CD11b protein expression is consistently increased in MRD cells. (A) Mean CD11b expression is significantly increased at day 15 in comparison with diagnosis (BM from 44 paired samples). (B) Percentages of patients with low (0-500 MESFs), medium (501-5000 MESFs) and high (> 5000 MESFs) CD11b expression at days 0 and 15. (C) Representative examples of consistently increased CD11b expression, depicted by flow cytometric histograms, under therapy.