Th17 immune responses in Brazilian dyslipidemic patients with atherosclerosis

Lymphocytes, macrophages, and immunological mediators are critical in atherogenesis, but Th17 cells are still little studied. We investigated blood lymphocyte profiles, cytometric changes in blood Th17 cells, and production of Th17-associated cytokines by peripheral blood mononuclear cells (PBMCs) stimulated with phytohemagglutinin (PHA) in dyslipidemic patients. Forty-nine Brazilian dyslipidemic patients, including 14 with negative coronary angiograms (CAs) and 35 with positive CAs (atherosclerosis), were classified into groups G1 and G2, respectively, and 27 healthy individuals without dyslipidemia were included in the control group (HI). In all participants, lipid profiles, CVD risk factors, atherogenic risk indexes, cytometry of blood T lymphocytes (CD4+ T, CD8+ T, and Th17 cells), and Th17 cytokine production were determined. Production of interleukin (IL)-17A, IL-17F, IL-21, and IL-22 was measured in culture supernatants of PHA-stimulated PBMCs. Patients with atherosclerosis exhibited low levels of high-density lipoprotein cholesterol and apolipoprotein A and showed increased atherogenic risk indexes and a higher frequency of prior acute myocardial infarction (AMI). CD8+ T-cell counts were lower in patients with previous AMI and higher in dyslipidemic obese individuals. Th17 cell frequency was increased in dyslipidemic women with atherosclerosis. PBMCs from patients with atherosclerosis produced less IL-17A and IL-21, but more IL-22. IL-17F production was unaltered. In summary, cytometric changes in CD8+ T and Th17 lymphocytes and altered production of Th17-associated cytokines were observed in these individuals and were related to endocrine factors, obesity, and AMI. The practical implications of these findings need to be investigated in future studies.