Associations of Monocyte Count and Other Immune Cell Types with Interstitial Lung Abnormalities.

Overview

abstract

RATIONALE: Higher blood monocyte counts are associated with worse survival in adults with clinically diagnosed pulmonary fibrosis. Their association with the development and progression of interstitial lung abnormalities (ILA) in humans is unknown. OBJECTIVES: We evaluated the associations of blood monocyte count, and other immune cell types, with ILA, high attenuation areas (HAA), and forced vital capacity (FVC) in four independent cohorts. METHODS: We included participants with measured monocyte counts and CT imaging enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA, n=484), Age/Gene Environment Susceptibility Study (AGES-Reykjavik, n=3,547), Genetic Epidemiology of COPD (COPDGene, n=2,719), and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points (ECLIPSE, n=646). MEASUREMENTS AND MAIN RESULTS: After adjustment for covariates, a 1-SD increment in blood monocyte count was associated with ILA in MESA (odds ratio (OR) 1.3, 95% CI 1.0-1.8), AGES-Reykjavik (OR 1.2, 95% CI 1.1-1.3), COPDGene (OR 1.3, 95% CI 1.2-1.4), and ECLIPSE (OR 1.2, 95% CI 1.0-1.4). A higher monocyte count was associated with ILA progression over 5 years in AGES-Reykjavik (OR 1.2, 95% CI 1.0-1.3). Compared with participants without ILA, there was a higher percentage of activated monocytes among those with ILA in MESA. Higher monocyte count was associated with greater HAA in MESA and lower FVC in MESA and COPDGene. Associations of other immune cell types were less consistent. CONCLUSIONS: Higher blood monocyte counts were associated with the presence and progression of interstitial lung abnormalities and lower FVC.