Pathogenesis of interstitial lung disease in systemic sclerosis.

Interstitial lung disease (ILD) is a frequent important complication of systemic sclerosis (SSc). Factors relevant to aetiopathogenesis of SSc are also central to SSc-ILD. Severity of SSc-ILD is variable but it has a major impact on morbidity and mortality. Factors determining SSc-ILD susceptibility reflect the genetic architecture of SSc and are increasingly being defined. There are aspects linked to immunogenomics and non-immunological genetic factors that may be less conserved and underlie some of the geographical and racial diversity of SSc. These associations may also underlie important links between autoantibody subgroups and patient level risk of SSc-ILD. Examination of blood and tissue samples and observational clinical research together with integrated analysis of in vitro and in vivo preclinical models have elucidated pathogenic mechanisms of SSc-ILD. These have confirmed the potential importance of immune mechanisms in the innate and adaptive immune systemic as well as a significant role for profibrotic pathways especially transforming growth factor beta (TGFbeta) and its regulators and downstream mediators. Recent analysis of clinical trial cohorts as well as integrated and multilevel high dimensional analysis of bio-samples has shed further light on SSc-ILD. This is likely to underpin future advances in stratified and precision medicine for treatment of SSc.