Tumor necrosis factor alpha (TNFα)-induced arteriolar thrombosis in vivo is increased in TNFR1-deficient mice. (a) Thrombotic arteriolar vessel occlusion in vivo was most accelerated with TNFα (5 ng/mL, 4 hours) in TNFR1-deficient mice. In mice lacking TNFR2 only or both TNF receptor subtypes, TNFα did not significantly affect arteriolar thrombosis. (b) In TNFR1−/− mice, the relative acceleration of arteriolar thrombus formation by TNFα was significantly stronger compared with wild-type mice. *Significantly different versus respective sham-treated animals at P <0.05 (n = 5 to 10). #Significantly different versus wild-type at P <0.05 (n = 5). TNFα, tumor necrosis factor alpha; TNFR1, tumor necrosis factor alpha receptor subtype 1; TNFR2, tumor necrosis factor alpha receptor subtype 2.