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

Introduction - 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. Subjects and methods - 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. Results - 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. Discussion - 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.