Elevated monocyte count predicts poor outcomes in idiopathic pulmonary fibrosis

The study by Scott et al. provides evidence that monocyte count may be a “novel, simple, and inexpensive prognostic biomarker in idiopathic pulmonary fibrosis,” according to an accompanying editorial.

Progress has been made in the treatment of idiopathic pulmonary fibrosis, but patient prognosis remains “challenging to predict,” wrote Michael Kreuter, MD, of University of Heidelberg, Germany, and Toby M. Maher, MB, MSc, PhD, of Royal Brompton Hospital in London and Imperial College London. “One lesson that can be learned from other respiratory disorders is that routinely measured cellular biomarkers, such as blood eosinophil counts in chronic obstructive pulmonary disease (COPD), can predict treatment responses” (Lancet Respir Med. 2019 Jun. doi: 10.1016/S2213-2600[19]30050-5).

Increased blood monocyte counts in idiopathic pulmonary fibrosis may reflect disease activity, which “could explain the outcome differences,” said Dr. Kreuter and Dr. Maher. “As highlighted by the investigators themselves, before introducing assessment of monocyte counts as part of routine clinical care for individuals with idiopathic pulmonary fibrosis, the limitations of this research should be taken into account. These include uncertainty around diagnosis and disease severity in a substantial subset of the patients, and the unknown effect of medical therapies (including corticosteroids and immunosuppressant and antifibrotic drugs) on monocyte counts and prognosis.” Researchers should validate the clinical value of blood monocyte counts in existing and future cohorts and evaluate the biomarker in clinical trials.

The editorialists have received compensation and funding from various pharmaceutical companies.