Cytokine and chemokine mRNA expressing cells in muscle tissues of experimental autoimmune myasthenia gravis

In-situ hybridization with labeled oligonucleotide probes was applied to ex plore cytokine and chemokine mRNA expression in sections of striated muscle , the target organ in experimental autoimmune myasthenia gravis (EAMG), ind uced in Lewis rats by immunization with acetylcholine receptor (AChR) and c omplete Freund's adjuvant (CFA). A transient burst of TNF-alpha, IL-1 beta and IL-6 mRNA expressing cells was detected during the early phase of EAMG. This cytokine pattern was related to muscular infiltration of macrophages. Levels of IL-4, IL-10, IFN-gamma, cytolysin and TGF-beta mRNA expressing c ells were low and observed mainly during the early phase of EAMG. C-C chemo kine RANTES, MCP, MIP-1 alpha and MIP-2 mRNA expressing cells were not dete cted over the course of EAMG. The low and transient expression of cytokines in EAMG muscle tissues suggests that the immune effector responses are unl ikely operated by infiltrating cells in muscle. Muscular infiltrations in E AMG are unlikely due to local accumulation of C-C chemokines. (C) 1998 Else vier Science B.V. All rights reserved.