Loss of gp96/grp94 results in macrothrombocytopenia. CBC analysis on WT (□, n = 5) and KO (■, n = 5) mice (A) or WT → WT (□, n = 4) and KO → WT (■, n = 5) bone marrow chimeras (B) 14 days PTD. RBC indicates red blood cells; PLT, platelets. *P < .05. (C) Representative Hem-3 staining of peripheral blood smears. (D) Ultrastructure transmission electron microscopy of WT and KO platelets. Magnifications are WT, 15 000×; and KO, 10 000×.