Mast cell depletion in murine chronic graft-versus-host disease

A murine model of chronic graft-versus-host disease (GVHD) was induced across minor histocompatibility barriers. This was done by injecting B10.D2 (H-2d) spleen cells into irradiated BALB/c (H-2d) mice. Chronic GVHD in this model includes features common to human idiopathic scleroderma, such as dermal fibrosis, loss of dermal fat and appendages, and a mononuclear cell filtrate. Serial skin biopsies showed a progressive loss of stainable mast cells in GVHD but not in irradiated controls. Mast cell depletion was noted as well in the tongue and kidney capsule of GVHD mice. Mast cell depletion was noted as early as 11 days after GVHD induction and persisted for at least 56 days. A hypothesis is put forth linking the T-cell activation of GVHD, mast cell degranulation, and increased fibrosis. The pertinence of this hypothesis to idiopathic scleroderma is pointed out.