Gain-of-function of Stat5a in mice with hypomorphic <i>Stat5a/b</i> alleles causes a fatal increase in circulating granulocytes.

<p>A. Kaplan–Meier curve illustrating the disease-free survival of mice expressing hyperactive Stat5 (MMTV-tTA TetO-Stat5) in the presence of two wildtype endogenous <i>Stat5a/b</i> alleles (<i>Stat5^+/+</i>) or in animals that carry <i>Stat5a/b</i> hypomorphic alleles in a heterozygous or homozygous configuration (<i>Stat5^+/</i>^Δ<i>N</i> and <i>Stat5</i>^{Δ<i>N/</i>Δ<i>N</i>}). B. Sections of lung tissues from diseased MMTV-tTA TetO-Stat5 <i>Stat5</i>^{Δ<i>N/</i>Δ<i>N</i>} mice and healthy MMTV-tTA TetO-Stat5 controls. Bar represents 100 µm. C. Relative contribution of lymphocytes, monocytes, and granulocytes to the total number of white blood cells (WBCs) (left panel) and total granulocyte counts (right panel) in healthy and diseased MMTV-tTA TetO-Stat5 <i>Stat5</i>^{Δ<i>N/</i>Δ<i>N</i>} mice and controls (<i>P</i> value, <i>t</i> test).