Inclusion body myositis: genetic factors, aberrant protein expression, andautoimmunity

Sporadic inclusion body myositis (s-IBM) is an inflammatory myopathy mainly affecting elderly individuals. It has a chronic progressive course leading to severe disability. Immunosuppressive treatment is in most instances ine ffective. S-IBM is morphologically characterized by mononuclear cell infilt rates and vacuolated muscle fibers with pathologic accumulation of a large number of different proteins. Recent research has focused on the expression of various factors that may contribute to the inflammatory reaction and th e typical inclusions. This review summarizes the new information on genetic factors, abnormal protein expression and inflammation, which provides a ba sis for linking the different typical morphologic features of s-IBM to a ca scade of pathogenic events. Curr Opin Rheumatol 2001, 13:469-475 (C) 2001 L ippincott Williams & Wilkins, Inc.