Dermal mast cell density in fingers reflects severity of skin sclerosis in systemic sclerosis

Abstract

Background Systemic sclerosis (SSc) is characterized by skin sclerosis, which develops from the distal extremities and spreads to the trunk. Although several reports have implied the involvement of mast cells in SSc based on examination of forearm skin specimens, there have been no studies that examined digital skin specimens.

Methods Skin biopsies were obtained from the distal one-third of the forearm and between distal and proximal interphalangeal joints from 46 SSc patients, as well as from 29 non-SSc patients and normal controls. Dermal mast cells were detected histologically using NanoZoomer digital pathology.

Results Dermal mast cell density was significantly higher in both the forearms and fingers in SSc patients compared with non-SSc patients and normal controls. Digital dermal mast cell density was significantly higher in patients with diffuse cutaneous SSc than in local cutaneous SSc patients and also in the anti-topoisomerase I antibody-positive group than in the negative group, though such tendency was not noted in the forearm dermis. Interestingly, digital dermal mast cell density tended to correlate negatively but significantly with disease duration, suggesting the possible involvement of dermal mast cells in the early pathological process.

Conclusion Digital accumulation of toluidine blue- and/or c-Kit-positive dermal mast cells appears to be involved in the early stages of the pathological processes of SSc, especially in patients positive for anti-topoisomerase I antibody.

Keywords::

• Systemic sclerosis
• Scleroderma
• Mast cells
• Inflammation
• Pathology

Acknowledgments

The authors thank Ms. T. Adachi for excellent technical assistance. This work was supported in part by a grant-in-aid for scientific research from the Ministry of Health, Labor, and Welfare of Japan, the Ministry of Education, Culture, Sports, Science, and Technology of Japan, and the University of Occupational and Environmental Health, Japan, through a UOEH grant for advanced research.

Conflict of interest

Y.T. has received consulting fees, speaking fees, and/or honoraria from Mitsubishi-Tanabe Pharma Corporation, Abbott Japan Co., Ltd., Eisai Co., Ltd., Chugai Pharmaceutical Co., Ltd., Janssen Pharmaceutical K.K., Santen Pharmaceutical Co., Ltd., Pfizer Japan Inc., Astellas Pharma Inc., Daiichi-Sankyo Co., Ltd., GlaxoSmithKline K.K., Astra-Zeneca, Otsuka Pharmaceutical Co., Ltd., Actelion Pharmaceuticals Japan Ltd., Eli Lilly Japan K.K., Nippon Kayaku Co., Ltd., UCB Japan Co., Ltd., Quintiles Transnational Japan Co. Ltd., Ono Pharmaceutical Co., Ltd., and Novartis Pharma K.K. and has received research grants from Bristol-Myers Squibb, MSD K.K., Chugai Pharmaceutical Co., Ltd., Mitsubishi-Tanabe Pharma Corporation, Astellas Pharma Inc., Abbott Japan Co., Ltd., Eisai Co., Ltd., and Janssen Pharmaceutical K.K.