Serum heat shock protein 27 levels in patients with systemic sclerosis: a possible biomarker of skin sclerosis.

Systemic sclerosis (SSc) is a connective tissue disease characterized by a triad of immunological abnormality, tissue fibrosis and vascular damage.1 Skin sclerosis is one of the most prominent manifestations of SSc, extension of which has been investigated as a surrogate marker that reflects organ involvements.2 Heat shock protein 27 (Hsp27), also known as heat shock protein B1, works as an intracellular molecular chaperone as well as an extracellular pro-inflammatory signalling molecule.3,4 In the skin, Hsp27 is constantly expressed mainly in the superficial layer of the epidermis and upregulated in response to environmental stress such as temperature change or chemical irritation.5,6 Previous studies have indicated that Hsp27 plays a protective role in inflammatory skin conditions and also takes part in tissue repair process.7,8 In atopic dermatitis, the amount of Hsp27 in the cornified layer was correlated with the local severity score.9 These insights suggest that Hsp27 is involved in the cutaneous response mechanism to inflammatory skin conditions, but its significance among SSc patients has not yet been elucidated. For the SSc subgroups, serum Hsp27 levels in dcSSc patients were significantly increased compared to healthy controls (13.72 [6.62-25.18] vs. 6.89 [4.17-8.67] ng/mL, I P i < 0.01 by Mann-Whitney's I U i -test), while there were no significant differences in the levels of serum Hsp27 between lcSSc and healthy controls ( I P i = 0.23 by Mann-Whitney's I U i -test). These results suggest that serum Hsp27 might be a promising biomarker that reflects the extension of skin sclerosis among SSc patients. [Extracted from the article]