Determinants of HIV disease progression among homosexual men registered in the Tricontinental Seroconverter Study

Understanding Immunity through the Lens of Disease Ecology

As we describe the immune system in ever more exquisite detail, we might find that no matter how successful, this approach will not be sufficient to understand the spread of infectious agents, their susceptibility to vaccine therapy, and human disease resistance. Compared with the strict reductionism practiced as a means of characterizing most biological processes, I propose that the progression and outcome of disease-causing host-parasite interactions will be more clearly understood through a focus on disease ecology.

Alcohol Use and Human Immunodeficiency Virus (HIV) Infection: Current Knowledge, Implications, and Future Directions

Alcohol use is common among people living with human immunodeficiency virus (HIV). In this narrative review, we describe literature regarding alcohol's impact on transmission, care, coinfections, and comorbidities that are common among people living with HIV (PLWH), as well as literature regarding interventions to address alcohol use and its influences among PLWH. This narrative review identifies alcohol use as a risk factor for HIV transmission, as well as a factor impacting the clinical manifestations and management of HIV. Alcohol use appears to have additive and potentially synergistic effects on common HIV-related comorbidities. We find that interventions to modify drinking and improve HIV-related risks and outcomes have had limited success to date, and we recommend research in several areas. Consistent with Office of AIDS Research/National Institutes of Health priorities, we suggest research to better understand how and at what levels alcohol influences comorbid conditions among PLWH, to elucidate the mechanisms by which alcohol use is impacting comorbidities, and to understand whether decreases in alcohol use improve HIV-relevant outcomes. This should include studies regarding whether state-of-the-art medications used to treat common coinfections are safe for PLWH who drink alcohol. We recommend that future research among PLWH include validated self-report measures of alcohol use and/or biological measurements, ideally both. Additionally, subgroup variation in associations should be identified to ensure that the risks of particularly vulnerable populations are understood. This body of research should serve as a foundation for a next generation of intervention studies to address alcohol use from transmission to treatment of HIV. Intervention studies should inform implementation efforts to improve provision of alcohol-related interventions and treatments for PLWH in healthcare settings. By making further progress on understanding how alcohol use affects PLWH in the era of HIV as a chronic condition, this research should inform how we can mitigate transmission, achieve viral suppression, and avoid exacerbating common comorbidities of HIV and alcohol use and make progress toward the 90-90-90 goals for engagement in the HIV treatment cascade.

Shifting Patterns of the HIV Epidemic in Southwest China: A Case Study Based on Sentinel Surveillance, 1995-2012

The HIV epidemic is experiencing a rapid shift in transmission profile in China. This study aims to examine the changes in magnitude, transmission pattern, and trend of the HIV epidemic in a typical Southwest Chinese prefecture over the period of 1995-2012. HIV surveillance data from the web-based reporting system were analyzed during this period. We investigated the temporal trends in the changing characteristics of HIV transmission, the HIV disease burden in key affected populations, and assessed the impacts on HIV disease progression due to scale-up of antiretroviral treatment. A total of 3556 HIV/AIDS cases were reported in Yuxi prefecture, Yunnan, over the study period. The number of HIV tests conducted has dramatically increased from 1041 in 1995 to 247,859 in 2012, resulting in a substantial increase in HIV diagnoses from 11 cases to 327 cases over the same period. Since 2005, cumulatively 1250 eligible people living with HIV (PLHIV) have received combination antiretroviral therapy which reduced AIDS disease progression from 9.0% (95% CI: 6.7-11.4%) in 1995 to 0.1% (0-0.3%) in 2012 (ptrend=0.0002). The primary mode of HIV transmission has been shifted from injection sharing (71.9% diagnoses in 1995-2004) to unsafe sexual contacts (82.6% diagnoses in 2012). Yuxi prefecture is experiencing a concentrated but shifting HIV epidemic. Scale-up of HIV testing is essential to effective sentinel surveillance and enhancing early diagnosis and treatment in PLHIV.

Chronic alcohol abuse and HIV disease progression: studies with the non-human primate model

The populations at risk for HIV infection, as well as those living with HIV, overlap with populations that engage in heavy alcohol consumption. Alcohol use has been associated with high-risk sexual behavior and an increased likelihood of acquiring HIV, as well as poor outcome measures of disease such as increased viral loads and declines in CD4+ T lymphocytes among those living with HIV-infections. It is difficult to discern the biological mechanisms by which alcohol use affects the virus:host interaction in human populations due to the numerous variables introduced by human behavior. The rhesus macaque infected with simian immunodeficiency virus has served as an invaluable model for understanding HIV disease and transmission, and thus, provides an ideal model to evaluate the effects of chronic alcohol use on viral infection and disease progression in a controlled environment. In this review, we describe the different macaque models of chronic alcohol consumption and summarize the studies conducted with SIV and alcohol. Collectively, they have shown that chronic alcohol consumption results in higher levels of plasma virus and alterations in immune cell populations that potentiate SIV replication. They also demonstrate a significant impact of chronic alcohol use on SIV-disease progression and survival. These studies highlight the utility of the rhesus macaque in deciphering the biological effects of alcohol on HIV disease. Future studies with this well-established model will address the biological influence of alcohol use on susceptibility to HIV, as well as the efficacy of anti-retroviral therapy.

The contribution of viral genotype to plasma viral set-point in HIV infection

Disease progression in HIV-infected individuals varies greatly, and while the environmental and host factors influencing this variation have been widely investigated, the viral contribution to variation in set-point viral load, a predictor of disease progression, is less clear. Previous studies, using transmission-pairs and analysis of phylogenetic signal in small numbers of individuals, have produced a wide range of viral genetic effect estimates. Here we present a novel application of a population-scale method based in quantitative genetics to estimate the viral genetic effect on set-point viral load in the UK subtype B HIV-1 epidemic, based on a very large data set. Analyzing the initial viral load and associated pol sequence, both taken before anti-retroviral therapy, of 8,483 patients, we estimate the proportion of variance in viral load explained by viral genetic effects to be 5.7% (CI 2.8-8.6%). We also estimated the change in viral load over time due to selection on the virus and environmental effects to be a decline of 0.05 log10 copies/mL/year, in contrast to recent studies which suggested a reported small increase in viral load over the last 20 years might be due to evolutionary changes in the virus. Our results suggest that in the UK epidemic, subtype B has a small but significant viral genetic effect on viral load. By allowing the analysis of large sample sizes, we expect our approach to be applicable to the estimation of the genetic contribution to traits in many organisms.

Alcohol, HIV/AIDS, and Liver Disease

Globally, there are over 33 million persons living with HIV/AIDS resulting in 1.8 million deaths annually. While the rate of HIV transmission is slowing, it is estimated that 2.6 million new infections occur yearly [1]. In the United States, there are approximately 1.2 million living with HIV/AIDS, with 50,000 new HIV infections and 17,000 deaths from the disease annually [2]. For those who can obtain effective antiretroviral therapy (ART), HIV/AIDS has become a chronic disease with life expectancies over 30 years [3]. Research in the last 10 years has revealed the importance of alcohol in the HIV/AIDS epidemic. Alcohol use, in moderate or hazardous amounts, has been associated with increased acquisition of HIV infection, progression of HIV infection, deleterious effects on HIV treatment, and acceleration in the comorbidities of HIV infection [4–9]. Yet alcohol remains the “forgotten drug” of the HIV/AIDS epidemic [10].

Is the virulence of HIV changing? A meta-analysis of trends in prognostic markers of HIV disease progression and transmission

OBJECTIVE

The potential for changing HIV-1 virulence has significant implications for the AIDS epidemic, including changing HIV transmission rates, rapidity of disease progression, and timing of ART. Published data to date have provided conflicting results.

DESIGN

We conducted a meta-analysis of changes in baseline CD4(+) T-cell counts and set point plasma viral RNA load over time in order to establish whether summary trends are consistent with changing HIV-1 virulence.

METHODS

We searched PubMed for studies of trends in HIV-1 prognostic markers of disease progression and supplemented findings with publications referenced in epidemiological or virulence studies. We identified 12 studies of trends in baseline CD4(+) T-cell counts (21, 052 total individuals), and eight studies of trends in set point viral loads (10 ,785 total individuals), spanning the years 1984-2010. Using random-effects meta-analysis, we estimated summary effect sizes for trends in HIV-1 plasma viral loads and CD4(+) T-cell counts.

RESULTS

Baseline CD4(+) T-cell counts showed a summary trend of decreasing cell counts [effect = -4.93  cells/μl per year, 95% confidence interval (CI) -6.53 to -3.3]. Set point viral loads showed a summary trend of increasing plasma viral RNA loads (effect = 0.013  log(10)  copies/ml per year, 95% CI -0.001 to 0.03). The trend rates decelerated in recent years for both prognostic markers.

CONCLUSION

Our results are consistent with increased virulence of HIV-1 over the course of the epidemic. Extrapolating over the 30 years since the first description of AIDS, this represents a CD4(+) T cells loss of approximately 148  cells/μl and a gain of 0.39  log(10)  copies/ml of viral RNA measured during early infection. These effect sizes would predict increasing rates of disease progression, and need for ART as well as increasing transmission risk.

Lung Disease in Older Patients with HIV

Successful treatment of HIV with combination antiretroviral therapy (ART) has resulted in an aging HIV-infected population. As HIV-infected patients are living longer, noninfectious pulmonary diseases are becoming increasingly prevalent with a proportional decline in the incidence of opportunistic infections (OIs). Pulmonary OIs such as Pneumocystis jirovecii pneumonia (PCP) and tuberculosis are still responsible for a significant proportion of pulmonary diseases in HIV-infected patients. However, bacterial pneumonia (BP) and noninfectious pulmonary diseases such as chronic obstructive pulmonary disease (COPD), lung cancer, pulmonary arterial hypertension (PAH), and interstitial lung disease (ILD) account for a growing number of pulmonary diseases in aging HIV-infected patients. The purpose of this chapter is to discuss the spectrum and management of pulmonary diseases in aging HIV-infected patients, although limited data exists to guide management of many noninfectious pulmonary diseases in HIV-infected patients. In the absence of such data, treatment of lung diseases in HIV-infected patients should generally follow guidelines for management established in HIV-uninfected patients.

Adding fuel to the fire: alcohol's effect on the HIV epidemic in Sub-Saharan Africa

Alcohol consumption adds fuel to the HIV epidemic in sub-Saharan Africa (SSA). SSA has the highest prevalence of HIV infection and heavy episodic drinking in the world. Alcohol consumption is associated with behaviors such as unprotected sex and poor medication adherence, and biological factors such as increased susceptibility to infection, comorbid conditions, and infectiousness, which may synergistically increase HIV acquisition and onward transmission. Few interventions to decrease alcohol consumption and alcohol-related sexual risk behaviors have been developed or implemented in SSA, and few HIV or health policies or services in SSA address alcohol consumption. Structural interventions, such as regulating the availability, price, and advertising of alcohol, are challenging to implement due to the preponderance of homemade alcohol and beverage industry resistance. This article reviews the current knowledge on how alcohol impacts the HIV epidemic in SSA, summarizes current interventions and policies, and identifies areas for increased research and development.

The emerging role of HLA-C in HIV-1 infection

Recently, genome-wide association studies have identified the major histocompatibility complex class I protein HLA-C as an important molecule that affects HIV disease progression. The association between HLA-C and HIV disease outcome was originally determined through a single nucleotide polymorphism (SNP) 35 kb upstream of the HLA-C locus. More recent work has focused on elucidating the functional significance of the -35 SNP, and several groups now have demonstrated HLA-C surface expression to be a key element in control of HIV viral load, with higher surface expression associating with slower disease progression. Most recently, control of HLA-C surface expression has been correlated with the presence of microRNA binding sites that affect HLA-C expression and control of HIV disease. This review highlights these results and explores the ways in which HLA-C surface expression could affect immune system function in the setting of HIV disease.

Genome-wide association scan in HIV-1-infected individuals identifying variants influencing disease course

Background

AIDS develops typically after 7–11 years of untreated HIV-1 infection, with extremes of very rapid disease progression (<2 years) and long-term non-progression (>15 years). To reveal additional host genetic factors that may impact on the clinical course of HIV-1 infection, we designed a genome-wide association study (GWAS) in 404 participants of the Amsterdam Cohort Studies on HIV-1 infection and AIDS.

Methods

The association of SNP genotypes with the clinical course of HIV-1 infection was tested in Cox regression survival analyses using AIDS-diagnosis and AIDS-related death as endpoints.

Results

Multiple, not previously identified SNPs, were identified to be strongly associated with disease progression after HIV-1 infection, albeit not genome-wide significant. However, three independent SNPs in the top ten associations between SNP genotypes and time between seroconversion and AIDS-diagnosis, and one from the top ten associations between SNP genotypes and time between seroconversion and AIDS-related death, had P-values smaller than 0.05 in the French Genomics of Resistance to Immunodeficiency Virus cohort on disease progression.

Conclusions

Our study emphasizes that the use of different phenotypes in GWAS may be useful to unravel the full spectrum of host genetic factors that may be associated with the clinical course of HIV-1 infection.

Alcohol and HIV disease progression: weighing the evidence

Heavy alcohol use is commonplace among HIV-infected individuals; however, the extent that alcohol use adversely impacts HIV disease progression has not been fully elucidated. Fairly strong evidence suggests that heavy alcohol consumption results in behavioral and biological processes that likely increase HIV disease progression, and experimental evidence of the biological effect of heavy alcohol on simian immunodeficiency virus in macaques is quite suggestive. However, several observational studies of the effect of heavy alcohol consumption on HIV progression conducted in the 1990s found no association of heavy alcohol consumption with time to AIDS diagnosis, while some more recent studies showed associations of heavy alcohol consumption with declines of CD4 cell counts and nonsuppression of HIV viral load. We discuss several plausible biological and behavioral mechanisms by which alcohol may cause HIV disease progression, evidence from prospective observational human studies, and suggest future research to further illuminate this important issue.

Impact of CCR5delta32 host genetic background and disease progression on HIV-1 intrahost evolutionary processes: efficient hypothesis testing through hierarchical phylogenetic models

The interplay between C-C chemokine receptor type 5 (CCR5) host genetic background, disease progression, and intrahost HIV-1 evolutionary dynamics remains unclear because differences in viral evolution between hosts limit the ability to draw conclusions across hosts stratified into clinically relevant populations. Similar inference problems are proliferating across many measurably evolving pathogens for which intrahost sequence samples are readily available. To this end, we propose novel hierarchical phylogenetic models (HPMs) that incorporate fixed effects to test for differences in dynamics across host populations in a formal statistical framework employing stochastic search variable selection and model averaging. To clarify the role of CCR5 host genetic background and disease progression on viral evolutionary patterns, we obtain gp120 envelope sequences from clonal HIV-1 variants isolated at multiple time points in the course of infection from populations of HIV-1-infected individuals who only harbored CCR5-using HIV-1 variants at all time points. Presence or absence of a CCR5 wt/Δ32 genotype and progressive or long-term nonprogressive course of infection stratify the clinical populations in a two-way design. As compared with the standard approach of analyzing sequences from each patient independently, the HPM provides more efficient estimation of evolutionary parameters such as nucleotide substitution rates and d(N)/d(S) rate ratios, as shown by significant shrinkage of the estimator variance. The fixed effects also correct for nonindependence of data between populations and results in even further shrinkage of individual patient estimates. Model selection suggests an association between nucleotide substitution rate and disease progression, but a role for CCR5 genotype remains elusive. Given the absence of clear d(N)/d(S) differences between patient groups, delayed onset of AIDS symptoms appears to be solely associated with lower viral replication rates rather than with differences in selection on amino acid fixation.

HIV-2 CRF01_AB: first circulating recombinant form of HIV-2

BACKGROUND

Five HIV-2-seropositive cases were recently identified in Japan, outside the HIV-2 endemic area of West Africa. To clarify the molecular epidemiology of HIV-2 in Japan, we analyzed sequences of these cases in detail.

METHODS

HIV-2 genetic groups were determined by gag and env sequences. For suspected recombinant isolates, the genetic structure was determined by full-length genomic analyses. To understand the history and evolution of HIV-2 recombinant isolates, we estimated the time of most recent common ancestor by Bayesian Markov chain Monte Carlo method.

RESULTS

Three isolates were determined as recombinants of groups A and B, and their mosaic genome structures were identical with that of 7312A, a recombinant isolate reported in 1990 from Côte d'Ivoire. Our 3 isolates and 7312A fulfilled the criteria for determining a circulating recombinant form (CRF). These isolates were verified by the Los Alamos HIV sequence database as the first CRF of HIV-2, HIV-2 CRF01_AB. The mean time of most recent common ancestor of CRF01_AB was estimated as between 1964 and 1973, several decades after the estimated emergence of HIV-2.

CONCLUSIONS

We recently identified HIV-2 CRF01_AB cases in Japan. This ectopic observation of the virus outside its original endemic area suggests an ongoing global spread of HIV-2 CRF01_AB.

Alcohol use accelerates HIV disease progression

The effects of alcohol abuse on HIV disease progression have not been definitively established. A prospective, 30-month, longitudinal study of 231 HIV(+) adults included history of alcohol and illicit drug use, adherence to antiretroviral therapy (ART), CD4(+) cell count, and HIV viral load every 6 months. Frequent alcohol users (two or more drinks daily) were 2.91 times (95% CI: 1.23-6.85, p = 0.015) more likely to present a decline of CD4 to <or=200 cells/microl, independent of baseline CD4(+) cell count and HIV viral load, antiretroviral use over time, time since HIV diagnosis, age, and gender. Frequent alcohol users who were not on ART also increased their risk for CD4 cell decline to <or=200 cells/mm(3) (HR = 7.76: 95% CI: 1.2-49.2, p = 0.03). Combined frequent alcohol use with crack-cocaine showed a significant risk of CD4(+) cell decline (HR = 3.57: 95% CI: 1.24-10.31, p = 0.018). Frequent alcohol intake was associated with higher viral load over time (beta = 0.259, p = 0.038). This significance was maintained in those receiving ART (beta = 0.384, p = 0.0457), but not in those without ART. Frequent alcohol intake and the combination of frequent alcohol and crack-cocaine accelerate HIV disease progression. The effect of alcohol on CD4(+) cell decline appears to be independent of ART, through a direct action on CD4 cells, although alcohol and substance abuse may lead to unmeasured behaviors that promote HIV disease progression. The effect of alcohol abuse on viral load, however, appears to be through reduced adherence to ART.

Pharmacologic consideration for the use of antiretroviral agents in the elderly

The prevalence of human immunodeficiency virus (HIV) infection among people older than 50 years is increasing. HIV-infected patients require lifelong treatment with antiretroviral agents to suppress viral replication and maintain immune function. The use of antiretroviral agents in the elderly can be complicated by multiple chronic comorbidities and coadministered non-HIV medications. The pharmacokinetics of antiretroviral agents may be altered due to age-related decrements in hepatic and renal function. The elderly may be more sensitive than younger people to antiretroviral drug toxicity. A better understanding of the pharmacokinetics of antiretroviral agents in the elderly is of importance for the successful management of complex antiretroviral regimens in this population.

Association of HLA-C and HCP5 gene regions with the clinical course of HIV-1 infection

BACKGROUND

Recently, a genome-wide association analysis revealed single-nucleotide polymorphisms (SNPs) in the gene regions of HLA-C and HCP5 to be associated with viral load at set point and SNPs in the RNF39/ZNRD1 gene region to be associated with HIV-1 disease course.

METHODS

We studied whether the association of these SNPs with viral load at set point could be replicated and whether these SNPs also associated with other clinical outcomes of HIV-1 infection in 335 HIV-1-infected homosexual participants from the Amsterdam Cohort Studies on HIV infection and AIDS (ACS).

RESULTS

Significant associations between the minor allele variants of SNPs HLA-C rs9264942 and HCP5 rs2395029 and a lower viral load at set point could be replicated in the ACS. Moreover, these SNPs were significantly associated with delayed progression to AIDS, AIDS-related death, and a CD4 T-cell count below 400 cells/mul. Both minor allele variants were independent predictors of disease progression, also when a CCR5 Delta32 heterozygous genotype was included in the analysis. However, predictive value was not independent from viral load and CD4 T-cell count at set point. The SNPs in the RNF39/ZNRD1 gene region were associated with set point CD4 T-cell count but not with disease course in the ACS.

CONCLUSION

The minor allele variants of SNPs in the HLA-C and HCP5 gene regions are also in the ACS associated with a lower viral load at set point and additionally with delayed HIV-1 disease progression. The association of these SNPs with the relatively early course of infection may help unravel their mode of action.

Increasing age at HIV seroconversion from 18 to 40 years is associated with favorable virologic and immunologic responses to HAART

BACKGROUND

Studies evaluating the effect of age on response to highly active antiretroviral therapy (HAART) have been limited by their inability to control for duration of human immunodeficiency virus (HIV) infection. We examined the effect of age at HIV seroconversion on response to HAART.

METHODS

A retrospective analysis of a longitudinal US military cohort of HIV-infected subjects. Time to and maintenance of viral suppression, rate of CD4 cell increase, and rate of progression to acquired immunodeficiency syndrome or death were compared across age groups using time-to-event methods.

RESULTS

Five hundred sixty-three HIV-infected adults who seroconverted after January 1, 1996, and started HAART were included. Increasing age at seroconversion was significantly associated with faster time to viral suppression (P = 0.002). Increasing age also correlated with duration of suppression, with a 35% reduction in risk of viral rebound for every 5-year increase in age above 18 years (hazard ratio: 0.65, 95% confidence interval 0.55 to 0.75). The rate of CD4 cell increase from 6 to 84 months post-HAART was significantly greater in those who seroconverted at older ages (P = 0.0002). Rates of progression to acquired immunodeficiency syndrome or death did not differ between groups.

CONCLUSIONS

Increasing age at seroconversion was associated with shorter time to and longer maintenance of viral suppression and a faster increase in CD4 cell count.

Aging and infectious diseases: workshop on HIV infection and aging: what is known and future research directions

Highly active antiretroviral treatment has resulted in dramatically increased life expectancy among patients with HIV infection who are now aging while receiving treatment and are at risk of developing chronic diseases associated with advanced age. Similarities between aging and the courses of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome suggest that HIV infection compresses the aging process, perhaps accelerating comorbidities and frailty. In a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the HIV Medical Association, the National Institute on Aging, and the National Institute on Allergy and Infectious Diseases, researchers in infectious diseases, geriatrics, immunology, and gerontology met to review what is known about HIV infection and aging, to identify research gaps, and to suggest high priority topics for future research. Answers to the questions posed are likely to help prioritize and balance strategies to slow the progression of HIV infection, to address comorbidities and drug toxicity, and to enhance understanding about both HIV infection and aging.

HIV-1 disease progression and mortality before the introduction of highly active antiretroviral therapy in rural Uganda

OBJECTIVE

To provide estimates of survival and progression to different HIV disease endpoints after HIV infection among adults in a rural Ugandan setting.

DESIGN

A prospective population-based cohort study.

METHODS

Eligible individuals at least 15 years of age with documented HIV seroconversion were recruited from a general population cohort in rural Uganda, along with a randomly selected proportion of HIV-prevalent and HIV-negative individuals. All participants were followed up every 3 months, and CD4 cell counts taken every 6 months in HIV-positive participants. Life tables and Kaplan-Meier functions were used to estimate survival patterns for all endpoints [death, time to World Health Organization (WHO) stage 2, 3, AIDS and CD4 cell count < 200 cells/mul]. Analysis of follow-up time was truncated when antiretroviral therapy (ART) became available in the area in January 2004.

RESULTS

We recruited 240 HIV incident cases, 108 prevalent cases and 257 HIV-negative controls. Crude mortality rates were 70.0 per 1000 person-years in HIV-positive, and 12.1 per 1000 person-years in HIV-negative individuals. The median time from seroconversion to death was 9.0 years (N = 240) and 6.2 years to a CD4 cell count less than 200 cells/mul or WHO stage 4 (N = 229). The median time from ART eligibility (CD4 cell count < 200 cells/mul, < 350 cells/mul and WHO stage 3, or WHO stage 4) to death was 34.7 months. Older age at seroconversion was a risk factor for faster progression to death and ART eligibility.

CONCLUSION

HIV progression in this African cohort is similar to that reported in industrialized countries before the widespread introduction of ART.

Higher set point plasma viral load and more-severe acute HIV type 1 (HIV-1) illness predict mortality among high-risk HIV-1-infected African women

BACKGROUND

There is limited information on the natural history of human immunodeficiency virus type 1 (HIV-1) infection in Africa, especially from individuals with well-defined dates of infection. We used data from a prospective cohort study of female sex workers in Mombasa, Kenya, who were followed up monthly from before the date of HIV-1 infection.

METHODS

Antiretroviral-naive women who had a well-defined date of HIV-1 infection were included in this analysis. The effects of set point plasma viral load (measured 4-24 months after infection), early CD4+ cell count, and symptoms of acute HIV-1 infection on mortality were assessed using Cox proportional hazards analysis.

RESULTS

Among 218 women, the median duration of follow-up after HIV-1 infection was 4.6 years. Forty women died, and at 8.7 years (the time of the last death), the cumulative survival rate was 51% by Kaplan-Meier analysis. Higher set point viral load, lower early CD4+ cell count, and more-symptomatic acute HIV-1 illness each predicted death. In multivariate analysis, set point viral load (hazard ratio [HR], 2.28 per 1 log10 copies/mL increase; P=.001) and acute HIV-1 illness (HR, 1.14 per each additional symptom; P=.05) were independently associated with higher mortality.

CONCLUSION

Among this group of African women, the survival rate was similar to that for HIV-1-infected individuals in industrialized nations before the introduction of combination antiretroviral therapy. Higher set point viral load and more-severe acute HIV-1 illness predicted faster progression to death. Early identification of individuals at risk for rapid disease progression may allow closer clinical monitoring, including timely initiation of antiretroviral treatment.

HIV and Aging

Between 2001 and 2004, the percentage of all HIV cases in patients aged >or=50 years increased from 17% to 23%. This concerning increase is expected to continue over the next decade. The increasing prevalence of HIV in these patients is a result of increased longevity in patients treated with highly active antiretroviral therapy (HAART) as well as new primary infections in older patients. While older patients may achieve virological suppression at the same rate as younger patients, the immunological benefit of HAART in older patients may be reduced compared with younger patients. In addition, the toxicities associated with HAART may be worse in older HIV patients, particularly those with underlying renal or hepatic insufficiency. All previous studies evaluating the virological and immunological benefits of HAART in older patients have had relatively small sample sizes and none has compared efficacy or rates of toxicity by HAART treatment class. Co-morbidities are more common in older than in younger patients and can impact on the management of HIV in these patients. Providers must be cognisant of drug-drug interactions and potential adverse effects of HAART regimens when selecting an ideal antiretroviral regimen for older HIV patients. Given the increased longevity and rates of malignancies in HIV-infected patients, providers should also be particularly vigilant in maintaining routine health screening in older HIV patients. Controlled trials on HIV epidemiology, pathogenesis, and therapeutic and clinical outcomes are also needed in older patients. As the HIV-infected population ages, there is a growing need to better determine the effectiveness of HAART in older patients, and to investigate factors associated with a more rapid course of HIV infection in patients aged >50 years.

Early markers of HIV-1 disease progression in a prospective cohort of seroconverters in Bangkok, Thailand: implications for vaccine trials

BACKGROUND

Some candidate HIV-1 vaccines may not prevent HIV-1 infection but may alter the course of disease. Surrogate endpoints based on early laboratory makers in HIV-1-infected persons who are antiretroviral therapy (ART)-naive will be useful for evaluating vaccine efficacy in slowing disease progression (VEp). We examined pretreatment HIV-1 viral loads and CD4 cell counts in recent HIV-1 seroconverters to inform selection of these endpoints.

METHODS

We studied 130 newly HIV-1-infected injection drug users identified from a prospective cohort of initially uninfected persons in Bangkok during 1995 through 1998. We analyzed trends in HIV-1 viral loads and CD4 cell counts as well as progression to the surrogate endpoint, defined as 2 consecutive CD4 cell counts of fewer than 350 cells/mm, during 24 months after the first HIV-1 seropositive (FP) visit.

RESULTS

Median HIV-1 RNA copies/mL with interquartile ranges were 43,693 (14,320-94,767) at the FP visit, 46,924 (16,273-104,314) at 6 months, 28,446 (11,292-54,325) at 12 months, and 18,080 (8713-54,059) at 18 months. HIV-1 viral loads at the FP visit and at 18 months were positively correlated (r = 0.53, P < 0.0001). Of 130 participants, 12% reached the surrogate endpoint by 6 months, 16% by 12 months, and 27% by 18 months. In Cox regression analyses, HIV-1 viral loads of more than 50,000 copies/mL at the FP visit (hazard ratio [HR] = 2.3, 95% confidence interval [CI]: 1.1-4.8) and first CD4 cell count of 500 or fewer cells/mm (HR = 7.6, 95% CI: 3.2-17.6) were independently associated with faster progression to the surrogate endpoint.

CONCLUSIONS

Participants with high HIV-1 RNA levels and low CD4 cell counts close to the time of seroconversion were more likely to experience early immunologic progression. Approximately one quarter of seroconverters reached the surrogate immunologic endpoint within 18 months of their FP visit and before starting ART, suggesting the utility of this endpoint for analyses of VEp in some ongoing and planned HIV-1 vaccine efficacy trials.

AIDS-defining illnesses among patients with HIV in Singapore, 1985 to 2001: results from the Singapore HIV Observational Cohort Study (SHOCS)

Background

The objective was to describe the causes of initial and overall AIDS-defining disease episodes among HIV patients in Singapore.

Methods

A retrospective observational cohort study was performed of all adult patients seen at the national HIV referral center between 1985 and 2001. Data were extracted from the patients' records by ten trained healthcare workers. AIDS-defining conditions were established using predefined criteria.

Results

Among 1504 patients, 834 had experienced one or more AIDS-defining diseases. The most frequent causes of the initial AIDS-defining episode were Pneumocystis carinii pneumonia (35.7%), Mycobacterium tuberculosis (22.7%) and herpes simplex (7.4%). In total 1742 AIDS-defining episodes occurred. The most frequent causes were Pneumocystis carinii pneumonia (25.1%), Mycobacterium tuberculosis (16.2%) and cytomegalovirus retinitis (9.5%).

Conclusions

The most frequent causes of AIDS-defining illnesses in Singapore are similar to those reported in the West, prior to the introduction of anti-retroviral therapy. Opportunistic infections remain the most frequent AIDS-defining illnesses.

The chemical bases of the various AIDS epidemics: recreational drugs, anti-viral chemotherapy and malnutrition

In 1981 a new epidemic of about two-dozen heterogeneous diseases began to strike non-randomly growing numbers of male homosexuals and mostly male intravenous drug users in the US and Europe. Assuming immunodeficiency as the common denominator the US Centers for Disease Control (CDC) termed the epidemic, AIDS, for acquired immunodeficiency syndrome. From 1981-1984 leading researchers including those from the CDC proposed that recreational drug use was the cause of AIDS, because of exact correlations and of drug-specific diseases. However, in 1984 US government researchers proposed that a virus, now termed human immunodeficiency virus (HIV), is the cause of the non-random epidemics of the US and Europe but also of a new, sexually random epidemic in Africa. The virus-AIDS hypothesis was instantly accepted, but it is burdened with numerous paradoxes, none of which could be resolved by 2003: Why is there no HIV in most AIDS patients, only antibodies against it? Why would HIV take 10 years from infection to AIDS? Why is AIDS not self-limiting via antiviral immunity? Why is there no vaccine against AIDS? Why is AIDS in the US and Europe not random like other viral epidemics? Why did AIDS not rise and then decline exponentially owing to antiviral immunity like all other viral epidemics? Why is AIDS not contagious? Why would only HIV carriers get AIDS who use either recreational or anti-HIV drugs or are subject to malnutrition? Why is the mortality of HIV-antibody-positives treated with anti-HIV drugs 7-9%, but that of all (mostly untreated) HIV-positives globally is only 1.4%? Here we propose that AIDS is a collection of chemical epidemics, caused by recreational drugs, anti-HIV drugs, and malnutrition. According to this hypothesis AIDS is not contagious, not immunogenic, not treatable by vaccines or antiviral drugs, and HIV is just a passenger virus. The hypothesis explains why AIDS epidemics strike non-randomly if caused by drugs and randomly if caused by malnutrition, why they manifest in drug- and malnutrition-specific diseases, and why they are not self-limiting via anti-viral immunity. The hypothesis predicts AIDS prevention by adequate nutrition and abstaining from drugs, and even cures by treating AIDS diseases with proven medications.

Improved methods and assumptions for estimation of the HIV/AIDS epidemic and its impact: Recommendations of the

UNAIDS and WHO produce biannual country-specific estimates of HIV/AIDS and its impact. These estimates are based on methods and assumptions that reflect the best understanding of HIV epidemiology and demography at the time. Where significant advances are made in epidemiological and demographic research, the methods and assumptions must evolve to match these advances. UNAIDS established an Epidemiology Reference Group in 1999 to advise them and other organisations on HIV epidemiology and methods for making estimates and projections of HIV/AIDS. During the meeting of the reference group in 2001, four priority areas were identified where methods and assumptions should be reviewed and perhaps modified: a) models of the HIV epidemic, b) survival of adults with HIV-1 in low and middle income countries, c) survival of children with HIV-1 in low and middle income countries, and d) methods to estimate numbers of AIDS orphans. Research and literature reviews were carried out by Reference Group members and invited specialists, prior to meetings held during 2001-2. Recommendations reflecting the consensus of the meeting participants on the four priority areas were determined at each meeting. These recommendations were followed in UNAIDS and WHO development of country-specific estimates of HIV/AIDS and its impact for end of 2001.

HIV-1 infection in rural Africa: is there a difference in median time to AIDS and survival compared with that in industrialized countries?

OBJECTIVES

To describe the progression times of HIV-1 infection from seroconversion to AIDS and to death, and time from first developing AIDS to death in rural Uganda. Also, to describe the proportion of individuals within the cohort dying with AIDS and the CD4 lymphocyte count before death.

DESIGN

A prospective, longitudinal, population-based cohort.

METHODS

Since 1990, 107 HIV-prevalent cases, 168 incident cases and 235 HIV-seronegative controls have been recruited into a cohort in rural Uganda. Participants are recruited from the general population and they are reviewed routinely every 3 months and at other times when ill.

RESULTS

The median time from seroconversion to death was 9.8 years. Age over 40 years at seroconversion was associated with more rapid progression (P < 0.001, log rank test). For the first 4 years of the study, HIV contributed little to the death rates in the HIV incident cases, but after 5 years, the contribution of HIV became greater and was particularly marked in the oldest age group. Survival rates in the cohort were similar to those in the general population. The median time from seroconversion to AIDS was 9.4 years and from AIDS to death was 9.2 months. Of those infected with HIV-1, 80% died with AIDS and 20% had a CD4 count < 10 x 106 cells/l.

CONCLUSIONS

Survival with HIV-1 infection is similar in Africa to industrialized countries before the use of antiretroviral therapy; when they do die, many of those in Africa are severely immunosuppressed and most have clinical features of AIDS.

HIV seroconversion interval and demographic characteristics: no evidence of selection bias

OBJECTIVES

To determine if the interval between the last negative and the first positive HIV test is associated with demographic characteristics of HIV seroconverters.

METHODS

A prospective cohort of patients with HIV seroconversion enrolled in the Lyons HIV hospital database was analysed. Comparisons of demographic characteristics were performed after stratification on the duration of the interval between the last HIV negative screening test and the first HIV positive screening test, which ranged from 1 day to 24 months. Linear regression methods were used to identify the covariates associated with a negative HIV antibody test followed by a positive test.

RESULTS

Age (p = 0.54), sex (p = 0.78), heterosexual route of infection (p = 0.78), other route (p = 0.40) compared with homosexual route, and estimated year of HIV infection (p value ranged from 0.84 to 0.95) were not associated with a shorter seroconversion interval after multivariate analyses. The presence of an acute HIV illness was the only predictor of a short seroconversion interval (p = 0.006) with a reduction of 84 days of the interval when it was reported.

CONCLUSIONS

No selection bias for demographic characteristics of HIV seroconverters seems associated with the length of the seroconversion interval, at least for intervals < or = 24 months.

Cofactors for HIV disease progression in a cohort of homosexual and bisexual men

To evaluate cofactors for progression of HIV infection, the authors identified 370 men with well-defined seroconversion dates and cofactor data among participants in the San Francisco City Clinic Cohort (SFCCC). Postseroconversion substance use, sexual behavior, and sexually transmitted diseases were assessed using multivariate proportional hazards models. Weekly use of hallucinogens strongly and independently predicted death (relative hazard [RH], 2.59; 95% confidence interval [CI], 1.56-4.28), as well as diagnosis of AIDS; weekly cocaine use also predicted mortality. Receptive anal intercourse with ejaculation was independently associated with mortality risk (RH, 1.45; 95% CI, 1.02-2.04) and AIDS. The associations of accelerated progression with weekly use of recreational drugs and unprotected receptive anal intercourse need to be confirmed in other prospective cohorts.

The practical significance of potential biases in estimates of the AIDS incubation period distribution in the UK register of HIV seroconverters

OBJECTIVES

To assess the practical significance of the following sources of bias for estimates of the AIDS incubation period in a large seroconverter cohort: estimation of the time of seroconversion; presentation with an HIV-related illness; preferential inclusion of survivors; loss to follow-up and analysis cut-off date; the inclusion of Kaposi's sarcoma as an AIDS event; death without an AIDS diagnosis; and representativeness of the HIV population.

METHODS

Standard non-parametric survival methods were used to estimate the AIDS incubation period distribution. The practical importance of each type of bias was assessed using various sensitivity analyses.

RESULTS

The potential sources of bias of most practical importance in this study were the right-censoring strategy and that due to lack of documentation of a negative HIV antibody test. Five different right-censoring strategies gave estimates of the median time to AIDS ranging from 8.1 to 10.8 years for the 1202 individuals enrolled in the UK Register of HIV Seroconverters. HIV-infected persons with a history of a previous antibody negative test which could not be verified appeared to progress to AIDS more rapidly than persons with such verification (Relative risk = 1.8, 95% confidence intervals = 1.3-2.3).

CONCLUSIONS

As a number of possible causes of bias can impact on results, care must be taken to document them and control for them wherever possible. In our study, this was particularly relevant in relation to the documentation of a previous HIV antibody negative test and the choice of analysis cut-off dates. As methods may differ between cohorts, comparison of the published results from one cohort with those of another may be misleading.

[AIDS-free time and survival of an injecting drug users HIV seroconvertors cohort]

OBJECTIVE

To analyze AIDS free time, survival and the pre-AIDS survival for a injecting drug users cohort (IDU) of HIV seroconvertors.

SUBJECT AND METHODS

Interval for seroconversion was available for 276 IDUs from Centers for AIDS Information and Prevention (CIPS) recruited between 1987 and until June of 1996. AIDS diagnosis and vital status dates were obtained by follow up at hospitals, mortality and AIDS registries, and CIPS visits. The end of follow up was December of 1996. Seroconversion date was estimated as the middle point between last HIV- and first HIV+. Kaplan-Meier extension and Cox regression for truncated data were fitted to estimate AIDS-free and survival times and to observe differences by sex, age consumption time and year of seroconversion. Weibull, and Log-normal parametric models were fitted to estimate median and percentiles of AIDS-free and survival times distribution.

RESULTS

34 cases have been identified as AIDS, 24 as deaths, 9 of them being before AIDS. 63.5% of the individuals were AIDS-free 7 years after seroconversion, and the probability of death was 25.50. Pre-AIDS mortality is around 8.7%. There were not significant differences by sex, age, consumption time and year of seroconversion. Log-normal model fitted better estimating an AIDS-free median time of 10.93 years and 13.67 survival years.

CONCLUSION

The incubation period of HIV infection in a cohort of seroconvertors in our environment was around 11 years, not different from that observed out of the Mediterranean area as Holland, Scotland or United States

Is the AIDS incubation time changing? A back-calculation approach

Contradictory literature was recently published on possible changes in AIDS incubation time over the period 1978-1994. The purpose of this work was to test if a change in incubation time (shortening or lengthening) was observed in France, either globally or in specific transmission groups (homosexual-bisexual men, heterosexual subjects), using a back-calculation approach. An age dependent TSI model (time since infection), which took into account a temporary treatment effect and allowed us to test for a change in the incubation time, was applied to the French AIDS cases (Réseau National de Santé Publique). The EM algorithm was used to maximize the likelihood and the best model was selected on the basis of the likelihood ratio statistic. The analysis on all AIDS cases indicated a shortening of the AIDS incubation time estimated to begin in 1983 (95 per cent CI 1982-1984). This shortening of incubation time was also apparent when analysis was restricted to homosexual-bisexual men and to heterosexual subjects. This shortening corresponded to a median incubation time of 9.6 years (95 per cent CI 8.1-10.5) for people infected at 30 years of age in 1983, versus 12.7 years for people infected at 30 years of age before the change.

Estimated HIV risk among Hispanics in a national sample of drug users

OBJECTIVE

To estimate and compare the HIV risks among three Hispanic subpopulations.

METHODS

Chronic drug users participating in a nationwide intervention study on drug use were interviewed with regard to drug use and sexual behavior. HIV risk was estimated using information about individuals' HIV-relevant behaviors, the social context (i.e., city) in which such behaviors occur, and published estimates of HIV transmission for various risk behaviors. Multiple linear regression analysis was used to investigate differences in estimated HIV risk between Puerto Rican, Mexican-American, and Mexican drug users, accounting for sociodemographic factors, sexual preference, and geographic region.

RESULTS

Puerto Ricans had significantly greater estimated overall HIV risk, estimated injection risk, and in general, significantly greater estimated sexual risk than Mexican Americans and Mexicans. No significant differences were found in any estimated risk between Mexican Americans and Mexicans in this sample. No significant differences were found among any of the subgroups for estimated risk from having anal sex while using a condom, or from having receptive anal sex without using a condom.

CONCLUSIONS

These findings suggest that Puerto Ricans who use drugs experience a higher risk of HIV infection than other Hispanic drug users. Research is needed to identify which economic, social, and cultural components account for this increased risk.

HIV vaccines

In summary, the development of HIV vaccines has progressed from simple first-generation env subunit vaccines to second-generation vaccines containing multiple subunits. Vaccines with epitopes for CMI and Ab responses have broadened the immune response and the potential efficacy of these vaccines. It is hoped that newer technologies including the development of adjuvants, new types of vaccines, such as naked DNA, and new delivery systems, such as liposomes, will evoke stronger immune responses with longer duration. Improved schedules for dosing and combinations of HIV vaccines may result in longer lasting immune responses. A phase III trial is anticipated to begin within the next 2 years. After a temporary lull, the outlook for HIV vaccine development is being met once again with strong enthusiasm and encouragement for the future.

Association between exercise and HIV disease progression in a cohort of homosexual men

PURPOSE

To study the relationship between exercise and human immunodeficiency virus (HIV) disease progression.

METHODS

415 individuals (156 HIV positive, 259 HIV negative), from a cohort study of 851 homosexual men from New York City, 1985-1991. By 1991, 68 of the 156 persons developed Acquired Immune Deficiency Syndrome (AIDS) and 49 died with AIDS. Exercise was defined as self-report of exercising 3-4 times/week or daily at entry; less was considered nonexercise. CD4 lymphocyte decline was constructed for each subject by modeling log CD4 count against time in days. The association between exercise and progression to AIDS and death with AIDS, adjusting for baseline CD4 count, was determined using Cox model. Linear regression was used to model CD4 decline with exercise for HIV positive and HIV negative groups separately, adjusting for initial CD4 count.

RESULTS

Having exercised was associated with slower progression to AIDS at 1 year (HR = 0.68, 90% confidence interval (CI): 0.4-1.17); hazard ratios (HR) at 2, 3, and 4 years were 0.96, 1.18, and 1.36, respectively. Having exercised was also associated with slower progression to death with AIDS at 1 year (HR = 0.37, 90% CI: 0.14-0.94) with hazard ratios at 2, 3, and 4 years of 0.68, 0.98, and 1.27, respectively, suggesting a protective effect close to the time exercise was assessed, but an increased risk after 2 years. Exercising 3-4 times/week had a more protective effect than daily exercise. Exercisers in the HIV positive group showed an increase in CD4 count during a year by a factor of 1.07.

CONCLUSION

Moderate physical activity may slow HIV disease progression.

Association of HLA profiles with early plasma viral load, CD4+ cell count and rate of progression to AIDS following acute HIV-1 infection. Multicenter AIDS Cohort Study

BACKGROUND

Host genetic factors, such as HLA alleles, play an important role in mediating the course of HIV-1 disease progression through largely undefined mechanisms.

OBJECTIVES

To examine the association of HLA markers with HIV-1 RNA plasma viral load and other factors associated with course of disease progression in HIV-1 infection.

DESIGN AND METHODS

A group of 139 HIV-1 seroconverters from the Multicenter AIDS Cohort Study had been typed for a variety of HLA markers. HIV-1 RNA plasma viral load was measured from frozen plasma specimens obtained approximately 9 months following seroconversion. CD4+ cell counts were available from the same study visit. Statistical analysis was performed using survival techniques and linear regression models to quantify the relative associations of an HLA score profile, HIV-1 RNA plasma viral load, CD4+ cell count and age with each other and with rate of progression to AIDS and death.

RESULTS

Cox proportional hazards models showed statistically significant differences in time to AIDS by HLA score profile category per unit increase [relative hazard (RH), 0.64; P < 0.0001], HIV-1 RNA plasma viral load per 10-fold increase (RH, 2.04; P = 0.0003), and CD4+ cell count per 100 cell (x 10(6)/l) increase (RH, 0.90; P = 0.02). Multivariate linear regression showed that viral load was 39% lower (P = 0.0001) for each unit increase in HLA score profile and 13% lower (P = 0.002) for each 100 cell (x 10(6)/l) increase in CD4+ cell count.

CONCLUSION

The means by which the HLA score profile influences the time to AIDS is probably through immunologic responses that affect the rate of HIV-1 replication, as manifested by the HIV-1 RNA plasma viral load during the first 6-12 months following acute infection.

Determinants of progression of HIV infection in a Greek hemophilia cohort followed for up to 16 years after seroconversion

Our objectives are to describe the progression of HIV disease and to assess the influence of hemophilia-related variables, age at infection, and antibodies to cytomegalovirus infection (anti-CMV) in a Greek cohort of 158 HIV-1-positive hemophilic men, who received prospective follow-up for up to 16 years after infection. A total of 79 patients had died, representing a cumulative progression rate of 72.4% (95% confidence interval [CI], 56.6-83.3). A significant proportion of the mortality (30%) resulted from conditions not formally related to AIDS, with liver failure and cerebral hemorrhage predominant. At 16 years after seroconversion, 66 patients had developed clinical AIDS, a cumulative progression rate of 58.2% (95% CI, 47.1%-86.3%) whereas 15 years after infection 81.5% (95% CI, 74.2%-87.9%) of the patients had AIDS or a CD4 cell count <200 cells/mm3. Hemophilia-related variables or presence of anti-CMV were not significantly associated with disease progression. Age at infection was a strong prognostic factor for all three endpoints. Appropriate modeling showed a nonlinear age effect, with a steeper increase of relative hazard for patients >40 years of age at seroconversion. The age effect remained significant even after controlling for current CD4 cell count. Further investigation is required to elucidate the mechanisms of the age effect and the contribution of HCV coinfection on the disease progression.

Has the rate of progression to AIDS changed in recent years?

OBJECTIVES

To investigate whether the rate of progression to AIDS has changed over time by testing an effect of the year of seroconversion on AIDS onset (Centers for Disease Control and Prevention 1987 revised classification), next to an effect of the calendar period of follow-up.

DESIGN

French multicentre prospective study of 385 homosexual and heterosexual subjects and 231 subjects from a multicentre study of European injecting drug users (IDU), all with a documented date of HIV-1 seroconversion.

METHOD

The effect of the year of seroconversion was compared by the log-rank test. Crude and adjusted relative hazard (ARH) were quantified using the Cox model. Calendar period of follow-up was studied separately for sexual exposure group and IDU and treated as a time-dependent variable in a Cox model.

RESULTS

In the 616 study subjects the year of seroconversion was not significantly related to AIDS occurrence (n = 108); the ARH was 0.88 [95% confidence interval (CI), 0.56-1.38] for those who seroconverted in 1988-1989, and 1.17 (95% CI, 0.61-2.25) for those who seroconverted after 1989, compared with those who seroconverted before 1988. In the sexual exposure group, a clear trend towards less rapid progression to AIDS was observed in subjects followed in 1991-1992 (ARH, 0.49; 95% CI, 0.24-0.99) and after 1992 (ARH, 0.54; 95% CI; 0.24-1.21), compared with those followed before 1991. This favorable trend was not observed in IDU despite a significant decrease over time of Pneumocystis carinii pneumonia as AIDS-defining illness. Conversely to sexual exposure groups, the frequency of antiretroviral treatment (mainly zidovudine) prescription was still low during the most recent calendar periods in IDU when the CD4 count threshold of 200 x 10(6)/l was reached.

CONCLUSIONS

No evidence was found of a change in the rate of progression to AIDS in subjects who seroconverted in recent years. Furthermore, conversely to sexual exposure groups, the lack of favorable trends in IDU users followed in recent years suggest that health-care systems are not always adapted to their lifestyles.

HIV-1 disease progression and AIDS-defining disorders in rural Uganda

BACKGROUND

The majority of people infected with HIV-1 live in Africa, yet little is known about the natural history of the disease in that continent. We studied survival times, disease progression, and AIDS-defining disorders, according to the proposed WHO staging system, in a population-based, rural cohort in Uganda.

METHODS

In 1990 we recruited a random sample of people already infected with HIV-1 (as prevalent cases) detected during the initial survey round of a general-population study to form a natural-history cohort. Individuals from the general-population cohort who seroconverted between 1990 and 1995 (incident cases) were also invited to enroll. Participants were seen routinely every 3 months and when they were III.

FINDINGS

By the end of 1995, 93 prevalent cases and 86 incident cases had been enrolled. Four patients in the prevalent group were in stage 4 (AIDS) at the initial visit. During the next 5 years, 37 prevalent cases progressed to AIDS. Seven incident cases progressed to AIDS and the cumulative progression to AIDS at 1, 3, and 5 years after seroconversion was 2%, 6%, and 22%, respectively. The cumulative probability of AIDS at 4 years from entering stages 1, 2, and 3 was 11%, 33%, and 58%, respectively. There were 47 deaths among prevalent cases and seven among incident cases during follow-up. The cumulative mortality 4 years after patients entered stages 1, 2, 3, and 4 was 9%, 33%, 56%, and 86%, respectively. The median survival after the onset of AIDS was 9.3 months.

INTERPRETATION

Our results are important for the setting of priorities and rationalisation of treatment availability in countries with poor resources. We found that progression rates to AIDS are similar to those in developed countries for homosexual cohorts and greater than for cohorts infected by other modes of transmission. However, we have found that the rates of all-cause mortality are much higher and the progression times to death are shorter than in developed countries.

HIV infection and aging: mechanisms to explain the accelerated rate of progression in the older patient

Age is an important predictor of progression in HIV infections. Not only do older individuals' develop AIDS more rapidly than younger persons, they die more quickly after developing an AIDS-defining illness. While the elderly have higher morbidity and mortality rates from viral and bacterial infections, the mechanism(s) responsible for the more rapid progression of HIV infection in older individuals has not been described. Our results demonstrate that the destruction of T cells in both young and old HIV infected patients progresses at the same rate. HIV 1-infected cells from older individuals do not appear more susceptible to immune mediated destruction. The more rapid progression appears due to an inability of older persons to replace functional T cells that are being destroyed. These findings suggest that improved survival in older HIV infected individuals will require more aggressive antiretroviral therapies as well as continued research to identify and preserve immune system elements that control the virus.

Associations of age, immunosuppression, and AIDS among homosexual men in the Tricontinental Seroconverter Study

To characterize the associations of age, immunosuppression, and AIDS outcomes, we evaluated serial measures of CD4+ lymphocytes from 376 homosexual men with documented dates of HIV-1 seroconversion registered in the Tricontinental Seroconverter Study. Using regression models and adjusting for variation within individuals, we found no association between age and the number of CD4+ lymphocytes at seroconversion or with CD4+ lymphocyte decline after seroconversion. Men who developed opportunistic infections had fewer CD4+ lymphocytes at the time of diagnosis compared with men who developed AIDS-defining Kaposi's sarcoma. Older age was significantly associated with higher numbers of CD4+ lymphocytes in individuals diagnosed with AIDS-defining Kaposi's sarcoma but was not significant for individuals with opportunistic infections. Because older age shortens the latency period of Kaposi's sarcoma and does not affect the CD4+ lymphocyte loss, it results in higher CD4+ lymphocytes at the time of diagnosis. These findings suggest distinct biologic mechanisms for various AIDS manifestations, which is important for clinical decision making and health care planning.

An HIV-1 natural history cohort and survival times in rural Uganda

OBJECTIVE

To describe a population-based rural cohort of HIV-1-seropositive and seronegative individuals established in 1990 in south-west Uganda, and determine survival times in the cohort.

DESIGN

Prospective cohort study.

METHODS

Participants were recruited from a large population study, and invited to attend a clinic every 3 months. They were seen by clinicians who administered detailed medical questionnaires and undertook a physical examination.

RESULTS

By the end of 1995, 390 (79%) of the 491 people asked to enrol in the natural history cohort (NHC) had done so. Ninety-three were prevalent cases of HIV infection detected during the initial survey round of the general population cohort in 1989/1990, 66 were subsequent incident cases, 177 were age-matched HIV-negative controls and 54 were HIV-negative spouses of HIV-positive individuals. Twenty participants seroconverted in the NHC. The age-standardized mortality rates per 1000 person-years for the prevalent, incident, and negative cases were 156.5 [95% confidence interval (CI), 115.8-211.4], 35.0 (95% CI, 16.4 75.0) and 13.5 (95% CI, 7.3-25.1), respectively. The median survival time from enrolment to death for the prevalent cases was 4.5 years (95% CI, 3.5- > 5.2); > 5.4 years from seroconversion for the incident cases; and > 5.2 years from enrolment for the HIV-negative cases. The 5-year cumulative survival for prevalents, incidents and HIV-negative participants was 46%, 83% and 94%, respectively.

CONCLUSIONS

We have described an NHC of HIV-positive and HIV-negative participants which is representative of the general population. The NHC was established over 5 years ago; it is continuing and we are maintaining good compliance rates. Survival probabilities in the cohort were lower than most other reported studies.

Comparison of progression and non-progression in injecting drug users and homosexual men with documented dates of HIV-1 seroconversion. European Seroconverter Study and the Tricontinental Seroconverter Study

OBJECTIVE

To compare the progression and non-progression of HIV infection among 418 injecting drug users (IDU) and 422 homosexual men with documented dates of HIV seroconversion from 12 cohorts.

METHODS

Seroconversion dates were calculated for each subject using a cohort-specific estimate of the cumulative HIV seroincidence over calendar time. In survival analysis, we studied the progression from seroconversion to AIDS and death by risk group. We compared non-progression between both risk groups by evaluating annual CD4 decline over the 7 years following seroconversion among AIDS-free subjects.

RESULTS

The relative hazard (RH) of AIDS for homosexual men compared with IDU was 1.54 before, and 1.21 after, adjusting for age at seroconversion and year of seroconversion. The risk of death from any cause for homosexual men compared with IDU increased over time since seroconversion. Fifty IDU died prior to AIDS, compared with seven homosexual men (unadjusted RH for homosexual men 0.10). Ignoring this pre-AIDS mortality, the crude RH of death for homosexual men compared with IDU was 2.05. Alter adjusting for age at seroconversion and year of seroconversion in multivariate analysis, the RH became 1.42. No differences in progression between subgroups aged 24 years or older could be demonstrated, but subjects < 24 years were found to be at a decreased risk. Proportions of non-progressors based on CD4 slope > or = 0 at 7 years following seroconversion were higher for IDU than for homosexual men. No differences were found in the proportion (approximately 5%) classified as non-progressors by criteria of both slope > or = 0 and absolute CD4 counts > 500 cells x 10(6)/l, even if pre-AIDS deaths and losses to follow-up were included.

CONCLUSIONS

We found little evidence for an effect of risk group on progression and non-progression. Pre-AIDS mortality was much higher among IDU than homosexual men. Pre-AIDS mortality and a nonlinear age effect should be considered in planning interventions as well as studies comparing risk groups and modelling the epidemic.

Dependence of the hazard of AIDS on markers

OBJECTIVE

To investigate the dependence of the hazard of symptomatic AIDS on various markers using a non-parametric method. The markers we consider are measures of time (time since infection and calendar date), measures of immune function (numbers and percentage of CD4 T cells) and serological activation markers (neopterin and beta 2-microglobulin).

METHODS

We adapted a non-parametric statistical method to estimate the hazard of AIDS. We considered both univariate analyses, in which each marker was considered separately and bivariate analyses of pairs of markers.

CONCLUSIONS

Using data from 356 seroconverters from the Multicenter AIDS Cohort Study, we found that in the univariate analyses the hazard of AIDS is dependent on all markers, with the strongest dependence for CD4 count and CD4 percentage. In the bivariate analyses we found that the time since infection is of little importance in determining the hazard of AIDS if the CD4 count or percentage are known, and is of minor additional value if one of the serological markers is known. In contrast, we found that both beta 2-microglobulin and neopterin do add some additional information to the hazard of AIDS if CD4 count or CD4 percentage are known.

Virologic and serologic markers of rapid progression to AIDS after HIV-1 seroconversion

The association between early virologic and immunologic events after human immunodeficiency virus type 1 (HIV-1) infection and progression of HIV-1 infection to acquired immunodeficiency syndrome (AIDS) was studied among 59 homosexual men with documented time of seroconversion. Epidemiologic factors, such as number of lifetime sexual partners, history of sexually transmitted diseases, and other factors, also were studied. All 17 seroconverters in the cohort who developed AIDS within 3 years (rapid progressors = RPs) were compared with 42 men without AIDS for at least 6 years seroconversion (nonrapid progressors = non-RPs). Plasma levels of HIV-1 RNA, p24 antigen, antibodies to HIV-1 structural genes, beta-2 microglobulin, neopterin, and interferon-alpha were measured at four time points: (a) the last seronegative visit, (b) the first seropositive visit, (c) the visit closest to AIDS (or the corresponding visit for the non-RPs) and (d) 6 years after seroconversion (for non-RPs). Up to seroconversion, the RPs had a significantly higher number of lifetime sexual partners than non-RPs (503 versus 171, respectively). At the first seropositive visit, RPs had significantly higher concentrations of plasma HIV-1 RNA (p < 0.01) and prevalence of p24 antigenemia (p < 0.001) and significantly lower levels of antibodies to the HIV-1 gag proteins p17 and p24 (p < 0.01-0.001) compared with non-RPs. These differences increased during follow-up visits. Antibodies to p66 and gp120 were significantly different only at the visit closet to AIDS (p < 0.001), as were beta-2 microglobulin and interferon alpha. These findings suggest that early virologic-immunologic events after HIV-1 infection may determine the rate of progression to AIDS. Anti-gag immune response may prevent rapid progression of HIV-1 disease and should be considered for future vaccine studies.