Predicting the Dynamics of Mild Cognitive Impairment According to Immunological Parameters

Abstract

Background: neuroin flammation is an important link in the pathogenesis of pre-dementia cognitive impairment and the development of dementia in Alzheimer’s disease.The aim of the study was to determine the prognostic value of inflaammatory markers (enzymatic activity of LE and its inhibitor alpha1-PI) at the stage of mild cognitive impairment for subsequent follow-up evaluation.Patients and methods: a total of 103 patients with an amnesic type of mild cognitive impairment (aMCI) aged 50 to 89 years (mean age 68.1 ± 9.4 years) were examined. Mental status of the patients was assessed clinically and by psychometric scales and tests. After 3 years of observation, the patients were divided into two groups depending on the dynamics of cognitive status: the 1st group consisted of 49 patients with progression of cognitive decline to the degree of dementia; the 2nd group included 54 patients with a stable state of cognitive functions. The control group included 61 subjects of the same age and gender. The enzymatic activity of leukocyte elastase (LE) and the functional activity of the α1-proteinase inhibitor (α1-PI) were determined in blood plasma. Cluster analysis was used to isolate immunotypes.Results: the functional activity of α1-PI at the starting point of the study in patients of both follow-up groups exceeded the control values (p = 0.000001, p = 0.000006, respectively). Follow-up groups differed in LE activity at the initial stage. In patients of the 1st group (with an increase in cognitive impairment) LE activity did not differ from the control values (p = 0.144651). Group 2 (with stable cognitive functions) was characterized by a significantly higher LE activity compared to the controls (p = 0.000000). Cluster analysis made it possible to identify two immunotypes that differed in LE activity. In the 1st cluster, LE activity was within the control range and below, it mainly included patients of the 1st follow-up group (68.3%). In the 2nd cluster LE activity exceeded the control values, this cluster mainly consisted of patients of the 2nd follow-up group (85.0%) (χ2 = 27.82, p = 0.0000).Conclusion: the revealed reliable differences in the distribution of follow-up groups for immunological clusters indicate the possibility of using indicators of LE and α1-PI activity for diagnosing and predicting the dynamics of mild cognitive decline.