From the Journals

Elevated monocyte count predicts poor outcomes in idiopathic pulmonary fibrosis

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A simple, inexpensive marker

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.


 

FROM THE LANCET RESPIRATORY MEDICINE

An increased monocyte count at the time of diagnosis predicts poor outcomes among patients with idiopathic pulmonary fibrosis and other fibrotic diseases, including hypertrophic cardiomyopathy, systemic sclerosis, and myelofibrosis, according to research published in The Lancet Respiratory Medicine.

Graham Beards/Wikipedia Creative Commons

Micrograph of Giemsa-stained monocytes

The data indicate that “a single threshold value of absolute monocyte counts of 0.95 K/mcL could be used to identify high-risk patients with a fibrotic disease,” said Madeleine K. D. Scott, a researcher at Stanford (Calif.) University, and coauthors. The results “suggest that monocyte count should be incorporated into the clinical assessment” and may “enable more conscientious allocation of scarce resources, including lung transplantations,” they said.

While other published biomarkers – including gene panels and multicytokine signatures – may be expensive and not readily available, “absolute monocyte count is routinely measured as part of a complete blood count, an inexpensive test used in clinical practice worldwide,” the authors said.

Further study of monocytes’ mechanistic role in fibrosis ultimately could point to new treatment approaches.

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