Abstract: Objective  To observe the expression of tumor necrosis factor-α (TNF-α), macrophage colony stimulating factor (M-CSF) and microRNA (miR)-181a in serum of patients with Alzheimer′s disease (AD) and their diagnostic value. 
Methods  A total of 140 AD patients diagnosed and treated in our hospital were selected as the research subjects (AD group), and they were divided into the mild group (n=52),the moderate group (n=49), and the severe group (n=39) according to the clinical dementia scale, and 50 healthy people who underwent physical examination during the same period were used as the control group. The relative expression of serum miR-181a was detected by real-time fluorescence quantitative PCR (RT-qPCR), and the levels of serum TNF-α and M-CSF were detected by enzyme-linked immunosorbent assay (ELISA). The correlation of serum TNF-α, M-CSF and miR-181a was analyzed by Pearson correlation. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of serum TNF-α, M-CSF and miR-181a expression in AD. 
Results  The expression levels of serum TNF-α, M-CSF and miR-181a in AD group were significantly higher than those in control group (t=49.291, 30.485, 28.313, all P＜0.05). There were statistically significant differences in the expressions of serum TNF-α, M-CSF and miR-181a among the mild, moderate and severe groups (all P＜0.05). Serum TNF-α in AD patients was significantly and positively correlated with the expressions of M-CSF and miR-181a (r=0.524, 0.610, both P＜0.05), and M-CSF was significantly and positively correlated with the expression of miR-181a (r=0.498, P＜0.05). Serum TNF-α＞27.18 ng/L, serum M-CSF＞635.81 ng/L and serum miR-181a＞1.83 were the risk factors of AD. The areas under the ROC curve (AUC) of serum TNF-α, M-CSF,miR-181a and joint testing were 0.741 (95%CI: 0.684-0.789), 0.693 (95%CI: 0.630-0.757), 0.727 (95%CI: 0.682-0.774) respectively, and 0.862 (95%CI: 0.818-0.899), and the AUC of combined detection in diagnosing AD was greater than that of TNF-α, M-CSF and miR-181a alone in diagnosis (Z=3.357, 5.894, 4.911, all P＜0.05). 
Conclusion  The expression of serum TNF-α, M-CSF and miR-181a in AD patients is increased, and the increased levels of the three are independent risk factors for AD, and the combined detection of the three has high value in the diagnosis of AD. 

Key words: Alzheimer′s disease, tumor necrosis factor-α, macrophage colony-stimulating factor