Chitinase-3-like Protein 1 (YKL-40) Is Expressed in Lesional Skin in Hidradenitis Suppurativa

BACKGROUND/AIM: Hidradenitis suppurativa (HS) is a chronic disease. Recently, we suggested, chitinase-3-like protein 1 (YKL-40) as a new biomarker for HS since its serum levels were found to be elevated in patients. The objective of this study was to examine YKL-40 tissue expression in HS. MATERIALS AND METHODS: The study was conducted on 7 patients with HS. The biopsies were obtained from lesional and non-lesional skin. The tissue expression of YKL-40 was assessed using an immunohistochemical method. RESULTS: Inflammatory infiltrates of various grades were visible in all samples of lesional skin. The inflammatory cells within those infiltrates showed a strong cytoplasmic expression of YKL-40. In non-lesional HS skin the pattern of YKL-40 expression was similar to that observed in healthy skin. CONCLUSION: Inflammatory infiltrates in HS skin lesions may be responsible for the elevated YKL-40 serum level. YKL-40 can be considered one of the most valuable biomarkers of HS.