Rapid detection of alteration of serum IgG in patients with schizophrenia after risperidone treatment by matrix-assisted laser desorption ionization/time-of-flight mass spectrometry.

RATIONALE: The aim of the study was to use a technique that combines acid hydrolysis and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF MS) in order to detect the serum biomarkers of patients diagnosed with schizophrenia both before and after four-week antipsychotic treatment with risperidone.

METHODS: During this study's two-year period, inpatients were diagnosed with schizophrenia using the Structured Clinical Interview for DSM-IV Axis I Disorders. Severity was then evaluated using the Positive and Negative Syndrome Scale both at baseline and at endpoint following four-week treatment with risperidone. The patients' serum biomarkers were quickly measured using acid hydrolysis and MALDI-TOF MS. The resulting peptides were then analyzed using MALDI-TOF MS. We constructed a receiver operating characteristic (ROC) curve for the evaluated biomarkers.

RESULTS: We recruited 20 pairs of participants for this study. The experimental group was treated with serum protein with HCl for 10 minutes to effectively hydrolyze abundant proteins. The target peptide, the immunoglobulin gamma chain (IgG), was then rapidly detected using this manner. A significant difference was found in the IgG levels of patients with schizophrenia before and after antipsychotic treatment. We constructed a ROC curve based on the IgG, and the area under said curve was 0.969. In comparison to conventional detection protocols, this method takes only minutes to complete and is also less costly.

CONCLUSIONS: This study found that applying acid hydrolysis with MALDI-TOF MS technology could rapidly differentiate serum IgG levels in patients with schizophrenia before and after being treated with risperidone. This IgG difference may enhance the understanding of mechanism of antipsychotic treatment of schizophrenia. Copyright © 2016 John Wiley & Sons, Ltd.