RESUMO
BACKGROUND: CD90 fibroblasts have been described arising from and replacing the homeostatic CD34 network in scleroderma, but have not been specifically examined in other forms of cutaneous fibrosis. OBJECTIVES: To address expression, timelines, and spatial relationships of CD90, CD34, and smooth muscle actin (SMA) expressing fibroblasts in scars and to examine for the presence of a CD34-to-CD90 transition. METHODS: One hundred and seventeen scars (reparative/hypertrophic/keloidal) were evaluated for CD90, CD34, and SMA expression. Double-staining immunohistochemistry for CD90/CD34 was performed to identify CD90/CD34 transitioning cells, confirmed by double-color immunofluorescence. In addition, some scars were double-stained with CD90/SMA, CD90/procollagen-1, or SMA/procollagen-1 to evaluate spatial relationships and active collagen synthesis. Expression was graded as diffuse, minority, and negative. RESULTS: Most scars demonstrate a CD90/CD34 pattern, and dual CD90/CD34 fibroblasts were observed in 91% of scars. In reparative scars, CD90 expression reverses to a CD34/CD90 state with maturation. Pathologic scars exhibit prolonged CD90 expression. Both CD90 and SMA fibroblasts collagenize scars, although CD90 fibroblasts are more prevalent. CONCLUSIONS: CD90 fibroblasts likely arise from the resting CD34 fibroblastic network. Actively collagenizing scar fibroblasts exhibit a CD90/CD34 phenotype, which is prolonged in pathologic scars. CD90 fibroblasts are likely important players in cutaneous scarring.
Assuntos
Antígenos CD34/metabolismo , Cicatriz Hipertrófica/metabolismo , Fibroblastos/metabolismo , Queloide/metabolismo , Regeneração , Pele/metabolismo , Antígenos Thy-1/metabolismo , Actinas/metabolismo , Biomarcadores/metabolismo , Cicatriz Hipertrófica/patologia , Colágeno Tipo I/metabolismo , Fibroblastos/patologia , Fibrose , Imunofluorescência , Humanos , Queloide/patologia , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Fenótipo , Pró-Colágeno/metabolismo , Pele/patologia , Fatores de TempoRESUMO
Autoimmunity-associated neutrophilic dermatoses are a recently recognized manifestation of connective tissue diseases, in particular, lupus erythematosus. These entities are clinically and sometimes histopathologically distinct from classic neutrophilic dermatoses. We describe a case of an autoimmunity-related neutrophilic dermatosis in a patient with rheumatoid arthritis. In addition to this uncommon association, there was an absence of mature neutrophils and a population of immature histiocytoid granulocytes. This unusual case expands the concept of histiocytoid neutrophilic dermatoses to include those seen in association with autoimmune connective tissue diseases.