Reconstitution of Immune Responses to Tuberculosis in Patients With HIV Infection Who Receive Antiretroviral Therapy

Cytokine responses induced by Mycobacterium tuberculosis in patients with HIV-1 infection and tuberculosis

“…20 HAART also restored immune responses to M. tuberculosis, although this restoration was found to be delayed and did not reach the levels seen in healthy, HIVnegative control subjects. 21 Indeed, one cohort study found that HAART reduced the incidence of HIV-associated tuberculosis by more than 80% in an area endemic with tuberculosis and HIV. 22 The results of this study suggest that the cellular immune responses of HIV-infected patients with/ without tuberculosis recovered as the CD4 cell count increased during the HAART period.…”

Tuberculosis in HIV-infected persons in the context of wide availability of highly active antiretroviral therapy

“…In fact, although it has been demonstrated that HAART can induce restoration of in vitro response to mycobacterial antigen [25], studies conducted in patients co-infected with HIV and tuberculosis suggest that recovery of cellular immunity against tuberculosis may be delayed, incomplete or absent in some individuals who have a good immunological and virological response to antiretroviral therapy [26,27], particularly when HAART is started at low CD4 lymphocytes count [24]. However, when interpreting data on CD4 lymphocyte counts at the time of diagnosis of tuberculosis it should be taken into account that active tuberculosis itself can cause immunosuppression, as suggested by the transient decrease in CD4 lymphocytes observed in a significant proportion of HIV-negative patients with tuberculosis [28,29].…”

HIV-1/Mycobacterium tuberculosisCoinfection Immunology: How Does HIV-1 Exacerbate Tuberculosis?

“…Another study followed coinfected patients for 12 months and found an increase in polyfunctional effector memory (CD27 Ϫ CD45RO ϩ ) and terminal memory (CD27 Ϫ CD45RO Ϫ ) CD4 T cell responses to PPD (98). Although antiretroviral therapy increases T cell responses in coinfected patients, these responses are significantly weaker than those of individuals with TB alone (85). Although antiretroviral therapy increases M. tuberculosis-specific T cell responses in coinfected individuals, this increase in M. tuberculosis-specific T cell responses may not always ameliorate TB pathology and may actually exacerbate TB (see the section on immune reconstitution inflammatory syndrome [IRIS] below) (2,24).…”

“…This susceptibility to TB is inversely proportional to the peripheral CD4 T cell count (51). Individuals coinfected with HIV and TB on HAART have a delayed increase in M. tuberculosis-specific T cell responses and may not reach levels observed in HIV Ϫ adults (85). Coinfected individuals on HAART may have excessive inflammation during immune reconstitution, and they may suffer from TB-associated IRIS, which occurs in two forms.…”