Interstitial pneumonia with autoimmune features

Interstitial lung disease (ILD) is an umbrella term for lung disease characterised by inflammation and fibrosis of the interstitium. ILD can be idiopathic or secondary to connective tissue disorders, drugs or environmental exposures. Before labelling it as idiopathic we have to rule out secondary causes. ILD is one of the most common extra-articular manifestations of connective tissue diseases (CTDs), causing significant morbidity and mortality. Patients with pre-existing CTD can develop ILD; some patients develop ILD against the background of either one or two clinical features of a CTD or isolated auto-antibody positivity. The current terminology for such an entity is interstitial pneumonia with autoimmune features (IPAF). The current criterion is based on three domains: clinical, serologic and morphologic. To satisfy the IPAF classification criteria, one needs to satisfy the mandatory criterion with one feature from two of the three domains. Classifying patients with this criterion helps in early initiation of immunosuppression and in monitoring them closely for development of features of a well defined CTD. There are a few limitations like the clinical domain being more skewed towards systemic sclerosis and in˜flammatory myositis, exclusion of antineutrophilic cytoplasmic antibody (ANCA) and cytoplasmic pattern in antinuclear antibody (ANA). There are no clear protocols for treatment of IPAF and most of the data has been extrapolated from the management of systemic sclerosis (SSc) ILD and idiopathic non-specific c interstitial pneumonia (NSIP). Progressive disease in spite of treatment demands stronger immunosuppressive agents. Studies on the role of antifibrotics in IPAF are underway, with few small studies showing positive outcomes. There are con˜flicting reports on the survival and outcome of the IPAF cohort. Certain studies suggest that they have better survival compared with idiopathic pulmonary fibrosis (IPF) though other studies contradict this statement.