ABSTRACT

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

Sonosuke Yukawa1, MD, Kunihiro Yamaoka1, MD, PhD, Norifumi Sawamukai1, MD, PhD, Shohei Shimajiri2, MD, PhD, Satoshi Kubo1, MD, Ippei Miyagawa1, MD, Koshiro Sonomoto1, MD, Kazuyoshi Saito1, MD, PhD, and Yoshiya Tanaka1, MD, PhD,

1 First Department of Internal Medicine, 2 Second Department of Pathology and Cell Biology, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Fukuoka, 807-8555, Japan

Correspondence to: Prof. Yoshiya Tanaka, MD, PhD
The First Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Kitakyushu, 807-8555,

Objective: Systemic sclerosis (SSc) is characterized by skin sclerosis, which develops from the distal extremities and spread to the trunk. However, several reports implied the involvement of mast cells in SSc based on examination of forearm skin specimens, but that there 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 cells density was significantly higher in both the forearms and fingers in SSc patients compared to non-SSc and normals. 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. Furthermore, digital dermal mast cell density correlated significantly with Rodnan’s Skin Thickness Score, which reflects systemic skin sclerosis.

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.