Interleukin-6 levels in cerebrospinal fluid inversely correlate to severity of Parkinson's disease.

Abstract

Several lines of evidence suggest that neuroimmune mechanisms may also be involved in neurodegeneration in Parkinson's disease (PD). The potential role of cytokines such as interleukin 6 (IL-6), in the interaction between neurons and immune system has been emphasized by recent findings. IL-6 induces acute phase protein synthesis, differentiation of neuronal cells and improves catecholaminergic and cholinergic cell survival in the brain. We determined levels of IL-6 in cerebrospinal fluid (CSF) of untreated parkinsonian patients and age- and sex-matched controls. Intensity of disease was evaluated by the Unified Parkinson's Disease Rating scale. Significantly elevated levels of IL-6 were found in the CSF of parkinsonian patients. Moreover a significant inverse correlation between severity of PD and IL-6 CSF levels appeared. Elevated IL-6 levels in the CSF of untreated parkinsonian patients may reflect the original condition in the course of disease. We speculate that an endogenous upregulation of IL-6 synthesis occurs in order to regenerate lesioned neurons probably at an early phase of the degenerative process in PD.