Age-related factors in cyclosporine-induced syngeneic graft-versus-host disease: regulatory role of marrow-derived T lymphocytes

Assessment of SGVHD Rats were examined daily for signs of clinical GVHD . Ear biopsies were taken at frequent intervals. Initial onset of SGVHD occurred within 7-14 d after discontinuation of CsA therapy and was presented as an acute GVHD with erythema and dermatitis (9) . Within 2 wk after onset, the disease progressed to a more chronic type of GVHD with alopecia and fibrosis (9) . Animals were followed 6-8 wk after discontinuation of CsA therapy to assess either a delayed appearance of disease, resolution of disease, or progression and development of extensive disease. Upon the development of chronic disease, the animals were killed. Previously described criteria were used for histologic documentation of GVHD (15) . Acute SGVHD was defined by the presence of dyskeratotic cells and vacuolar degeneration lymphocytic exocytosis, epidermal destruction with vascular changes of the basal layer, dyskeratotic cells, and lymphocytec dermal, and/or epidermal infiltration . Animals with extensive disease were killed and autopsies were performed. The skin, tongue, liver, intestine, and spleen were histologically examined for the presence of GVHD . Histological examination and diagnosis of SGVHD were performed by an observer blinded to experimental protocol .