Serum Levels of Il-6 May Correlate With Cognitive Impairment in AD

Serum IL-6 levels may serve as biomarkers for Alzheimer's disease.

Patients with Alzheimer’s disease may have higher serum IL-6 levels than subjects with mild cognitive impairment and healthy controls, according to data presented at the 2017 American Psychiatric Association Annual Meeting, held May 20 -24, in San Diego, California.

Since mild cognitive impairment and Alzheimer’s disease are thought to share several pathological features, Hyun Kim, MD, PhD and Kang Joon Lee from the psychiatry department at the Ilsanpaik Hospital in Daehwa-dong, Goyang-si, South Korea, compared serum cytokine levels in patients with Alzheimer’s disease, subjects who had mild cognitive impairment, and healthy controls in order to assess the correlation between cytokine levels and cognitive performance.

The researchers recruited 35 patients with Alzheimer’s disease, 29 patients with mild cognitive impairment, and 28 healthy controls from Ilsanpaik Hospital. They obtained patient demographic and neuropsychological information, and measured peripheral cytokine levels, specifically tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels in all subjects.

After adjusting for age, they observed a significant difference in IL-6 levels (P =0.045), but not in TNF-α (P =0.082) levels, in the 3 groups. Patients with Alzheimer’s disease had higher IL-6 levels than subjects with mild cognitive impairment and healthy controls. TNF-α and IL-6 levels negatively and positively correlated with Mini-Mental State Examination and Global Deterioration Scale scores, respectively. TNF-α and IL-6 levels were also positively correlated with each other.

“This study suggests that…serum TNF-α and IL-6 levels might be negatively correlated with cognitive function,” Dr Kim said. “We expect serum IL-6 levels might have the role of biomarkers for Alzheimer’s disease.”

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Kim H, Lee KJ. Serum tumor necrosis factor-α and interleukin-6 levels in Alzheimer’s disease and mild cognitive impairment. Presented at: 2017 American Psychiatric Association, May 20-24, in San Diego, California. Abstract #P5-75.