Clinical and Immunological Aspects of Delusional Disorders in Paranoid Schizophrenia

Abstract

Background: insufficient study of heterogeneous delusional disorders in schizophrenia and the role of inflammation in the development of the disease served as the basis for this study. The aim: to establish the role of immune mechanisms in the processes of the interaction of different forms of delusional symptom complexes in schizophrenia. Patients: 60 patients (mean age 38.4 ± 1.11 years) with the diagnosis “paranoid schizophrenia, continuous progressive course” (F20.00, ICD-10) were included in the study. The state of patients was defined by persistent delusional/hallucinatory delusional disorders. Based on the clinical assessment, patients were divided into three groups: 27 patients (group 1) with interpretative delusion, 22 patients (group 2) with delusion of influence based on the phenomena of mental automatism, and 11 examinees (group 3) with mixed forms of delusions (interpretative and delusions of influence with mental automatism). The control group consisted of 17 mentally and somatically healthy people, comparable with the patients by sex and age. Methods: inflammatory and autoimmune markers leukocyte elastase (LE) and α1-proteinase inhibitor (α1-PI) activity, leukocyte inhibitor index (LII) and antibody (aAb) level to S100B and MBP were determined in the blood. Results: in all groups of patients, an increase in the activity of LE and α1-PI was revealed compared with the control (p < 0.05). In group 2, an increase in aAb level to S100B was also detected (p < 0.05). Intra-group differences in LE activity served as the basis for dividing patients into three clusters. Cluster 1 was characterized by moderate activation of the immune system and was represented mainly by patients with interpretative delusions (54.5% of patients in the corresponding clinical group). Clusters 2 and 3 were distinguished by a higher level of immune system activation. A distinctive feature of cluster 3 was low LE activity against the background of high α1-PI activity and elevated level of aAb to S100B. Clusters 2 and 3 were represented mainly by patients with delusion of influence (74.1%). Сonclusion: the study confirmed the involvement of inflammation in the pathophysiology of delusional disorders in paranoid schizophrenia and allowed us to identify the relationship between the psychopathological structure of these disorders and the features of the spectrum of immune markers. The highest level of activation of the immune system, as well as immunological features presumably indicating impaired permeability of the blood-brain barrier, were associated mainly with delusions of influence with the phenomena of mental automatism.