Evolving impact of the COVID-19 pandemic on lung transplant recipients: A single-center experience

BACKGROUND

Lung transplant recipients (LTRs) are at increased risk of morbidity and mortality from coronavirus disease 2019 (COVID-19); however, the disease course has changed as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants have mutated. We compared COVID-19-related clinical outcomes in LTRs at different stages of the pandemic. We also identified risk factors for developing severe COVID-19 independent of the dominant SARS-CoV-2 variant.

METHODS

This single-center, retrospective cohort study of LTRs with COVID-19 used Cox regression analyses and bootstrapping to identify factors affecting COVID-19 severity.

RESULTS

Between March 2020 and August 2022, 195 LTRs were diagnosed with COVID-19, almost half (89 [45.6%]) during the Omicron period. A total of 113 (58.5%) LTRs were hospitalized and 47 (24.1%) died. Age >65 years increased the risk of hospitalization and death. Although infection with the Omicron variant was associated with a lower risk of hospitalization, the median length of hospital stay (10 days, [interquartile range, 5-19]) was similar between the variants. Intensive care unit (ICU) admission and death were more common with the Delta variant but comparable between the original, Alpha, and Omicron variants. Remdesivir and molnupiravir reduced the risk of hospitalization, and monoclonal antibody therapy reduced the risk of ICU admission, intubation, and death. Vaccination and pre-exposure prophylaxis (PrEP) with tixagevimab-cilgavimab did not significantly reduce COVID-19-related ICU admission, intubation, or mortality among LTRs.

CONCLUSIONS

LTRs with COVID-19 continue to have high hospitalization rates and prolonged hospital stays, despite the reduced virulence of the Omicron variant. More effective PrEP and therapeutic interventions for COVID-19 among vulnerable patient groups are needed.

Late-Onset Exudative Pleural Effusions Without Concomitant Airway Obstruction or Lung Parenchymal Abnormalities: A Novel Presentation of Chronic Lung Allograft Dysfunction

Restrictive allograft syndrome (RAS) is an aggressive variant of CLAD characterized by progressive restrictive ventilatory decline and persistent pleuro-parenchymal changes that can be seen on chest CT. We identified four lung transplant recipients with a progressive restrictive ventilatory defect due to lymphocyte-predominant exudative pleural effusions, but no pleuro-parenchymal abnormalities typical of RAS. Using molecular analysis, we also found increased levels of previously described immune markers of RAS, including NFkB, 20S proteasome, lipocalin, TNFα, and TGFβ, within the circulating small extracellular vesicles of the remaining living lung transplant recipient. Despite the absence of lung parenchymal changes, these patients had a poor prognosis with rapid deterioration in allograft function and no response to pleural-based interventions such as thoracentesis, decortication, and pleurodesis. We hypothesize that these cases represent a distinct CLAD phenotype characterized by progressive restriction due to pleural inflammation, lymphocyte-predominant pleural effusion, resultant compressive atelectasis, and eventual respiratory failure in the absence of lung parenchymal involvement.

Immune responses of lung transplant recipients against SARS-CoV-2 and common respiratory coronaviruses: Evidence for pre-existing cross-reactive immunity

Humoral and cellular immune responses to SARS-CoV-2 and other coronaviruses in lung transplant recipients are unknown. We measured antibodies and T cell responses against the SARS-CoV-2 spike S2 and nucleocapsid antigens and spike antigens from common respiratory coronaviruses (229E, NL63, OC43, and HKU1) after vaccination or infection of LTxRs. 148 LTxRs from single center were included in this study: 98 after vaccination and 50 following SARS-CoV-2 infection. Antibodies were quantified by enzyme-linked immunosorbent assay. The frequency of T cells secreting IL2, IL4, IL10, IL17, TNFα, and IFNγ were enumerated by enzyme-linked immunospot assay. Our results have shown the development of antibodies to SARS-CoV-2 spike protein in infected LTxRs (39/50) and vaccinated LTxRs (52/98). Vaccinated LTxRs had higher number of T cells producing TNFα but less cells producing IFNγ than infected LTxRs in response to the nucleocapsid antigen and other coronavirus spike antigens. We didn't find correlation between the development of antibodies and cellular immune responses against the SARS-CoV-2 spike protein after vaccination. Instead, LTxRs have pre-existing cellular immunity to common respiratory coronaviruses, leading to cross-reactive immunity against SARS-CoV-2 which likely will provide protection against SARS-Cov-2 infection.

Prior SARS-CoV-2 infection may not alter the clinical course of COVID-19 in lung transplant recipients: A single-center experience

BACKGROUND

In the general population, prior infection with SARS-CoV-2 reduces the risk of severe COVID-19; however, studies in lung transplant recipients (LTRs) are lacking. We sought to describe the clinical course of COVID-19 recurrence and compare outcomes between the first and second episodes of COVID-19 in LTRs.

METHODS

We conducted a retrospective, single-center cohort study of LTRs with COVID-19 between January 1, 2022, and September 30, 2022, during the Omicron wave. We compared the clinical course of a second episode of COVID-19 to that of the patients' own first episode and to that of LTRs who developed a first episode during the study period.

RESULTS

During the study period, we identified 24 LTRs with COVID-19 recurrence and another 75 LTRs with a first episode of COVID-19. LTRs who survived the initial episode of COVID-19 had a similar disease course with recurrence, with a trend toward reduced hospitalization (10 (41.6%) vs. 4 (16.7%), p = .114). Furthermore, compared to LTRs with a primary infection during the Omicron wave, those with a reinfection had a non-statistically significant trend toward reduced hospitalizations (aOR .391, 95% CI [.115-1.321], p = .131), shorter lengths-of-stay (median, 4 vs. 9 days, p = .181), and reduced intensive care unit admissions, intubations, and COVID-19-related mortality.

CONCLUSIONS

LTRs who survive the first episode of COVID-19 are likely to have a similar clinical course with recurrent episodes. Although recurrent COVID-19 may be milder, larger, well-powered studies are needed to confirm this observation. Ongoing precautions are warranted.

Pre-exposure Prophylaxis with Tixagevimab-cilgavimab did not Reduce Severity of COVID-19 in Lung Transplant Recipients with Breakthrough Infection

Lung transplant recipients (LTRs) have an increased risk of COVID-19-related morbidity and mortality. Tixagevimab-cilgavimab (tix-cil) is a long-acting monoclonal antibody combination granted Emergency Use Authorization approval by the US Food and Drug Administration for COVID-19 pre-exposure prophylaxis (PrEP) in immunocompromised patients. We sought to determine whether tix-cil 300-300 mg reduced the incidence and disease severity of severe acute respiratory syndrome coronavirus 2 infection in LTRs during the Omicron wave.

Methods

We performed a retrospective, single-center cohort study of LTRs who had received a COVID-19 diagnosis between December 2021 and August 2022. We compared baseline characteristics and clinical outcomes after COVID-19 between LTRs who received tix-cil PrEP and those who did not. We then conducted propensity-score matching based on baseline characteristics and therapeutic interventions and compared clinical outcomes between the 2 groups.

Results

Of 203 LTRs who received tix-cil PrEP and 343 who did not, 24 (11.8%) and 57 (16.6%), respectively, developed symptomatic COVID-19 (hazard ratio [HR], 0.669; 95% confidence interval [CI], 0.415-1.079; P = 0.099). The hospitalization rate of LTRs with COVID-19 during the Omicron wave trended lower in the tix-cil group than in the non-tix-cil group (20.8% versus 43.1%; HR, 0.430; 95% CI, 0.165-1.118; P = 0.083). In propensity-matched analyses, 17 LTRs who received tix-cil and 17 LTRs who did not had similar rates of hospitalization (HR, 0.468; 95% CI, 0.156-1.402; P = 0.175), intensive care unit admission (HR, 3.096; 95% CI, 0.322-29.771; P = 0.328), mechanical ventilation (HR, 1.958; 95% CI, 0.177-21.596; P = 0.583), and survival (HR, 1.015; 95% CI, 0.143-7.209; P = 0.988). COVID-19-related mortality was high in both propensity-score-matched groups (11.8%).

Conclusions

Breakthrough COVID-19 was common among LTRs despite tix-cil PrEP, possibly due to reduced efficacy of monoclonal antibodies against the Omicron variant. Tix-cil PrEP may reduce the incidence of COVID-19 in LTRs, but it did not reduce disease severity during the Omicron wave.

Loss of IGFBP2 mediates alveolar type 2 cell senescence and promotes lung fibrosis

Accumulation of senescent cells contributes to age-related diseases including idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding proteins (IGFBPs) regulate many biological processes; however, the functional contributions of IGFBP2 in lung fibrosis remain largely unclear. Here, we report that intranasal delivery of recombinant IGFBP2 protects aged mice from weight loss and demonstrated antifibrotic effects after bleomycin lung injury. Notably, aged human-Igfbp2 transgenic mice reveal reduced senescence and senescent-associated secretory phenotype factors in alveolar epithelial type 2 (AEC2) cells and they ameliorated bleomycin-induced lung fibrosis. Finally, we demonstrate that IGFBP2 expression is significantly suppressed in AEC2 cells isolated from fibrotic lung regions of patients with IPF and/or pulmonary hypertension compared with patients with hypersensitivity pneumonitis and/or chronic obstructive pulmonary disease. Altogether, our study provides insights into how IGFBP2 regulates AEC2-cell-specific senescence and that restoring IGFBP2 levels in fibrotic lungs can prove effective for patients with IPF.

Hospitalized patients with irreversible lung injury from COVID-19 have higher morbidity but similar 1-year survival after lung transplant compared to hospitalized patients transplanted for restrictive lung disease

BACKGROUND

Hospitalized lung transplant (LT) recipients (LTRs) have higher post-LT morbidity and mortality than those who are well enough to wait for transplant at home. Outcomes after LT for COVID-19-associated acute respiratory distress syndrome (CARDS) may be even worse; thus, we compared post-LT outcomes between hospitalized LTRs transplanted for CARDS and those transplanted for restrictive lung disease (RLD).

METHODS

Between 2014 and 2021, hospitalized LTRs ≥18 years old with CARDS or RLD were included. Primary and secondary outcomes were 1-year post-LT survival and postoperative morbidity. For each patient in the CARDS group, an analysis of 1-to-1 matched patients from the RLD group was performed using logistic regression modeling.

RESULTS

Of 764 LTRs, 163 (21.3%) were hospitalized at the time of LT; 132 met the inclusion criteria: 11 (8.3%) were transplanted for CARDS and 121 (91.7%) for RLD. LTRs with CARDS were younger with longer pre-LT hospitalization stays and higher rates of pretransplant mechanical ventilation, dialysis, and ECMO as a bridge to transplant. A propensity-matched analysis demonstrated comparable rates of intrathoracic adhesions, posttransplant duration of mechanical ventilation, PGD3 at 72 hours, and delayed chest closure. Compared to LTRs with RLD, those with CARDS had significantly longer posttransplant hospital stays and a higher prevalence of ACR ≥A2 and DSA >2000 MFI, but comparable 1-year survival rates.

CONCLUSION

Even with careful selection, LT for patients with CARDS was associated with significant morbidity; however, 1-year survival of recipients with CARDS was comparable to that of matched hospitalized recipients with RLD.

Morbidity of antireflux surgery in lung transplant and matched nontransplant cohorts is comparable

BACKGROUND

Safety data on perioperative outcomes of laparoscopic antireflux surgery (LARS) after lung transplantation (LT) are lacking. We compared the 30-day readmission rate and short-term morbidity after LARS between LT recipients and matched nontransplant (NT) controls.

METHODS

Adult patients who underwent LARS between January 1, 2015, and October 31, 2021, were included. The participants were divided into two groups: LT recipients and NT controls. First, we compared 30-day readmission rates after LARS between the LT and NT cohorts. Next, we compared 30-day morbidity after LARS between the LT cohort and a 1-to-2 propensity score-matched NT cohort.

RESULTS

A total of 1328 patients (55 LT recipients and 1273 NT controls) were included. The post-LARS 30-day readmission rate was higher in LT recipients than in the overall NT controls (14.5% vs. 2.8%, p < 0.001). Compared to matched NT controls, LT recipients had a lower prevalence of paraesophageal hernia, a smaller median hernia size, and higher peristaltic vigor. Also compared to the matched NT controls, the LT recipients had a lower median operative time but a longer median length of hospital stay. The proportion of patients with a post-LARS event within 30 postoperative days was comparable between the LT and matched NT cohorts (21.8% vs 14.5%, p = 0.24).

CONCLUSIONS

Despite a higher perceived risk of comorbidity burden, LT recipients and matched NT controls had similar rates of post-LARS 30-day morbidity at our large-volume center with expertise in transplant and foregut surgery. LARS after LT is safe.

Incidentally Detected Malignancies in Lung Explants

Introduction: Incidentally detected malignancies in lung explants portend risk of early cancer recurrence and metastases with posttransplant immunosuppression. We present a series of lung transplant recipients with previously unverified malignancies in native lung explants. Design: We reviewed the histopathology, radiographic imaging, and management of lung explant malignancies at our institution over 10 years (2011-2020). Endpoints were survival and allograft rejection. Results: An explant malignancy was found in 1.3% (11/855) of lung transplant recipients (6 [55%] men; median age 68 years; 6 [55%] ex-smokers [median pack-years, 25]). Nine (82%) were adenocarcinoma, 1 (9%) was squamous cell carcinoma (SCC), and 1 (9%) was follicular lymphoma. Three patients (27%) had multifocal involvement (≥3 lobes), 4 (36%) had nodal involvement, and the median (range) tumor size was 2.7 (0.4-19) cm. The median interval between last imaging and transplant was 58 (29-144) days. Mycophenolate mofetil was discontinued or reduced in all; everolimus was used in 2 patients, and cisplatin-pemetrexed chemotherapy was used in 2 patients. The prevalence of acute cellular rejection and chronic rejection was 27% and 9%, respectively. Lung recipients with cancer had significantly lower survival than those without (36.4% vs 67.3%, p = 0.002); median survival was 27 (17, 65) months in 4 recipients who were alive and cancer-free at the end of the study period. Conclusions: Unidentified malignancies, commonly adenocarcinoma, can be detected in explanted native lungs. Pneumonectomy may be curative in SCC, lymphoproliferative disorders, and stage I adenocarcinoma. Modulating immunosuppression to prevent allograft rejection and tumor proliferation is warranted.

Lung Transplantation for COVID-19-Induced Respiratory Failure: Single-Center Case Series

Purpose

Prior to the COVID-19 (C19) pandemic, adult respiratory distress syndrome (ARDS) was an unusual indication for lung transplant (LT); thus, short- and long-term outcomes data are lacking. As the pandemic continues, there is an increased need for post-LT data. Thus, we report our single-center experience transplanting 11 patients for C19 ARDS.

Methods

We conducted a chart review of LT recipients (LTRs) transplanted for C19 ARDS between 8/1/21 and 7/31/21. Descriptive statistics were used.

Results

Most LTRs were male (82%, n=9). The median age at LT, body mass index, and lung allocation score were 47 (43, 54) years, 28.9 (26, 30) kg/m2, and 84.5 (60, 88), respectively. The median interval from initial hospitalization to listing and listing to LT was 119 (97, 124) and 5 (4, 11) days, respectively. Pretransplant COVID-related morbidities included venous thromboembolism (55%, n=6), hemorrhage requiring transfusion (36%, n=4), pneumothorax (55%, n=6), bacterial pneumonia (82%, n=9), bacteremia (45%, n=5), fungemia (36%, n=4), renal failure requiring renal replacement therapy (RRT; 9%, n=1), cerebrovascular event (9%, n=1), and musculoskeletal weakness (100%, n=11). Most patients required mechanical ventilation (91%, n=10), and 55% (n=6) were intubated at the time of LT. Furthermore, most patients required ECMO support (73%, n=8) and 36% (n=4) were on ECMO at the time of LT. Intraoperatively, 64% (n=7) of patients required cardiopulmonary bypass, 73% (n=8) had severe intrathoracic adhesions, 73% (n=8) had delayed chest closure, and 18% (n=2) had an unexpected return to the operating room. Prevalence of primary graft dysfunction grade 2 or 3 at 72 hours was high (91%, n=10), median duration of mechanical ventilation after LT was 10 (6, 19) days, but no one required ECMO rescue. To date, 10 (91%) LTRs have been discharged, and 2 (20%) have been readmitted within 30 days; the median post-LT hospital stay was 18 (14, 24) days; all discharged LTRs required acute rehabilitation for a median of 17.5 (14, 23) days. Ten LTRs (91%) at a median of 208 (167, 245) days post-LT; 1 LTR died 344 days post-LT of treatment-refractory allograft failure due to aspiration and antibody-mediated rejection.

Conclusion

Despite pre-LT critical illness, intraoperative challenges, and prolonged post-LT recovery, LT appears feasible for carefully selected patients with irreversible C19 ARDS.

A Comparison of Short-Term Morbidity and Mortality Among Inpatient Lung Transplant Recipients Transplanted for COVID-19 and Other Restrictive Lung Diseases

Purpose

Patients with respiratory failure (RF) who are hospitalized at the time of lung transplant (LTx) have higher post-LTx morbidity and mortality than those who are well enough to remain at home. Complications may be even worse in patients transplanted for COVID-19 (C19), as they are commonly critically ill having endured prolonged mechanical ventilation, ECMO support, myopathy, malnutrition, and superimposed infections. In a retrospective cohort study, we compared inpatient lung transplant recipients (LTxRs) transplanted for C19 vs. other underlying restrictive lung diseases (RLDs)

Methods

After IRB approval, patients who underwent inpatient LTx between 1/1/2014 and 8/31/2021 were categorized by indication: C19 or RLD. We excluded LTxRs <18 years old, a primary indication for LTx other than UNOS disease group D, and redo LTx. Primary outcomes were postoperative morbidity and 90-day survival.

Results

Out of 163 inpatient LTxRs, 141 met inclusion criteria: 11 (7.8%) with C19 and 130 (92.2%) with RLD. LTxRs with C19 were younger, had a longer pre-LTx hospital stay, and more likely needed pre-LTx mechanical ventilation and ECMO support. LTxRs with C19 were also more likely to have severe adhesions intraoperatively and their chest was more commonly left open after LTx due to a perceived risk of ongoing bleeding. In addition, LTxRs with C19 had a higher prevalence of PGD3 at 72 hours and longer post-LTx hospital stays and trended toward longer post-LTx mechanical ventilation and need for inpatient rehabilitation. The 2 groups had similar 90-day survival (C19, 100% vs. RLD, 95.4%, p=0.472), however, LTxRs with C19 had a higher incidence of acute cellular rejection and DSA production (>2,000 MFI) within 6 months of transplant.

Conclusion

LTxRs with C19 are typically sicker and have more post-LTx complications than LTxRs with RLD hospitalized at the time of LTx. However, 90-day survival is comparable and high in both groups. Long-term follow-up is needed.

Persistent Subclinical SARS-CoV-2 Isolation After Redo Lung Transplant for COVID-19-Induced Lung Injury

Introduction

Lung transplantation (LTx) is lifesaving for patients with irreversible lung injury due to COVID-19; however, all viable virus must be cleared before transplant. Prolonged viral shedding is common, particularly among immunosuppressed patients. Thus, ongoing detection of SARS-CoV-2 RNA may delay transplant and prolong hospitalization. We report a case of an LTx recipient who developed COVID-19-associated lung injury with prolonged viral shedding that persisted following redo LTx.

Case Report

A 48-year-old man developed COVID-19 17 months after bilateral LTx. His illness rapidly progressed to hypoxemic respiratory failure requiring bilevel ventilation and prone positioning. He was treated with corticosteroids, remdesevir, convalescent plasma, anticoagulation, and reduced immunosuppression. Tocilizumab was not administered as data supporting its use was unavailable. Despite aggressive therapy, he remained hypoxemic and developed radiographic evidence of pulmonary fibrosis. SARS-CoV-2 was persistently isolated between November 2020 and April 2021; the PCR cycle threshold in March 2021 was 32, indicating a low level of viral RNA. There was no evidence of antibodies to SARS-CoV-2. Finally, after 2 negative nasopharyngeal swabs in April, he underwent redo bilateral LTx in May 2021, 163 days after his initial diagnosis. Postoperative critical illness myopathy required prolonged mechanical ventilation, nutrition via a feeding tube, and 19 days at an acute rehabilitation center. Routine surveillance bronchoscopy 40 days after retransplant revealed SARS-CoV-2 in bronchoalveolar lavage fluid and again in a nasal wash sample. He had no COVID-19 symptoms at the time of viral isolation, and inflammatory markers were normal. He was empirically treated with casirivimab and imdevimab, with resolution of SARS-CoV-2 isolation 8 days later.

Summary

Prolonged viral shedding is common in immunocompromised patients with COVID-19; however, ongoing viral isolation is not a reliable indicator of active viral replication and transmissibility. Our patient had persistent SARS-CoV-2 isolation after redo LTx with no evidence of COVID-19 or allograft injury. Thus, persistent viral shedding alone may not be an absolute contraindication to LTx and additional factors such as PCR cycle threshold and time from original infection should be considered.

Lung Transplant Candidates With Pretransplant Gastroesophageal Reflux and Antibodies to Lung Self-antigens Have Shorter CLAD-free Survival After Transplant

Pre–lung transplant (LTx) gastroesophageal reflux (GER) and circulating antibodies against the lung self-antigens (SAbs) collagen V and K-alpha-1 tubulin may predispose recipients to chronic lung allograft dysfunction (CLAD). We aimed to study the association of pre-LTx GER or pre-LTx SAbs with CLAD.

Restrictive allograft syndrome vs bronchiolitis obliterans syndrome: Immunological and molecular characterization of circulating exosomes

BACKGROUND

Chronic lung allograft dysfunction in lung transplant recipients (LTxRs) has 2 phenotypes: obstructive bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). Our goal was to define distinct immunologic markers of exosomes from LTxRs with BOS or RAS.

METHODS

Plasma was collected from LTxRs with BOS (n = 18), RAS (n = 13), and from stable LTxRs (n = 5). Antibodies to lung self-antigens (SAgs) were determined by ELISA. Exosomes were isolated by ultracentrifugation. Donor specific antibodies to HLA were quantified using Luminex. Exosomes were characterized for lung SAgs, transcription factors, 20S proteasome, HLA class I and II, and polymeric immunoglobulin receptor protein using western blot. Exosome miRNA was analyzed using NanoString. The exosome-induced immune response was determined in mice.

RESULTS

LTxRs with RAS, but not BOS, had donor specific antibodies at diagnosis. CIITA, NFkB, polymeric immunoglobulin receptor protein, 20S proteasome, HLA-DQ, and HLA-DR were significantly higher in RAS exosomes than in BOS exosomes. RAS plasma had high levels of proinflammatory cytokines and distinct exosomal miRNA. Immunization of C57BL/6 mice with RAS exosomes showed severe inflammation and peribronchial fibrosis, whereas BOS exosomes induced patchy inflammation and fibrosis.

CONCLUSION

LTxRs with BOS or RAS had exosomes with distinct molecular and immunologic profiles. RAS samples had a higher concentration of proinflammatory factors, HLA class II, lung SAgs, and antibodies to HLA class II molecules, indicating severe allograft injury. Mice immunized with RAS exosomes developed lesions in airways, pleura, interlobular septum, and alveoli, whereas BOS exosomes induced mild to patchy inflammation with lung fibrosis.

ISHLT consensus document on lung transplantation in patients with connective tissue disease: Part I: Epidemiology, assessment of extrapulmonary conditions, candidate evaluation, selection criteria, and pathology statements

Patients with connective tissue disease (CTD) and advanced lung disease are often considered suboptimal candidates for lung transplantation (LTx) due to their underlying medical complexity and potential surgical risk. There is substantial variability across LTx centers regarding the evaluation and listing of these patients. The International Society for Heart and Lung Transplantation-supported consensus document on lung transplantation in patients with CTD standardization aims to clarify definitions of each disease state included under the term CTD, to describe the extrapulmonary manifestations of each disease requiring consideration before transplantation, and to outline the absolute contraindications to transplantation allowing risk stratification during the evaluation and selection of candidates for LTx.

Two Cases of Spontaneous Bleeding in Lung Transplant Recipients Treated with Systemic Anticoagulation for COVID-19

Introduction

COVID-19 promotes inflammation and a hypercoagulable state. Antithrombotic therapies may be administered for thromboprophylaxis in those with severe infection requiring hospitalization. Spontaneous bleeding is an infrequent, yet life-threatening complication in patients receiving systemic anticoagulation.

Case Report

Two bilateral lung transplant recipients - 77-year-old female with idiopathic pulmonary fibrosis (patient A) and 69-year-old male with chronic obstructive pulmonary disease (patient B) - each presented with several days’ history of dyspnea, cough, and fatigue at 29-months and 11-months post-transplant, respectively; RT-PCR was positive for SARS-CoV-2 infection in both. Over the course of the next few days, patient A rapidly deteriorated with need for intubation despite initial treatment with antibiotics and corticotherapy. Patient B experienced gradual worsening of respiratory symptoms, which required high-flow oxygen supplementation and IV antibiotics. Inflammatory markers were elevated in both patients, and CT of the chest was consistent with atypical pneumonia in each. Patient A received convalescent plasma as a rescue therapy, and patient B received remdesivir with convalescent plasma. Given the hypercoagulable state in each, patient A and B received enoxaparin and IV heparin, respectively. Slowly, hemoglobin and platelet counts dropped in both patients, with need for transfusion and hemodynamic support. CT of the abdomen revealed a left gluteal intramuscular hematoma in patient A; CT of the chest, abdomen, and pelvis revealed a spontaneous chest wall hematoma and small area of retroperitoneal bleeding in patient B (Figure 1A and B).

Summary

These cases raise awareness for the viral-induced hypercoagulable state observed during the disease course. Clinicians should be cautious to avoid any hemorrhagic complications associated with thromboprophylaxis in selected cases, particularly in at-risk immunosuppressed patients.

SARS-CoV-2 Re-Infection in a Lung Transplant Recipient

Introduction

Since the onset of the SARS-CoV-2 pandemic, increasing evidence has shown waning immunity after initial SARS-CoV-2 infection, and re-infection in patients with a prior history of COVID-19 has been reported. We report a case of SARS-CoV-2 re-infection in a lung transplant recipient 3 months after initial illness.

Case Report

The patient is a 56-year-old man with a history of bilateral lung transplant in August 2018 for idiopathic pulmonary fibrosis. His post-transplant course was complicated by insulin-dependent diabetes mellitus (HbA1c 5.8%), chronic renal insufficiency (eGFR nadir 48 mL/min/1.73m²), and peripheral arterial disease requiring bilateral below-knee amputations. At the time of transplant, he was induced with basiliximab and remained on standard 3-drug immunosuppression with mycophenolate mofetil (500 mg BID), prednisone (5 mg daily), and tacrolimus. He contracted SARS-CoV-2 from his wife and tested positive for the virus on July 2, 2020 after presenting to the emergency department (ED) with headache, chills, nausea, body aches, shortness of breath, and generalized weakness. His oxygen saturation and chest X-ray were normal, and he was therefore discharged from the ED to recover at home. His symptoms resolved 17 days after diagnosis and serial SARS-CoV-2 testing via nasal washing were positive on July 16, 2020 and negative on July 30, 2020 and August 11, 2020. In addition, on October 21, 2020, he tested positive for SARS-CoV-2 antibodies (3.41, positive: index ≥1.4). On October 23, 2020, he presented to the ED with generalized chest pain, low-grade fever (100.1F), dyspnea, and weakness. His nasal swab was positive for SARS-CoV-2 and CT of the chest showed bibasilar ground-glass opacities consistent with atypical infection vs. atelectasis. His labs were notable for a CRP of 132 mg/L, ferritin of 2,307 ng/mL, LDH 304 units/L, D-dimer 240 ng/mL, and procalcitonin of 0.05 ng/mL. He was admitted for monitoring and treated with remdesivir, corticosteroids, and anticoagulation.

Summary

We present a case of SARS-CoV-2 re-infection 3 months after initial illness in a lung transplant recipient living in a high-incidence area. Unexpectedly, recurrent infection occurred despite development of SARS-CoV-2 antibodies. This case speaks to the vulnerability of this patient population to COVID-19 and the need for ongoing precautions to prevent infection even among patients who have seroconverted.

COVID-19 in a lung transplant recipient: Exploring the diagnostic role of circulating exosomes and the clinical impact of advanced immunosuppression

Exosomes isolated from plasma of lung transplant recipients with allograft injury contain donor‐derived lung self‐antigens (collagen V and Kα1 tubulin) and human leukocyte antigen (HLA) molecules. We present a case of a 76‐year‐old, female lung transplant recipient treated for acute cellular rejection with methylprednisolone and anti‐thymocyte globulin, who subsequently contracted SARS‐CoV‐2 and developed a sharp increase in the mean fluorescent intensity of anti‐HLA antibodies. Analysis of circulating exosomes during rejection, but before SARS‐CoV‐2 infection, revealed the presence of lung self‐antigens and HLA class II molecules. After the patient contracted SARS‐CoV‐2, exosomes with the SARS‐CoV‐2 spike protein were also found. After resolution of infectious symptoms, exosomes with SARS‐CoV‐2 spike protein were no longer detected; however, exosomes with lung self‐antigens and HLA class II molecules persisted, which coincided with a progressive decline in spirometric flows, suggesting chronic lung allograft dysfunction. We propose that the analysis of circulating exosomes may be used to detect allograft injury mediated by both rejection and infection. Furthermore, the detection of exosomes containing viral proteins may be helpful in identifying allograft injury driven by viral pathogens.

Nocardia prophylaxis, treatment, and outcomes of infection in lung transplant recipients: A matched case-control study

BACKGROUND

Lung transplant recipients are at heightened risk for nocardiosis compared to other solid organ transplant recipients, with incidence rates as high as 9% and up to 30% associated mortality. No controlled studies assessing risk factors for nocardiosis in this high-risk population have been reported.

METHODS

Patients undergoing lung transplantation at a single center between 2012 and 2018 and diagnosed with nocardiosis post-transplant were matched 1:2 to uninfected control subjects on the basis of age, transplant date, and sex.

RESULTS

The incidence of nocardiosis in this lung transplant population was 3.4% (20/586), occurring a median of 9.4 months (range 4.4-55.2) post-transplant. In multivariable analysis, consistent use of trimethoprim/sulfamethoxazole (TMP/SMX) in the 12 weeks prior to diagnosis was independently associated with protection against nocardiosis (OR 0.038; 95% CI 0.01-0.29; P = .002). Augmented immunosuppression in the 6 months prior to diagnosis was independently associated with the development of nocardiosis (OR 9.94; 95% CI 1.62- 61.00; P = .013). Six case patients (30%) had disseminated disease; all-cause 6-month mortality was 25%. The most common species was Nocardia farcinica (7/17 isolates), which was associated with dissemination and mortality. The most active antibiotics were TMP/SMX (100%), linezolid (100%), and amikacin (76%). Imipenem was only active against 4/17 isolates (24% susceptibility), with two isolates becoming non-susceptible later in therapy.

CONCLUSIONS

Trimethoprim/sulfamethoxazole prophylaxis was shown to be protective against nocardiosis in lung transplant recipients, while augmented immunosuppression conferred increased risk. Institutional epidemiologic data are needed to best guide empiric therapy for Nocardia, as historical in vitro data may not predict local susceptibilities.

Chronic Lung Allograft Dysfunction: Immune Responses Induced by Circulating Exosomes with Lung-Associated Self-Antigens

Exosomes, nanovesicles shown to regulate physiological processes in vivo, have been implicated in pathological conditions including cancer, autoimmune disease, infectious disease, neurodegenerative disease, and allograft rejection. Studies of lung transplant recipients with primary graft dysfunction, respiratory viral infection, and (acute) rejection have demonstrated circulating exosomes containing donor-mismatched human leukocyte antigen and lung-associated self-antigens, K-alpha 1 tubulin and collagen V, indicating that exosomes are originating from the transplanted organ. These circulating exosomes likely play a role in activating immune responses that lead to increased risk of chronic lung allograft dysfunction, as exosomes efficiently present their antigens to the immune system by all known pathways of antigen recognition (i.e., direct, indirect, and semidirect pathways). Here, we discuss exosome biogenesis, describe their contents, and address the mechanism of exosome-mediated activation of immune responses that lead to allograft rejection, especially after lung transplantation.

Circulating exosomes with lung self-antigens as a biomarker for chronic lung allograft dysfunction: A retrospective analysis

BACKGROUND

Exosomes isolated from plasma of lung transplant recipients (LTxRs) with bronchiolitis obliterans syndrome (BOS) contain human leukocyte antigens and lung self-antigens (SAgs), K-alpha 1 tubulin (Kα1T) and collagen type V (Col-V). The aim was to determine the use of circulating exosomes with lung SAgs as a biomarker for BOS.

METHODS

Circulating exosomes were isolated retrospectively from plasma from LTxRs at diagnosis of BOS and at 6 and 12 months before the diagnosis (n = 41) and from stable time-matched controls (n = 30) at 2 transplant centers by ultracentrifugation. Exosomes were validated using Nanosight, and lung SAgs (Kα1T and Col-V) were detected by immunoblot and semiquantitated using ImageJ software.

RESULTS

Circulating exosomes from BOS and stable LTxRs demonstrated 61- to 181-nm vesicles with markers Alix and CD9. Exosomes from LTxRs with BOS (n = 21) showed increased levels of lung SAgs compared with stable (n = 10). A validation study using 2 separate cohorts of LTxRs with BOS and stable time-matched controls from 2 centers also demonstrated significantly increased lung SAgs-containing exosomes at 6 and 12 months before BOS.

CONCLUSIONS

Circulating exosomes isolated from LTxRs with BOS demonstrated increased levels of lung SAgs (Kα1T and Col-V) 12 months before the diagnosis (100% specificity and 90% sensitivity), indicating that circulating exosomes with lung SAgs can be used as a non-invasive biomarker for identifying LTxRs at risk for BOS.

Emergence of letermovir resistance in a lung transplant recipient with ganciclovir-resistant cytomegalovirus infection

Following a year of valganciclovir prophylaxis, a lung transplant recipient developed cytomegalovirus (CMV) infection that became resistant to ganciclovir, as confirmed by detection of UL97 kinase mutation M460V and a previously uncharacterized UL54 DNA polymerase mutation L516P. The latter mutation is now shown to confer ganciclovir and cidofovir resistance. As predicted from the viral genotype, foscarnet therapy was effective, but resumption of valganciclovir as secondary prophylaxis resulted in a plasma viral load rebound to 3.6 log₁₀ copies/mL several weeks later. Valganciclovir was then replaced by letermovir, resulting in gradual viral load reduction in the first 5 weeks to below the quantitation limit (2.7 log₁₀ copies/mL) for 1 week, followed by 10 weeks of rising viral loads reaching 4.3 log₁₀ copies/mL while on letermovir. At this point, CMV genotypic testing revealed UL56 mutation C325Y, which confers absolute resistance to letermovir. Retreatment with foscarnet was successful. This case adds to the considerable list of proven ganciclovir resistance mutations, and provides an early experience with letermovir resistance after off-label therapeutic use. This experience is consistent with in vitro observations of rapid emergence of letermovir-resistant CMV after drug exposure.

Successful Lung Re-transplant in a Patient with Cepacia Syndrome due to Burkholderia ambifaria

Chronic airway inflammation and infection drive morbidity and mortality among patients with cystic fibrosis (CF). While Haemophilus influenzae and Staphylococcus aureus predominate in children, the prevalence of Pseudomonas aeruginosa increases as patients age. Other bacteria, including species within the Burkholderia cepacia complex (Bcc), are also more prevalent among adults with CF. Species within the Bcc accelerate lung function decline and can trigger development of "cepacia syndrome," both before and after lung transplantation. As a result, some centers advise against lung transplantation for Bcc-infected patients; however, little is known about the relative virulence of uncommon Bcc species. We describe a successful lung re-transplant in a patient with CF, chronic Burkholderia ambifaria airway infection, and cepacia syndrome.

A 46-Year-Old Man With Dyspnea, Hypoxemia, and Radiographic Asymmetry After Redo Bilateral Lung Transplantation

CASE PRESENTATION

A 46-year-old man underwent redo bilateral sequential lung transplantation for rapidly progressive bronchiolitis obliterans syndrome that developed 3.5 years after initial transplantation. In the operating room, he was sedated and intubated with a dual lumen endotracheal tube with subsequent single right-lung ventilation and left allograft implantation. His pulmonary arterial pressure became elevated with reperfusion of the newly implanted left lung, which required initiation of cardiopulmonary bypass to facilitate implantation of the right lung. After implantation and reperfusion of the right lung, the patient was weaned from cardiopulmonary bypass. His chest was closed and he was transferred to the thoracic intensive care unit. On arrival to the intensive care unit, the patient was intubated, sedated, and had an oxygen saturation of 92% on a fraction of inspired oxygen of 100%, positive end-expiratory pressure of 10 cm H₂O, and 20 parts per million of inhaled nitric oxide. He had a Swan-Ganz catheter in the right internal jugular vein that measured a mean pulmonary arterial pressure of 33 mm Hg and a pulmonary arterial systolic pressure of 63 mm Hg, which remained persistently elevated and prompted further diagnostic evaluation.

Prolonged Barium-Impaction Ileus in Two Lung Transplant Recipients With Systemic Sclerosis: Case Report

Lung transplantation can be a life-saving measure for people with end-stage lung disease from systemic sclerosis. However, outcomes of lung transplantation may be compromised by gastrointestinal manifestations of systemic sclerosis, which can involve any part of the gastrointestinal tract. Esophageal and gastric disease can be managed by enteral feeding with the use of a gastrojejunal feeding tube. In this report, we describe the clinical courses of 2 lung transplant recipients with systemic sclerosis who experienced severe and prolonged barium-impaction ileus after insertion of a percutaneous gastrojejunal feeding tube.

Frailty Phenotypes, Disability, and Outcomes in Adult Candidates for Lung Transplantation

RATIONALE

Frailty is associated with morbidity and mortality in abdominal organ transplantation but has not been examined in lung transplantation.

OBJECTIVES

To examine the construct and predictive validity of frailty phenotypes in lung transplant candidates.

METHODS

In a multicenter prospective cohort, we measured frailty with the Fried Frailty Phenotype (FFP) and Short Physical Performance Battery (SPPB). We evaluated construct validity through comparisons with conceptually related factors. In a nested case-control study of frail and nonfrail subjects, we measured serum IL-6, tumor necrosis factor receptor 1, insulin-like growth factor I, and leptin. We estimated the association between frailty and disability using the Lung Transplant Valued Life Activities disability scale. We estimated the association between frailty and risk of delisting or death before transplant using multivariate logistic and Cox models, respectively.

MEASUREMENTS AND MAIN RESULTS

Of 395 subjects, 354 completed FFP assessments and 262 completed SPPB assessments; 28% were frail by FFP (95% confidence interval [CI], 24-33%) and 10% based on the SPPB (95% CI, 7-14%). By either measure, frailty correlated more strongly with exercise capacity and grip strength than with lung function. Frail subjects tended to have higher plasma IL-6 and tumor necrosis factor receptor 1 and lower insulin-like growth factor I and leptin. Frailty by either measure was associated with greater disability. After adjusting for age, sex, diagnosis, and transplant center, both FFP and SPPB were associated with increased risk of delisting or death before lung transplant. For every 1-point worsening in score, hazard ratios were 1.30 (95% CI, 1.01-1.67) for FFP and 1.53 (95% CI, 1.19-1.59) for SPPB.

CONCLUSIONS

Frailty is prevalent among lung transplant candidates and is independently associated with greater disability and an increased risk of delisting or death.

Clinical outcomes of lung transplant recipients with telomerase mutations

BACKGROUND

Successful lung transplantation for patients with pulmonary fibrosis from telomerase mutations may be limited by systemic complications of telomerase dysfunction, including myelosuppression, cirrhosis, and malignancy. We describe clinical outcomes in 14 lung transplant recipients with telomerase mutations.

METHODS

Subjects underwent lung transplantation between February 2005 and April 2014 at 5 transplant centers. Data were abstracted from medical records, focusing on outcomes reflecting post-transplant treatment effects likely to be complicated by telomerase mutations.

RESULTS

The median age of subjects was 60.5 years (interquartile range = 52.0-62.0), 64.3% were male, and the mean post-transplant observation time was 3.2 years (SD ± 2.9). A mutation in telomerase reverse transcriptase was present in 11 subjects, a telomerase RNA component mutation was present in 2 subjects, and an uncharacterized mutation was present in 1 subject. After lung transplantation, 10 subjects were leukopenic and 5 did not tolerate lymphocyte anti-proliferative agents. Six subjects developed recurrent lower respiratory tract infections, 7 developed acute cellular rejection (A1), and 4 developed chronic lung allograft dysfunction. Eight subjects developed at least 1 episode of acute renal failure and 10 developed chronic renal insufficiency. In addition, 3 subjects developed cancer. No subjects had cirrhosis. At data censorship, 13 subjects were alive.

CONCLUSIONS

The clinical course for lung transplant recipients with telomerase mutations is complicated by renal disease, leukopenia with intolerance of lymphocyte anti-proliferative agents, and recurrent lower respiratory tract infections. In contrast, cirrhosis was absent, acute cellular rejection was mild, and development of chronic lung allograft dysfunction was comparable to other lung transplant recipients. Although it poses challenges, lung transplantation may be feasible for patients with pulmonary fibrosis from telomerase mutations.

Procalcitonin predicts mortality in HIV-infected Ugandan adults with lower respiratory tract infections

BACKGROUND AND OBJECTIVE

In low and middle-income countries where HIV infection is prevalent, identifying patients at high risk of dying from lower respiratory tract infections is challenging and validated prognostic models are lacking. Serum procalcitonin may be a useful prognostic tool in these settings. We sought to determine if elevated serum procalcitonin is associated with increased in-hospital mortality and to combine serum procalcitonin with available clinical characteristics to create a clinically useful prognostic model.

METHODS

We conducted a prospective, nested case-control study of 241 HIV-infected adults admitted to Mulago Hospital in Kampala, Uganda with cough ≥2 weeks in duration. We collected demographic and clinical information, baseline serum for procalcitonin analysis, and followed patients to determine in-hospital mortality.

RESULTS

Serum procalcitonin was a strong and independent predictor of inpatient mortality (aOR = 7.69, p = 0.01, sensitivity = 93%, negative predictive value = 97%). Best subset multivariate analysis identified 3 variables that were combined into a prognostic model to risk stratify patients; these variables included respiratory rate ≥30 breaths/minute (aOR = 2.07, p = 0.11), oxygen saturation <90% (aOR = 3.07, p = 0.02), and serum procalcitonin >0.5 ng/ml (aOR = 7.69, p = 0.01). The predicted probability of inpatient mortality ranged from 1% when no variables were present, to 42% when all variables were present.

CONCLUSIONS

Elevated serum procalcitonin >0.5 ng/ml is an independent predictor of in-hospital mortality. Elevated serum procalcitonin, tachypnea, and hypoxemia may be combined into a prognostic model to identify patients at high risk of dying in the hospital. This model may be used to estimate the probability of death and to guide triage and treatment decisions.