Suppressive effects of 4-acetylaminophenylacetic acid (actarit) on experimental autoimmune encephalomyelitis in rats.

To elucidate the efficacy of 4-acetylaminophenylacetic acid (actarit), an anti-rheumatic drug, on neuroinflammatory diseases such as multiple sclerosis, the effects of actarit on both actively induced and adoptively transferred experimental autoimmune encephalomyelitis (EAE) were studied. Daily intraperitoneal administration of actarit during the effector phase of active EAE and transferred EAE suppressed the clinical manifestation and pathological findings of EAE at doses of 300 mg/kg or higher. The percentages of CD4 and CD25 positive cells in the infiltrating cells in the CNS were reduced by this treatment. Semi-quantitative cytokine analysis revealed that the mRNA expression of TNF-alpha and INF-gamma in spinal cords and spleens of actarit treated active EAE rats was significantly reduced compared with vehicle treated EAE rats. The mRNA expression of IL-10 on day 17 in spleens of actarit-treated EAE rats was significantly upregulated. Actarit is potentially useful for the treatment of neuroimmunological disorders, such as multiple sclerosis.