Peripheral blood complement factors C2 and C3 as biomarkers of clinical efficacy in patients with first-episode schizophrenia after aripiprazole treatment

Objective: The objective of this study was to identify serum complement factor-based biomarkers indicative of clinical efficacy in patients with first-episode schizophrenia (SCZ) following treatment with aripiprazole.

Methods: The retrospective study cohort comprised 40 patients diagnosed with first-episode SCZ (SCZ group) and 40 healthy individuals (control group). Quantitative analyses were conducted on five complement factors, namely complement component 1 (C1), C2, C3, C4, and the 50% hemolytic complement (CH50). Baseline serum complement factor levels were compared between the SCZ and control groups. Patients diagnosed with SCZ underwent a 4-week treatment regimen with aripiprazole. The severity of psychiatric symptoms in these patients was assessed using the Positive and Negative Symptom Scale (PANSS) and the Brief Psychiatric Rating Scale-18 Item Version (BPRS). Comparative analyses were conducted on PANSS and BPRS scores, as well as serum complement factor levels, both prior to (pre-treatment group) and following aripiprazole administration (post-treatment group). Pearson's correlation test was employed to evaluate the relationships between changes in serum complement factor levels and the reduction rates of PANSS/BPRS scores.

Results: At baseline, patients with SCZ exhibited significantly elevated levels of C1, C2, C3, C4, and CH50 compared to the control group (P < 0.05). Moreover, following treatment, there was a significant reduction in the PANSS total score, positive symptom score, negative symptom score, and BPRS score in the post-treatment group compared to the pre-treatment group (P < 0.05). Furthermore, patients in the post-treatment group exhibited a significant reduction in serum levels of C2, C3, and C4, alongside a significant increase in the serum level of CH50 compared to those in the pre-treatment group (P < 0.05). Additionally, the baseline serum C2 levels and the variations in serum C2 levels pre- and post-treatment exhibited a negative correlation with the reduction rate of PANSS/BPRS scores (P < 0.05). Similarly, both the baseline serum C3 levels and the changes in serum C3 levels pre- and post-treatment were negatively correlated with the reduction rate of PANSS/BPRS scores (P < 0.05).

Conclusion: Baseline serum levels of C2 and C3, as well as their variations pre- and post-treatment, may serve as biomarkers for predicting clinical efficacy in patients with first-episode SCZ undergoing treatment with aripiprazole.