“…The cell surface antigens analyzed include HLA-DR, the receptor tyrosine kinases c-kitR (CD117) and Tie2 (CD202b), the interleukin-3 cytokine receptor (IL-3R, CD123) and CD33. Although all of these antigens have been well documented to be expressed by various classes of human hematopoietic PCs, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57 the number of studies investigating their expression by human HSCs is sparse. 58, 59, 60, 61, 62 …”