The impact of recent advances in immunology and cancer therapy on nuclear medicine

The explosive expansion of knowledge in immunology in recent decades has al ready affected the research and practice of nuclear medicine in several way s. New hematopoietic cells have been isolated and their functions discovere d, including hematopoietic stem cells and dendritic cells (DCs). Many new h umeral factors have been found that have potent effects on cells, including cytokines, growth factors, and specialized proteins. Radiolabeled compound s are needed to follow the pharmacodynamics of the humeral factors and to f ollow the migration of mobile cells in animals and humans. In this article, only DCs, cytokines, and growth factors used clinically are discussed. DCs are essential for defense against infectious diseases. Autologous DCs cult ured for a week and pulsed with tumor antigens have already proved highly i mmunogenic compared with other methods for activating cytotoxic T cells, an d preliminary studies suggest that DCs are more potent for tumor cell killi ng than monoclonal antibodies. DCs, unfortunately, also play an important r ole in causing certain human diseases. In allograft transplants, residual d onor DCs are responsible for the cellular rejection; if they could be elimi nated, rejection could be prevented. These cells are also detrimental in rh eumatoid arthritis, other autoimmune diseases, asthma, and chronic obstruct ive pulmonary disease. Cytokines such as interleukin-2 and such growth fact ors as granulocyte-macrophage colony-stimulating factor and granulocyte col ony-stimulating factor, administered to patients with malignancies to allev iate the leukopenia of chemotherapy agents, frequently alter the tissue dis tribution of radiopharmaceuticals; these alterations may be confused with d isease. Copyright (C) 2001 by W.B. Saunders Company.