Abstract

SOUB, Claudia Regina Wanderley; CARRIJO ROCHAEL, Mayra  and  CUZZI, Tullia. Granuloma annulare: tissue distribution of factor XIIIa⁺ dermal dendrocytes, thrombomodulin⁺ dermal cells and CD68⁺ macrophages. An. Bras. Dermatol. [online]. 2003, vol.78, n.3, pp. 289-298. ISSN 1806-4841.  http://dx.doi.org/10.1590/S0365-05962003000300005.

BACKGROUND: A subgroup of macrophage related dermal cells expresses the pro-coagulation factor XIIIa, while others express the anti-coagulation cofactor thrombomodulin. These cells can be involved in inflammatory and reparative tissue events. OBJETIVES: We investigated the participation of factor XIIIa⁺ dermal cells and thrombomodulin⁺ (TM⁺) dermal cells in the histopathological picture of granuloma annulare which is characterized by collagen necrobiosis and macrophagic infiltrate. METHODS: The histopathological picture of granuloma annulare observed in 23 skin biopsies was classified according to presence of complete or incomplete collagen degeneration and distribution of dermal infiltrate. Factor XIIIa⁺ dermal dendrocytes and thrombomodulin⁺ dermal cells were recognized by specific antibodies applied in immunohistochemical protocols; a macrophage marker (CD68) was also used. Distribution of distinct cell subsets were observed and semiquantitative analysis performed. RESULTS: Factor XIIIa⁺ dendrocytes were rarely detected in the lesion while thrombomodulin⁺ and CD68⁺ cells represented a considerable part of cell infiltrate. They were seen at its periphery (palisade arrangement), among degenerated collagen or diffusely distributed. A tendency was noted for association between higher semiquantification of thrombomodulin⁺ cells and both lower semiquantification of FXIIIa⁺ dendrocytes and histological type II. Dermal dendrocyte hyperplasia around the lesion was detected. CONCLUSION: The different tissue distribution of the FXIIIa⁺ cells and TM⁺ cells could reflect their distinct and complementary roles in the recovery of dermal tissue and in the lesion evolutive process in granuloma annulare.

Keywords : factor XIIIa; granuloma annulare; thrombomodulin.