Th17/Treg imbalance induced by increased incidence of atherosclerosis in patients with Systemic Lupus Erythematosus (SLE)

Abstract

The objective of the study was to investigate whether the immunological factors in patients with Systemic Lupus Erythematosus (SLE) and a high incidence of atherosclerosis correlate with a Th17/Treg imbalance. All cases were recruited from the Affiliated Hospital of Guilin Medical University: a random sample of 42 cases with SLE and atherosclerosis, 39 positive control cases with SLE alone with no anomalies detected via coronary artery angiography or carotid color Doppler ultrasound examination, as well as 45 normal controls based on physical examination were included. The serum expression levels of IL-10, IL-17, IL-6, TNF-α, Th17, Th17 cell transcription factor RORγt, and Treg cell transcription factor Foxp3 were measured in each group of patients. Correlations among Th17/Treg, their secreted cell factors, transcription factors, SLE, and SLE with concurrent atherosclerosis (SLE + AS) were analyzed. The results are as follows: (1) total cholesterol and triacylglycerol levels in the SLE and SLE + AS groups were higher than those in the control group (P < 0.05 and P < 0.01); (2) serum IL-10 in the SLE + AS group was lower than the SLE and control groups; however, serum IL-17 and IL-6 levels in the SLE + AS group were elevated compared to the SLE and control groups (average P < 0.01); (3) the percentage of Treg cells in the SLE + AS patients was lower than those found in the SLE and control groups; in contrast, percentages of serum Th17 cells in SLE + AS patients were higher than the SLE and control groups (average P < 0.01); (4) FoxP3 expression in the SLE + AS group was lower than levels observed in the SLE and control groups (average P < 0.05); in contrast, RORγt expression in the SLE + AS group was higher than levels found in the SLE and control groups (average P < 0.05). The abnormal balance between Th17 cells and Treg cells in SLE + AS patients has obvious implications for Th17 migration. The results suggest that Th17 cell proportion and function can be enhanced, relatively or absolutely, whereas the proportion and function of Treg cells can abate, relatively or absolutely. This imbalance may be an important reason for the high incidence of SLE with atherosclerosis.