Sangeeta Bhorade

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. Diagnosis of BOS requires careful exclusion of other complications that can cause delayed lung allograft dysfunction http://ow.ly/AZmbr

Analysis and Characterization of Antiviral Drug–Resistant Cytomegalovirus Isolates from Solid Organ Transplant Recipients

The development of cytomegalovirus (CMV) disease and subsequent emergence of drug-resistant strains was examined in a large group of solid organ transplant recipients; drug-resistant CMV was detected in a total of 30 transplant recipients (20 lung, 5 kidney, 4 heart, and 1 liver). Drug resistance was confirmed both phenotypically and genotypically. The sequences of drug-resistant CMV strains from the same patient differed from drug-susceptible baseline sequences only at single sites previously confirmed to confer drug resistance. At least 1 isolate from each patient had a mutation in the UL97 phosphotransferase coding sequence. Mutations in the DNA polymerase gene were found in 6 of 38 sequenced strains. Lung transplant recipients had the highest incidence of drug-resistant virus: of the 30 patients, 28 were CMV-seronegative transplant recipients of CMV-seropositive organs, which strongly supports the premise that drug resistance is most prevalent in that transplant population.

Obesity and Primary Graft Dysfunction after Lung Transplantation: The Lung Transplant Outcomes Group Obesity Study

RATIONALE Obesity has been linked to acute lung injury and is a risk factor for early mortality after lung transplantation. OBJECTIVES To examine the associations of obesity and plasma adipokines with the risk of primary graft dysfunction after lung transplantation. METHODS We performed a prospective cohort study of 512 adult lung transplant recipients with chronic obstructive pulmonary disease or interstitial lung disease enrolled in the Lung Transplant Outcomes Group Study. In a nested case-control study, we measured plasma leptin, adiponectin, and resistin before lung transplantation and 6 and 24 hours after lung transplantation in 40 cases of primary graft dysfunction and 80 control subjects. Generalized linear mixed models and logistic regression were used to estimate risk ratios and odds ratios. MEASUREMENTS AND MAIN RESULTS Grade 3 primary graft dysfunction developed within 72 hours of transplantation in 29% participants. Obesity was associated with a twofold increased risk of primary graft dysfunction (adjusted risk ratio 2.1; 95% confidence interval, 1.7-2.6). The risk of primary graft dysfunction increased by 40% (confidence interval, 30–50%) for each 5 kg/m(2) increase in body mass index after accounting for center, diagnosis, cardiopulmonary bypass, and transplant procedure. Higher plasma leptin levels were associated with a greater risk of primary graft dysfunction (sex-adjusted P = 0.02). The associations of both obesity and leptin with primary graft dysfunction tended to be stronger among those who did not undergo cardiopulmonary bypass. CONCLUSIONS Obesity is an independent risk factor for primary graft dysfunction after lung transplantation.

Emergence of ganciclovir-resistant cytomegalovirus in lung transplant recipients.

BACKGROUND Since ganciclovir-resistant cytomegalovirus (CMV) disease was initially described in a patient with acquired immunodeficiency syndrome (AIDS) in 1986, the incidence of ganciclovir-resistant CMV disease appears to be increasing in immunocompromised patients. More recently, there have been sporadic reports of ganciclovir-resistant CMV disease in solid organ transplantation. METHODS We retrospectively assessed the incidence of ganciclovir-resistant CMV disease in all lung transplant recipients transplanted between 6/93 and 6/01 at Loyola University Medical Center. All patients underwent routine CMV blood culture, shell vial assay as well as phenotypic and genotypic anti-viral susceptibility testing according to a pre-determined schedule. The number of CMV episodes, intravenous ganciclovir use, acute and chronic rejection and survival data were documented for all patients. RESULTS Twelve of 212 (6%) transplant recipients developed ganciclovir-resistant CMV disease. Ganciclovir resistance was associated with a higher number of CMV episodes (3.4 +/- 2.3 episodes/patient vs 1.7 +/- 0.7 episodes/patient [p < 0.05]) and an increased exposure to cumulative intravenous ganciclovir in the primary CMV-mismatched (D(+)R(-)) population (22 +/- 10 vs 13 +/- 7 days [p < 0.05]) compared with patients who did not develop ganciclovir resistance. In addition, the use of daclizumab therapy was associated with a 7-fold greater likelihood of developing ganciclovir resistance (p < 0.0001). The presence of ganciclovir-resistant CMV disease in our population was associated with a decreased survival that could be attributed to CMV disease itself (p < 0.05). CONCLUSIONS By screening all lung transplant recipients with CMV disease for ganciclovir resistance, we were able to detect a higher incidence of ganciclovir-resistant CMV disease (6%) than previously seen in solid organ transplantation. High-risk patients (D(+)R(-) CMV serostatus) who receive anti-lymphocytic therapy should be monitored aggressively and treated to prevent the development of ganciclovir resistance and avert a negative outcome.

Critical Role of Serum Response Factor in Pulmonary Myofibroblast Differentiation Induced by TGF-β

Transforming growth factor-beta (TGF-beta) is a cytokine implicated in wound healing and in the pathogenesis of pulmonary fibrosis. TGF-beta stimulates myofibroblast differentiation characterized by expression of contractile smooth muscle (SM)-specific proteins such as SM-alpha-actin. In the present study, we examined the role of serum response factor (SRF) in the mechanism of TGF-beta-induced pulmonary myofibroblast differentiation of human lung fibroblasts (HLF). TGF-beta stimulated SM-alpha-actin expression in HLF, which paralleled with a profound induction of SRF expression and activity. Inhibition of SRF by the pharmacologic SRF inhibitor (CCG-1423), or via adenovirus-mediated transduction of SRF short hairpin RNA (shSRF), blocked the expression of both SRF and SM-alpha-actin in response to TGF-beta without affecting Smad-mediated signaling of TGF-beta. However, forced expression of SRF on its own did not promote SM-alpha-actin expression, whereas expression of the constitutively transactivated SRF fusion protein (SRF-VP16) was sufficient to induce SM-alpha-actin expression, suggesting that both expression and transactivation of SRF are important. Activation of protein kinase A (PKA) by forskolin or iloprost resulted in a significant inhibition of SM-alpha-actin expression induced by TGF-beta, and this was associated with inhibition of both SRF expression and activity, but not of Smad-mediated gene transcription. In summary, this is the first direct demonstration that TGF-beta-induced pulmonary myofibroblast differentiation is mediated by SRF, and that inhibition of myofibroblast differentiation by PKA occurs through down-regulation of SRF expression levels and SRF activity, independent of Smad signaling.

Immunosuppression for lung transplantation

Immunosuppression remains the mainstay of therapy for successful outcomes after lung transplantation. The need for optimal immunosuppression became evident to maintain long-term graft survival and to navigate the delicate balance between infection and rejection. Over the past two decades, immunosuppression for solid organ transplantation has evolved to target multiple immune pathways with the hope of decreasing both acute and chronic allograft rejection. Although current maintenance therapy after lung transplantation typically includes a calcineurin inhibitor, antimetabolite and corticosteroid therapy, newer therapies including induction therapy with biological agents, mTOR inhibitors, and salvage therapies including photopheresis and total lymphoid irradiation have emerged as alternate therapeutic options. This review will discuss both the current immunosuppressive medications that are used as well as different therapeutic combinations that are currently employed. In addition, we will discuss the current literature regarding the efficacy of these agents in lung transplantation.

Cylex ImmuKnow assay levels are lower in lung transplant recipients with infection.

BACKGROUND Current monitoring systems of immunosuppression in solid-organ transplant recipients are typically focused on prevention of clinical toxicities of immunosuppressive drugs. Unfortunately, these strategies are often not tailored to the individual and do not determine the optimal level of immunosuppression for these patients. Recently, the Cylex Immune Cell Function Assay (ImmuKnow; Cylex, Inc., Columbia, MD) was approved by the U.S. Food and Drug Administration (FDA) to measure global immune response in solid-organ transplant patients receiving immunosuppressive therapy. We sought to identify the level of functional immunity as measured by the ImmuKnow assay in lung transplant recipients and to correlate these values with the dose and trough levels of immunosuppression as well as other clinical parameters in lung transplant recipients. METHODS We assessed the functional immune response by the ImmuKnow assay in 143 sequential blood samples from 57 lung transplant recipients from Loyola University Medical Center. RESULTS The average ImmuKnow assay in stable lung transplant recipients was 244 +/- 138 adenosine triphosphate (ATP) ng/ml and the median level was 236 ATP ng/ml (range 5 to 669 ATP ng/ml), approximately 703 +/- 695 days after lung transplantation. There was no correlation between ImmuKnow levels and tacrolimus trough levels. Stepwise multiple regression analysis identified African American race as an independent predictor of ImmuKnow assay levels when age, gender and underlying diagnosis were taken into account (p < 0.04). Fifteen infected lung transplant recipients had a lower ImmuKnow level at the time of their infections as compared with stable lung transplant recipients (111 +/- 83 vs 283 +/- 143 ATP ng/ml, respectively, p = 0.0001). Sixteen of the remaining 42 patients had low ImmuKnow assay values (<225 ATP ng/ml), but did not have active infection. There were only 2 patients with acute rejection of Grade A1 in this cohort. There were no identifiable associations of the ImmuKnow level with either acute rejection episode. CONCLUSIONS The Cylex ImmuKnow assay levels were lower in infected lung transplant recipients compared with non-infected recipients and increased with treatment of these infections. It remains unclear whether the ImmuKnow assay reflects over-immunosuppressed individuals at risk of infection or bone marrow suppression by infectious agents. Further investigation will determine the role of the ImmuKnow assay in tailoring immunosuppression in lung transplant recipients.

Monocyte-derived alveolar macrophages drive lung fibrosis and persist in the lung over the life span.

Little is known about the relative importance of monocyte and tissue-resident macrophages in the development of lung fibrosis. We show that specific genetic deletion of monocyte-derived alveolar macrophages after their recruitment to the lung ameliorated lung fibrosis, whereas tissue-resident alveolar macrophages did not contribute to fibrosis. Using transcriptomic profiling of flow-sorted cells, we found that monocyte to alveolar macrophage differentiation unfolds continuously over the course of fibrosis and its resolution. During the fibrotic phase, monocyte-derived alveolar macrophages differ significantly from tissue-resident alveolar macrophages in their expression of profibrotic genes. A population of monocyte-derived alveolar macrophages persisted in the lung for one year after the resolution of fibrosis, where they became increasingly similar to tissue-resident alveolar macrophages. Human homologues of profibrotic genes expressed by mouse monocyte-derived alveolar macrophages during fibrosis were up-regulated in human alveolar macrophages from fibrotic compared with normal lungs. Our findings suggest that selectively targeting alveolar macrophage differentiation within the lung may ameliorate fibrosis without the adverse consequences associated with global monocyte or tissue-resident alveolar macrophage depletion.

Low rate of acute lung allograft rejection after the use of daclizumab, an interleukin 2 receptor antibody.

Background. The incidence and the severity of acute lung allograft rejection has been linked to the development of bronchiolitis obliterans syndrome. Therefore, we investigated the effects of daclizumab, a humanized monoclonal antibody directed against the alpha subunit of the interleukin 2 receptor, in reducing acute rejection after transplantation. Methods. We retrospectively evaluated 27 patients who received daclizumab as induction immunosuppression and compared them with a historical control group of 34 patients. Both groups received similar immunosuppressive regimens involving tacrolimus, prednisone, and either azathioprine or mycophenolate mofetil. All patients received cytomegalovirus and aspergillus prophylaxis. Results. Twenty-one patients in the control group and 22 patients in the daclizumab group were available for analysis at 6 months after lung transplantation. Ten (48%) patients in the control group had at least grade 2 acute rejection compared with four (18%) in the daclizumab group (P <0.04). The incidence of infection was similar in both groups. One patient in each group developed posttransplant lymphoproliferative disease. Conclusion. Therapy with daclizumab resulted in a significant decrease in the incidence of grade 2 or greater acute rejection after lung transplantation compared with historical controls. There seems to be no increase in the incidence of adverse effects in the patients treated with daclizumab.

Decreased percentage of CD4+FoxP3+ cells in bronchoalveolar lavage from lung transplant recipients correlates with development of bronchiolitis obliterans syndrome.

Background. Lung transplantation, in patients with end-stage lung disease, is limited by chronic rejection, which occurs with an incidence and severity exceeding most other transplanted organs. Alloimmune responses play an important role in progression to chronic rejection that manifests as bronchiolitis obliterans syndrome (BOS), but no biomarker can currently predict the progression to BOS. Studies in animal models suggest that intragraft T regulatory cells (Tregs) are important in maintaining transplantation tolerance, and FoxP3 is the protoypic Treg marker. Methods. Leukocytes in blood and bronchoalveolar lavage (BAL) fluid were compared for expression of FoxP3 by flow cytometry in 14 stable lung transplant recipients and 6 lung transplant recipients who eventually developed BOS. Results. Stable patients, compared with patients who subsequently developed BOS, consistently had a significantly increased percentage of FoxP3+ cells among CD4+ cells in BAL and greater levels of the Treg-attracting chemokine CCL22. These differences were observed in limited sequential analyses, before, at the time of acute rejection, and postacute rejection. In this pilot study, a threshold of 3.2% CD4+/FoxP3+ cells in the BAL distinguished stable recipients from those subsequently developing BOS within the first 2 years posttransplantation. Conclusion. The proportion of FoxP3+ cells among CD4+ cells in BAL may help to predict lung allograft outcome and guide therapeutic immunosuppression in lung transplant recipients.