Molecular markers of systemic autoimmune disorders: the expression of MHC-located HSP70 genes is significantly associated with autoimmunity development
Abstract
Objective To analyse the expression regulation of two inducible HSP70 genes - HSPAIA and HSPAIB - located within the major histocompatibility complex (MHC) in patients with various systemic autoimmune diseases and to prove the reliability of MHC-located HSP70 genes as molecular markers reflecting the autoimmune process. Methods 94 adult patients with idiopathic inflammatory myopathy (IIM, n=31), systemic lupus erythematosus (SLE, n=31) or systemic sclerosis (SSc, n=32) and 37 healthy individuals were analysed.
The mRNA expression level was determined using quantitative real-time PCR method. The expression of intracellular HSP70 was established by flow cytometry. the extracelhdar HSP70 protein was measured in plasma samples using a commercially available sandwich enzyme-linked inununosorbent assay (ELISA).
Results The expression of HSPAIA gene was significantly up -regulated in patients with autoimmune diseases (SLE: p<0.01; SSc: p<0.01; IIM: p<0.0001) compared to healthy controls. The expression of HSPAIB gene was increased only in patients with myosins (p<0.05).
Furthermore, the HSPAIB gene expression is associated with the HLA-DRB1*03 risk allele in patients with IIM. In addition, we have found a relation between HSPAIA gene expression regulation and the presence of disease specific autoantibodies in patients with SLE and myosins.
The level of intracellular HSP70 was not increased; however, the level of extracelhdar HSP70 protein was increased in patients suffering from SSc and IIM as compared to controls. Conclusion The results suggest an involvement of the MHC-linked HSP70 genes in the pathology of studied autoimmune disorders.
Therefore, the HSPAIA and HSPAIB genes might serve as an interesting candidate molecule for development of distinct types of autoimmunities.