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NEUROLOGY 2007;69:42-49
© 2007 American Academy of Neurology

Differential expression of cytokines in painful and painless neuropathies

Nurcan Üçeyler, MD, Jan P. Rogausch, Klaus V. Toyka, MD and Claudia Sommer, MD

From the Department of Neurology, University of Würzburg, Germany.

Address correspondence and reprint requests to Dr. N. Üçeyler, Neurologische Klinik der Universität, Josef-Schneider-Str. 11, 97080 Würzburg, Germany; ueceyler_n{at}klinik.uni-wuerzburg.de

Background: Pain is a common symptom in peripheral neuropathies. The factors determining why some peripheral neuropathies are painful and others are not are incompletely understood. Pro-inflammatory cytokines have been implicated to play a crucial role in the generation of pain.

Objective: To investigate whether cytokine profiles differ between patients with painful or painless neuropathy.

Methods: In this prospective study, we analyzed blood mRNA and protein levels of the pro-inflammatory cytokines interleukin-2 (IL-2) and tumor necrosis factor- (TNF) and the anti-inflammatory cytokines IL-4 and IL-10 in 32 patients with painful neuropathy, 20 patients with painless neuropathy, and 38 healthy control subjects, using quantitative real-time PCR and ELISA.

Results: Patients with a painful neuropathy had about twofold higher IL-2 mRNA (p = 0.001) and TNF mRNA (p < 0.0001) and protein levels (p = 0.009) than healthy control subjects and about twofold higher IL-2 and TNF mRNA (p = 0.03; p = 0.001) and protein levels (p = 0.04; p = 0.04) than patients with painless neuropathy. In contrast, mRNA levels of the anti-inflammatory cytokine IL-10 were about twofold higher in patients with painless neuropathy than in patients with painful neuropathy (p = 0.001) and controls (p = 0.004). IL-4 protein levels were 20-fold higher in patients with painless neuropathy (p < 0.0001) and 17-fold higher in patients with painful neuropathy (p < 0.0001) than in healthy control subjects.

Conclusions: A pro-inflammatory cytokine profile seems to be associated with pain in the setting of a peripheral neuropathy, corroborating findings in animal models with experimental painful neuropathies. This may have implications for future treatment strategies.

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Supplemental data at www.neurology.org

Supported by Bundesministerium für Bildung und Forschung (BMBF), Deutscher Forschungsverbund Neuropathischer Schmerz (DFNS), and research funds from the University of Würzburg.

Disclosure: The authors report no conflicts of interest.

Received August 25, 2006. Accepted in final form February 9, 2007.

This article has been cited by other articles:

				J Ludwig, A Binder, J Steinmann, G Wasner, and R Baron Cytokine expression in serum and cerebrospinal fluid in non-inflammatory polyneuropathies J. Neurol. Neurosurg. Psychiatry, November 1, 2008; 79(11): 1268 - 1274. [Abstract] [Full Text] [PDF]