Hypoxia-exposed WT mice developed thrombocytopenia, whereas in Nbeal2^−/− mice, platelet count did not further decrease. (A) Platelet counts were decreased in Nbeal2^−/− compared with WT mice at baseline and after 3 days of hypoxia. At day 21, platelet counts decreased in hypoxic WT mice. (B) MPV was decreased in hypoxic Nbeal2^−/− compared with WT mice at baseline and after 3 days of hypoxia. (C) Hemoglobin (Hgb) increased in hypoxic WT and Nbeal2^−/− mice at days 3 and 21. (D) There was no difference in total white blood cell (WBC) count between WT and Nbeal2^−/− at baseline or with hypoxia. (E-G) In Nbeal2^−/− mice at baseline and at day 3, the percentages of circulating neutrophils and monocytes were increased, and the percentage of circulating lymphocytes was decreased compared with WT mice. In Nbeal2^−/− mice at day 21, the percentage of circulating monocytes decreased, whereas the percentage of circulating neutrophils remained elevated and circulating lymphocytes remained decreased compared with WT mice. Statistics: P ≤.05 by 2-way analysis of variance (ANOVA) with Tukey post hoc analysis. Comparisons: (∗) WT compared with WT baseline, (#) Nbeal2^−/− compared with Nbeal2^−/− baseline, (^) WT compared with Nbeal2^−/−. MPV, mean platelet volume; NMX, normoxia.