Gastroesophageal reflux as a reversible cause of allograft dysfunction after lung transplantation

Gastroesophageal reflux (GER) is increasingly recognized as contributing to a number of pulmonary disorders. The relationship of GER to pulmonary allograft dysfunction after lung transplantation is unknown. In this report, we describe a lung transplant recipient who developed an acute decline in pulmonary function several months after a retransplantation for chronic rejection. A pulmonary workup at that time, including bronchoscopy with biopsy, revealed bronchial inflammation with no allograft rejection or infection. Because of increasing GI symptoms after retransplantation, the patient also underwent additional testing, which revealed severe acid reflux. The treatment of this patient's acid reflux with Nissen fundoplication surgery resulted in a prompt and sustained improvement in his pulmonary function. We suggest that GER should be considered among the potential causes of allograft dysfunction after lung transplantation.     

Infection transmission among lung transplant couples

The risk of transmission of infections in partnerships between 2 transplant recipients is unknown. The aim of this study was to evaluate transmission in such couples. In this single‐center study, lung transplant (LTx) couples were identified among outpatients between 1988 and 2016. Infection rates per year and survival were compared to matched LTx‐recipients not living in a transplant partnership. Twelve transplant couples were analyzed with cumulative 65 years of relationship. Overall infections were similar between LTx‐couples and matched LTx‐patients. No significant differences were noted in bacterial infections (.12 vs .27 per year), community‐acquired viral (CARV) infections (.26 vs .22 per year), rejection treatments (.22 vs .12 per year), or hospitalizations (.26 vs .46 per year) in transplant couples and matched controls, respectively. There was no transmission of any microbial colonization from 1 partner to the other. Five cases of simultaneously detected CARV infections occurred (metapneumovirus [3], H1N1 [1], and respiratory syncytial virus [RSV; 1]). Three couples exhibited cytomegalovirus (CMV) reactivation in both partners at the same time with confirmed seronegativity before transplantation. In this case series of 12 lung transplant couples, the partnerships between 2 transplant recipients have no greater risk of bacterial infection and colonization transmission in comparison with recipients not living in a transplant relationship. However, transplant couples should be informed about the risk for transmission of viral infections, which could impact the development of chronic lung allograft dysfunction (CLAD).     

Lung transplant infection

Lung transplantation has become an accepted therapeutic procedure for the treatment of end‐stage pulmonary parenchymal and vascular disease. Despite improved survival rates over the decades, lung transplant recipients have lower survival rates than other solid organ transplant recipients. The morbidity and mortality following lung transplantation is largely due to infection‐ and rejection‐related complications. This article will review the common infections that develop in the lung transplant recipient, including the general risk factors for infection in this population, and the most frequent bacterial, viral, fungal and other less frequent opportunistic infections. The epidemiology, diagnosis, prophylaxis, treatment and outcomes for the different microbial pathogens will be reviewed. The effects of infection on lung transplant rejection will also be discussed.     

Donor‐transmitted parvovirus infection in a kidney transplant recipient presenting as pancytopenia and allograft dysfunction

Abstract: Parvovirus B19 is a nonenveloped single‐stranded DNA virus that commonly causes a benign childhood infection typically manifesting as a ‘slapped‐cheek’ rash. In immunodeficient hosts, this infection can cause persistent anemia and occasionally pancytopenia. Recently, direct renal involvement has been reported in renal transplant recipients leading to various forms of glomerulopathy and allograft dysfunction. Most cases are primary infections and are donor transmitted through the transplanted organ. Clinical and virological response to intravenous immunoglobulin (Ig) is usually excellent. We describe a case of donor‐transmitted parvovirus infection in a 23‐year‐old male who received his first cadaver renal transplant. The patient had an uncomplicated postoperative course with immediate graft function. Eight weeks after transplantation, he presented with fever, polyarthralgia, pancytopenia, and allograft dysfunction. Serological studies revealed elevated IgM titers against parvovirus B19. A renal biopsy was performed, which showed no evidence of acute rejection but with moderate degree of tubular damage. Parvovirus B19 viral DNA was detected in the renal tissue via polymerase chain reaction (PCR). The patient received a 10‐day course of intravenous Ig (400 mg/kg/day) with excellent response. His blood count normalized and the allograft improved to baseline function. The incidence of parvovirus infection in renal transplant patients is probably underestimated, because patients are not routinely screened for it and anemia and/or pancytopenia in these patients are often ascribed to immunosuppressive drugs. Because this infection is treatable, we conclude that parvovirus B19 infection should be actively considered in transplant patients presenting with pancytopenia and allograft dysfunction.     

Lung transplantation in IIP: A review

The idiopathic interstitial pneumonias (IIP) encompass a large and diverse subtype of interstitial lung disease (ILD) with idiopathic pulmonary fibrosis (IPF) and non‐specific interstitial pneumonia (NSIP) being the most common types. Although pharmacologic treatments are available for most types of IIP, many patients progress to advanced lung disease and require lung transplantation. Close monitoring with serial functional and radiographic tests for disease progression coupled with early referral for lung transplantation are of great importance in the management of patients with IIP. Both single and bilateral lung transplantation are acceptable procedures for IIP. Procedure selection is a complex decision influenced by multiple factors related to patient, donor and transplant centre. While single lung transplant may reduce waitlist time and mortality, the long‐term outcomes after bilateral lung transplantation may be slightly superior. There are numerous complications following lung transplantation including primary graft dysfunction, chronic lung allograft dysfunction (CLAD), infections, gastroesophageal reflux disease (GERD) and airway disease that limit post‐transplant longevity. The median survival after lung transplantation is 4.7 years in patients with ILD, which is less than in patients with other underlying lung diseases. Although long‐term survival is limited, this intervention still conveys a survival benefit and improved quality of life in suitable IIP patients with advanced lung disease and chronic hypoxemic respiratory failure.     

Lung transplantation in Hong Kong: 12 years of experience

Background and objective: A lung transplant programme was launched in August 1994 at Grantham Hospital in Hong Kong with the first single‐lung transplant performed in July 1995. A retrospective study was undertaken of all patients who had undergone lung transplantation and their outcomes analysed. Methods: Data were collected from hospital and outpatient records. Results: There were 12 transplants (two single‐lung and 10 double‐lung) performed in the 12 years to December 2006. No postoperative or early mortality was observed. In addition to the usual complications there were two cases of early pulmonary tuberculosis and one rare case of delayed fungal sternotomy infection. The 1‐year, 3‐year and 5‐year survival rates were 100%, 100% and 76.2%, respectively. All fatalities were related to the consequences of chronic rejection or its treatment. Conclusions: Despite the limited experience and the small case volume, the survival of patients was good and comparable with international experience.     

Immune mechanisms of lung allograft rejection

Extended survival after lung transplantation is primarily limited by progressive airflow obstruction and fibrotic obliteration of the small airways, termed bronchiolitis obliterans syndrome (BOS) and bronchiolitis obliterans (BO), respectively. BO is thought to represent the pulmonary-specific manifestation of chronic allograft rejection and the end result of a spectrum of different immunological insults to the allograft. Historically, research has focused on the adaptive immune system and its cellular-based rejection as the driving factor in the development of BO. Recent research in animal lung transplant models and human lung transplant recipients has identified that chemokines, humoral immunity, autoimmunity, and innate immunity also contribute to lung allograft rejection and BO. This review explores the complex immunological mechanisms that promote the high rate of pulmonary allograft failure and significantly impair survival after lung transplantation. We also identify areas for further research critical to improving transplant outcomes.     

Elevation of interleukin-15 protein expression in bronchoalveolar fluid in acute lung allograft rejection

BACKGROUND: Acute rejection remains a major source of morbidity in lung transplantation. Although interleukin (IL)-2 has been the principal T-cell growth factor implicated in acute rejection, IL-2 blockade does not prevent acute rejection completely. Recently, IL-15, a stromal cell-derived cytokine, has been found to share a similar biological function with IL-2. We hypothesized that IL-15 levels may be elevated in acute lung rejection in the presence of IL-2 blockade. METHODS: Acute allograft rejection developed in 21 of 42 lung transplant recipients. BAL fluid (BALF) was analyzed for IL-2 and IL-15 protein expression by standard enzyme-linked immunosorbent assay. RESULTS: The average (+/- SD) BALF IL-15 level was higher in lung transplant recipients with acute rejection compared to those without rejection (25 +/- 25 pg/mL vs 4.5 +/- 1.5 pg/mL, respectively; p < 0.0001). In addition, there appeared to be a bimodal distribution of BALF IL-15 levels in lung transplant recipients with acute rejection. BALF IL-2 levels were not associated with acute rejection. BALF IL-15 levels were not associated with bacterial, fungal, or cytomegalovirus infection. CONCLUSION: These data show that BALF IL-15 levels are elevated in acute lung allograft rejection in the presence of IL-2 receptor blockade and may be an important mediator for acute rejection in lung transplantation.     

Radionuclide imaging of acute lung transplant rejection with annexin V

STUDY OBJECTIVES: Early detection and treatment of lung transplant rejection is critical for preservation of pulmonary graft function. Damage to pulmonary allografts is mediated by apoptotic cell death induced by the alloreactive T lymphocytes that infiltrate lung grafts. Previous studies demonstrate that acute cardiac allograft rejection can be visualized using radiolabeled annexin V. This study was done to determine whether this technique could visualize acute rejection in a rodent model of unilateral orthotopic lung transplantation. DESIGN: Eighteen Sprague-Dawley ACI rats underwent removal of their left lung followed by orthotopic transplant of either an allogeneic (PVG, immunologically mismatched; N = 10) or a syngeneic (ACI, immunologically matched) pulmonary graft (N = 8). Animals were imaged 1 h after IV injection of 1 mCi (37.0 MBq) of (99m)Tc-annexin V 1 to 7 days after transplantation. RESULTS: Lungs receiving the allograft demonstrated moderate to marked mononuclear infiltration of the perivascular, interstitial, and peribronchial tissues. No mononuclear infiltrates were noted in the native right lungs nor in the syngeneic transplants. Region of interest image analysis revealed significant (p < 0.0005) increases of transplant to normal lung activity ratios 3 to 7 days after allograft surgery. The increased annexin V uptake in these lungs was confirmed at biodistribution assay (allograft 151% greater than isograft activity, p < 0.005). CONCLUSIONS: Acute experimental lung transplant rejection can be noninvasively identified using (99m)Tc-annexin V. Radiolabeled annexin V may be a clinically useful noninvasive screening tool for acute rejection.     

Respiratory Viruses in Solid Organ Transplant Recipients

Solid organ transplantation is often lifesaving, but does carry an increased risk of infection. Respiratory viral infections are one of the most prevalent infections, and are a cause of significant morbidity and mortality, especially among lung transplant recipients. There is also data to suggest an association with acute rejection and chronic lung allograft dysfunction in lung transplant recipients. Respiratory viral infections can appear at any time post-transplant and are usually acquired in the community. All respiratory viral infections share similar clinical manifestations and are all currently diagnosed using nucleic acid testing. Influenza has good treatment options and prevention strategies, although these are hampered by resistance to neuraminidase inhibitors and lower vaccine immunogenicity in the transplant population. Other respiratory viruses, unfortunately, have limited treatments and preventive methods. This review summarizes the epidemiology, clinical manifestations, therapies and preventive measures for clinically significant RNA and DNA respiratory viruses, with the exception of SARS-CoV-2. This area is fast evolving and hopefully the coming decades will bring us new antivirals, immunologic treatments and vaccines.     

Life in the allogeneic environment after lung transplantation

Because infection and rejection are the principal complications of any transplant procedure and because the alveolar macrophage is crucial to the defense of the lung from infection and may play a role in lung allograft rejection, we have begun to assess functions of this cell that are thought to be important in lung defense from infection and in transplant immunity. Antimicrobial functions include chemotaxis, which is a mechanism for recruiting macrophages to sites of inflammation and phagocytosis, and intracellular killing of microorganisms. As an accessory cell, the alveolar macrophage is necessary for an effective immune response to develop against either microorganisms or transplantation antigens. Our results indicate that the chemotactic, phagocytic but not the killing capability of alveolar macrophages from lung recipients is impaired. Alveolar macrophages and blood monocytes from lung recipients are also significantly impaired in their support for mitogen and antigen presentation to lymphocytes. Thus, the generation of an effective immune response to a microorganism may be impaired. Alveolar macrophages from lung recipients, however, function as well as those from normal subjects in stimulating lymphocyte proliferation in response to donor antigens (primed lymphocyte test) or unreleated allogeneic antigens (mixed lymphocyte reaction), while their respective blood monocytes function poorly in this regard. Our conclusions are that the antimicrobial functions of the alveolar macrophage are impaired after lung transplantation and this may be one mechanism to explain the unusual susceptibility of the lung allograft to infection. Those functions related to transplant immunity, however, are preserved and indicate that the alveolar macrophage may play a role in allograft rejection.     

Double lung transplantation in an HIV‐positive patient with Mycobacterium kansasii infection

Good outcomes with kidney and liver transplantation in HIV‐positive patients have led clinicians to recommend lung transplantation in HIV‐positive patients based on extrapolated data. Pre‐transplant mycobacterial infection is associated with an increased risk of developing new infection or aggravating existing infection, though it does not contraindicate transplantation in non‐HIV–infected patients. However, no data exists regarding the outcome of HIV‐positive patients with pre‐transplant mycobacterial infection. We report a case of double lung transplantation in a 50‐year‐old HIV‐positive patient with alpha‐1 antitrypsin deficiency. Prior to transplantation, Mycobacterium kansasii was isolated in one sputum culture and the patient was considered merely colonized as no clinical evidence of pulmonary or disseminated disease was present. The patient successfully underwent a double lung transplantation. Nontuberculous mycobacterial infection was diagnosed histologically on examination of native lungs. Surveillance and watchful waiting were chosen over treatment of the infection. HIV remained under control post‐transplantation with no AIDS‐defining illnesses throughout the follow‐up. A minimal acute rejection that responded to increased corticosteroids was reported. At 12 months post‐transplant, a bronchiolitis obliterans syndrome was diagnosed after a drop in FEV1. No evidence of isolation nor recurrence of nontuberculous mycobacteria was reported post‐transplantation. At 15 months post‐transplant, the patient remained stable with an FEV1 of 30%. The presence of pre‐transplant nontuberculous mycobacterial infection did not translate into recurrence of nontuberculous mycobacterial infection post‐transplant. Whether it contributed to bronchiolitis obliterans syndrome remains unknown.     

Adenovirus causing fever,upper respiratory infection,and allograft nephritis complicated by persistent asymptomatic viremia

A 20‐year‐old woman, with renal transplant complicated by recurrence of focal segmental glomerulosclerosis and post‐transplant lymphoproliferative disorder, presented nearly 2 years after transplantation with fever, conjunctivitis, and sinus congestion. She was found to have severe adenovirus (ADV)‐induced granulomatous interstitial nephritis, confirmed by immunohistochemical staining for ADV in the renal biopsy, without urinary symptoms, hematuria, or laboratory evidence of a change in allograft function. Fever, upper respiratory tract symptoms, and evidence of adenoviral infection in the allograft resolved with decreased immunosuppression and treatment with cidofovir and intravenous immunoglobulin. Creatinine rose during treatment and remained elevated, possibly related to cidofovir nephrotoxicity. Despite therapy and continued reduction in immunosuppression, asymptomatic low‐level viremia persisted for a year. In renal transplant patients with ADV infection, allograft involvement should be highly suspected even without overt urinary symptoms or laboratory evidence of allograft dysfunction. Demonstration of allograft involvement may prompt alternative management that could limit continued allograft infection. No clear recommendations exist for management of asymptomatic ADV viremia in solid organ transplant patients.     

Bacterial infections in lung transplantation

Lung transplantation has lower survival rates compared to other than other solid organ transplants (SOT) due to higher rates of infection and rejection-related complications, and bacterial infections (BI) are the most frequent infectious complications. Excess morbidity and mortality are not only a direct consequence of these BI, but so are subsequent loss of allograft tolerance, rejection, and chronic lung allograft dysfunction due to bronchiolitis obliterans syndrome (BOS). A wide variety of pathogens can cause infections in lung transplant recipients (LTRs), including a number of nosocomial pathogens and other multidrug-resistant (MDR) pathogens. Although pneumonia and intrathoracic infections predominate, LTRs are at risk of a number of types of infections. Risk factors include altered anatomy and function of airways, impaired immunity, the microbial flora of the donor and recipient, underlying medical conditions, and genetic factors. Further work on immune monitoring has the potential to improve outcomes. The infecting agents can be derived from the donor lung, pre-existing recipient flora, or acquired from the environment over time. Certain infections may preclude lung transplantation, but this varies from center to center, and more recent studies suggest fewer patients should be disqualified. New molecular methods allow microbiome studies of the lung, gut, and other sites that may further our knowledge of how airway colonization can result in infection and allograft loss. Surveillance, early diagnosis, and aggressive antimicrobial therapy of BI is critical in LTRs. Antibiotic resistance is a major barrier to successful management of these infections. The availability of new agents for MDR Gram-negatives may improve outcomes. Other new therapies, such as bacteriophage therapy, show promise for the future. Finally, it is important to prevent infections through peri-transplant prophylaxis, vaccination, and infection control measures.     

Lung retransplantation in the modern era

Chronic lung allograft dysfunction remains the leading cause of long-term morbidity and mortality for lung transplant recipients. Lung retransplantation currently represents the only therapeutic option for patients for refractory allograft dysfunction. However, debate remains regarding both the efficacy and ethicality of lung retransplantation in light of the shortage of lung allografts. The aim of this review is to discuss the available literature on lung retransplantation in the current era. Through this we hope to provide insight into ideal patient selection, donor organ selection, surgical approaches, and future considerations within the field in order to improve outcomes and best address organ utilization while a waitlist continues to exist. Lung retransplantation in select patients can offer comparable survival outcomes to primary lung transplantation. However, several risk factors including retransplantation with the first year of primary transplantation, older age, poor functional status, and ICU level requirements prior to transplantation are associated with worsened outcomes. Donor organ selection considerations are comparable to those in primary lung transplantation. However, surgical approach is often impacted by dense pleural and mediastinal adhesions in the recipient which increase the complexity of the hilar dissection. The postoperative course is often more complex for patients undergoing retransplantation compared to those undergoing primary lung transplant as well. However, pending more data on long term outcomes in lung retransplantation and the potential impact of retransplant recipients on waitlist mortality, lung retransplantation should remain in use primarily for the treatment of chronic graft dysfunction in carefully selected patients.     

Viral infections in lung transplantation

Viral infections account for up to 30% of all infectious complications in lung transplant recipients, remaining a significant cause of morbidity and even mortality. Impact of viral infections is not only due to the direct effects of viral replication, but also to immunologically-mediated lung injury that may lead to acute rejection and chronic lung allograft dysfunction. This has particularly been seen in infections caused by herpesviruses and respiratory viruses. The implementation of universal preventive measures against cytomegalovirus (CMV) and influenza (by means of antiviral prophylaxis and vaccination, respectively) and administration of early antiviral treatment have reduced the burden of these diseases and potentially their role in affecting allograft outcomes. New antivirals against CMV for prophylaxis and for treatment of antiviral-resistant CMV infection are currently being evaluated in transplant recipients, and may continue to improve the management of CMV in lung transplant recipients. However, new therapeutic and preventive strategies are highly needed for other viruses such as respiratory syncytial virus (RSV) or parainfluenza virus (PIV), including new antivirals and vaccines. This is particularly important in the advent of the COVID-19 pandemic, for which several unanswered questions remain, in particular on the best antiviral and immunomodulatory regimen for decreasing mortality specifically in lung transplant recipients. In conclusion, the appropriate management of viral complications after transplantation remain an essential step to continue improving survival and quality of life of lung transplant recipients.     

Primary cutaneous mucormycosis in a lung transplant recipient: case report and concise review of the literature

Abstract: Mucormycosis (zygomycosis) is an invasive, opportunistic fungal infection caused by organisms of the class Zygomycetes. Immunocompromised individuals, including both solid organ and hematopoietic stem cell transplant recipients, are preferentially affected. Among solid organ transplant (SOT) recipients, the sinuses, with or without involvement of the orbits and cerebrum, are the most common sites of disease, although the pulmonary allograft appears to be targeted following lung transplantation. Here, we describe the unique case of a lung transplant recipient who developed multifocal cutaneous mucormycosis without involvement of the pulmonary allograft, and review the published literature regarding incidence, treatment, and prognosis of primary cutaneous mucormycosis following SOT.     

High prevalence of gastroesophageal reflux in children after lung transplantation

Bronchiolitis obliterans and its clinical correlate bronchiolitis obliterans syndrome (BOS) are a major cause of morbidity and mortality following lung transplantation. Gastroesophageal reflux disease (GERD) may be a contributing factor for the development of BOS. Since 2002, all recipients of lung and heart-lung transplantation at our institution have been routinely investigated for GERD. In this observational study, we report on the prevalence of GERD in this population, including all pediatric patients undergoing single (SLTx) or double (DLTx) lung transplantation or heart-lung (HLTx) transplantation from January 2003-May 2004. GERD was assessed 3-6 months after transplantation by 24-hr pH testing. The fraction time (Ft) with a pH < 4 within a 24-hr period was recorded. Spirometry data, episodes of confirmed acute rejection, and demographic data were also collected. Ten transplant operations were performed: 4 DLTx, 1 SLTx, and 5 HLTx. Nine patients had cystic fibrosis. One patient had end-stage pulmonary disease secondary to chronic aspiration pneumonia and postadenovirus lung damage. Of 10 patients tested, 2 had severe GERD (Ft > 20%), 5 had moderate GERD (Ft 10-20%), 2 had mild GERD (Ft 5-10%), and 1 had no GERD. The only patient in this group with no GERD had a Nissen fundoplication pretransplant. All study patients were asymptomatic for GERD. All patients with episodes of rejection had moderate to severe GERD posttransplant. There was no association between severity of GERD and peak spirometry results posttransplant. Moderate to severe GERD is common following lung transplantation in children.     

Is it bronchiolitis obliterans syndrome or is it chronic rejection: a reappraisal?

Chronic rejection (obliterative bronchiolitis) is the single most important cause of chronic allograft dysfunction and late mortality after lung transplantation. As this condition is difficult to prove using biopsy specimens, a clinical term, bronchiolitis obliterans syndrome (BOS) has been in use for >10 yrs to describe the progressive decrease of pulmonary function. However, before diagnosing a patient as having BOS, based on a sustained and progressive decrease in forced expiratory volume in one second and/or forced mid-expiratory flow between 25-75% of forced vital capacity, different confounding factors have to be eliminated. Treatment of BOS mainly consists of an increase or a change in the immunosuppressive drug regimen, which may lead to more pronounced infectious complications. Recently, two new options have become available to treat patients with BOS, treatment of gastro-oesophageal reflux and azithromycin. In the present paper, the authors give an overview of the current data on these two modalities, which may lead to a restoration of the pulmonary function in some of the patients, illustrating once more the fact that bronchitis obliterans syndrome is not always a manifestation of chronic rejection.