Thrombocytopenia in adenovirus and LPS-treated mice. Platelet counts were assessed following tail vein injection of 1 × 10¹¹ adenoviral particles into each of Balb/C and C57/ BL6 mice. The platelet count falls significantly at 24 hours (Balb/c: n = 8, P < .001; C57BL/6: n = 6, P = .002) and returns to normal at 1 week. In Balb/c mice receiving 0.4 ng LPS, the platelet count falls significantly as early as 1 hour (n = 3, P = .04) and remains low at 5 and 24 hours (n = 3, P = .02). Values are the mean ± SEM.