AUTOANTIGEN-INDUCED IL-13 MESSENGER-RNA EXPRESSION IS INCREASED IN BLOOD MONONUCLEAR-CELLS IN MYASTHENIA-GRAVIS AND MULTIPLE-SCLEROSIS

Evidence has been presented for the involvement of immune mechanisms i n the pathogenesis of myasthenia gravis (MG) and multiple sclerosis (M S). The production of autoantibodies in both diseases is regulated by T-cells by means of cytokines, Interleukin-13 (IL-13) is mainly produc ed by T-helper type 2 cells and induces B-cell proliferation and antib ody class switch. The role of IL-13 in MG and MS is not known. We empl oyed in situ hybridization with synthetic radiolabelled oligonucleotid e probes to detect and enumerate blood and cerebrospinal fluid (CSF) m ononuclear cells (MNC) expressing IL-13 mRNA from patients with MG, MS , optic neuritis (ON), other inflammatory neurological diseases (OIND) and healthy controls. MG is associated with elevated levels of acetyl choline receptor (AChR) reactive IL-13 mRNA expressing blood MNC compa red to control patients. In MS, numbers of MBP-reactive IL-13 mRNA exp ressing MNC were higher compared to cultures without antigen stimulati on, The levels of MBP-reactive IL-13 mRNA positive MNC were higher in MS compared to MG, but not other controls, There were no differences i n spontaneous IL-13 mRNA expressing blood MNC numbers between MG, MS, ON and control patients. The data suggest the involvement of IL-13 in both MG and MS.