Background Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease, predisposing to an increased risk of infection. A complete picture of these infections is lacking.
Research question Describe the characteristics and clinical outcomes of patients diagnosed with aPAP, and to identify risk factors associated with opportunistic infections.
Methods We conducted a retrospective cohort including all patients diagnosed with aPAP between 2008 and 2018 in France and Belgium. Data were collected using a standardised questionnaire including demographics, comorbidities, imaging features, outcomes and microbiological data.
Results We included 104 patients, 2/3 were men and median age at diagnosis was 45 years. With a median follow-up of 3.4 years (IQR 1.7–6.6 years), 60 patients (58%), developed at least one infection, including 23 (22%) with opportunistic infections. Nocardia spp was the main pathogen identified (n=10). Thirty-five (34%) patients were hospitalised due to infection. In univariate analysis, male gender was associated with opportunistic infections (p=0.04, OR=3.88; 95% CI (1.02 to 22.06)). Anti-granulocyte macrophage colony-stimulating factor antibody titre at diagnosis was significantly higher among patients who developed nocardiosis (1058 (316–1591) vs 580 (200–1190), p=0.01). Nine patients had died (9%), but only one death was related to infection.
Interpretation Patients with aPAP often presented with opportunistic infections, especially nocardiosis, which highlights the importance of systematic search for slow-growing bacteria in bronchoalveolar lavage or whole lung lavage.
- pulmonary alveolar proteinosis
- GM-CSF autoantibody
- opportunist lung infections
- bacterial Infection
Data availability statement
Data can be made available upon reasonable request.
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DLP and SJ are joint senior authors.
DLP and SJ contributed equally.
Correction notice This article has been corrected since it was published Online First. Figure 1 has been corrected.
Contributors AM fulfilled the role of guarantor. DLP did the analysis. AM, DLP, PT and SJ cowrote the original draft. AM, RB, LW-S, YU, EG, GP, MR-G, JT, EBergot, JC, SM-A, ABergeron, EBlanchard, BB, PB, ABourdin, PRB, SH, CHM, SQ, HN, CC, BC, YG, DM, CM, PT, VC, DLP and SJ contributed substantially to the investigation and data collection, as well to reviewing and editing the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests The authors reported no conflict of interest related to this work. SMA reports having received consultancy for board membership, consultancy or speaker fees from AstraZeneca, Boehringer Ingelheim, Novartis and Roche, GSK, BMS, Chiesi and Pfizer; and travel support from Boehringer Ingelheim. Other authors have nothing to disclose.
Provenance and peer review Not commissioned; externally peer reviewed.
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