THE VALUE OF ALZHEIMER'S DISEASE-ASSOCIATED NEUROFILAMENT PROTEIN COMBINED WITH AΒ1-42/P-TAU-181 RATIO FOR THE DIAGNOSIS OF ALZHEIMER'S

Congyang Yan^{1, #}, Maojun Miao^{2, #}, Bing Liu³, Wenchao Qiu⁴, Ming Chen⁴, Liandong Zhao⁴, Wenwei Zou^{4, *}

¹Department of Neurology, Lianshui People`s Hospital - <sup>2</sup>Department of Neurology, Baoying People`s Hospital - ³Department of Neurology, Siyang Hospital of Chinese medicine - ⁴Department of Neurology, Huaian Hospital Affiliated to Xuzhou Medical University

Objective: To analyze the value of Alzheimer's disease (AD)-associated neurofilament protein (AD7c-NTP) combined with Aβ1-42/P-tau-181 for the diagnosis of AD.

Methods: A total of 65 patients with AD admitted to our hospital from January 2019 to January 2020 were included in the observation group, while 40 healthy people examined in our hospital during the same period were included in the control group. The fasting veins of patients from the two groups were used to collect 5ml of blood and 10ml of first mid-stream urine in the morning. The levels of AD7c-NTP, Aβ1-42, and P-tau-181 in serum were detected by enzyme-linked immunosorbent assay. All patients were assessed using the Intelligent Mental State Examination Scale (MMSE), clinical dementia rating (CDR) scale, and daily living capacity scale (ADL) were used to calculate the ratio of Aβ1-42/P-tau-181. Spearman's rank correlation coefficient was used to analyze the correlation of AD7c-NTP and Aβ1-42/P-tau-181 ratio with the results of the MMSE, CDR, and ADL. An ROC curve was used to analyze the value of AD7c-NTP combined with the Aβ1-42/P-tau-181 ratio for the diagnosis of AD.

Results: The levels of AD7c-NTP and P-tau-181 in the observation group were significantly higher than those in the control group, while the ratios of Aβ1-42 and Aβ1-42/P-tau-181 were significantly lower than those in the control group (p<0.05 or <0.01). The ADL and CDR levels in the observation group were significantly higher than those in the control group, while the MMSE levels were significantly lower than those in the control group (p<0.01). AD7c-NTP was positively correlated with ADL and CDR (r = 0.419, 0.572, p<0.05 or <0.01), and negatively correlated with MMSE (r=-0.628, p<0.05). Aβ1-42/P-tau-181 ratio was negatively correlated with ADL (r=-0.516, p<0.05) and CDR (r=-0.582, p <0.05), and positively correlated with MMSE (r=0.431, p<0.01). ROC curve analysis showed that using the AUC of AD7c-NTP to diagnose AD was 0.851, while the best cutoff value was 79.46ng/ml, the sensitivity was 80.45%, and the specificity was 83.49%. For using the ratio of Aβ1-42/P-tau-181 to diagnose AD, the AUC was 0.741, the optimal cutoff value was 12.71, the sensitivity was 78.49%, and the specificity was 74.12%. The AUC of the combined diagnosis of AD was 0.910, while the sensitivity was 93.14% and the specificity was 91.74%.

Conclusion: In AD patients, AD7c-NTP levels were significantly higher than those in healthy people, while the ratios of Aβ1-42/P-tau-181 were significantly lower than those in healthy people. Moreover, a correlation exists between changes in the level and the severity of AD patients. A certain value exists in this regard, and the combined diagnostic value of the two is the highest, which can serve an important role in the diagnosis of AD.