Primate Monocytes - CD14, CD16 - Ziegler-Heitbrock

Chronic Cannabis Use is Associated with Altered Monocyte Phenotype, Immune Response, and Depression in Physically Active Individuals.

Abstract

INTRODUCTION: This study evaluated depression, monocyte phenotype, and immune function in physically active cannabis users. METHODS: Participants (N=23) were classified as either cannabis users (CU, n=11) or non-users (NU, n=12). White blood cells isolated from blood were analyzed for co-expression of cluster of differentiation 14 (CD14) and 16 (CD16) using flow cytometry. Lipopolysaccharide (LPS) was cultured with whole blood and assessed for interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) release. RESULTS: The percentage of white blood cells classified as monocytes was not different between groups; however, CU had a significantly greater percentage of monocytes classified as intermediate (p=0.02). When standardized per milliliter of blood, CU had significantly greater numbers of total monocytes (p=0.01), classical monocytes (p=0.02), and intermediate monocytes (p=0.01). Intermediate monocytes per milliliter of blood were positively correlated to the number of times CU used cannabis per day (r=0.864, p<0.01), and Beck Depression Inventory-II (BDI-II) score (r=0.475, p=0.03), which was significantly greater in CU (5.1+-4.8) compared to NU (0.8+-1.0; p<0.01). CU released significantly less TNF-alpha per monocyte in response to LPS. CONCLUSIONS: Cannabis users had altered monocyte phenotypes and function compared to NU. Elevations in intermediate monocytes were positively correlated with measures of cannabis use and BDI-II score.