What are the clusters of differentiation nomenclature

The Human Leukocyte Differentiation Antigens (HLDA) Workshops were initiated1 to bring order to the chaos that existed in 1984, as immunologists generated large numbers of monoclonal antibodies reactive with leukocyte cell-surface molecules, each with different associated nomenclatures. This analytical method identified clusters of antibodies with very similar patterns of binding to leukocytes at various stages of differentiation: hence the "cluster of differentiation" (CD) nomenclature. This provided a common nomenclature that allowed the scientific community to communicate results in a universal language. Studies of immunity and diseases of the immune system have been greatly facilitated over the last 30 years by the HLDA Workshops which have used antibodies to characterise many of the molecules involved in immunological processes, and have provided a nomenclature system, the CD system, which is used universally.