Skeletal muscle cell MHC I expression: implications for statin-induced myopathy

Statins can induce necrotizing or inflammatory myopathies in some patients. Increased major histocompatibility complex class I (MHC I) expression has been shown in muscle biopsies of statin-induced myopathy. Therefore, we investigated the effect of statins on the expression of MHC I in muscle cells. Using flow cytometry and polymerase chain reaction (PCR), the rhabdomyosarcoma cell line TE671 and primary cultured skeletal muscle cells (SKMC) were investigated for MHC I expression after incubation with different statins and/or interferon-gamma (IFN-gamma). TE671 and SKMC express MHC I in the untreated condition. Statins alone reduced the expression of MHC I in SKMC and had no effect on MHC I in TE671 cells. Statins potentiated the MHC I-inducing effect of IFN-gamma in TE671, but not in SKMC, neither at the protein level nor at the mRNA level. The increased muscle MHC I expression in statin-induced myopathy might not be induced directly by statins themselves.