IVIG rescues partially macrothrombocytopenia in G6b-deficient mice.WT and G6b KO mice received 2 g/kg IVIG intravenously once a day for 20 days. (A) Platelet counts and (B) volumes were measured before (day 0), and 15 and 20 days after IVIG administration. IVIG partially rescued the macrothrombocytopenia observed in G6b KO mice 15 days after treatment (A-B), with this effect being reduced by day 20. (C) GPVI and (D) α2β1 platelet surface expression in WT and G6b KO mice measured using flow cytometry after 15 days of 2 g/kg IVIG administration. A marginal recovery of GPVI and α2β1 expression was observed in G6b-deficient treated mice. n = 4 mice per genotype per condition. ∗P < .05, ∗∗∗P < .001, 2-way ANOVA with Tukey’s test, mean ± SEM.