Dendritic cell distribution in mycosis fungoides vs. inflammatory dermatosis and other T-cell skin lymphoma.

Dendritic cells (DCs) are antigen-presenting cells with an important role in the innate and adaptive immune system. In skin lesions, cutaneous DCs (Langerhans cells, dermal DCs and plasmacytoid DCs) are involved in immune activation in inflammatory benign lesions, as well as in malignant lymphoid proliferations. Density and distribution of DCs in the dermal infiltrate can be helpful to differentiate benign, reactive infiltrate from malignant nature of the lymphoid population. We performed a retrospective study including 149 patients: 35 with mycosis fungoides, 35 with spongiotic dermatitis, 35 with psoriasis, 35 with lupus and 9 with cutaneous T-cell lymphomas (other than mycosis fungoides), diagnosed using histopathological and immunohistochemical stains. Density and distribution of DCs were evaluated using specific markers (CD1a, CD11c and langerin). In all cases, numerous DCs were identified in the dermal infiltrate. Their number was significantly increased in mycosis fungoides and T-cell lymphomas and moderately increased in inflammatory lesions. Variable patterns of distribution were identified such as clusters of DCs with arachnoid extension in mycosis fungoides, nodular pattern in inflammatory lesions and dispersed distribution with peripheric accumulation in T-skin lymphomas. Therefore, immunohistochemical characterization of DC distribution can be an adjuvant tool in differential diagnosis in inflammatory dermatosis and skin lymphomas.

Interaction between a 3D collagen matrix used for periodontal soft tissue regeneration and T-lymphocytes: An in vitro pilot study.

Previous experimental models showed that activation of the immune system, particularly T cells, is required for optimal healing following wounds or surgery in the oral cavity. Therefore, studies to explore the interactions between the immune system and the collagen matrix are mandated. The specific aim of the present study was to analyze the interactions between T lymphocytes and a resorbable three-dimensional (3D) collagen matrix routinely used for soft tissue regeneration during periodontal surgery. Peripheral venous blood samples were collected from five patients. Following Ficoll-Paque separation, mononuclear cells were grown on fully resorbable 3D collagen matrices for 5 days. Lymphocytes were analyzed by flow cytometry for different surface markers, including CD4, CD8, CD38 and CD69. Cell viability and late apoptosis/necrosis were assessed in each group using an apoptosis assay based on Annexin V/propidium iodide staining. After 5 days in contact with the collagen matrix, the T cells expressed different surface markers. The overall T cell population increased significantly in the collagen matrix group compared to the respective controls (31.9±6.5 vs. 38.7±3.8%). CD8 and CD69 also increased significantly compared to their controls (CD69: 19.7±3.0 vs. 27.1±4.5% for collagen vs. control groups). At the same time, CD4 and CD38 expression was similar in both groups. Viability and apoptosis/necrosis were also identical in the samples and controls. These results show that the interaction between the collagen matrix and the immune cells stimulated activation of T cells and did not impair the healing process.