Creatine kinase isozymes in the serum and CSF of schizophrenic patients

Newly admitted psychotic patients often have elevations of serum creatine kinase (CK) enzymatic activity. Previous studies indicate that this increase consists of the muscle (MM) isozyme, and increases in the brain (BB) isozyme have not been observed. Using sensitive and specific radioimmunoassays that detect both active and inactive enzyme, we measured CK-MM and CK-BB in the serum and CSF of 100 patients with schizophrenia who were not newly admitted but whose conditions varied from acute to chronic to determine whether CK-MM or CK-BB appears in the CSF and whether CK-BB can be found in the serum of these patients. We found no unusual concentrations of either isozyme in CSF. We did observe a few elevations in serum CK-BB levels, but this test does not appear to be of diagnostic value for schizophrenic patients who are not newly admitted.