Background: Pulmonary alveolar proteinosis (PAP) is a rare syndrome caused by several distinct diseases leading to progressive dyspnoea, hypoxaemia, risk of respiratory failure and early death due to accumulation of proteinaceous material in the lungs. Diagnostic strategies may include computed tomography (CT) of the lungs, bronchoalveolar lavage (BAL), evaluation of antibodies against granulocyte–macrophage colony-stimulating factor (GM-CSF), genetic testing and, eventually, lung biopsy. The management options are focused on removing the proteinaceous material by whole lung lavage (WLL), augmentation therapy with GM-CSF, rituximab, plasmapheresis and lung transplantation. The presented diagnostic and management guidelines aim to provide guidance to physicians managing patients with PAP.Methods: A European Respiratory Society Task Force composed of clinicians, methodologists and patients with experience in PAP developed recommendations in accordance with the ERS Handbook for Clinical Practice Guidelines and the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach. This included a systematic review of the literature and application of the GRADE approach to assess the certainty of evidence and strength of recommendations. The Task Force formulated five PICO (Patients, Intervention, Comparison, Outcomes) questions and two narrative questions to develop specific evidence-based recommendations.Results: The Task Force developed recommendations for the five PICO questions. These included management of PAP with WLL, GM-CSF augmentation therapy, rituximab, plasmapheresis and lung transplantation. Also, the Task Force made recommendations regarding the use of GM-CSF antibody testing, diagnostic BAL and biopsy based on the narrative questions. In addition to the recommendations, the Task Force provided information on the hierarchy of diagnostic interventions and therapy.Conclusions: The diagnosis of PAP is based on CT and BAL cytology or lung histology, whereas the diagnosis of specific PAP-causing diseases requires GM-CSF antibody testing or genetic analysis. There are several therapies including WLL and augmentation therapy with GM-CSF available to treat PAP, but supporting evidence is still limited.

Interstitial lung diseases (ILDs) are a set of heterogeneous lung diseases characterised by inflammation and, in some cases, fibrosis. These lung conditions lead to dyspnoea, cough, abnormalities in gas exchange, restrictive physiology (characterised by decreased lung volumes), hypoxaemia and, if progressive, respiratory failure. In some cases, ILDs can be caused by systemic diseases or environmental exposures. The ability to treat or cure these ILDs varies based on the subtype and in many cases lung transplantation remains the only curative therapy. There is a growing body of evidence that both common and rare genetic variants contribute to the development and clinical manifestation of many of the ILDs. Here, we review the current understanding of genetic risk and ILD.

Introduction: Interstitial lung diseases (ILDs) can be caused by mutations in theSFTPA1andSFTPA2genes, which encode the surfactant protein (SP) complex SP-A. Only 11SFTPA1orSFTPA2mutations have so far been reported worldwide, of which five have been functionally assessed. In the framework of ILD molecular diagnosis, we identified 14 independent patients with pathogenicSFTPA1orSFTPA2mutations. The present study aimed to functionally assess the 11 different mutations identified and to accurately describe the disease phenotype of the patients and their affected relatives.Methods: The consequences of the 11SFTPA1orSFTPA2mutations were analysed bothin vitro, by studying the production and secretion of the corresponding mutated proteins andex vivo, by analysing SP-A expression in lung tissue samples. The associated disease phenotypes were documented.Results: For the 11 identified mutations, protein production was preserved but secretion was abolished. The expression pattern of lung SP-A available in six patients was altered and the family history reported ILD and/or lung adenocarcinoma in 13 out of 14 families (93%). Among the 28SFTPA1 or SFTPA2mutation carriers, the mean age at ILD onset was 45 years (range 0.6–65 years) and 48% underwent lung transplantation (mean age 51 years). Seven carriers were asymptomatic.Discussion: This study, which expands the molecular and clinical spectrum of SP-A disorders, shows that pathogenicSFTPA1orSFTPA2mutations share similar consequences for SP-A secretion in cell models and in lung tissue immunostaining, whereas they are associated with a highly variable phenotypic expression of disease, ranging from severe forms requiring lung transplantation to incomplete penetrance.

Background: Survivors of severe-to-critical coronavirus disease 2019 (COVID-19) may have functional impairment, radiological sequelae and persistent symptoms requiring prolonged follow-up. This pragmatic study aimed to describe their clinical follow-up and determine their respiratory recovery trajectories, and the factors that could influence them and their health-related quality of life.Methods: Adults hospitalised for severe-to-critical COVID-19 were evaluated at 3 months and up to 12 months post-hospital discharge in this prospective, multicentre, cohort study.Results: Among 485 enrolled participants, 293 (60%) were reassessed at 6 months and 163 (35%) at 12 months; 89 (51%) and 47 (27%) of the 173 participants initially managed with standard oxygen were reassessed at 6 and 12 months, respectively. At 3 months, 34%, 70% and 56% of the participants had a restrictive lung defect, impaired diffusing capacity of the lung for carbon monoxide (D_LCO) and significant radiological sequelae, respectively. During extended follow-up, bothD_LCOand forced vital capacity percentage predicted increased by means of +4 points at 6 months and +6 points at 12 months. Sex, body mass index, chronic respiratory disease, immunosuppression, pneumonia extent or corticosteroid use during acute COVID-19 and prolonged invasive mechanical ventilation (IMV) were associated withD_LCOat 3 months, but not its trajectory thereafter. Among 475 (98%) patients with at least one chest computed tomography scan during follow-up, 196 (41%) had significant sequelae on their last images.Conclusions: Although pulmonary function and radiological abnormalities improved up to 1 year post-acute COVID-19, high percentages of severe-to-critical disease survivors, including a notable proportion of those managed with standard oxygen, had significant lung sequelae and residual symptoms justifying prolonged follow-up.