X-linked vacuolated myopathy - TNF-alpha and IFN-gamma expression in muscle fibers with MHC class I on sarcolemma

The presence and the distribution of tumor necrosis factor-alpha, interfero n-gamma, and p65 subunit of nuclear factor-kappaB, molecules known to induc e synergistically and to mediate major histocompatibility complex (MHC) cla ss I expression, were determined in muscle sections from control and X-link ed vacuolated myopathy patients. MHC class I colocalized with tumor necrosi s factor-alpha and interferon-gamma, as well as with p65, in most of the me mbrane attack complex- and/or calcium-positive muscle fibers in X-linked va cuolated myopathy. These results suggest that the expression of MHC class I in X-linked vacuolated myopathy could be induced by tumor necrosis factor- alpha and interferon-gamma and partly mediated by nuclear factor-kappaB.