[Immunity and aging].

Immune senescence is usually understood as a progressive and unavoidable decline of the immune function with increasing age. In the light of recent observations, this classical concept needs to be revised. More than just a simple waning of activity, immune senescence appears as a true dysfunction in the immune system. On the biological level, the age-related changes of the complex network of interactions between the various participants of the immune system result in the loss of some activities and in increase of other activities. On the clinical level, the disturbances of this interactive network lead to an inefficient and sometimes inappropriate or aberrant immune response. A better understanding of the molecular basis of immune senescence will hopefully allow the identification and characterization of the underlying mechanisms. Prevention and treatment of some aspects of age-associated immune dysfunction are already possible by hormone replacement therapy.