Vitamin D Receptor mRNA Expression From Muscle Tissue is Significantly Different Between Idiopathic Inflammatory Myopathy and Limb-girdle Muscular Dystrophy Type 2B Patients

Background: Vitamin D receptor(VDR), Th17 related CC chemokine receptor 6(CCR6), Treg related Foxp3 and CD8+T related granzyme B(GrB) contributed to the development of many autoimmune diseases. However, there are no available data addressing the expression of these mRNA of these proteins in the muscles in idiopathic inflammatory myopathy (IIM) and limb-girdle muscular dystrophy type 2B (LGMD2B). Methods: We have evaluated the levels of 4 mRNAs including VDR, CCR6, Foxp3, GrB in the muscle and muscle related enzymes in the blood of 14 patients with idiopathic inflammatory myopathy, 4 patients with LGMD2B and 7 controls who did not have histopathological signs of any muscle diseases. Results: The expressions of all measured mRNAs and muscle related enzymes were highest in IIM. The mRNA levels in LGMD2B were also higher than those in the controls. A significant difference of VDR mRNA expression was observed between IIM and LGMD2B. Conclusions: Th17, Treg, CD8+T are involved in the development of IIM and LGMD2B. The elevation of VDR expression may provide us with clues as a potential therapy to treat these diseases.