Do Circulating Monocytes Promote and Predict Idiopathic Pulmonary Fibrosis Progression?

Despite the availability of pharmacologic therapies, idiopathic pulmonary fibrosis (IPF) is still a clinical challenge. It is a lethal disease with a clinical course that cannot be predicted at the time of diagnosis. The high burden of suffering in IPF, the need to prioritize a select few for transplantation, and the high mortality highlight the need for better, simpler, and clinically applicable prognostic tools. In airways disease, eosinophil counts are routinely used for subphenotyping, directed therapy, and assessment of therapy responses. Growing evidence supports that innate and adaptive immune cells disrupt normal lung repair. Some key studies have brought to light that several circulating immune populations have the potential to reflect and predict disease outcome either by RNA, protein, or cellular counts. Here, Kreuter and colleagues performed a retrospective pooled analysis in 2,067 patients from randomized double blinded phase III studies, ASCEND (Assessment of Pirfenidone to Confirm Efficacy and Safety in Idiopathic Pulmonary Fibrosis), CAPACITY (Clinical Studies Assessing Pirfenidone in IPF: Research of Efficacy and Safety Outcomes), and INSPIRE (Effect of Interferon gamma-1b on Survival in Patients with Idiopathic Pulmonary Fibrosis), to determine whether monocyte count at baseline was associated with IPF progression.