The human immunodeficiency virus type 1 (HIV-1) and Mycobacterium
tuberculosis, the etiologic agent of tuberculosis (TB), co-infect
around 6 million people worldwide. In Rio de Janeiro, Brazil, 24% of
notified AIDS cases had TB and 5 to 20% of notified TB cases are HIV-1
seropositive. Several authors have already described the deleterious
association between these two microorganisms. Here, we will overview the
immune response to M. tuberculosis and the effect of association
with HIV-1 infection. The natural history of M. tuberculosis
infection indicates that the emergence of delayed-type hypersensitivity
(DTH) and presumably specific acquired resistance is associated with
control of the initial infection in 95% of normal hosts; the other 5%
develop progressive primary TB. In addition, 5-10% of the infected persons
eventually will reactivate latent pulmonary or extrapulmonary foci several
years after infection. HIV-infected individuals and AIDS patients have a
remarkable susceptibility to TB, increasing 113-fold and 170-fold the risk
of TB reactivation, respectively. In addition, it has been shown that TB
accelerates the HIV infection and disease progression.
