%0 Journal Article %T An exploratory study investigating biomarkers associated with autoimmune pulmonary alveolar proteinosis (aPAP). %A Campo I %A Meloni F %A Gahlemann M %A Sauter W %A Ittrich C %A Schoelch C %A Trapnell BC %A Gupta A %J Sci Rep %V 12 %N 1 %D 05 2022 24 %M 35610268 %F 4.996 %R 10.1038/s41598-022-11446-8 %X Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare lung disorder involving production of autoantibodies against endogenous granulocyte-macrophage colony-stimulating factor (GM-CSF). This study aimed to identify biomarkers that could be used to monitor for aPAP, particularly in patients treated with anti-GM-CSF antibodies. This was an exploratory, prospective, observational, single-center study. Pre-specified biomarkers were evaluated between baseline and Day 120 in serum/plasma, whole blood, sputum and exhaled breath condensate from patients with aPAP, healthy volunteers, and patients with chronic obstructive pulmonary disease (COPD) and asthma (not treated with anti-GM-CSF and with no evidence of aPAP). Pulmonary function tests were also performed. Overall, 144 individuals were enrolled (aPAP: n = 34, healthy volunteers: n = 24, COPD: n = 40 and asthma: n = 46). Plasma GM-CSF levels were lower, and Krebs von den Lungen 6 and GM-CSF autoantibody ranges were higher, in patients with aPAP compared with other populations. Surfactant proteins-A and -D, lactate dehydrogenase and carcinoembryonic antigen ranges partially or completely overlapped across populations. Most plasma biomarkers showed high sensitivity and specificity for detection of aPAP; GM-CSF and GM-CSF autoantibody concentrations demonstrated equivalent sensitivity for differentiating aPAP. In addition to characteristic GM-CSF autoantibodies, assessment of plasma GM-CSF may identify individuals at risk of developing aPAP.Trial registration: EudraCT, 2012-003475-19. Registered 23 July 2012- https://eudract.ema.europa.eu/ .