# Relationships Between Circulating Lipids, Lipoproteins, and Lymphocyte Subsets in the Multi-Ethnic Study of Atherosclerosis

## TL;DR

This study explores how blood lipids and lipoproteins are linked to different types of lymphocytes in a diverse group of people.

## Contribution

It identifies novel associations between specific lipoproteins and immune cell subsets in a large multi-ethnic cohort.

## Key findings

- Higher HDL-cholesterol is linked to increased memory B-cells.
- Higher LDL and triglycerides are associated with inflammatory T-cells.
- HDL-lipoproteins are linked to fewer senescent T-cells.

## Abstract

Pre-clinical studies demonstrated lipids and lipoproteins influence T-cell phenotype. Several large cohort studies have also observed that plasma lipids and lipoproteins are associated with white blood cell and lymphocyte counts. However, there are little data on the relationships of lipids or lipoproteins with lymphocyte subsets in large, community-based, multi-ethnic cohorts.

The purpose of this study was to evaluate associations of plasma lipid and lipoprotein fractions with circulating lymphocyte subsets in participants of the Multi-Ethnic Study of Atherosclerosis (MESA).

MESA recruited 6,814 adults (aged 45–84 years) free of clinical cardiovascular disease at the baseline exam between 2000–2002. This study included 1,735 participants (49% male, 36% White) with lipoprotein and immune cell phenotyping data at baseline. Multivariable linear regression models evaluated associations between lipoprotein concentration (analyzed per 1-standard deviation (SD) increment) and lymphocyte subsets.

Following correction for multiple hypothesis testing (p < 0.0006), higher high-density lipoprotein (HDL)-cholesterol was associated with higher proportions of memory B-cells, while HDL-lipoprotein concentration was associated with lower pan B-cells. In analyses not corrected for multiple hypothesis testing (p < 0.05), higher concentrations of total-cholesterol, low-density lipoprotein (LDL) cholesterol and LDL-lipoproteins, triglycerides and triglyceride-rich lipoproteins were associated with higher proportions of several T-cell subsets associated with inflammation and senescence. Conversely, a higher concentration of HDL-lipoproteins were associated with lower proportions of senescence-associated T-cells.

These results indicate plasma lipids and lipoproteins may play a role in influencing circulating immune cells. If confirmed in longitudinal studies, these findings may have implications for the development of therapeutics targeting inflammation in patients with elevated lipids.