Background Brain‐derived neurotrophic factor (BDNF) exerts protective roles against dyslipidemia, atherosclerosis, and inflammation in cardiovascular diseases; meanwhile, it retards CD4+ T cell differentiation into T helper (Th)1 and Th17 cells. Hence, this study aimed to investigate the linkage of serum BDNF with Th1/Th2 ratio, Th17/regulatory T (Treg) ratio, and major adverse cardiovascular events (MACE) risk in the coronary heart disease (CHD) patients. Methods This prospective study detected serum BDNF in 210 CHD patients, 50 disease controls (DCs), and 50 healthy controls (HCs) using an enzyme‐linked immunosorbent assay. For CHD patients only, the proportion of Th1, Th2, Th17, and Treg cells in blood CD4+ T cells was calculated by flow cytometry. Results The BDNF varied among CHD patients, DC, and HC (p < 0.001). Specifically, BDNF was declined in CHD patients compared with DCs (p < 0.001) and HCs (p < 0.001). In CHD patients, BDNF was negatively related to Th1 cells (p = 0.031), Th1/Th2 ratio (p = 0.026), Th17 cells (p = 0.001), and Th17/Treg ratio (p = 0.002). Concerning the prognosis, BDNF was reduced in patients with MACE occurrence compared to patients without MACE occurrence (p = 0.006). Furthermore, BDNF showed a trend (lacked statistical significance) to relate to longer MACE‐free survival (p = 0.059). Besides, BDNF was related to the absence of obesity (p = 0.019), decreased total cholesterol (p = 0.043), low‐density lipoprotein cholesterol (p = 0.019), C‐reactive protein (p = 0.012), and Gensini score (p = 0.005). Conclusion Serum BDNF negatively correlates with Th1/Th2 ratio, Th17/Treg ratio, and estimates lower MACE risk in CHD patients.

Objective Long non‐coding RNA KQT‐like subfamily, member 1 opposite strand/antisense transcript 1 (KCNQ1OT1) could regulate lipid metabolism, vascular smooth muscle cell function, inflammation, and atherosclerosis. This study aimed to evaluate whether lncRNA KCNQ1OT1 could serve as a biomarker for reflecting coronary heart disease (CHD) patients' disease situation and prognosis. Methods LncRNA KCNQ1OT1 expression was determined in peripheral blood mononuclear cells from 267 CHD patients, 50 disease controls (DCs) (unexplained chest pain), and 50 healthy controls (HCs) by the RT‐qPCR method. TNF‐α, IL‐17A, VCAM‐1, and ICAM‐1 were determined by the ELISA procedure in serum from CHD patients only. The mean (95% confidential interval) follow‐up duration was 16.0 (15.3–16.8) months. Results LncRNA KCNQ1OT1 was highest in CHD patients, followed by DCs, and lowest in HCs (p < 0.001). LncRNA KCNQ1OT1 could distinguish the CHD patients from DCs (area under the curve [AUC]: 0.757) and from the HCs (AUC: 0.880). LncRNA KCNQ1OT1 was positively associated with triglyceride (p = 0.026), low‐density lipoprotein cholesterol (p = 0.023), cardiac troponin I (p = 0.023), and C‐reactive protein (p = 0.001). Besides, lncRNA KCNQ1OT1 was also positively linked with the Gensini score (p = 0.008). Furthermore, lncRNA KCNQ1OT1 was positively related to the TNF‐α (p < 0.001), IL‐17A (p = 0.008), and VCAM‐1 (p = 0.003). LncRNA KCNQ1OT1 was elevated in CHD patients with MACE compared to those without MACE (p = 0.006); moreover, lncRNA KCNQ1OT1 high was associated with shorter MACE‐free survival (p = 0.018). Conclusion Circulating lncRNA KCNQ1OT1 expression not only reflects the stenosis degree, blood lipid level, and inflammation status but also predicts the MACE risk, while a large‐scale study is needed for verification.