Since the publication of the first edition of the Handbook of Human Immunology in 1997, major scientific achievements have directly contributed to an increased understanding of the complexities of the human immune system in health and disease. Whether as a result of the sequencing of the entire human genome, or of technological advancements, several new components of the immune system have been revealed, along with new technologies for their measurement and evaluation.

Major breakthroughs in the field include an increase in the number of recognized "clusters of...