An increased prevalence of serum anti-MCV antibody is observed in the serum of patients with idiopathic pulmonary fibrosis (IPF) but the clinical relevance of these antibodies is unknown.

Patients from our center with a diagnosis of IPF according to the 2018 ATS/ERS/JRS/ALAT guidelines and at least one anti-MCV assay available were selected. All patients were part of the prospective cohort European IPF registry and selected between 03/2010 and 03/2018. We constituted two groups of patients according to the anti-MCV status at baseline to compare their characteristics at baseline and the evolution of lung function, survival and/or transplantation status.

Anti-MCV data were available for 101 patients, of whom 86 had complete clinical data available. Twenty-nine (34 %) patients had a positive anti-MCV assay (MCV+), at a low level in most patients (29 UI/mL [IQR 25—40]), and 57 (66 %) patients a negative assay (MCV-). MCV+ patients were 20 men and 9 women, with a median age of 73 years [IQR 67—78]. MCV- patients were 49 men and 8 women with a median age of 72 years [IQR 64—77]. Sixty-two (75 %) patients were ex-smokers and 5 (6 %) were active smokers. Median cumulative tobacco smoke exposure was 22.5 (15.0–38.6) and was similar in both groups. Lung function test results and HRCT pattern distribution was similar in both groups at baseline. The median duration of follow-up was 3.5 years [IQR 2.1—5.0]. Lung function decline was similar in both groups. During the study period, 31 (36 %) patients died or have been transplanted with no difference in transplant-free survival status between the two groups.

Low level anti-MCV autoimmunity was prevalent in IPF patients