Effect of Runx1 haploinsufficiency on peripheral T-cell subsets. Lymph node cells were isolated from either wild-type (left) or Runx1⁺/^- (right) mice, stained for CD19, CD3, CD4, and CD8, and the relative frequency of CD19⁺ B cells and CD3⁺CD4⁺ and CD3⁺CD8⁺ T-cell subsets was determined by flow cytometry. The percentage of cells positive for the indicated cell surface markers is noted in the figure.