Mast cells stimulate lymphangiogenesis in the gingiva of patients with periodontal disease.

The presence and distribution of lymphatic vessels and mast cells in the gingiva under normal and pathological conditions have been reported by several studies, but the relationship between them during inflammatory lymphangiogenesis is virtually unknown. The aim of the present study was to investigate the lymphatic microvessel density (LMVD) and mast cell density (MCD) in the gingiva of patients with periodontal disease compared to normal-like gingiva. Gingival punch biopsies from 51 patients with periodontal disease were investigated. MCs and LVs were detected by double-immunohistochemistry, using primary antibodies against mast cell tryptase and D2-40. The inflammatory infiltrate was evaluated on a scale from 0 (absent) to +3 (severe inflammation). MCs and LVs were counted in the same microscopic field for each case at ×200 magnification. We found a significant increase in the number of both MCs and LVs in cases with mild and moderate inflammatory changes, followed by a slight decrease in cases with severe inflammation. We have shown a particular association between MCs and LVs that may support the contribution of MCs to the development of the lymphatic vasculature in inflammatory conditions. MCD correlated with LMVD in all cases with mild and moderate inflammatory changes, but not in cases with severe inflammation. No correlation was found between MCD/LMVD and the density of the inflammatory infiltrate. Our results suggest the potential involvement of MCs in the induction and maintenance of lymphangiogenesis in the gingiva of patients with periodontal disease in the early steps of evolution.