Discovery of the leukocyte adherence defect--a historical perspective.

Leukocyte adherence deficiency (LAD) is characterized by bacterial infections at peripheral tissue sites whose defense requires exit of neutrophils from the vasculature. LAD is unique in that one of the basic and common cell properties, adherence, is involved in this defect in host defense. The molecular understanding of LAD catalyzed a continuing revolution in the investigation and understanding of cell adherence phenomena inside and outside of the immune system. The explosive gain of knowledge directly attributable to the recognition of LAD may make this disease the most important inborn error of host defense yet recognized. The recognition of this defect through the interaction of a number of investigators is explored in this report. An attempt is made to reveal the background events that made the discovery of this defect possible. The relationship between the understanding of the physiology of this disease and the rapid understanding of the molecular defect is examined. Finally, the significance of this disease and its understanding in relation to biologic discovery in general are discussed.