Complement System Marker for Assessing the Effectiveness of Therapy in Patients with Autism Spectrum Disorder and Childhood Schizophrenia
Authors: Cheremnykh E. G. , Pozdnyakova A. N. , Balakireva E. E. , Nikitina S. G. , Blinova T. E. , Shalina N. S. , Yakupova L. P. , Kulikov A. V. , Shushpanova O. V. 
Published: January 2025

Background: assessment of the effectiveness of antipsychotic therapy is generally based on the knowledge, experience of the psychiatrist, and psychometric scales. However, all changes in a person’s mental state can be both a consequence and a cause of changes in biochemical processes, one of which is the complement system (CS). In addition to the fact that CS is the most important factor in innate immunity, its proteins, especially C3, are ubiquitous and directly involved in organismal and cellular homeostasis. CS includes its connection with coagulation, which compensates for the lack of activation potential of the cascade proteolytic complement system, as the first link of immunity. The deficiency is associated with excessive consumption of CS proteins in pathologically altered processes, which also determine mental pathologies. A change in the level of this connection allows one to determine changes in the overall level of homeostasis, for example, as a result of treatment. A new marker for assessing the level of coagulation-complement coupling, equal to the difference in the functional activity of CS in plasma and serum (d), may increase the reliability of assessing the effectiveness of therapy. Objective: justification for the use of this marker of the complement system in combination with mental state assessments on psychometric scales and electroencephalography results to analyze the effectiveness of therapy for patients with autism and schizophrenia aged 8–14 years. Patients and Methods: the study included 7 patients aged 8 to 14 years (10 ± 2.2) with a diagnosis “Childhood autism, F84.0 (ICD-10)” and 11 patients aged 11 to 14 years (13 ± 1.4) with a diagnosis “Schizophrenia, F20 (ICD-10)”. The assessment of the condition before and after treatment was carried out using the following scales: for patients with autism — CARS (Childhood Autism Rating Scale), BFCRS (Bush–Francis Catatonia Rating Scale), CGI-S (General Clinical Severity Scale); for patients with schizophrenia — PANSS (Positive and Negative Syndrome Scale) and CGI-S. A neurophysiological study of all patients was carried out with spectral analysis and topographic mapping using the NeuroKM computer system (Russia). A calculated parameter equal to the difference (d) of the functional activity of the complement system (faCS) in plasma and serum was used as a biological marker of CS. FaCS was assessed using the method on the ciliates Tetrahymena pyriformis and the Biolat device. Results: in 14 out of 18 patients, positive changes in mental state were observed, which corresponded to positive changes in marker d, as well as positive changes in ratings on scales and EEG results, in accordance with all assessments, 14 out of 18 patients from both groups showed positive changes in their condition, in 3 patients resistance to psychopharmacotherapy and minimal positive dynamics of the condition were noted; the marker of the complement system in these patients decreased slightly upon discharge; in one patient assessments of the biological marker and scales were contradictory. Conclusion: in most patients (14 out of 18 people), the selected therapy was effective, and the new candidate marker d of the complement system changed in the same direction (its normalization was noted) with clinical symptoms and neurophysiological parameters. The results of the study suggest that the candidate marker d reflects changes in the patients’ conditions as a result of treatment.