Decrease in lymphocytes in the spleen of GSNOR−/− mice. Weight (A), total leukocyte counts (B), and CD4, CD8, CD19, and CD11b cell counts (C) in spleens of wildtype (WT) and GSNOR−/− (KO) mice. D, Flow cytometric analysis of gated CD4 T cells. The data are mean (± SE) from WT (n = 4-9) and KO (n = 4-11) mice. **, P < 0.01.