Total transferrin in cerebrospinal fluid is a novel biomarker for spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is caused by cerebrospinal fluid (CSF) leakage. Patients with SIH experience postural headaches, nausea, etc., due to CSF hypovolemia. Imaging studies and clinical examinations, such as radioisotope (RI) scintigraphy, are useful for diagnosing SIH. However, 20-30% of patients do not show typical morphology and clinical test results. We previously reported that CSF contains transferrin (Tf) isoforms:"brain-type" Tf derived from the choroid plexus and "serum-type" Tf derived from blood. We showed that both isoforms increased in the CSF of patients with SIH by Western blotting. In the present study, we demonstrate that conventional ELISA for quantifying total Tf is useful for diagnosing SIH more accurately than Western blotting. In addition, SIH with chronic subdural hematoma (CSDH) was also accurately diagnosed.　Total Tf in the CSF can serve as a useful biomarker for diagnosing SIH with or without CSDH.