Soluble CSF interleukin 2 receptor as indicator of neurosarcoidosis

Neurosarcoidosis (NS) represents an important differential diagnosis of multiple sclerosis (MS). However, thus far no reliable laboratory marker of neurosarcoidosis exists. The objective of this study was to evaluate whether cerebrospinal fluid (CSF) levels of soluble interleukin 2 receptor (sIL2-R) distinguish NS and other inflammatory disorders of the central nervous system. For this purpose, 139 paired CSF and serum samples from 11 patients with NS, 21 with MS, 10 with CNS vasculitis, 22 with bacterial meningitis, 17 with viral meningitis/encephalitis, seven with neurotuberculosis, and 18 healthy donors were assessed for sIL2-R using an enzyme-linked immunosorbent assay. We found that sIL2-R CSF levels above 150 pg/ml identified untreated NS patients with an overall accuracy of 93% against a group of non-infectious CNS-diseases. Furthermore, an increase in sIL2-R in the CSF was associated with and preceded the outbreak of new neurological symptoms. In conclusion, these findings suggest that sIL2-R measurement in the CSF may be a valuable tool in the diagnosis and follow-up of patients with suspected and proven neurosarcoidosis.