HIV disease and alcohol
independently influence the human immune system, so it stands to reason that,
together, their influence may be additive. Here, we review the evidence that
alcohol can exacerbate HIV’s influence on the immune system, thereby affecting
disease progression and transmission. We focus particularly on alcohol’s effect
on the mucosal immune system in the tissues of the gastrointestinal tract, the
genital tract and the lungs, all of which play a role in transmission and
progression of HIV disease.
Alcohol use disorder (AUD) and HIV infection both affect the
immune system and frequently coexist in the same person, potentially
multiplying the risk of infectious disease. Infectious disease, in turn,
continues to be a major health concern and leading cause of morbidity and
mortality worldwide, despite major advances in our understanding of the immune
system, improvements in sanitation practices, and use of antibiotics, vaccines,
and antiviral drugs.
Infection with HIV is particularly troublesome for
the immune system because it infects and destroys immune system cells called T
helper lymphocytes or CD4+ T
cells. Untreated, the disease progresses over a few years to AIDS, leading to
eventual death for most people. The disease is transmitted from infected to
uninfected people through biological fluids containing the virus, most commonly
through sexual contact but also through contaminated needles and other means.
Since its discovery in the early 1980s, HIV infection has become a pandemic,
causing an estimated 36 million deaths. The World Health Organization estimates
that in 2012, of the 35 million people living with HIV/AIDS (PLWHA), 2.3
million were newly infected and 1.6 million died of AIDS-related causes despite
increased availability of effective antiretroviral therapy (ART) (Joint United Nations Programme on HIV/AIDS 2013).
AUD in the form of alcohol abuse and alcohol
addiction are the most common and costly form of substance abuse in the United
States and represent a global health problem. For PLWHA, rates of heavy
drinking are even higher than those in the general population (Galvan et al. 2002).
One study found that 82% of HIV-infected patients consumed alcohol, and half
were classified as hazardous drinkers (Lefevre et al. 1995).
Because AUD and HIV infection frequently coexist, studies have tried to
understand the influence of alcohol consumption on the transmission and
progression of HIV disease. For one, heavy alcohol consumption increases the
risk of HIV transmission through its propensity to increase the likelihood of
risky sexual behavior, including unprotected sex with multiple partners (Rehm et al. 2012; Shuper et al. 2009; Stall et al. 1986).
However, as detailed at length in this issue, AUD also may affect innate immune
defenses and adaptive immune responses and thereby potentially increase the
likelihood of HIV transmission over and above alcohol’s known behavioral
associations with infection risk. Once infected, studies find that PLWHA with
AUD perform poorly at multiple levels of the HIV treatment cascade, including
adherence to ART, resulting in a higher likelihood of virologic nonsuppression (Azar et al. 2010; Chander et al. 2006; Palepu et al. 2003).
Large observational studies show that hazardous alcohol consumption decreases
overall survival in PLWHA in what seems to be a dose-dependent manner (Braithwaite et al. 2007).
In 2010, this journal devoted an issue to the many consequences of alcohol
consumption on HIV transmission with an emphasis on prevention, HIV disease
pathogenesis, progression and treatment, and the impact of alcohol–HIV
comorbidity on the lung, liver, heart, and brain (Bryant et al. 2010).
Here, we focus on the impact of alcohol on the host
defense response to HIV infection. In particular, we review the evidence that
alcohol exacerbates HIV’s influence on the immune system and affects disease
progression and transmission. In particular, we discuss alcohol’s effect on the
mucosal immune system in the tissues of the gastrointestinal tract, the genital
tract, and the lungs, all of which play a role in transmission and progression
of HIV disease…
Full article at: http://goo.gl/IaIzXU
By:
Gregory J. Bagby, Ph.D., is Kai and Earl Rozas Professor in the Departments of Physiology and Internal Medicine; Angela M. Amedee, Ph.D., is associate professor in the Department of Microbiology, Immunology, and Parasitology; Robert W. Siggins, Ph.D., is assistant professor in the Department of Physiology; Patricia E. Molina, M.D., Ph.D., is Richard Ashman Professor and head of the Department of Physiology and director; and Steve Nelson, M.D., is dean of the School of Medicine and John H. Seabury Professor in the Departments of Internal Medicine and Physiology; all at the Alcohol and Drug Abuse Center of Excellence in the School of Medicine at Louisiana State University Health Sciences Center, New Orleans, Louisiana. Ronald S. Veazey, D.V.M., Ph.D., is professor in the Department of Pathology and Laboratory Medicine at the Tulane University School of Medicine, New Orleans, Louisiana, and chair of the Division of Comparative Pathology at Tulane National Primate Research Center, Covington, Louisiana.
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