[Immunologic changes associated with human immunodeficiency virus (HIV)]

Infection by HIV usually leads to dysfunction of the immune system which, facilitates the development of opportunistic infections or neoplasia in which almost always are fatal. The pathological process associated with this infection involves, characteristically, the destruction or malfunction of helper T lymphocytes (CD4+), due to, besides other factors, direct parasitism of the virus or to the secondary immune response, which seems to include autoimmune mechanisms. These pathological changes, along with the action of the virus on other components of the immune system, disturb the production of trophic factors and also the proliferation, differentiation and effector ability of different cells of the immune system. The long latent period, when a large number of infected individuals remain asymptomatic or with only minor clinical and/or laboratory disturbances suggest the possible role of some as yet uncharacterized cofactors, either inherent to the host or to other environmental agents; these cofactors may play a role in the modulation of the progression to this syndrome (AIDS).