The idea of haematopoietic stem cell transplantation (HSCT) returns back to the sixties of the previous century, based on using high dose radiation/chemotherapy to destroy the diseased marrow and suppress the patient’s immune system for the donor cells to engraft.
Initial attempts failed, more laboratory studies were conducted, and by 1968, the first transplants were successful for patients with primary immune deficiency disorders[1]. The first successful non-relative transplantation was performed in 1973 in a 5-year old subject with a diagnosis of severe combined immunodeficiency (SCID) [2] . Later they could successfully transplant patients with thalassemia and sickle cell disease [3].

Scientific basis for HSCT
Haematopoiesis from the Greek term for “blood making” is the process of replacing mature and functional blood cells continuously over the entire lifetime of an individual. Pluripotent hemopoietic stem cells (HSCs) ,based on niches, is characterized mainly by self-renewal. On division of the mother cell, the daughter cells fully copy the biological properties of the mother stem cell. This prevents exhaustion of the HSCs. HSCs undergo aging with time, with decline in function, this obviously raises questions when it comes to solicit elderly individuals to donate HSCs for the benefit of a related patient [4].
The differentiation of the HSCs is usually represented as an inverted tree, with successive homogenous populations. The mechanism of differentiation was thought to be split between myeloid and lymphoid series