Consequences of viral infections for lymphocyte compartmentalization and homeostasis

The immune system has evolved to deal with pathogens. Analysing what happens during the course of infectious processes provides insights into the limits of lymphocyte homeostasis. Virus infections greatly alter normal T- and B-cell prevalence and localization patterns. Any mechanism that ‘counts’ T cells and B cells seems to be disrupted, at least while antigen persists. There is no simple ‘dumping’ process that controls numbers in the blood. Though the cell-surface ‘language’ that determines lymphocyte trafficking patterns must be central to modulating the consequences of infectious diseases, it is far from clear how such interactions maintain the system in reasonable balance.