Clinical and immunological characteristics of depressive patients with a clinical high risk of schizophrenia

Abstract

Objective: To study clinical and immunological characteristics of depressive patients with high clinical risk of schizophrenia. Materials and methods: We examined 30 depressive patients with attenuated positive symptoms (APS), which indicates a clinically high risk of schizophrenia, 20 depressive patients without APS and 27 healthy volunteers with no mental disorders. APS identified according to the presence of three or more scores on at least one of the following items on the Scale of Prodromal Symptoms (SOPS) positive symptoms subscale: P1 (Unusual thought content/Delusional ideas), P2 (Suspiciousness/Persecutory ideas) and P4 (Perceptual abnormalities/Hallucinations). The psychometric assessment was carried out on the Hamilton Depression Rating Scale (HDRS), SOPS, and the Scale for Assessment of Negative Symptoms (SANS). The activity of leukocyte elastase (LE) and α1-proteinase inhibitor (α1-PI), the autoantibodies to neoantigens S100B and myelin basic protein, and the ratio of LE and α1-PI activity or Leukocyte Inhibitory Index (LII) were determined. Results: The activity of inflammatory markers LE and α1-PI was increased in patients in both clinical groups compared with controls. In the total group of patients, the associations between LII and the score on the positive subscale SOPS, and between LII and the score on the negative subscale SOPS and SANS scale with the most pronounced association with the SANS subscales «Affective Flattening or Blunting» and «Alogia» were established. Conclusion: The identified correlations between immune response features and positive and negative symptoms in depressive patients may have prognostic value for establishing a high risk of schizophrenia.