Biomarker for psychiatric and neurological disorders

Abstract

The purpose of the present invention is to provide: a biomarker for psychiatric and neurological disorders, in particular, a biomarker for diagnosing psychiatric and neurological disorders; and a test kit and test method for psychiatric and neurological disorders. The inventors discovered that there is a significant increase in the concentration of free κ immunoglobulin chains and free λ immunoglobulin chains in the blood samples from patients with psychiatric and neurological disorders. Consequently, the present invention provides a biomarker for psychiatric and neurological disorders that includes at least one selected from the group consisting of free κ immunoglobulin chains, free λ immunoglobulin chains, and fragments thereof. Using this biomarker for psychiatric and neurological disorders enables the psychiatric and neurological disorders to be easily tested and diagnosed with the blood samples from the subjects. The biomarker enables more effective tests and diagnoses to be conducted combining inflammatory cytokines in the blood of patients with psychiatric and neurological disorders.

1 - 13 . (canceled) 
     
     
         14 . A method for diagnosing schizophrenia or autism in a subject, comprising measuring the amount of a biomarker for schizophrenia or autism in a sample from the subject, wherein the biomarker is at least one member selected from the group consisting of a free κ immunoglobulin chain, a free λ immunoglobulin chain, and fragments thereof. 
     
     
         15 . A method for diagnosing schizophrenia or autism in a subject, comprising the steps of:
 (a) measuring the amount of a biomarker for schizophrenia or autism in a sample from the subject, wherein the biomarker is at least one member selected from the group consisting of a free κ immunoglobulin chain, a free λ immunoglobulin chain, and fragments thereof; and   (b) comparing the amount with the amount of that from a normal subject.   
     
     
         16 . The method of  claim 14 , wherein the sample is a blood sample. 
     
     
         17 . The method of  claim 16 , wherein the blood sample is serum. 
     
     
         18 . The method of  claim 14 , wherein the free κ immunoglobulin chain comprises the amino acid sequence of SEQ ID NO: 2 or 3 and the free λ immunoglobulin chain comprises the amino acid sequence of SEQ ID NO: 6. 
     
     
         19 . The method of  claim 14 , wherein the free κ immunoglobulin chain comprises the amino acid sequence of SEQ ID NO: 1 and the free λ immunoglobulin chain comprises the amino acid sequence of SEQ ID NO: 6. 
     
     
         20 . The method of  claim 14 , wherein the biomarker further comprises an inflammatory cytokine. 
     
     
         21 . The method of  claim 19 , wherein the inflammatory cytokine is at least one member selected from the group consisting of interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), and tumor necrosis factor-alpha (TNF-alpha). 
     
     
         22 . The method of  claim 14 , for diagnosing schizophrenia. 
     
     
         23 . The method of  claim 14 , for diagnosing autism.