Macrophage and CD8 T cell discordance are associated with acute lung allograft dysfunction progression.

BACKGROUND: Acute lung allograft dysfunction (ALAD) is an imprecise syndrome denoting concern for the onset of chronic lung allograft dysfunction (CLAD). Mechanistic biomarkers are needed that stratify risk of ALAD progression to CLAD. We hypothesized that single cell investigation of bronchoalveolar lavage (BAL) cells at the time of ALAD would identify immune cells linked to progressive graft dysfunction. METHODS: We prospectively collected BAL from consenting lung transplant recipients for single cell RNA sequencing. ALAD was defined by a ≥10% decrease in FEV1 not caused by infection or acute rejection and samples were matched to BAL from recipients with stable lung function. We examined cell compositional and transcriptional differences across control, ALAD with decline, and ALAD with recovery groups. We also assessed cell-cell communication. RESULTS: BAL was assessed for 17 ALAD cases with subsequent decline (ALAD declined), 13 ALAD cases that resolved (ALAD recovered), and 15 cases with stable lung function. We observed broad differences in frequencies of the 26 unique cell populations across groups (p = 0.02). A CD8 T cell (p = 0.04) and a macrophage cluster (p = 0.01) best identified ALAD declined from the ALAD recovered and stable groups. This macrophage cluster was distinguished by an anti-inflammatory signature and the CD8 T cell cluster resembled a Tissue Resident Memory subset. Anti-inflammatory macrophages signaled to activated CD8 T cells via class I HLA, fibronectin, and galectin pathways (p < 0.05 for each). Recipients with discordance between these cells had a nearly 5-fold increased risk of severe graft dysfunction or death (HR 4.6, 95% CI 1.1-19.2, adjusted p = 0.03). We validated these key findings in 2 public lung transplant genomic datasets. CONCLUSIONS: BAL anti-inflammatory macrophages may protect against CLAD by suppressing CD8 T cells. These populations merit functional and longitudinal assessment in additional cohorts.

Design and implementation of a digital health home spirometry intervention for remote monitoring of lung transplant function.

BACKGROUND: We developed an automated, chat-based, digital health intervention using Bluetooth-enabled home spirometers to monitor for complications of lung transplantation in a real-world application. METHODS: A chat-based application prompted patients to perform home spirometry, enter their forced expiratory volume in 1 second (FEV1), answer symptom queries, and provided patient education. The program alerted patients and providers to substantial FEV1 decreases and concerning symptoms. Data was integrated into the electronic health record (EHR) system and dashboards were developed for program monitoring. RESULT: Between May 2020 and December 2021, 544 patients were invited to enroll, of whom 427 were invited remotely and 117 were enrolled in-person. 371 (68%) participated by submitting ≥1 FEV1 values. Overall engagement was high, with an average of 197 unique patients submitting FEV1 data per month. In-person enrollees submitted an average of 4.6 FEV1 values per month and responded to 55% of scheduled chats. Home and laboratory FEV1 values correlated closely (rho = 0.93). There was an average of 133 ± 59 FEV1 decline alerts and 59 ± 23 symptom alerts per month. 72% of patients accessed education modules, and the program had a high net promoter score (53) amongst users. CONCLUSIONS: We demonstrate that a novel, automated, chat-based, and EHR-integrated home spirometry intervention is well accepted, generates reliable assessments of graft function, and can deliver automated feedback and education resulting in moderately-high adherence rates. We found that in-person onboarding yields better engagement and adherence. Future work will aim to demonstrate the impact of remote care monitoring on early detection of lung transplant complications.

Critical Care of the Lung Transplant Patient.

Lung transplantation is a therapeutic option for end-stage lung disease that improves survival and quality of life. Prelung transplant admission to the intensive care unit (ICU) for bridge to transplant with mechanical ventilation and extracorporeal membrane oxygenation (ECMO) is common. Primary graft dysfunction is an important immediate complication of lung transplantation with short- and long-term morbidity and mortality. Later transplant-related causes of respiratory failure necessitating ICU admission include acute cellular rejection, atypical infections, and chronic lung allograft dysfunction. Lung transplantation for COVID-19-related ARDS is increasingly common..

Improvements in frailty contribute to substantial improvements in quality of life after lung transplantation in patients with cystic fibrosis.

BACKGROUND: While lung transplantation (LTx) improves health-related quality of life (HRQL) in cystic fibrosis (CF), the determinants of this improvement are unknown. In other populations, frailty-a syndrome of vulnerability to physiologic stressors-is associated with disability and poor HRQL. We hypothesized that improvements in frailty would be associated with improved disability and HRQL in adults with CF undergoing LTx. METHODS: In a single-center prospective cohort study from 2010 to 2017, assessments of frailty, disability, and HRQL were performed before and at 3- and 6-months after LTx. We assessed frailty by the short physical performance battery (SPPB). We assessed disability with the Lung Transplant Valued Life Activities scale (LT-VLA) and HRQL by the Medical Outcomes Study Short Form Physical and Mental Component Summary scales (SF12-PCS, -MCS), the Airway Questionnaire 20-Revised (AQ20R), and the Euroqol 5D (EQ5D). We tested the association of concurrent changes in frailty and lung function on disability and HRQL by linear mixed-effects models adjusted for sex and body mass index. RESULTS: Among 23 participants with CF, improvements in frailty and lung function were independently associated with improved disability and some HRQL measures. For example, each 1-point improvement in SPPB or 200 mL improvement in FEV1 was associated with improved LT-VLA disability by 0.14 (95%CI: 0.08-0.20) and 0.07 (95%CI: 0.05-0.09) points and improved EQ5D by 0.05 (95%CI: 0.03 to 0.07) and 0.02 (95%CI: 0.01-0.03) points, respectively. CONCLUSION: Improvement in frailty is a novel determinant of improved disability and HRQL in adults with CF undergoing LTx.

Management and clinical outcomes after lung transplantation in patients with pre-transplant Mycobacterium abscessus infection: A single center experience.

BACKGROUND: Preoperative Mycobacterium abscessus infection is often considered a contraindication to lung transplantation because of its association with poor outcomes after transplant. Detailed strategies for bridging to transplant, post-operative management, and data regarding outcomes are lacking. METHODS: We reviewed outcomes in subjects with M abscessus infection who underwent lung transplantation between 2010 and 2018 at the University of California San Francisco. M abscessus infection was defined by American Thoracic Society (ATS) criteria. Data collected included age, FEV1 , BMI, LAS, antibiotic regimens, and other management decisions. Time to chronic lung allograft dysfunction (CLAD) and survival were also assessed. RESULTS: Of 387 lung transplant recipients, seven were infected with M abscessus at the time of listing. All received multiple antibiotics before transplant. While all subjects converted to smear negative for acid-fast bacilli before listing, five of the seven remained culture-positive at the time of transplant. After transplant, subjects received a median of 6 months of a multi-antibiotic regimen. One subject developed a post-operative M abscessus soft tissue infection that was treated medically. Six of the seven subjects survived the observation period; one died unrelated to M abscessus. Time to CLAD and survival were similar to a contemporary comparator group of CF transplant recipients. CONCLUSION: Lung transplant recipients with M abscessus infection have a low incidence of recurrent infection, excellent survival, and freedom from CLAD when an aggressive management and surveillance strategy is utilized. Given these findings, M abscessus infection may not be considered a contraindication to lung transplantation.