Moving towards the definition of new clusters of designation at the 6th International Workshop on Leukocyte Differentiation Antigens

Moving Towards the Definition of New Clusters of Designation at the 6th International Workshop on Human Leukocyte Differentiation Antigens. A Brief Description of the Recently Clustered Molecules.The defining characteristic of a stem cell is its capacity for extensive self-renewal and retention of multilineage differentiation potential. The complex series of events required to guarantee self-renewal, proliferation and differentiation leads to the concept that the stem cell compartment has to be very heterogeneous and hierarchical. The transition from the primitive quiescent stem cell to the active functional hemopoietic cell requires various intermediate stages characterised by the progressive loss of the self-renewal capacity and progressive lineage restriction and commitment. This complex system is maintained through the action of several regulatory molecules and signals originating from the hemopoietic microenviroment.. Up to now, a large number of growth factors, interleukins, and inhibitory proteins have been identified, and their role in the regulation of the differentiation and proliferation processes have been extensively verified by many authors.