The study shows that people with moderately high triglyceride levels have immune cells (T cells) that look more inflamed at the gene level, which could help explain why high triglycerides raise heart disease risk. Lower triglyceride levels seem to reverse this inflammation pattern.

Triglycerides and T cells play a key role in atherosclerosis, the leading cause of cardiovascular disease (CVD). Moderately elevated triglycerides have emerged as a causal risk factor, and T cells are a prominent component of atherosclerotic plaques. This cross-sectional study examined transcriptomic differences in T cells among patients with varying triglyceride levels via RNA sequencing. We analyzed CD4⁺ and CD8⁺ T cells from 49 participants, including those with primary (genetic) and secondary moderate hypertriglyceridemia, severe hypertriglyceridemia, and hypotriglyceridemia. Patients with primary moderate hypertriglyceridemia exhibited a proinflammatory transcriptomic profile, including increased interleukin-6 receptor (IL6R) expression, which is implicated in CVD risk. Similar patterns appeared in CD8⁺ T cells and, to a lesser extent, in secondary moderate hypertriglyceridemia patients. Conversely, transcriptomic differences were reversed in hypotriglyceridemia and absent in severe hypertriglyceridemia patients. These findings suggest that elevated triglycerides may contribute to CVD by promoting a proinflammatory transcriptomic profile in T cells.