A retrospective multicenter cohort study
To assess whether immune cells may identify patients with idiopathic pulmonary fibrosis at greater risk of poor outcomes, Ms. Scott and her collaborators conducted a retrospective multicenter cohort study.
They first analyzed transcriptome data from 120 peripheral blood mononuclear cell samples of patients with idiopathic pulmonary fibrosis, which they obtained from the Gene Expression Omnibus at the National Center for Biotechnology Information. They used statistical deconvolution to estimate percentages of 13 immune cell types and examined their associations with transplant-free survival. Their discovery analysis found that estimated CD14+ classical monocyte percentages above the mean correlated with shorter transplant-free survival times (hazard ratio, 1.82), but percentages of T cells and B cells did not.
The researchers then validated these results using samples from patients with idiopathic pulmonary fibrosis in two independent cohorts. In the COMET validation cohort, which included 45 patients with idiopathic pulmonary fibrosis whose monocyte counts were measured using flow cytometry, higher monocyte counts were significantly associated with greater risk of disease progression. In the Yale cohort, which included 15 patients with idiopathic pulmonary fibrosis, the 6 patients who were classified as high risk on the basis of a 52-gene signature had more CD14+ monocytes than the 9 low-risk patients did.
In addition, Ms. Scott and her collaborators looked at complete blood count values in the electronic health records of 45,068 patients with idiopathic pulmonary fibrosis, systemic sclerosis, hypertrophic cardiomyopathy, or myelofibrosis in Stanford, Northwestern, Vanderbilt, and Optum Clinformatics Data Mart cohorts.