The effect of cigarette smoking on the development of AIDS in HIV-1-seropositive individuals

Weight loss and body mass index as predictors of HIV disease progression to AIDS in adults. Aquitaine cohort, France, 1985-1997

OBJECTIVE

To assess the performance of weight related nutritional markers (reported involuntary weight loss greater than 10%, measured weight loss and body mass index-BMI-) in predicting HIV disease progression.

DESIGN

Multirisk cohort of HIV-1 infected patients.

METHOD

The three nutritional variables were studied in Cox proportional hazard models as time dependant variables.

RESULTS

The sample included 2376 subjects (median follow up: 43.1 months), of those 675 experienced an AIDS defining event. After adjustment for well known prognostic factors, the reported weight loss greater than 10% tripled the risk of progression to clinical AIDS (Hazard ratio [HR] 3.0. 95% confidence interval [CI] 2.5-3.7). For measured weight loss under 5%. between 5% and 10% and greater than 10% of baseline weight compared with no weight loss, hazard ratios were respectively 1.8 (CI 1.5-2.2), 2.6 (CI 2.1-3.2) and 5.1 (CI 4.1-6.4). The relative risks of AIDS were 1.7 (CI 1.3-2.2) for BMI between 17 kg/m2 and 18.5 kg/m2, 2.6 (CI 1.7-4.0) for BMI between 16 kg/m2 and 17 kg/m2 and 4.7 (CI 3.0-7.4) for BMI under 16 kg/m2.

COMMENTS

Even a limited weight loss measured at a given time during follow up increases the risk of HIV progression; moreover, a simple cross-sectionnal measure of BMI has a good predictive value for subsequent development of clinical disease.

Exposure to cigarette tar inhibits ribonucleotide reductase and blocks lymphocyte proliferation

Cigarette smoking causes profound suppression of pulmonary T cell responses, which has been associated with increased susceptibility to respiratory tract infections and decreased tumor surveillance. Exposure of human T cells to cigarette tar or its major phenolic components, hydroquinone and catechol, causes an immediate cessation of DNA synthesis without cytotoxicity. However, little is known of the mechanisms by which this phenomenon occurs. In this report we demonstrate that hydroquinone and catechol inhibit lymphocyte proliferation by quenching the essential tyrosyl radical in the M2 subunit of ribonucleotide reductase.

Activation-inactivation of HIV-1 in the lung

The lung is prominently afflicted during the course of HIV-1 disease by both infectious and noninfectious complications. Direct or indirect effects of HIV-1 are likely central to the pathogenesis of these complications. Thus, any changes in viral load locally would negatively impact on the lung. This review focuses on the endogenous influences (immune effector cells, surfactant) and the exogenous factors (including infections such as tuberculosis and noninfectious exposures like cigarette smoke) that may contribute to activation or inactivation of HIV-1 in the lung.

Human immunodeficiency virus infection, AIDS, and smoking cessation: the time is now

Treatments for persons who are infected with human immunodeficiency virus (HIV) or who have developed AIDS have advanced to the point where death is no longer the inevitable outcome of diagnosis. Combination antiretroviral therapy has made HIV infection less of a terminal condition and more of a medically manageable chronic disease. Thus, efforts to improve the health status and quality of life of HIV-infected persons have become one of the highest treatment priorities for the next decade. Cigarette smoking is highly prevalent among HIV-infected persons, and quitting smoking would greatly improve the health status of these individuals. However, to date, no studies have evaluated the efficacy of a smoking-cessation intervention specifically tailored to this population. This article reviews the evidence and rationale for advancing smoking-cessation treatments specifically tailored to the needs of HIV-infected persons and provides recommendations for future treatment studies.

Suppression of human IL-1beta, IL-2, IFN-gamma, and TNF-alpha production by cigarette smoke extracts

BACKGROUND

Although cigarette smoking is known to have detrimental effects on the immune system, the nature of the immunosuppressive agent or agents is poorly understood.

OBJECTIVE

The purpose of the current study was to evaluate the effects of cigarette smoke extracts from high-tar (unfiltered Camel), medium-tar (Marlboro), and low-tar (Carlton) cigarettes on the in vitro production of IL-1beta, IL-2, IFN-gamma, and TNF-alpha.

METHODS

The concentrations of hydroquinone and catechol in cigarette smoke extracts were determined by using HPLC. Human PBMCs were treated with cigarette smoke extracts, hydroquinone, or catechol, and stimulated with anti-CD3 and phorbol-12-myristate-13-acetate. Cytokine levels in the supernatants were quantified by ELISA.

RESULTS

Pretreatment of PBMCs with cigarette smoke extracts derived from a single high- or low-tar cigarette suppressed the production of IL-1beta, IL-2, IFN-gamma, and TNF-alpha by greater than 90% without significant loss of cell viability. Nicotine, at a concentration comparable with that found in the highest-tar cigarettes (200 microg/mL), suppressed the production of IL-2, IFN-gamma, and TNF-alpha by only 21% to 38%. Catechol (50 micromol/L) inhibited production of IL-2 and IL-1beta by 62% to 73% but had little effect on TNF-alpha or IFN-gamma production. In contrast, hydroquinone inhibited the production of all 4 cytokines with IC(50) values ranging from 3 micromol/L(IL-1beta) to 29 micromol/L (IFN-gamma). However, HPLC determination of the hydroquinone concentrations in cigarette smoke extracts from single Camel (33+/-4 micromol/L), Marlboro (13+/-2 micromol/L), and Carlton (<1 micromol/L) cigarettes clearly demonstrated that the potent inhibitory effects of the low-tar cigarettes could not be accounted for by either hydroquinone or catechol.

CONCLUSION

These studies indicate that cigarette smoke contains potent inhibitors of cytokine production, at least one of which is present even in low-tar cigarettes.

Human immunodeficiency virus and respiratory infection

Pulmonary disease remains a major problem for the 33 million individuals who are thought to be infected with human immunodeficiency virus (HIV) worldwide. Respiratory infections are responsible for a large number of the 2 million deaths that occur each year in association with HIV disease. In countries where the majority of the population can access highly active antiretroviral therapy, morbidity and mortality rates have been cut by up to 80%. This has allowed the withdrawal of specific opportunistic infection prophylaxis when immune restoration is deemed to be adequate. Recommendations have been published concerning Pneumocystis carinii prophylaxis. This year has also seen further reports of drug-resistant isolates of Pneumocystis carinii. The clinical relevance of this is still debated. Tuberculosis remains a global problem. The complexity of the interactions between specific anti-HIV and anti-tuberculous treatment have been highlighted. In the developing world, the importance of immunization and prophylaxis (against bacteria and mycobacteria) have recently been further defined in a number of studies.

Evidence that anoreceptive intercourse with ejaculate exposure is associated with rapid CD4 cell loss

OBJECTIVE

To determine whether ejaculate exposure through anoreceptive intercourse is associated with rapid CD4 cell loss.

DESIGN

Self-reported behavioral, demographic data and blood samples were gathered longitudinally at ten semiannual visits from individuals participating in the Multicenter AIDS Cohort Study (MACS).

PATIENTS/PARTICIPANTS

A group of 937 HIV-seropositive men who were continuously followed for four to ten semiannual visits.

OUTCOME MEASURES

A loss of 10% or more in CD4 cells between the first two of any three consecutive semiannual visits that was followed by a 10% or greater loss between the second and third visits.

RESULTS

A period of rapid CD4 cell loss over three semiannual visits occurred in 389 of the 937 (42%) HIV-seropositive men studied. Men who reported one or more anoreceptive intercourse partners with whom they were exposed to ejaculate (RAI-E) during the 12 months immediately preceding their visits were more than twice as likely to show this rapid CD4 cell loss compared with men with no such partners.

CONCLUSIONS

The association between RAI-E partnerships and rapid CD4 cell loss suggests factors associated with ejaculate exposure (e.g., sexually transmitted diseases) may hasten the clinical progression of HIV disease. It is suggested that infectious diseases, which are known to be associated with ejaculate exposure, may be the causal factor underlying the association between RAI-E partnerships and rapid CD4 cell loss in these men, although the presence of these diseases was not ascertained in these data. HIV-infected individuals should be cautioned against unprotected anoreceptive intercourse.

The growth and the control of human immunodeficiency virus in the lung: implications for highly active antiretroviral therapy

In recent years, it has become apparent that the lung is an important niche for the proliferation of human immunodeficiency virus (HIV), which may have implications for highly active antiretroviral therapy (HAART). The lung itself is a major site for the opportunistic infections associated with the progression to acquired immune deficiency syndrome (AIDS), specifically Pneumocystis carinii, Myobacterium tuberculosis and pyogenic bacteria. These cases of active pulmonary complications are direct indicators of enhanced progression to AIDS-defining illness and increased morbidity and mortality. It is therefore essential that the interaction between the lung and HIV is fully understood. Recent research indicates the lung may be a major sanctuary for the virus, with distinct evolution and replication in contrast to other target organs for HIV. In this review, we will discuss the recent findings of HIV infection, evolution, host factors involved in the control of HIV within the lung and the impact this may have on current therapy.

Immunomodulatory effects of cigarette smoke

Cigarette smoke is a major health risk factor which significantly increases the incidence of diseases including lung cancer and respiratory infections. This increased susceptibility may result from cigarette smoke-induced impairment of the immune system. While the acute effects of cigarette smoke on the immune system are less clear, chronic exposure to cigarette smoke or nicotine causes T cell unresponsiveness. This apparent T cell anergy may account for or contribute to the immunosuppressive and anti-inflammatory properties of cigarette smoke/nicotine. Nicotine-induced immunosuppression may result from its direct effects on lymphocytes, indirectly through its effects on the neuroendocrine system, or both.

The effects of nicotine on the immune system

Although considerable work has been done on the potential health effects of smoking, little is known about the contribution of nicotine to those effects. This paper presents an overview of the immune system, and a discussion of the existing literature on the effects of tobacco smoke and nicotine on immunity. Treatment with nicotine has been shown to influence all aspects of the immune system, including alterations in humoral and cellular immunity. In addition, preliminary data suggest that gender and genetic factors impact on the immunological effects of nicotine. Finally, the possible mechanisms that might mediate the effects of nicotine are discussed.

Effect of nicotine on the immune system: possible regulation of immune responses by central and peripheral mechanisms

Nicotine (NT) treatment impairs T-cell receptor (TCR)-mediated signaling, leading to the arrest of T cells in the G1 phase of the cell cycle and inhibition of the antibody plaque-forming cell (AFC) response to sheep red blood cells (SRBC). This paper summarizes some of the previous findings related to cigarette smoke/NT and the immune response, and presents preliminary evidence suggesting that mice chronically treated with NT (0.5 mg/day/kg body weight) have a depressed inflammatory response in the turpentine-induced abscess model of inflammation. This ability of nicotine to attenuate an inflammatory response may also be the cause of reduced mortality of chronically nicotine-treated mice from acute influenza A pneumonitis. Moreover, in LEW rats, decreased anti-SRBC AFC responses were also observed after intracerebroventricular (i.c.v.) administration of relatively small concentrations of NT (28 micrograms/day/kg body weight) which, when given peripherally, did not affect the AFC response. In vitro the addition of NT to T cells increased protein tyrosine kinase (PTK) activity and intracellular Ca2+ concentration [Ca2+]i. These results support the hypothesis that NT alters immune responses by directly interacting with T cells, as well as indirectly through brain-immune interactions.

Effect of smoking on the clinical progression of HIV-1 infection

Cigarette smoking as a risk factor in progression of HIV-1 disease was investigated in the Multicenter AIDS Cohort Study of homosexual men. Longitudinal data for T-cell subsets, HIV-related clinical symptoms, smoking behavior, and AIDS medication use were collected semiannually from 2,499 HIV-1-seropositive men for up to 9 years. Survival methods, including Kaplan-Meier analysis and multivariate Cox regression models, were used to assess the effect of cigarette smoking on development of Pneumocystis carinii pneumonia (PCP), AIDS, death, and self-reported oral thrush. After adjustment for CD4+ lymphocyte count and use of antiretroviral and anti-PCP medications, smoking was not significantly associated with progression to PCP, AIDS, or death in either the HIV-seroprevalent or-seroincident cohort members. Among men who had baseline CD4+ cell counts > 200/microliter, smoking was associated with a 40% increase in the hazard of oral thrush (p < or = 0.01). These data indicate that cigarette smoking does not have a major effect on the progression of HIV-1 infection to AIDS or death but may affect the incidence of oral thrush.

Effect of cigarette smoking on HIV-related oral lesions

To determine whether the presence of specific oral lesions is associated with cigarette smoking among HIV-infected patients, we analyzed cross-sectional data (CD4 cell count, smoking history, and oral examination findings) from 1,058 HIV-infected male patients who received clinical care at the University of California, San Francisco. Oral AIDS Center Clinic. To control for potential confounding by the level of immune suppression, final analyses were limited to participants (n = 693) on whom CD4 cell count data (within 180 days of study visit) were available. Six percent of subjects had normal examination findings, 16% had nonnormal findings (but none of the six lesions of interest), 47% had lesions of a single type, and 31% had a combination of two or more types of lesions. After adjusting for CD4 cell count, current smokers were significantly more likely to have candidiasis (odds ratio [OR] = 1.84; 95% confidence interval [CI] 1.34-2.54) and warts (OR = 2.09; 95% CI 1.15-3.81) and less likely to have aphthous ulcers (OR = 0.24; 95% CI 0.14-0.42) than were current nonsmokers. These results suggest a strong association between cigarette smoking and the presence of specific HIV-related oral lesions.

Cigarette smoking, bacterial pneumonia, and other clinical outcomes in HIV-1 infection. Terry Beirn Community Programs for Clinical Research on AIDS

Cigarette smoking has been associated with impaired immune defenses and an increased risk of certain infectious and neoplastic diseases in HIV-1 seronegative populations. We examined the relationship between cigarette smoking and clinical outcome in a prospective cohort of 3221 HIV-1-seropositive men and women enrolled in the Terry Beirn Community Programs for Clinical Research on AIDS. Differences in clinical outcomes between never, former, and current cigarette smokers were assessed using proportional hazards regression analysis. After adjustment for CD4+ cell count, prior disease progression, use of antiretroviral therapy, and other covariates, there was no difference between current smokers and never smokers in the overall risk of opportunistic diseases [relative hazard (RH) = 1.05; 95% confidence interval (CI) 0.90-1.23; p = 0.52] or death (RH = 1.00; 95% CI 0.86-1.18; p = 0.97). However, current smokers were more likely than never smokers to develop bacterial pneumonia (RH = 1.57; 95% CI 1.14-2.15; p = 0.006), oral candidiasis (RH = 1.37; 95% CI 1.16-1.62; p = 0.0002), and AIDS dementia complex (RH = 1.80; 95% CI 1.11-2.90; p = 0.02). In addition, current smokers were less likely to develop Kaposi's sarcoma (RH = 0.58; 95% CI 0.39-0.88; p = 0.01) and several other non-respiratory tract diseases. If confirmed by other studies, these findings have important clinical implications.

Iron withholding: a defense against viral infections

A variety of laboratory and clinical investigations during the past 15 years have observed that one of the dangers of excessive iron is its ability to favor animal viral infections. The metal is essential for host cell synthesis of virions and can also impair defense cell function and increase oxidative stress. In both animal models and humans, viral infections cause upregulation of the iron withholding defense system. Factors that suppress the system enhance viral progression; factors that strengthen the system augment host defense. Procedures designed to reinforce the system are being developed and tested; some of these may become useful adjuncts in prevention and management of viral diseases.

Comorbidity and survival in HIV-infected men in the San Francisco Men's Health Survey

The course of disease associated with infection with the human immunodeficiency virus varies widely. Some patients deteriorate rapidly, while others live for years, even after an illness that defines the acquired immunodeficiency syndrome (AIDS). In this study, comorbidity, or the presence of concurrent health problems, was investigated prospectively as a possible co-factor for different rates of decline in 395 homosexual/bisexual men in the San Francisco Men's Health Study (SFMHS) who were infected with the human immunodeficiency virus (HIV). Comorbidity data obtained from baseline interviews included both chronic and infectious diseases as well as depression. Smoking, alcohol, and drug use were also examined. The most prevalent comorbid conditions were sexually transmitted diseases (90%) and hepatitis B infection (76%). Most chronic and acute concurrent health conditions were not significant discrete predictors of survival to AIDS or death after controlling for immune status and markers of disease progression. Significantly, other risk factors (e.g., depression and smoking) were found to be associated with more rapid progression. Men with symptoms of depression had a higher risk of progression of AIDS diagnosis; the relative hazard (RH) was 1.4 (95% confidence interval [CI], 1.00-2.08); smoking was associated with higher risk of death (RH, 1.6; 95% CI, 1.20-2.17). Older age was marginally associated with poorer survival to death. No associations were found between survival and alcohol and drug use.

Maternal-Fetal Transmission of Human Immunodeficiency Virus

The World Health Organization estimates that by year 2000, 10 million children will be infected with human immunodeficiency virus type 1 (HIV-1) at birth and will subsequently develop AIDS. Perinatally acquired infections account for the majority of all HIV-1 cases in children, with an estimated mother-to-infant transmission rate of more than 30%. It is not clear why more than half of the children born to HIV-1-infected mothers are uninfected. Maternal transmission of HIV-1 occurs at three levels: prepartum, intrapartum, and postpartum. Several maternal parameters including advanced clinical stages of the mother, low CD4+ lymphocyte counts, maternal immune response to HIV-1, recent infection, high level of circulating HIV-1, and maternal disease progression have been implicated in an increased risk of mother-to-infant transmission of HIV-1. Viral factors influencing mother-to-infant transmission are not known. Furthermore, several other factors such as acute infection during pregnancy, presence of other sexually transmitted diseases (STD) or other chronic infections, vaginal bleeding, disruption of placental integrity, premature rupture of membrane (PROM), and preterm PROM have been associated with mother-to-infant transmission of HIV-1. In addition, tobacco and cigarette smoking during pregnancy have been shown to triple the rate of maternal transmission of HIV-1. The AIDS Clinical Trial Group (ACTG) suggested that zidovudine (ZDV) can reduce therate of mother-to-infant transmission of HIV-1 if administered to HIV-1-infected pregnant women with CD4 counts greater than 200. Moreover, this study failed to take into consideration several factors that may influence maternal transmission of HIV-1. However, the molecular mechanisms involved in mother-to-infant transmission of HIV-1 are not understood, which makes it more difficult to define strategies for effective treatment and prevention of HIV-1 infection in children. Several groups are engaged in the understanding of the molecular and biological properties of HIV-1 influencing mother-to-infant transmission. Results from my and several other laboratories suggest that the minor genotypes, subtypes, or variants of HIV-1 found in a genetically heterogeneous virus population of infected mothers are transmitted to their infants. The minor HIV-1 genotype predominates initially as a homogeneous population in the infant and then becomes diverse as the infant matures. Furthermore, transmission of a major or multiple HIV-1 genotypes from mother to infant has been reported. Taken together, these results strongly suggest that there are differences among the molecular and biological properties of the maternal variants that are transmitted to the infants and the maternal variants that are not transmitted to the infants. The understanding of the molecular and biological properties of the transmitted viruses will enable researchers to target a particular subtype in the mothers that is transmitted to the infants. Copyright 1996 S. Karger AG, Basel

Cutaneous manifestations and consequences of smoking

Cigarette smoking is strongly linked to serious internal diseases such as cancer, cardiovascular disease, and lung disease. However, the external manifestations and consequences of smoking are relatively unknown. Although generally less ominous, the cutaneous manifestations of smoking may be associated with significant morbidity. This article reviews the known adverse effects on the skin of smoking.

Active confrontational coping predicts decreased clinical progression over a one-year period in HIV-infected homosexual men

The association between stressful life events, psychiatric symptoms, coping, and social support and HIV disease progression one year later were studied in 51 HIV-infected asymptomatic and early symptomatic homosexual men. Dependent variables were CD4 counts and clinical progression. No associations between the psychosocial parameters and CD4 counts were found. Active confrontation with HIV infection as a coping strategy was predictive of decreased clinical progression at one year follow-up, after taking into account baseline biomedical and behavioral variables. These results show that active coping strategies may have an effect on disease progression, possibly mediated by greater compliance with medical treatments or by psychoneuroimmunological mechanisms.