Association Between Peptide Antigen-Related Antibody Levels and the Short- and Long-Term Efficacy of Antipsychotic Treatment in Drug-Naïve First-Episode Schizophrenia Patients

Objective: This study investigated the relationships between baseline peptide antigen-related IgG levels and 8-week antipsychotic drug (APD) treatment response rates and one-year treatment outcomes, as well as the relationships between changes in peptide antigen-related IgG levels and one-year treatment outcomes, in first-episode schizophrenia (FES) patients.

Methods: Sixteen peptide antigen-related IgGs from proteins encoded by schizophrenia-related genes were selected on the basis of several selection criteria from a 2022 genome-wide association study. Novel peptide antigen-related IgG levels were measured in drug-naïve FES patients at baseline (n = 155) and in plasma samples from 60 healthy controls (HCs). At the one-year follow-up, 57 patients completed both symptom and autoantibody assessments. Statistical analyses included t tests, Pearson correlation analysis, linear regression analysis, linear mixed-effects models, and simple slope analysis.

Results: Anti-MOB4 IgG and anti-PDIA3 IgG levels were significantly lower in drug-naïve FES patients compared to HCs and showed a negative correlation with baseline excitement factor scores. Baseline anti-EMB IgG levels were associated with the 8-week treatment response, whereas anti-MAD1L1 IgG levels were correlated with one-year outcomes in drug-naïve FES patients. The one-year trajectory of changes in anti-FURIN IgG, anti-MAPK3 IgG, and anti-ACTR1B IgG levels was related to remission.

Conclusion: This study revealed that patients with schizophrenia had autoimmune abnormalities, with different peptide antigen-related IgG being associated with short-term or long-term treatment efficacy, and that these antibody levels were regulated by APDs.