PHYSIOLOGY AND PATHOPHYSIOLOGY OF DENDRITIC CELLS

Dendritic cells are antigen-presenting cells derived from the hematopo ietic stem cell. The dendritic cell family includes Langerhans' cells (CD1a-positive dendritic cells of the skin), and antigen-presenting ce lls that are found in the lymphoreticular system and throughout the or gan parenchyme. Dendritic cells play a key role in both the primary an d secondary immune responses. Several studies indicate that these cell s participate in antitumor immunity, tumor surveillance, graft-versus- host disease, and in the pathogenesis of clinical syndromes of unknown origin or those induced by viruses, such as the human immunodeficienc y virus. Different disorders are characterized by an abnormal prolifer ation and accumulation of dendritic cells; for example, the Langerhans ' histiocytes, which accumulate in Langerhans' cell histiocytosis. In this review the immunophenotypic, morphological, and functional charac teristics of the dendritic cell family is described. The clinical and laboratory studies suggesting a unique role for these cells in various syndromes and diseases are reviewed. The Langerhans' cell histiocytos es and the malignant disorders associated with transformation of cells belonging to the dendritic cell family, are discussed. Copyright (C) 1997 by W.B. Saunders Company.