Clinical and Serological Characteristics of a Monocentric Cohort of Patients Affected by Interstitial Pneumonia with Autoimmune Features (IPAF).

Introduction: Interstitial lung diseases (ILDs) are diseases characterised by excessive deposition of collagen matrices in the pulmonary interstitium. Some of them are considered idiopathic (idiopathic pulmonary fibrosis - IPF), others are related to known pathologies such as connective tissue diseases (CTDs-ILD). Patient affected by ILD and features referable to CTD, not satisfying CTD criteria, are called Interstitial pneumonia with autoimmune features (IPAF) patients. Objective: The aim of this report was to investigate clinical and serologic features of a monocentric cohort of patients with IPAF. Another objective was to describe the autoantibody profile, clinical features, High Resolution Computerised Tomography (HRCT) and Nailfold Video Capillaroscopy (NVC) patterns. Methods: 36 IPAF patients were consecutively enrolled. Clinical, serological, and morphological features were collected. Results: 36 consecutive IPAF patients were enrolled from January 2021 to January 2022. Raynaud's phenomenon was the most frequent symptom identified. We also described other signs and symptoms not included in IPAF criteria. 36,1% of patients demonstrated a Usual Interstitial Pneumonia (UIP) pattern by HRCT. Pulmonary arterial pressure estimation (PAPs) resulted elevated (≥ 25 mmHg) in 6 patients. Antinuclear antibodies (ANA) ≥ 1/80 was the most frequent autoantibody, followed by anti-Ro, in patients with UIP pattern and Non-Specific Interstitial Pneumonia (NSIP) pattern at HRCT. NVC highlighted non-specific microangiopathy as the most common pattern especially in UIP patients. Conclusions: This paper may contribute to stimulate the interest in better characterisation of clinical, serologic, and instrumental features for IPAF patients by redefining IPAF classification criteria in order to treat them as best as possible.