the management of immunosuppressive therapy in the presence of a viral infection. This review was developed to gather the evidence on antiviral activity of the mTORi against the viruses that most commonly reactivate in adult solid organ recipients: cytomegalovirus (CMV), polyomavirus, Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), and hepatitis C virus (HCV). A rapid review methodology and evaluation of quality and consistency of evidence based on the GRADE system was used. The existing literature was variable in nature, although indicating a potential advantage of mTORi in CMV, polyomavirus, and HHV8 infection, and a most doubtful relation with EBV and HCV infection. Several recommendations about the management of these infections are presented that can change certain current patterns of immunosuppression and help to improve the prognosis of the direct and indirect effects of viral infection in solid organ recipients.

Posttransplant solid organ malignancies in lung transplant recipients: a single-center experience and review of the literature

PURPOSE

Solid-organ tumor incidences are higher in solid organ transplant patients than in the general population. The aim of this study was to analyze solid-organ tumor frequency and characteristics in a population of lung transplant patients and provide a brief review of the literature.

METHODS

A retrospective analysis was conducted of all patients who underwent a lung transplant in the Lung Transplant Program at the University Hospital of Siena, Italy, from 2001 to 2014 (n = 119). Patients' demographics, pretransplant characteristics, immunosuppressive therapy, and infectious factors were recorded.

RESULTS

Nine patients with a median age of 59.0 years (range 50-63) of our cohort developed a solid-organ tumor (7.5%). Most of the patients experienced nonmelanoma skin cancer (44.4%); the others were diagnosed with lung cancer (22.2%), breast cancer (22.2%), and colon-rectal cancer (11.2%). The median time from transplantation to tumor diagnosis was 895.0 days (range 321-2046). No differences in pretransplant characteristics, immunosuppressive therapy, or infectious factors were found between patients who developed solid organ tumors and those who did not.

CONCLUSIONS

The present study confirmed that de novo malignancies are a major issue in lung transplant patients; in particular, skin and lung cancers demonstrated a higher incidence rate. Oncologic treatment of these patients is complex, requiring close collaboration between the transplant team and oncologist. Strict screening programs are key factors for an early diagnosis and to allow for prompt treatment resulting in a better outcome.

Detection of Epstein-Barr virus DNAemia after lung transplantation and its potential relationship with the development of post-transplant complications

BACKGROUND

Recent studies suggest that Epstein-Barr virus DNAemia (EBVd) may act as a surrogate marker of post-transplant immunosuppression. This hypothesis has not been tested so far in lung transplant (LT) recipients.

METHODS

We included 63 patients undergoing lung transplantation at our center between October 2008 and May 2013. Whole blood EBVd was systematically assessed by real-time polymerase chain reaction assay on a quarterly basis. The occurrence of late complications (overall and opportunistic infection [OI] and chronic lung allograft dysfunction [CLAD]) was analyzed according to the detection of EBVd within the first 6 months post transplantation.

RESULTS

Any EBVd was detected in 30 (47.6%) patients. Peak EBVd was higher in patients with late overall infection (2.23 vs. 1.73 log10 copies/mL; P = 0.026) and late OI (2.39 vs. 1.74 log10 copies/mL; P = 0.004). The areas under receiver operating characteristic curves for predicting both events were 0.806 and 0.871 respectively. The presence of an EBVd ≥2 log10 copies/mL during the first 6 months post transplantation was associated with a higher risk of late OI (adjusted hazard ratio [aHR] 7.92; 95% confidence interval [CI] 2.10-29.85; P = 0.002). Patients with detectable EBVd during the first 6 months also had lower CLAD-free survival (P = 0.035), although this association did not remain statistically significant in the multivariate analysis (aHR 1.26; 95% CI 0.87-5.29; P = 0.099).

CONCLUSIONS

Although preliminary in nature, our results suggest that the detection of EBVd within the first 6 months after transplantation is associated with the subsequent occurrence of late OI in LT recipients.

Infectious Triggers of Chronic Lung Allograft Dysfunction

Survival after lung transplantation is limited in large part due to the high incidence of chronic rejection, known as chronic lung allograft dysfunction (CLAD). Pulmonary infections are a frequent complication in lung transplant recipients, due both to immunosuppressive medications and constant exposure of the lung allograft to the external environment via the airways. Infection is a recognized risk factor for the development of CLAD, and both acute infection and chronic lung allograft colonization with microorganisms increase the risk for CLAD. Acute infection by community acquired respiratory viruses, and the bacteria Pseudomonas aeruginosa and Staphylococcus aureus are increasingly recognized as important risk factors for CLAD. Colonization by the fungus Aspergillus may also augment the risk of CLAD. Fostering this transition from healthy lung to CLAD in each of these infectious episodes is the persistence of an inflammatory lung allograft environment.

Long-term impact of CMV infection on allografts and on patient survival in renal transplant patients with protocol biopsies

Cytomegalovirus (CMV) infection is a frequent complication of early posttransplantation. This study examines its impact on chronic allograft changes, long-term graft loss, and patient survival. We studied 594 patients who had protocol biopsies at 6 wk, and 3 and 6 mo posttransplantation. Chronic allograft changes were evaluated according to the updated Banff classification [interstitial fibrosis/tubular atrophy (IF/TA), vascular and glomerular lesions]. Follow-up data were available for up to 10 yr. CMV infection was diagnosed in 153 of 594 patients (26%) in the first year after transplantation, mostly within the first 3 mo. Graft survival was reduced in patients with CMV ( P = 0.03) as well as the combined allograft/patient survival ( P = 0.008). Prevalence of IF/TA at 6 wk after transplantation was already threefold higher in patients who experienced CMV infection later on compared with patients without CMV ( P = 0.005). In multivariate analyses, CMV viremia or disease was not a significant factor for graft loss or death. In conclusion, patients with CMV infection posttransplantation show more chronic allograft changes early on, even before CMV infection, and development of IF/TA is not more prevalent in patients with CMV. Our data do not support a significant role of CMV in patient and graft outcomes.

T-lymphocyte subsets in lung transplant recipients: association between nadir CD4 T-cell count and viral infections after transplantation

BACKGROUND

Little is known about the kinetics of T-cell subsets in lung transplant recipients (LTR) and their association with the occurrence of opportunistic infections (OI).

OBJECTIVES

To analyze the kinetics of T-lymphocyte subsets in LTR and the association between nadir CD4 T-cell count and viral infections after transplantation.

STUDY DESIGN

Serial measurements of peripheral blood CD4 and CD8 T-cell counts obtained during the first year post-transplantation from 83 consecutive LTR and their correlation with both viral OI and community-acquired infections post-transplantation were retrospectively analyzed.

RESULTS

LTR with a nadir CD4 T-cell count <200 cells/μl had consistently lower CD4 and CD8 T-cell counts than LTR with a nadir CD4 T-cell count >200 cells/μl (p<0.001). In LTR with a nadir CD4 T-cell count <200 cells/μl, the cumulative incidence of viral infections detected in peripheral blood and in bronchoalveolar lavage (BAL) samples was higher than in LTR with a nadir CD4 T-cell count >200 cells/μl (p=0.0012 and p=0.0058, respectively). A nadir CD4 T-cell count <200 cells/μl within the first three months post-transplantation predicted a higher frequency of viral infectious episodes in BAL samples within the subsequent six month period (p=0.0066).

CONCLUSIONS

Stratification of patients according to nadir CD4 T-cell count may represent a new and simple approach for early identification of patients at risk for subsequent virus infections.

The lung microbiome after lung transplantation

Lung transplantation survival remains significantly impacted by infections and the development of chronic rejection manifesting as bronchiolitis obliterans syndrome (BOS). Traditional microbiologic data has provided insight into the role of infections in BOS. Now, new non-culture-based techniques have been developed to characterize the entire population of microbes resident on the surfaces of the body, also known as the human microbiome. Early studies have identified that lung transplant patients have a different lung microbiome and have demonstrated the important finding that the transplant lung microbiome changes over time. Furthermore, both unique bacterial populations and longitudinal changes in the lung microbiome have now been suggested to play a role in the development of BOS. In the future, this technology will need to be combined with functional assays and assessment of the immune responses in the lung to help further explain the microbiome's role in the failing lung allograft.

An international ISHLT/ATS/ERS clinical practice guideline: diagnosis and management of bronchiolitis obliterans syndrome

Bronchiolitis obliterans syndrome (BOS) is a major complication of lung transplantation that is associated with poor survival. The International Society for Heart and Lung Transplantation, American Thoracic Society, and European Respiratory Society convened a committee of international experts to describe and/or provide recommendations for 1) the definition of BOS, 2) the risk factors for developing BOS, 3) the diagnosis of BOS, and 4) the management and prevention of BOS. A pragmatic evidence synthesis was performed to identify all unique citations related to BOS published from 1980 through to March, 2013. The expert committee discussed the available research evidence upon which the updated definition of BOS, identified risk factors and recommendations are based. The committee followed the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) approach to develop specific clinical recommendations. The term BOS should be used to describe a delayed allograft dysfunction with persistent decline in forced expiratory volume in 1 s that is not caused by other known and potentially reversible causes of post-transplant loss of lung function. The committee formulated specific recommendations about the use of systemic corticosteroids, cyclosporine, tacrolimus, azithromycin and about re-transplantation in patients with suspected and confirmed BOS. The diagnosis of BOS requires the careful exclusion of other post-transplant complications that can cause delayed lung allograft dysfunction, and several risk factors have been identified that have a significant association with the onset of BOS. Currently available therapies have not been proven to result in significant benefit in the prevention or treatment of BOS. Adequately designed and executed randomised controlled trials that properly measure and report all patient-important outcomes are needed to identify optimal therapies for established BOS and effective strategies for its prevention.

Detection of cytomegalovirus (CMV) by real-time PCR in fecal samples for the non-invasive diagnosis of CMV intestinal disease

BACKGROUND

Cytomegalovirus (CMV) infection of the gastrointestinal tract can cause CMV intestinal disease (CMV-ID), a severe complication in immunocompromised patients. Current gold standard for diagnosing CMV-ID requires the analysis of colon biopsies. Testing of fecal samples by CMV PCR might be a non-invasive diagnostic alternative, but data on this method is scarce.

OBJECTIVES

To evaluate the use of quantitative CMV real-time PCR in fecal samples for diagnosing CMV-ID.

STUDY DESIGN

Fecal samples and lower intestinal tract biopsies from 66 patients were analyzed by quantitative CMV PCR. To evaluate the diagnostic significance of CMV detection by PCR in fecal samples, patients were classified according to the etiology of their intestinal disease (based on results of endoscopy, histopathology and quantitative CMV DNA detection in biopsies) into three groups: "CMV-ID", "non-CMV-ID", and "equivocal".

RESULTS

10/66 fecal samples were tested positive by quantitative CMV PCR, but CMV DNA loads were low (range <1000-11,000copies/ml). CMV detection by PCR in fecal samples was positive in 8/12 patients of the CMV-ID group, resulting in a sensitivity of 67% for diagnosing CMV-ID. With two exceptions, fecal CMV PCR was negative in the non-CMV-ID group (45/47) indicating a good specificity (96%). Moreover, CMV DNA detection in feces was associated with high CMV DNA levels in intestinal biopsies.

CONCLUSIONS

Negative CMV PCR results from fecal samples cannot exclude CMV-ID and thus have to be confirmed by analyzing intestinal biopsies. However, positive fecal PCR results are diagnostically useful and might help to circumvent invasive diagnostic procedures as endoscopy.

Bronchiolitis Obliterans Syndrome and Chronic Lung Allograft Dysfunction: Evolving Concepts and Nomenclature

Bronchiolitis obliterans syndrome (BOS) eventually occurs in the majority of lung transplant recipients who survive beyond 1 year, can greatly impair quality of life, and is, directly or indirectly, the major cause of delayed allograft dysfunction and recipient death. A number of associated events or conditions are strongly associated with the risk for developing BOS; these include acute rejection, gastroesophageal reflux, infections, and autoimmune reactions that can occur in the setting of alloimmune responses to the lung allograft as recipients are given intense immunosuppression to prevent allograft rejection. The term chronic lung allograft dysfunction (CLAD) is being increasingly used to refer to recipients with late allograft dysfunction that meets the spirometric criteria for the diagnosis of BOS, but clinicians should recognize that such dysfunction can occur for a variety of reasons other than BOS. The recently identified entity of restrictive allograft syndrome, which is now recognized as a relatively distinct phenotype of CLAD, has features that differentiate it from classic obstructive BOS. A number of other entities that can also significantly affect allograft function must also be considered when significant allograft dysfunction is encountered following lung transplantation.

The Role of Infections in BOS

Background: Infectious agents, particularly cytomegalovirus (CMV), have long been considered to be potential triggers for BOS, although the exact magnitude of the role of infections and the mechanisms thereof remain an area of active research. Methods: This chapter will review previous literature and newer results concerning the possible roles of CMV, other herpesviruses, community-acquired respiratory viruses, bacteria (including Pseudomonas, other gram-negative, gram-positive, and atypical organisms), and fungi, including colonization as well as invasive infection. Results: The text reviews and evaluates the body of literature supporting a role for these infectious agents as risk factors for BOS and time to BOS. Changing patterns of infection over time are taken into account, and studies that have shown an association between BOS (or lack thereof) and CMV are reviewed. Strategies for prevention or early treatment of infections are discussed as potential means of preserving allograft function long term. Immunizations, stringent infection-control practices, and antimicrobial treatment including newer therapies will be discussed. Conclusion: In addition to the classic literature that has focused on CMV, an expanding spectrum of infectious organisms has been implicated as possible risk factors for BOS. Increasing knowledge of the impact of long-term antiviral suppression, prophylaxis, and outcomes of early therapy will help guide future recipient management.

Viremia after lung transplant: a cohort study on risk factors and symptoms associated with detection of Epstein-Barr virus

Background-The frequency and impact of detection of Epstein-Barr virus in the blood of lung and heart-lung transplant recipients in the postoperative period is poorly characterized.Objective-To investigate the frequency of virus detection, associated clinical symptoms and risk factors, and influence of virus detection on outcome.Methods-A cohort of 98 lung transplant recipients were monitored for Epstein-Barr virus in blood before transplant and during their posttransplant hospital stay (median 4 weeks, range 1-21 weeks). Patients were followed up for retransplant or death for a median of 17 months.Results-Epstein-Barr virus DNA was detected in 15 recipients (18.1%) before and in 39 recipients (41.5%) after transplant. Median viral load after transplant was 2300 copies per milliliter of blood (range, 900-45 000 copies/mL). Detection of Epstein-Barr virus DNA before transplant and mechanical ventilation before transplant were associated with detection of Epstein-Barr virus DNA after transplant. Shortness of breath, fatigue, and hoarseness were associated with detection of viral DNA after transplant. The incidence of retransplant or death was not increased in recipients who had viral DNA detected in their blood.Conclusions-Epstein-Barr virus DNA in the blood before transplant and mechanical ventilation before transplant were associated with detection of viral DNA after transplant. Detection of viral DNA after transplant was frequent and clinically relevant.

A review of bronchiolitis obliterans syndrome and therapeutic strategies

Lung transplantation is an important treatment option for patients with advanced lung disease. Survival rates for lung transplant recipients have improved; however, the major obstacle limiting better survival is bronchiolitis obliterans syndrome (BOS). In the last decade, survival after lung retransplantation has improved for transplant recipients with BOS. This manuscript reviews BOS along with the current therapeutic strategies, including recent outcomes for lung retransplantation.

Impact of CMV infection on acute rejection and long-term renal allograft function: a systematic analysis in patients with protocol biopsies and indicated biopsies

BACKGROUND

Higher rates of acute rejection (AR) and reduced graft survival have been reported in patients with cytomegalovirus (CMV) infection, but an association between these factors remains controversial.

METHODS

In this study, serial protocol biopsies (PBs) and clinically indicated biopsies (IBs) from a large cohort of renal allograft recipients (n &frac14; 594) were analyzed to examine the relation between CMV and AR.

RESULTS

Patients with CMV were more likely to receive IB (85 of the 153 patients; 56%) compared to patients without CMV (138 of 441 patients; 32%; P = 0.003). However, this did not translate into a greater number of patients with episodes of acute cellular rejection on histopathology in IBs. Analysis of PBs revealed a significantly higher number of episodes of rejection per patient with CMV infection (P = 0.04), but only in a subgroup of patients with triple immunosuppression. Long-term graft function post-transplantation was analyzed in four different subgroups according to CMV infection and/or AR. Differences in renal function were apparent within the first 6 weeks after transplantation and persisted during follow-up, with the best renal function in patients without AR or CMV, whereas patients with both AR and CMV had the worst (P < 0.012 at 1 year; P < 0.001 at 2 years). On average, the latter group had significantly older donors and more often delayed graft function.

CONCLUSIONS

Our data suggests that the link between CMV and AR is far less significant than previously thought. Outcome in patients with CMV may be more determined by coexisting conditions like high donor age and delayed graft function.

Herpesviruses detection by quantitative real-time polymerase chain reaction in bronchoalveolar lavage and transbronchial biopsy in lung transplant: viral infections and histopathological correlation

The monitoring of herpesvirus infection plays a central role in lung transplantation (LT). Herein we evaluated the prevalence of human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), human herpesvirus-7 (HHV-7), and Epstein-Barr Virus (EBV) DNA in bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB) specimens from LT patients. We associated the findings with the occurrence of interstitial pneumonia, acute rejection, or organizing pneumonia. Viral DNA was detected using real-time polymerase chain reaction (PCR) on 76 paired samples (BAL and TBB) from 27 patients who were receiving a universal combined prophylaxis (cytomegalovirus [CMV] immunoglobulin [Ig] + gancyclovir or valgancyclovir). Histopathological analysis was performed in accordance with the International Society for Heart and Lung Transplantation (ISHLT) criteria. Overall, HCMV results were positive in 25/76 (32.9%) specimens (BAL and/or TBB); HHV-6 in 16 (21.1%); HHV-7 in 40 (52.6%); and EBV in 13 (17.1%). Interstitial pneumonia was diagnosed in 6/76 (7.9%) cases: 5 (83.3%) were positive to HCMV (combined specimens; P < .0001); 5 (83.3%) to HHV-7; and 2 (33.3%) to EBV. An acute rejection episode was diagnosed in 19/76 (25%) cases: 7 (36.8%) were positive to HCMV; 5 (26.3%) to HHV-6; 10 (52.6%) to HHV-7, and 3 (15.8%) to EBV. No significant association was observed between virus detection or load and acute rejection. Organizing pneumonia was diagnosed in 4/76 (5.3%) cases: 1 (25%) positive to HCMV; 4 (100%) to HHV-6 (P < .05); 2 (50%) to HHV-7; and none to EBV. In conclusion, the prevalence of HCMV tended to be lower than that reported in the literature, confirming the importance of universal combined prophylaxis. HCMV was a relevant agent for interstitial pneumonia; although the small numbers limit the statistical analysis, our data did not support an association between herpesviruses and acute rejection episodes, whereas the role of HHV-6 in the pathogenesis of organizing pneumonia deserves further study. Viral detection on TBB could represent an adjunctive tool to complement that on BAL.

Epstein-Barr virus-associated pneumonia and bronchiolitis obliterans syndrome in a lung transplant recipient

We report the case of a 25-year-old lung and liver transplant recipient who developed respiratory failure. High levels of Epstein-Barr virus (EBV) genome copies were detectable in respiratory tract specimens, while the search for various other viral, bacterial or fungal pathogens remained empty. Post-transplant lymphoproliferative disease was excluded. Due to the rapid progression of respiratory insufficiency, a re-transplantation of the lung was performed. EBV-encoded small RNAs could be demonstrated by in situ hybridization within pneumocytes and lymphocytes of the explanted lung tissue. The clinical situation improved soon after re-transplantation, and the EBV load detected in the lower respiratory tract decreased significantly.

Changing trends in infectious disease in heart transplantation

BACKGROUND

During the past 25 years, advances in immunosuppression and the use of selective anti-microbial prophylaxis have progressively reduced the risk of infection after heart transplantation. This study presents a historical perspective of the changing trends of infectious disease after heart transplantation.

METHODS

Infectious complications in 4 representative eras of immunosuppression and anti-microbial prophylaxis were analyzed: (1) 38 in the pre-cyclosporine era (1978-1980), (2) 72 in the early cyclosporine era (1982-1984), where maintenance immunosuppression included high-dose cyclosporine and corticosteroid therapy; (3) 395 in the cyclosporine era (1988-1997), where maintenance immunosuppression included cyclosporine, azathioprine, and lower corticosteroid doses; and (4) 167 in the more recent era (2002-2005), where maintenance immunosuppression included cyclosporine and mycophenolate mofetil.

RESULTS

The overall incidence of infections decreased in the 4 cohorts from 3.35 episodes/patient to 2.03, 1.35, and 0.60 in the more recent cohorts (p < 0.001). Gram-positive bacteria are emerging as the predominant cause of bacterial infections (28.6%, 31.4%, 51.0%, 67.6%, p = 0.001). Cytomegalovirus infections have significantly decreased in incidence and occur later after transplantation (88 +/- 77 days, pre-cyclosporine era; 304 +/- 238 days, recent cohort; p < 0.001). Fungal infections also decreased, from an incidence of 0.29/patient in the pre-cyclosporine era to 0.08 in the most recent era. A major decrease in Pneumocystis jiroveci and Nocardia infections has also occurred.

CONCLUSIONS

The overall incidence and mortality associated with infections continues to decrease in heart transplantation and coincides with advances in immunosuppression, the use of selective anti-microbial prophylaxis, and more effective treatment regimens.

Quantification of cytomegalovirus DNA levels in intestinal biopsies as a diagnostic tool for CMV intestinal disease

BACKGROUND

CMV intestinal disease (CMV-ID) is a serious complication in immunocompromised patients and mainly diagnosed by clinical, endoscopic and histopathologic findings, whereas qualitative CMV-PCR in tissue samples is not recommended for diagnosis due to its low positive predictive value (PPV).

OBJECTIVES

To study the interpretation and diagnostic use of CMV-quantification by PCR in intestinal tissue biopsies to recognize CMV-ID. To develop cut-off intestinal CMV-loads attributing illness to CMV.

STUDY DESIGN

CMV-genome copies in 163 biopsies from the lower intestinal tract of immunocompromised patients were determined by quantitative real-time PCR, normalized to the cell number, and retrospectively compared to histopathological analysis, clinical findings and occurrence of CMV-antigenemia. Two cut-off intestinal CMV-loads, cut-off(histo) and cut-off(clin), were defined using histopathological or clinical criteria as gold standard, respectively.

RESULTS

CMV was detected in 32.5% of biopsies with a more than six log range of CMV-concentrations (1 x 10(-4)-1.4 x 10(2)copies/cell). Notably, biopsies with histopathologically or clinically confirmed CMV-ID had a significantly higher CMV-load (p<0.001). Cut-off(histo) and cut-off(clin) were defined at the intestinal CMV-load of 0.14 and 0.01 copies/cell, respectively, and improved the PPV. However, cut-off(histo) showed a decreased sensitivity for clinically defined CMV-ID cases. Interestingly, many patients with CMV-ID showed no concomitant CMV-antigenemia, suggesting a localized intestinal CMV-replication.

CONCLUSIONS

Quantification of CMV in intestinal biopsies is a useful diagnostic tool allowing the definition of cut-off values that can predict CMV-ID more accurate than qualitative PCR results. Further prospective studies have to clarify wether these cut-offs can improve diagnostics and treatment of CMV-ID in day-to-day clinical practice.