CD34+ stem cells are multipotent and can give rise to all cell types in blood. While compromising only 1.5% of bone marrow mononuclear cell population, CD34+ stem cells are responsible for all lymphohematopoietic lineages and are now commonly used clinically as they have been shown to provide long-term durable donor-derived host lymphohematopoietic reconstitution. CD34+ cells are isolated using positive immunomagnetic cell separation procedures from bone marrow.