Enlargement of lymphatic vessels in the joints of tumor necrosis factor-transgenic (TNF-Tg) mice. Joint sections from TNF-Tg mice or wild-type (WT) littermates were immunostained with anti-LYVE-1 or CD31 antibody. (a) Micrographs (× 20) show increased numbers and diameters of LYVE-1+ lymphatic vessels in the synovium of TNF-Tg mice. (b) The area and number of lymphatic vessels within the synovium were counted. Values are the means plus standard deviation of five TNF-Tg mice and six WT mice. *p < 0.05 versus WT samples. LYVE-1, lymphatic endothelial hyaluronan receptor 1.