Intravenous liposomal prednisolone downregulates in situ TNF-alpha production by T-cells in experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) relapses are treated with high-dose IV glucocorticosteroids. Here we investigated mechanisms of long-circulating polyethylene glycol-coated liposomes encapsulating prednisolone (PL) in adoptive transfer experimental autoimmune encephalomyelitis. Rats received IV 10 mg/kg PL 6, 18, or 42 hr before sacrifice at disease maximum. In formalin-fixed, paraffin-embedded spinal cord we employed a nonfluorescent immunohistochemical (IHC) double labeling. We stained for tumor necrosis factor-alpha (TNF-alpha) in combination with a T-cell antigen. Compared with PBS-containing liposomes, PL at 18 hr, and more at 42 hr, significantly reduced the rate of TNF-alpha double-labeled T-cells. This correlated with an ameliorated disease score at day 5 after PL 42 hr. Our results help to further understand mechanisms of action of drug targeting by liposomal steroids, with possible implications for treatment of autoimmune disorders such as MS.