Health Behaviors and Immunity in HIV Infection

Drug and alcohol use is associated with a wide variety of immunological effects that may have direct health implications for HIV-infected individuals. Alcohol use is related to decreased lymphocyte number and proliferative responses.

Alcoholism and related liver disease is associated with impaired NKCC and decreased NK cell numbers. Evidence suggests that alcohol abuse may amplify the suppressive effects of depression on NKCC. The use of substances ranging from injected drugs to cigarettes has been associated with faster disease progression in HIV-infected people. Thus, it is plausible that substance abuse may contribute to a decline in immunological status and possibly faster disease progression.

Little is known about the direct immunomodulatory effects of different forms of sexual behaviors, but it is plausible that repeated exposure to novel strains of HIV and other sexually transmitted pathogens, such as herpes simplex virus (HSV) and human papillomavirus (HPV), may contribute directly to the development of opportunistic infections (e.g., systemic HSV-2 infections) and cancers (e.g., HPV-associated cervical and anal intraepithelial neoplasias). In addition, exposure to these pathogens may indirectly contribute to accelerated disease course by promoting HIV replication.

Maintaining positive health behaviors such as adequate sleep, nutrition, exercise, and, perhaps most important, adherence to prescribed medications are a central part of managing HIV infection. Triple combination antiretroviral therapy with protease inhibitors offers some hope that viral replication can be slowed more efficiently and with a lower likelihood of resistance or undue side effects than prior antiretroviral regimens. Failure to adhere to the rigid and demanding medication regimens can substantially increase the risk of developing drug-resistant strains of the virus.

The resulting treatment philosophy, now more than ever, views HIV infection as a chronic disease in which patient management is critical. Incomplete adherence cannot only compromise the effects of the particular protease inhibitor being used, but can also reduce the efficacy of other related compounds to which cross-resistance has developed.

The key is consistent adherence to a demanding medication schedule in the context of an already stressful daily existence. Because depressed affect, substance use, risky sexual behaviors, and poor adherence to HIV medications may all contribute to adverse health outcomes among HIV-infected individuals, it is also important to understand the factors that intervene on these phenomena.