http://eng.ryumachi-jp.com/library/Downloads/mr_supple_all_2012.pdf

Role of mast cells in the pathogenesis of polymyositis
Kotaro Suzuki, Masaya Yokota, Hiroshi Nakajima
Department of Allergy and Clinical Immunology, Chiba University
Hospital
Conflict of interest: None
Mast cells have long been recognized as the major effector
cells in allergic diseases such as asthma, allergic rhinitis, and atopic
dermatitis. In addition, recent studies have revealed a new role
of mast cells in the pathogenesis of autoimmune disease models
including autoantibody-induced arthritis, experimental autoimmune
encephalomyelitis, and insulin-dependent diabetes mellitus.
While mast cells are located in skeletal muscle, their roles in the
pathogenesis of autoimmune skeletal muscle diseases have not
been clarified. Recently, a murine model of polymyositis, namely
C protein-induced myositis (CIM), has been established by Sugihara
et al. CIM has been shown to exhibit similar pathological features
to those found in human polymyositis including a massive infiltration
of CD8+ T cells and macrophages in the endomysium of
skeletal muscles. However, the role of mast cells in the development
of CIM remains unknown. To address this issue, we first examined
the incidence and severity of CIM in mast cell-deficient
WBB6F1-KitW/KitWv mice (W/Wv mice). We found that the incidence
and histological scores of CIM were significantly reduced
in W/Wv mice as compared with those in wild-type (WT) mice. In
addition, reconstitution of mast cells in W/Wv mice with bone
marrow-derived mast cells (BMMCs) restored the incidence and
histological scores of CIM. These results indicate that mast cells
play critical roles in the development of CIM and suggest that mast
cells could be possible therapeutic targets in patients with polymyositis.