Complications in HIV treatment

TB and co-infection news from IAS

by Bill Farrand

TB/HIV: Still a deadly combination

Several studies examined the role of tuberculosis (TB) co-infection as the leading cause of death for those with HIV disease worldwide as well as new approaches to treatment.

One study of 155 individuals in Cambodia looked at the incidence of Tuberculosis-associated Immune Reconstitution Inflammatory Syndrome (TB-IRIS), a significant complication of early antiretroviral therapy (ART) in high TB incidence settings. The study aimed to characterize TB-IRIS and the potential role of simple tests in the diagnosis of TB-IRIS and discovered a correlation with increased PPD-specific T-cell responses detected by a blood test.

PPD is the skin test that is given to detect the presence of TB by a small welt at the pin-prick site as an immune response in those with a normal immune system. In patients with compromised immune systems, no reaction appears, so these findings show that an immune response to PPD can be detected through a blood test that measures the release of interferon-y as an immune response, rather than the skin inflammation reaction that a person with a normal immune system would have. These findings may prove useful in the early diagnosis of TB-IRIS for those starting ART so that proper treatment for TB can be initiated at the same time.

Also presented were findings on dosing protocols of Viramune (nevirapine) for patients with HIV and tuberculosis co-infection as part of ART in conjunction with rifampicin in resource-limited settings where the TB burden is high. In studies prior to the introduction of ART, the use of Viramune in conjunction with rifampicin was shown to reduce plasma levels of Viramune by up to 20%. However, it was concluded that overall immunological results were comparable between 400 mg and 600 mg Viramune regimens when accompanied by ART and rifampicin.

A study out of Brazil, where there is free access to ART, compared mortality rates between patients who had HIV/TB co-infection and patients with TB who are HIV-negative, and found the incidence of death from TB to be over seven times higher for the HIV-positive group than the HIV-negative group.

Cancer and HIV

Meta-studies of HIV-positive transplant recipients have associated a higher rate of mainly infection-related cancers than was previously thought. Infection-related cancers are caused by previous viral infections and express in specific types of cancers. The study revealed higher incidence of Hodgkins lymphoma associated with prior infection of the Epstein-Barr virus; oral, anal, and genital cancers associated with human papillomavirus (HPV); and liver and stomach cancers associated with hepatitis B and C.

Another study has shown the usefulness of HPV DNA screening in addition to Pap smears for HIV-positive males as an indicator of the need for further or more frequent testing for anal cancers. This outcome has significant implications for long-term care of HIV patients and standards of care.

On the positive side, a second study on HPV in men has shown potential for use of the HPV vaccine recently approved for use in females in the prevention of cervical cancer, and has been found to be well tolerated and to show increased immune response even in cases of severe immune suppression. These findings will need further studies to determine the efficacy of the vaccine against progression to these anal cancers for men with prior HPV infection.

Routine screening for skin cancers other than Kaposi’s sarcoma are called for by the findings of yet another study, which showed a higher incidence of basal cell carcinomas and melanomas in an HIV-positive cohort than in the general population.

A study in the U.S. aimed at the incidence of non-AIDS defining cancers found an increased risk of seven types of cancer, further confirming the need for more effective routine screening as part of long-term HIV care.

Hepatitis B and C

In another analysis from the SMART study, HIV treatment interruption in patients co-infected with either hepatitis B or C was found to increase the risk of death.