ITGA4 and Bloom syndrome: In BLM-treated mice, Gr-1 + CD11b + cells expressed high levels of neutrophil-specific marker Gr-1 and Ly-6G and low levels of F4/80, CD49d (α4 integrin, expression of which has been associated with M-MDSC) and CD115 (M-CSF receptor) (Fig. 2a-b).