The immunology of infection

Infections have exerted a strong selective pressure on the evolution of the human immune system, the different components of which have evolved to resist infection by particular micro-organisms. An increasing number of individual human genes that influence the outcome of specific infections have been identified. Deficiency of specific components of the immune system (as a result of either genetic or acquired disorders) predisposes to characteristic patterns of infection. The immune response may also contribute to the pathogenesis of infectious disease.