While two repetitions of immunocapture with 10 μL of CD34 microbeads each were necessary to capture about 75% CD34+ exosomes present in 100 μg of supernatant-derived exosomes, one 10 μL aliquot of CD34 microbeads was sufficient for capture of all CD34+ exosomes from 100 μg of exosomes obtained from AML plasma. The gene discussed is CD34; the disease is acute myeloid leukemia.