Cytokine analysis in multiple sclerosis by competitive RT - PCR: A decreased expression of IL-10 and an increased expression of TNF-alpha in chronic progression.

Multiple sclerosis (MS) is an inflammatory, demyelinating disease that is specific to the central nervous system. Cytokines are thought to be key mediators of the autoimmune attack against central nervous system myelin in MS. To investigate the involvement of cytokines in MS, the mRNA levels of interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), interleukin-4 (IL-4) and interleukin-10 (IL-10) in peripheral blood mononuclear cells without stimulation in vitro were quantified by a competitive reverse transcription polymerase chain reaction technique. The level of IL-10 specific mRNA was significantly decreased in 47 MS patients compared with 42 healthy controls (P<0.0001). TNF-alpha was significantly increased in MS patients compared with healthy controls (P=0.014), especially in the patients with chronic progressive MS (P=0.0003). Thus we conclude that there are significant in vivo alterations in cytokine gene expression in the periphery in MS.