Abstract
The role of mucosal autoimmunity in Idiopathic Pulmonary Fibrosis (IPF) is raised by the detection of autoantibodies directed against lung epithelial antigens in these patients. Anti-Parietal Cell Antibodies (APCA) are often present in autoimmune gastritis. Their search is part of the diagnostic assessment of suspected IPF in our center.
Among 310 patients with IPF diagnosed between 2007 and 2014, 19 APCA positive patients (APCA+ IPF) were identified. We retrospectively collected clinical, lung function and imaging (HRCT) data and compared them with 19 APCA negative IPF patients (APCA- IPF) matched on the date of assessment.
APCA+ IPF were 16 men, mean age 71 yr, 47% former smokers (14 pack-years). The median titer of APCA was 1:160 (max > 1:1280, min 1:80). Fifteen patients (79%) had other low titers autoantibodies (11 ANA, 1 MPO p-ANCA, 1 anti-thyroid, 2 anti-MCV). A pernicious anemia was present in 5 patients (26%) and preceded the fibrosis in 3 cases. HRCT pattern was typical UIP (n=8), possible UIP (n=6), inconsistent with UIP (n=2). With a mean follow up of 31 months, 2 (11%) had an exacerbation and 7 (37%) died.
As compared with APCA- IPF, APCA+ IPF had less severe respiratory disease at diagnosis (DLCO 57% vs 43% pred), preserved PaO2 (85±8 mmHg vs 74±11 mmHg), less honeycombing on HRCT (58% vs 89%), and less neutrophils in BAL (5.4% vs 15.9%). The 12 months FVC decline tended to be slower in ACPA+ patients (+91 ml vs -114 ml / +5% vs -4 %, p = 0.2) but survival was similar.
We conclude that anti-parietal cell autoimmunity is detected in some IPF patients. APCA positivity does not influence the prognosis of the disease but could reflect a common autoimmune process involving the lungs and the stomach.
- Copyright ©the authors 2016
