The Assessment of Major Histocompatibility Complex (MHC) Class-I Expression in Different Neuromuscular Diseases

Abstract

Background Major histocompatibility complex (MHC) class-1 antigen is a glycoprotein expressed in all nucleated cells. The aim of this study was to assess MHC class-I expression in different neuromuscular diseases. Methods The authors reviewed the data of 54 patients with neuromuscular diseases. Anti MHC class-I antibody was performed on the frozen muscle tissues using immunohistochemistry. MHC class-I was scored based on its expression on muscle fibers (0: normal, 1: expression <5 fibers, 2: expression in 5–10 fibers, 3: expression in >10 fibers). The pattern was only assessed in cases with MHC class-I scored 3 as: (1: Sarcocapillary, 2: Sarcocapillary and necrotic fibers, 3: Perifascicular). The relationship between MHC class-I expression and neuromuscular diseases was statistically analyzed. Results The mean age of the patients was 39.1 ± 18.5 years. Around 50% of patients showed normal CK levels and 5% of the cases showed elevated CK levels. There was a significance difference in MHC class-I expression between cases with normal and elevated CK levels when MHC class-I score was 3 (p= 0.020). There was a significant difference in MHC class-I expression among different neuromuscular diseases (p<0.001). All cases with idiopathic inflammatory myopathies (IIMs) have expressed MHC class-I in more than 10 fibers. MHC class-I was expressed in 15 cases of non-IIMs. Conclusion MHC class-I cannot be solely used as a biomarker to distinguish IIMs from non-IIMs. The presence of MHC class-I molecules in non-IIMs might be related to immunoproteasomes mechanism. Further studies, with different muscle proteins expression and genomic sequencing, must be conducted to understand the role of MHC Class-I in neuromuscular diseases.

Clinical, histologic and prognostic features of clinically amyopathic dermatomyositis

“…Among these, the inflammatory marker detected in all 5 cases was an increase in MHC-I on the sarcolemma of muscle fibres. Elevated MHC-I in muscle fibres is a highly sensitive indicator for myopathy (19,20). MHC-I usually participates in the antigen presentation process and is generally underexpressed in the sarcoplasm (21), while it is expressed only in endomysial capillaries.…”

Major histocompatibility complex I‐induced endoplasmic reticulum stress mediates the secretion of pro‐inflammatory muscle‐derived cytokines

“…We are mindful that MHC I expression is not wholly restricted to myositis and that analysis of biopsies from a range of muscular dystrophies, also report significant sarco‐capillary expression of MHC I. 50 …”

“…Even though our findings provide the foundation for the role of MHC I‐mediated myokine release, further experiments on patient‐derived cells are needed to contextualize these findings. We are mindful that MHC I expression is not wholly restricted to myositis and that analysis of biopsies from a range of muscular dystrophies, also report significant sarco‐capillary expression of MHC I 50 …”

Autoantibodies in the pathogenesis of idiopathic inflammatory myopathies: Does the endoplasmic reticulum stress response have a role?

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