Acute human immunodeficiency virus type 1 infection

The effects of early antiretroviral therapy and its discontinuation on the HIV-specific antibody response

HIV-specific antibodies become detectable and continue to increase in frequency during primary infection. The effects of early antiretroviral treatment (ART) and its discontinuation on the evolution of this immune response have not been systematically analyzed. To investigate the associations between antibody titer, viral load, and ART, we used a less-sensitive enzyme-linked immunosorbant assay (LS-EIA) to measure changes in HIV-1-specific antibody levels in treated and untreated subjects undergoing primary infection. In this longitudinal study, antibody levels gradually increased in therapy-naive subjects, reaching a plateau approximately 40 weeks postinfection. In contrast, antibody titers remained low among subjects receiving ART. Subjects who discontinued ART exhibited a more rapid rise in antibody titers than therapy-naive subjects, suggesting the presence of an enhanced B cell response. These results demonstrate that early ART prevents the typical evolution of the HIV-1-specific antibody response and can alter the expected kinetics of this response in subjects discontinuing therapy.

An information-motivation-behavioral skills model of adherence to antiretroviral therapy

HIV-positive persons who do not maintain consistently high levels of adherence to often complex and toxic highly active antiretroviral therapy (HAART) regimens may experience therapeutic failure and deterioration of health status and may develop multidrug-resistant HIV that can be transmitted to uninfected others. The current analysis conceptualizes social and psychological determinants of adherence to HAART among HIV-positive individuals. The authors propose an information-motivation-behavioral skills (IMB) model of HAART adherence that assumes that adherence-related information, motivation, and behavioral skills are fundamental determinants of adherence to HAART. According to the model, adherence-related information and motivation work through adherence-related behavioral skills to affect adherence to HAART. Empirical support for the IMB model of adherence is presented, and its application in adherence-promotion intervention efforts is discussed.

Reasons for testing and clinical and demographic profile of adolescents with non-perinatally acquired HIV infection

OBJECTIVES

We sought to examine the demographic, clinical, and behavioral characteristics; reasons for HIV testing; and factors that contribute to delays in entry into specialized HIV care after diagnosis of HIV infection among adolescents in an urban clinic in Georgia.

METHODS

All of the data for this study were obtained solely by medical chart review. Demographic, clinical, behavioral, and HIV testing data were abstracted from medical charts of 59 non-perinatally HIV-infected adolescents who were aged 13 to 18 years and entered care at the pediatric and adolescent HIV clinic of a Georgia hospital during 1999-2002. HIV-infected adolescents were compared by demographic, clinical, and behavioral characteristics as well as by circumstances surrounding HIV testing. Recent seroconversion was defined as having a documented negative or indeterminate HIV antibody test (confirmed) or a self-reported negative HIV test (probable) < or =6 months before HIV diagnosis.

RESULTS

Of 59 HIV-infected adolescents, 35 (59%) were female and 56 (95%) were black/African American. Fifteen (25%) had > or =1 sexually transmitted infection when they entered care. All female (vs 38% male) adolescents were infected through heterosexual sexual intercourse; 9 (26%) were pregnant at the time of HIV diagnosis. Adolescents whose HIV was diagnosed at non-health care facilities entered HIV care much later than adolescents whose HIV was diagnosed at health care facilities (median: 108 vs 25 days). Approximately one half of adolescents had CD4+ T-cell counts <350 cells per microL and/or HIV-1 viral loads >55,000 copies per mL at entry into care. Twenty-seven (46%) adolescents had a previous negative HIV test; 7 had confirmed recent seroconversion, and 3 had probable recent seroconversion. Among adolescents with a documented reason for testing, routine medical screening was the most frequent reason for HIV testing; few adolescents were documented as having self-initiated HIV testing.

CONCLUSIONS

Strategies are needed to implement timely linkage to medical services of adolescents who receive a diagnosis of HIV infection at non-health care facilities and to increase HIV testing, prevention efforts, and recognition of recent HIV infection among sexually active adolescents.

The development and utility of a clinical algorithm to predict early HIV-1 infection

The association between self-reported clinical factors and recent HIV-1 seroconversion was evaluated in a prospective cohort of 4652 high-risk participants in the HIV Network for Prevention Trials (HIVNET) Vaccine Preparedness Study. Eighty-six individuals seroconverted, with an overall annual seroconversion rate of 1.3 per 100 person-years. Four self-reported clinical factors were significantly associated with HIV-1 seroconversion in multivariate analyses: recent history of chlamydia infection or gonorrhea, recent fever or night sweats, belief of recent HIV exposure, and recent illness lasting > or =3 days. Two scoring systems, based on the presence of either 4 or 11 clinical factors, were developed. Sensitivity ranged from 2.3% (with a positive predictive value of 12.5%) to 72.1% (with a positive predictive value of 1%). Seroconversion rates were directly associated with the number of these clinical factors. The use of scoring systems comprised of clinical factors may aid in detecting early and acute HIV-1 infection in vaccine and microbicide trials. Organizers can educate high-risk trial participants to return for testing during interim visits if they develop these clinical factors. Studying individuals during early and acute HIV-1 infection would allow scientists to investigate the impact of the intervention being studied on early transmission or pathogenesis of HIV-1 infection.

Primary HIV-1 infection sets the stage for important B lymphocyte dysfunctions

OBJECTIVES

To investigate the effects of primary HIV-1 infection (PHI) and of two antiretroviral therapies [highly active antiretroviral therapy (HAART) or reverse transcriptase inhibitors (RTI)] on activation, differentiation and survival of B cells.

METHODS

Naive and memory B cells from three groups [PHI (31), chronic infection (26) and healthy donors (12)] were studied for surface expression of Fas, LAIR-1, CD70, intracellular expression of Bcl-2 and spontaneous apoptosis. Fluorescence activated cell sorting (IgD+IgM+CD19+CD27+) and short-term cell culture to analyse induction of CD25 on B cells were performed in five patients with PHI. Patients with PHI were sampled at baseline, and after 1 and 6 months of therapy. Results were analysed by parametric and non-parametric tests and by mathematical modelling.

RESULTS

In PHI, B cells were significantly decreased; naive and memory B lymphocytes showed a high degree of activation, manifested by hypergammaglobulinaemia, altered expression of Fas and LAIR-1, and high rate of spontaneous apoptosis. Antiretroviral treatment improved the activation/differentiation status of B cells, reduced apoptosis to levels comparable to those in healthy individuals and restored the ability of B cells to respond to T cell-dependent activation. B cells showed slightly better recovery in patients taking HAART than in those taking RTI. Decreased IgM-positive memory B cells and lower induction of CD25 expression on B cells upon T cell activation at diagnosis of PHI was shown in five patients tested. These parameters normalized after 6 months of therapy.

CONCLUSION

B cell dysfunctions found in chronic HIV-1 infection appear during PHI and initiation of antiretroviral therapy early during infection may help to preserve the B cell compartment.

Perils at mucosal front lines for HIV and SIV and their hosts

HIV-1 and simian immunodeficiency virus (SIV), as well as their hosts, face perils at mucosal front lines in early infection. At these sites, 'resting' CD4+ memory T cells fuel infection (because they are hosts for virus), depleting CD4+ memory T cells throughout the lymphoid tissues, particularly in the gut, and eliciting an immunosuppressive regulatory T-cell response that impairs host defence. But HIV-1 and SIV also risk elimination at the earliest stage of infection, at the mucosal point of entry, if founder populations of infected cells do not expand sufficiently to establish a self-propagating infection. Microbicides and vaccines could increase these viral vulnerabilities at mucosal front lines.

Health department collaboration with emergency departments as a model for public health programs among at-risk populations

OBJECTIVES

Accessing at-risk and underserved populations for intervention remains a major obstacle for public health programs. Emergency departments (EDs) care for patients not otherwise interacting with the health care system, and represent a venue for such programs. A variety of perceived and actual barriers inhibit widespread implementation of ED-based public health programs. Collaboration between local health departments and EDs may overcome such barriers. The goal of this study was to assess the effectiveness of a health department-funded, ED-based public health program in comparison with other similar community-based programs through analysis of data reported by health department-funded HIV counseling and testing centers in one Ohio county.

METHOD

Data for HIV counseling and testing at publicly funded sites in southwestern Ohio from January 1999 through December 2002 were obtained from the Ohio Department of Health. Demographic and risk-factor profiles were compared between the counseling and testing program located in the ED of a large, urban teaching hospital and the other publicly funded centers in the same county.

RESULTS

A total of 26,382 patients were counseled and tested; 5,232 were ED patients, and 21,150 were from community sites. HIV positivity was 0.86% (95% confidence interval [CI] 0.64%, 1.15%) in the ED and 0.65% (95% CI 0.55%, 0.77%) elsewhere. The ED program accounted for 19.8% of all tests and 24.7% of all positive results. The ED notified 77.3% of individuals testing positive and 84.4% of individuals testing negative. At community program centers, 88.3% of patients testing positive and 63.8% of patients testing negative were notified of results. All ED patients notified of positive status were successfully referred to infectious disease specialists.

CONCLUSIONS

Public health programs can operate effectively in the ED. EDs should have a rapidly expanding role in the national public health system.

Primary HIV Infection

Primary HIV infection refers to the events surrounding acquisition of HIV infection. It is associated with a nonspecific clinical syndrome that occurs 2 to 4 weeks after exposure in 40% to 90% of individuals acquiring HIV. Patients identified before seroconversion often have very high plasma HIV RNA titers that, without treatment, gradually decrease to reach a set point. Treatment of primary HIV infection with highly active antiretroviral therapy does not prevent establishment of chronic infection. However, very early therapy could potentially decrease the viral set point, prevent viral diversification, preserve immune function, improve clinical outcomes, and decrease secondary transmission. These benefits have not yet been definitely demonstrated. Transmission of viral strains with decreased susceptibility to antiviral drugs has led to recommendations for resistance testing in primary infection before initiation of therapy. Immunomodulators and vaccines are also under study as adjuvant therapy for treatment of primary HIV infection.

Prevalence of primary HIV infection in symptomatic ambulatory patients

PURPOSE

Recognizing primary human immunodeficiency virus (HIV) infection is important for public health. The prevalence in outpatient settings is largely unknown but would be useful in developing testing guidelines. The objective of this study is to estimate the national prevalence of primary HIV infection in symptomatic ambulatory patients regardless of risk factors.

METHODS

Patients 13 to 54 years old with each of 17 primary HIV infection symptoms, as well as other reported reasons for their visit consistent with primary HIV infection, were identified from the 2000 National Ambulatory Medical Care and National Hospital Ambulatory Medical Surveys to provide the denominator for the prevalence estimate. These survey data can be extrapolated to represent 90% of all US ambulatory care visits, including those to physician's offices, emergency departments, and hospital clinics. Patients with symptoms and diagnoses inconsistent with a viral illness were excluded. The estimate for the numerator was derived from Centers for Disease Control and Prevention estimates and the medical literature.

RESULTS

Patients complaining of fever and other visit reasons consistent with primary HIV infection had a disease prevalence of 0.66% (0.57%-1.02%), those with rash had a prevalence of 0.50% (0.31%-0.82%), and those with pharyngitis had a prevalence of 0.16% (0.11%-0.22%). Patients with other symptoms represented numbers of visits insufficient for reliable estimates of their prevalence.

CONCLUSIONS

These estimates of the prevalence of primary HIV infection in ambulatory patients with fever, rash, and pharyngitis can aid with development of clinical testing guidelines and clinical decisions around testing for acute HIV infection.

The cost-effectiveness of expanded testing for primary HIV infection

PURPOSE

Primary infection with the human immunodeficiency virus (HIV) is a major factor in the HIV epidemic. Most patients become symptomatic and seek care, but seldom are they tested or is their condition diagnosed. The objectives of this study are to determine whether it is cost-effective to expand testing for primary HIV infection to a larger cohort of patients, and, if so, which diagnostic assay is most cost-effective.

METHODS

We undertook a cost-effectiveness analysis of testing a hypothetical cohort of more than 3 million outpatients with fever and other viral symptoms regardless of HIV risk factors using 3 diagnostic assays: p24 antigen enzyme immunosorbent assay (EIA), HIV-1 RNA assay, and third-generation HIV-1 EIA. Antiretroviral therapy was started when the CD4 cell count decreased to 350/microL. Outcome measures were the incremental cost-effectiveness of the diagnostic assays, number of cases identified, cases avoided in sexual partners, and threshold prevalence. For sensitivity analyses, we used 50,000 dollars as the threshold for cost-effectiveness.

RESULTS

At the baseline prevalence of 0.66%, p24 antigen EIA testing was the most cost-effective option at a cost of 30,800 dollars per quality-adjusted life-year gained when compared with no testing. There were 17,054 cases identified, and infection was avoided in 435 partners. Probabilistic sensitivity analysis, in which the estimates for all variables are varied simultaneously, determined that expanded testing with p24 antigen EIA compared with no testing had a 67% probability of being cost-effective at the baseline prevalence and a 71% probability at a prevalence of 1%.

CONCLUSIONS

Expanded testing for primary HIV infection with p24 antigen EIA may be a sound expenditure of health care resources.

HIV in adolescents

Adolescence is a time of dramatic physical, emotional, cognitive, and social change that brings new vulnerabilities. Youth represent half of all new HIV infections in the United States and the rest of the world. The number of newly infected adolescents who acquire the disease behaviorally and the number of perinatally infected children surviving into adolescence have both contributed to this growth. This article reviews the most recent epidemiology of HIV/AIDS in adolescents, gives guidance on clinical practice, including medical and psychosocial care, and examines prevention issues, including counseling and testing, which are needed to make programs effective for youth.

The challenges of HIV vaccine development and testing

A vaccine against HIV remains the best hope for bringing the epidemic under control. An intensive global effort is underway to develop such a vaccine; however, the challenges are considerable. Several new vaccine technologies that have been developed and shown promise in animal models are now being tested in early phase safety trials in humans. Because there is no laboratory assay that will predict whether an HIV vaccine can protect humans from infection, clinical trials involving thousands of volunteers will need to be conducted to determine the efficacy of HIV vaccines. These trials need to take place in the developing countries that bear the burden of the epidemic, requiring a substantial amount of infrastructure development and capacity building.

Emergency Department HIV Testing and Counseling: An Ongoing Experience in a Low-Prevalence Area

STUDY OBJECTIVE

Despite recommendations, emergency department (ED)-based HIV screening is not widespread, and feasibility studies are generally limited to settings with high HIV prevalence (>1%). This investigation was to evaluate an ongoing, publicly funded, ED-based HIV counseling and testing program in a low-prevalence area.

METHODS

We reviewed a database of patients treated by an ED-based HIV counseling and testing program at a large, urban, teaching hospital for 1998 to 2002. ED patients at risk for HIV were targeted for standard serologic testing and counseling. Data were collected prospectively using standardized forms as part of clinical operations rather than in the context of rigorous research methodology; patient-oriented outcomes were not assessed. Counselors were trained according to Centers for Disease Control and Prevention guidelines, and health department guidelines for counseling and testing centers were followed. The main outcome measure was the number and proportion of patients newly diagnosed with HIV.

RESULTS

Eight thousand five hundred seventy-four patients were approached; 5,504 consented to HIV testing. Mean age was 29 years (SD 9.4 years), 76% were black, and 50% were men. Five thousand three hundred seventy-four (97.6%) patients tested negative and 39 (0.7%) patients tested positive. Seventy-five percent of negative-test patients and 79% of positive-test patients were notified of test results. Information for seropositive patients not notified of results was forwarded to the health department. All notified HIV-positive patients entered treatment. Risk factors included sexually transmitted disease (47%), multiple sexual partners (40%), unprotected sex while using drugs or alcohol (30%), men having sex with men (5%), and intravenous drug use (4%).

CONCLUSION

Identification of HIV-positive patients is possible in low-prevalence ED settings. In this instance, it was possible to perpetuate an ED-based HIV intervention program during an extended time. Although our work expands the profile of ED-based HIV counseling and testing beyond previous reports, the results should not be overgeneralized.

Immunodominance of HIV-1-specific CD8(+) T-cell responses in acute HIV-1 infection: at the crossroads of viral and host genetics

The development of HIV-1-specific CD8(+) T-cell responses during acute HIV-1 infection is associated with a dramatic decline in HIV-1 replication and the resolution of the acute retroviral syndrome. These HIV-1-specific CD8(+) T cells typically target a small number of viral epitopes in a distinct hierarchical order, and high-level viremia in chronic progressive infection leads to broadly diversified HIV-1-specific CD8(+) T-cell responses with a less clear immunodominance pattern. It is argued here that the specific hierarchical pattern of immune responses in acute HIV-1 infection is the result of a tightly regulated process that, among other factors, is critically impacted by the kinetics of viral protein expression, the HLA class I background of the infected individual and the autologous sequence of the infecting virus.

Transmission of HIV-1 during primary infection: relationship to sexual risk and sexually transmitted infections

OBJECTIVE

To study primary HIV-1 infections (PHI) using molecular and epidemiological approaches in order to assess correlates of transmission in this population.

METHODS

Individuals with PHI were recruited prospectively from a discrete cohort of 1235 individuals under follow-up in a well-defined geographical area between 1999 and 2003. PHI was diagnosed by one of the following: negative HIV antibody test within 18 months, evolving antibody response, or application of the serological testing algorithm for recent HIV seroconversion. The pol gene was sequenced to identify genotypic resistance and facilitate molecular epidemiological analysis. Clinical data were collected and linked in an irretrievable fashion when informed consent was obtained.

RESULTS

A total of 103 individuals with PHI diagnosed between 1999 and 2003 were included in the study; 99 (96%) were male and 90 (91%) were men who have sex with men. Viruses from 35 out of 103 (34%) appeared within 15 phylogenetically related clusters. Significant associations with clustering were: young age, high CD4 cell count, number of sexual contacts, and unprotected anal intercourse (UAI) in the 3 months before diagnosis (P < 0.05 for all). High rates of acute sexually transmitted infections (STI) were observed in both groups with a trend towards higher rates in those individuals with viruses within a cluster (42.9 versus 27.9%; P = 0.13).

CONCLUSION

High rates of partner change, UAI and STI are factors that facilitate onward transmission during PHI. More active identification of individuals during PHI, the management of STI and highly active antiretroviral therapy may all be useful methods to break transmission networks.

Prophylaxis of HIV infection

The number of people infected with HIV continues to increase relentlessly. Post-exposure prophylaxis (PEP) following exposure to HIV infection may prevent established HIV infection. Such intervention is supported by biological plausibility and limited data from animal and human studies. Antiretroviral prophylaxis is associated with significant side effects and the risk should be weighed against the potential benefits. PEP should be considered after significant occupational and non-occupational exposures. However, PEP is not suitable for individuals with repeated high-risk behaviour who are not willing to adhere to risk reduction practices. Primary prevention strategies remain the mainstay for control of the HIV epidemic and cannot be replaced by PEP. Guidance for PEP following exposure to HIV infection is available in many countries worldwide.

Gender differences in human immunodeficiency virus type 1-specific CD8 responses in the reproductive tract and colon following nasal peptide priming and modified vaccinia virus Ankara boosting

Induction of mucosal anti-human immunodeficiency virus type 1 (HIV-1) T-cell responses in males and females will be important for the development of a successful HIV-1 vaccine. An HIV-1 envelope peptide, DNA plasmid, and recombinant modified vaccinia virus Ankara (rMVA) expressing the H-2D(d)-restricted cytotoxic T lymphocyte P18 epitope were used as immunogens to test for their ability to prime and boost anti-HIV-1 T-cell responses at mucosal and systemic sites in BALB/c mice. We found of all prime-boost combinations tested, an HIV-1 Env peptide subunit mucosal prime followed by systemic (intradermal) boosting with rMVA yielded the maximal induction of gamma interferon (IFN-gamma) spot-forming cells in the female genital tract and colon. However, this mucosal prime-systemic rMVA boost regimen was minimally immunogenic for the induction of genital, colon, or lung anti-HIV-1 T-cell responses in male mice. We determined that a mucosal Env subunit immunization could optimally prime an rMVA boost in female but not male mice, as determined by the magnitude of antigen-specific IFN-gamma responses in the reproductive tracts, colon, and lung. Defective mucosal priming in male mice could not be overcome by multiple mucosal immunizations. However, rMVA priming followed by an rMVA boost was the optimal prime-boost strategy for male mice as determined by the magnitude of antigen-specific IFN-gamma responses in the reproductive tract and lung. Thus, prime-boost immunization strategies able to induce mucosal antigen-specific IFN-gamma responses were identified for male and female mice. Understanding the cellular and molecular basis of gender-determined immune responses will be important for optimizing induction of anti-HIV-1 mucosal immune responses in both males and females.

HIV and anesthesia

Human immunodeficiency virus [HIV disease or acquired immunodeficiency syndrome (AIDS)] is the greatest health crisis of the twentieth and early twenty-first century. In sub-Saharan Africa, the epidemic rivals the "Black Death" of fourteenth-century Europe. AIDS is a multiorgan disease that has broad implications for anesthesiologists. New drug therapies are highly effective in most cases and have significant potential for drug interactions. The purpose of this article is to help anesthesiologists better manage persons who have HIV/AIDS in the operating room, labor and delivery suite, and other areas in which this patient population will require an increasing amount of care.

A pathophysiological approach to antiretroviral therapy

A discussion of the pathophysiology of HIV infection is important not only to understand both routine and novel therapeutic approaches, but also to appreciate the challenges of long-term control and viral eradication. This article will first briefly review certain pathophysiologic principles of HIV infection that have particular therapeutic implications, and then discuss general tenets of antiretroviral therapy, followed by new developments in the field.

Immunopathogenesis of oropharyngeal candidiasis in human immunodeficiency virus infection

Oropharyngeal and esophageal candidiases remain significant causes of morbidity in human immunodeficiency virus (HIV)-infected patients, despite the dramatic ability of antiretroviral therapy to reconstitute immunity. Notable advances have been achieved in understanding, at the molecular level, the relationships between the progression of HIV infection, the acquisition, maintenance, and clonality of oral candidal populations, and the emergence of antifungal resistance. However, the critical immunological defects which are responsible for the onset and maintenance of mucosal candidiasis in patients with HIV infection have not been elucidated. The devastating impact of HIV infection on mucosal Langerhans' cell and CD4(+) cell populations is most probably central to the pathogenesis of mucosal candidiasis in HIV-infected patients. However, these defects may be partly compensated by preserved host defense mechanisms (calprotectin, keratinocytes, CD8(+) T cells, and phagocytes) which, individually or together, may limit Candida albicans proliferation to the superficial mucosa. The availability of CD4C/HIV transgenic mice expressing HIV-1 in immune cells has provided the opportunity to devise a novel model of mucosal candidiasis that closely mimics the clinical and pathological features of candidal infection in human HIV infection. These transgenic mice allow, for the first time, a precise cause-and-effect analysis of the immunopathogenesis of mucosal candidiasis in HIV infection under controlled conditions in a small laboratory animal.

Loss of HIV-1-specific CD8+ T cell proliferation after acute HIV-1 infection and restoration by vaccine-induced HIV-1-specific CD4+ T cells

Virus-specific CD8(+) T cells are associated with declining viremia in acute human immunodeficiency virus (HIV)1 infection, but do not correlate with control of viremia in chronic infection, suggesting a progressive functional defect not measured by interferon gamma assays presently used. Here, we demonstrate that HIV-1-specific CD8(+) T cells proliferate rapidly upon encounter with cognate antigen in acute infection, but lose this capacity with ongoing viral replication. This functional defect can be induced in vitro by depletion of CD4(+) T cells or addition of interleukin 2-neutralizing antibodies, and can be corrected in chronic infection in vitro by addition of autologous CD4(+) T cells isolated during acute infection and in vivo by vaccine-mediated induction of HIV-1-specific CD4(+) T helper cell responses. These data demonstrate a loss of HIV-1-specific CD8(+) T cell function that not only correlates with progressive infection, but also can be restored in chronic infection by augmentation of HIV-1-specific T helper cell function. This identification of a reversible defect in cell-mediated immunity in chronic HIV-1 infection has important implications for immunotherapeutic interventions.

The HIV-1 HLA-A2-SLYNTVATL is a help-independent CTL epitope

The CTL response to the HLA-A*0201-restricted, HIV-1 p17 Gag(77-85) epitope (SLYNTVATL; SL9) has been extensively studied in patients. Although this reactivity is exceptionally prominent in chronically infected patients and inversely correlated to viral load, SL9-specific CTLs (SL9-CTLs) are rarely detected in acute infection. To explore the cellular basis for this unusual manifestation, SL9-CTLs primed ex vivo from naive circulating CD8(+) T cells of healthy, seronegative donors were generated and characterized. SL9 appeared to differ from other well-studied A*0201-restricted epitopes in several significant respects. In contrast to published reports for influenza and melanoma peptides and the HIV gag IV9 epitope studied here in parallel, SL9-CTLs were primed by immature but not mature autologous dendritic cells. Highly activated SL9-CTLs produce sufficient autocrine mediators to sustain clonal expansion and CTL differentiation for months without CD4(+) T cells or exogenous IL-2. Moreover, SL9-CTLs were sensitive to paracrine IL-2-induced apoptosis. IL-2 independence and sensitivity to paracrine IL-2 were also characteristic of SL9-CTLs immunized by dendritic cells transduced by a nonreplicating lentiviral vector encoding full-length Gag. In vitro-primed SL9-CTLs resembled those derived from patients in degeneracy of recognition and functional avidities for both SL9 and its natural mutations. Together, these data show that SL9 is a highly immunogenic, help-independent HIV epitope. The scarcity of SL9-CTLs in acute infection may result from cytokine-induced apoptosis with the intense activation of the innate immunity. In contrast, SL9-CTLs that constitutively produce autocrine help would predominate during CD4-diminished chronic infection.

PSC-RANTES blocks R5 human immunodeficiency virus infection of Langerhans cells isolated from individuals with a variety of CCR5 diplotypes

Topical microbicides that effectively block interactions between CCR5(+) immature Langerhans cells (LC) residing within genital epithelia and R5 human immunodeficiency virus (HIV) may decrease sexual transmission of HIV. Here, we investigated the ability of synthetic RANTES analogues (AOP-, NNY-, and PSC-RANTES) to block R5 HIV infection of human immature LC by using a skin explant model. In initial experiments using activated peripheral blood mononuclear cells, each analogue compound demonstrated marked antiviral activity against two R5 HIV isolates. Next, we found that 20-min preincubation of skin explants with each RANTES analogue blocked R5 HIV infection of LC in a dose-dependent manner (1 to 100 nM) and that PSC-RANTES was the most potent of these compounds. Similarly, preincubation of LC with each analogue was able to block LC-mediated infection of cocultured CD4(+) T cells. Competition experiments between primary R5 and X4 HIV isolates showed blocking of R5 HIV by PSC-RANTES and no evidence of increased propagation of X4 HIV, data that are consistent with the specificity of PSC-RANTES for CCR5 and the CCR5(+) CXCR4(-) phenotype of immature LC. Finally, when CCR5 genetic polymorphism data were integrated with results from the in vitro LC infection studies, PSC-RANTES was found to be equally effective in inhibiting R5 HIV in LC isolated from individuals with CCR5 diplotypes known to be associated with low, intermediate, and high cell surface levels of CCR5. In summary, PSC-RANTES is a potent inhibitor of R5 HIV infection in immature LC, suggesting that it may be useful as a topical microbicide to block sexual transmission of HIV.

HIV-1 Nef is preferentially recognized by CD8 T cells in primary HIV-1 infection despite a relatively high degree of genetic diversity

OBJECTIVE

To compare the magnitude, breadth and protein specificity of HIV-1-specific CD8 T-cell responses against the clade B consensus sequence during primary and chronic HIV-1 infection and to analyze the impact of viral diversity on the localization of detected responses.

METHODS

HIV-1-specific CD8 T-cell responses against the clade B consensus sequence in individuals with acute (n = 10), early (n = 19) and chronic (n = 10) infection were longitudinally assessed using an interferon-gamma EliSpot assay.

RESULTS

CD8 T-cell responses against clade B consensus sequences were preferentially directed against central regions of Nef during primary HIV-1 infection, despite a relatively higher degree of genetic diversity compared with other subsequently targeted regions. In subjects with acute and early infection, Nef-specific CD8 T-cell responses against the consensus Nef sequence represented 94 and 46% of the total magnitude of HIV-1-specific CD8 T-cell responses, respectively. Subjects with untreated chronic infection exhibited broadly diversified CD8 T-cell responses against more conserved viral regions, with only 17% of virus-specific T-cell responses targeting Nef. The initial immunodominance of Nef persisted in individuals with treated acute infection, but shifted rapidly to Gag, Env and Pol in subjects with continuous antigen exposure.

CONCLUSION

These data show that despite relatively high sequence variability, viral regions within the clade B consensus sequence of Nef are preferentially recognized during primary HIV-1 infection. Later diversification of responses to other proteins during prolonged antigen exposure provides evidence of the initial preferential immunogenicity of Nef epitopes compared to similarly conserved regions within other viral proteins.

Roles of target cells and virus-specific cellular immunity in primary simian immunodeficiency virus infection

There is an ongoing debate on whether acute human immunodeficiency virus infection is controlled by target cell limitation or by virus-specific cellular immunity. To resolve this question, we developed a novel mathematical modeling scheme which allows us to incorporate measurements of virus load, target cells, and virus-specific immunity and applied it to a comprehensive data set generated in an experiment involving rhesus macaques infected with simian immunodeficiency virus. Half of the macaques studied were treated during the primary infection period with reagents which block T-cell costimulation and as a result displayed severely impaired virus-specific immune responses. Our results show that early viral replication in normal infection is controlled to a large extent by virus-specific CD8(+) T cells and not by target cell limitation.

Acute HIV revisited: new opportunities for treatment and prevention

Inability to recognize incident infection has traditionally limited both scientific and public health approaches to HIV disease. Recently, some laboratories have begun adding HIV nucleic acid amplification testing to HIV diagnostic testing algorithms so that acute (antibody-negative) HIV infections can be routinely detected within the first 1-3 weeks of exposure. In this review article, we will highlight critical opportunities for HIV treatment and prevention that are presented by these diagnostic strategies.

Primary human immunodeficiency virus infection presenting as acute pancreatitis

Primary human immunodeficiency virus (HIV) infection can present in a variety of ways. It is important to recognize acute HIV infection, for personal and public health reasons. We present an unusual case of primary HIV infection manifesting as acute pancreatitis.

Primary HIV type 1 infection

Emerging evidence suggests that early events in human immunodeficiency virus type 1 (HIV-1) infection may play a critical role in determining disease progression. Although there is limited evidence on which to base medical decisions, the diagnosis and treatment of acute HIV-1 infection may have virologic, immunologic, and clinical benefits. In addition, rapid diagnosis of infection may prevent unknowing transmission of HIV-1 during a period of high-level viremia. We review the basic principles of primary HIV-1 infection, clinical and diagnostic markers of acute seroconversion, approaches to management, and new therapeutic strategies.

Primary HIV infection

Primary HIV infection is a critical and highly dynamic time period in the course of HIV infection. The initial pathologic processes are important in determining long-term disease progression. In the absence of our ability to eradicate the virus, identifying individuals during primary HIV infection and performing interventions that optimize outcome are important to provide adequate care to a newly infected patient and, from a public health perspective, to identify sexual networks and provide a platform to reduce HIV exposures during a time of high viremia.

Acute Human Immunodeficiency Virus Infection in Patients Presenting to an Urban Urgent Care Center

Acute infection with human immunodeficiency virus (HIV) is often accompanied by a flu-like illness, and early identification and treatment may help control the infection and prevent transmission. We enrolled patients who presented to an urban urgent care center with any symptoms of a viral illness and any recent potential risk for HIV infection, and we tested them for acute HIV infection using enzyme-linked immunosorbent and RNA assays. Of 499 patients enrolled over a 1-year period, acute HIV infection was diagnosed in 5 (1.0%; 95% confidence interval [CI], 0.1%-1.9%), and chronic HIV infection was diagnosed in 6 (1.2%; 95% CI, 0.2%-2.2%). There were no false-positive results of the RNA assay. No signs or symptoms reliably distinguished patients with acute HIV infection from those who were HIV uninfected. Given the importance of this diagnosis, testing for acute HIV infection using RNA and antibody assays should be offered to all patients in similar settings with viral symptoms and any risk factors for HIV infection.

Early versus delayed antiretroviral therapy in patients with HIV infection : a review of the current guidelines from an immunological perspective

The development and implementation of highly active antiretroviral therapy (HAART) for the treatment of the human immunodeficiency virus has revolutionised the care of patients with this disease. Despite the positive impact that antiretroviral therapy has had on the lives of individuals with HIV infection, the adverse effects, potential long-term toxicities, complexity of regimens, development of drug resistance and cost have made decisions about when to initiate HAART difficult. The benefits and risks of antiretroviral therapy vary considerably among patients at different stages of disease, mainly as a result of the irreversible destruction of the immune system that occurs as HIV infection progresses. In acute HIV infection, the primary aim of treatment is preservation and reconstitution of HIV-specific immune function. In symptomatic or late-stage disease, the goal is control of viral replication with resulting improvement in non-HIV-specific immunity, which leads to decreased morbidity and increased survival. The most controversial decision involves when to start therapy in persons with asymptomatic chronic HIV, where the benefits are less well established and may be outweighed by the drawbacks, depending on the individual patient. In all patients, the advantages and disadvantages must be considered carefully, and the readiness and ability of the individual to adhere to a complex multidrug regimen needs to be assessed before the initiation of therapy.

Acute human immunodeficiency virus syndrome in an adolescent

Acute human immunodeficiency virus (HIV) seroconversion illness is a difficult diagnosis to make because of its nonspecific and protean manifestations. We present such a case in an adolescent. A 15-year-old boy presented with a 5-day history of fever, sore throat, vomiting, and diarrhea. The patient also reported a nonproductive cough, coryza, and fatigue. The patient's only risk factor for HIV infection was a history of unprotected intercourse with 5 girls. Physical examination was significant for fever, exudative tonsillopharyngitis, shotty cervical lymphadenopathy, and palpable purpura on both feet. Laboratory studies demonstrated lymphopenia and mild thrombocytopenia. Hemoglobin, serum creatinine, and urinalysis were normal. The following day, the patient remained febrile. Physical examination revealed oral ulcerations, conjunctivitis, and erythematous papules on the thorax; the purpura was unchanged. Serologies for hepatitis B, syphilis, HIV, and Epstein-Barr virus were negative. Bacterial cultures of blood and stool and viral cultures of throat and conjunctiva showed no pathogens. Coagulation profile and liver enzymes were normal. Within 1 week, all symptoms had resolved. The platelet count normalized. Repeat HIV serology was positive, as was HIV DNA polymerase chain reaction. Subsequent HIV viral load was 350 000, and the CD4 lymphocyte count was 351/mm3. HIV is the seventh leading cause of death among people aged 15 to 24 in the United States, and up to half of all new infections occur in adolescents. Our patient presented with many of the typical signs and symptoms of acute HIV infection: fever, fatigue, rash, pharyngitis, lymphadenopathy, oral ulcers, emesis, and diarrhea. Other symptoms commonly reported include headache, myalgias, arthralgias, aseptic meningitis, peripheral neuropathy, thrush, weight loss, night sweats, and genital ulcers. Common seroconversion laboratory findings include leukopenia, thrombocytopenia, and elevated transaminases. The suspicion of acute HIV illness should prompt virologic and serologic analysis. Initial serology is usually negative. Diagnosis therefore depends on direct detection of the virus, by assay of viral load (HIV RNA), DNA polymerase chain reaction, or p24 antigen. Both false-positive and false-negative results for these tests have been reported, further complicating early diagnosis. Pediatricians should play an active role in identifying HIV-infected patients. Our case, the first report of acute HIV illness in an adolescent, emphasizes that clinicians should consider acute HIV seroconversion in the appropriate setting. Recognition of acute HIV syndrome is especially important for improving prognosis and limiting transmission. It is imperative that we maintain a high index of suspicion as primary care physicians for adolescents who present with a viral syndrome and appropriate risk factors.

Primary Human Immunodeficiency Virus Type 1 Infection in a Patient with Acute Rhabdomyolysis

Primary human immunodeficiency virus type 1 (HIV-1) infection (acute retroviral syndrome) has been well characterized as a mononucleosis-like illness. Manifestations of HIV-1 infection such as pharyngitis, fever, morbilliform rash, myalgias, arthralgias, nausea, headache, emesis, and lymphadenopathy have been reported. Acute rhabdomyolysis has been reported as part of the acute retroviral syndrome on 11 different occasions. We report the case of a primary HIV-1 infection with acute rhabdomyolysis and review critically the other case reports.

Envelope diversity, coreceptor usage and syncytium-inducing phenotype of HIV-1 variants in saliva and blood during primary infection

OBJECTIVE

To determine whether oral fluids can serve as a model for studying HIV-1 shedding, we compared the genetic diversity, coreceptor use, and syncytium-inducing (SI) phenotype of viral variants in saliva and blood during primary HIV-1 infection.

DESIGN

Observational cross-sectional cohort study.

METHODS

Blood plasma and saliva were sampled from 17 men early in primary HIV-1 infection. Viral diversity, predicted X4/R5 genotype and SI phenotype in samples were determined by heteroduplex tracking assays (HTAs) targeting the V1/V2 and V3 gp120 regions, sequence analyses and MT-2 cell assay.

RESULTS

Identical or very similar HTA banding and deduced amino acid sequence patterns in the V1/V2 and V3-encoding regions were observed between paired fluids of each subject. As assessed by V1/V2 HTA, 10 subjects had a single major viral variant and seven subjects exhibited multiple yet highly related variants. Two subjects had V1/V2 variants in blood that were identical to saliva but present in different relative abundances. A sexual transmission pair exhibited genetically dissimilar variants, suggesting transmission of a minor variant or rapid evolution during initial viremia. All subjects harbored R5 non-SI variants.

CONCLUSIONS

Relatively homogenous viral populations detected in plasma and saliva prior to seroconversion suggests that HIV-1 is disseminated to oral fluids early in infection and reflects the quasispecies in blood. These findings suggest that the oral cavity may serve as an easily accessible surrogate model for studying the dynamics of HIV-1 shedding at mucosal sites.

Dynamics of HIV viremia and antibody seroconversion in plasma donors: implications for diagnosis and staging of primary HIV infection

OBJECTIVES

The characterization of primary HIV infection by the analysis of serial plasma samples from newly infected persons using multiple standard viral assays.

DESIGN

A retrospective study involving two sets of archived samples from HIV-infected plasma donors. (A) 435 samples from 51 donors detected by anti-HIV enzyme immunoassays donated during 1984-1994; (B) 145 specimens from 44 donors detected by p24 antigen screening donated during 1996-1998.

SETTING

Two US plasma products companies.

MAIN OUTCOME MEASURES

The timepoints of appearance of HIV-1 markers and viral load concentrations during primary HIV infection.

RESULTS

The pattern of sequential emergence of viral markers in the 'A' panels was highly consistent, allowing the definition and estimation of the duration of six sequential stages. From the 'B' panels, the viral load at p24 antigen seroconversion was estimated by regression analysis at 10 000 copies/ml (95% CI 2000-93 000) and the HIV replication rate at 0.35 log copies/ml/day, corresponding to a doubling time in the preseroconversion phase of 20.5 h (95% CI 18.2-23.4 h). Consequently, an RNA test with 50 copies/ml sensitivity would detect HIV infection approximately 7 days before a p24 antigen test, and 12 days before a sensitive anti-HIV test.

CONCLUSION

The sequential emergence of assay reactivity allows the classification of primary HIV-1 infection into distinct laboratory stages, which may facilitate the diagnosis of recent infection and stratification of patients enrolled in clinical trials. Quantitative analysis of preseroconversion replication rates of HIV is useful for projecting the yield and predictive value of assays targeting primary HIV infection.

Longitudinal assessment of changes in HIV-specific effector activity in HIV-infected patients starting highly active antiretroviral therapy in primary infection

Both the magnitude and breadth of HIV-specific immunity were evaluated longitudinally on samples collected from six subjects starting highly active antiretroviral therapy (HAART) preseroconversion (group 1), 11 recently infected subjects starting HAART postseroconversion (group 2), five subjects starting HAART in the second half of the first year of infection (group 3), and six persons starting treatment in the chronic phase of infection (group 4). HIV-specific immunity was measured by IFN-gamma ELISPOT, detecting the frequency of cells responding to a panel of HLA-restricted HIV-1 peptides. Intracellular cytokine staining was used to detect the frequency of HIV-1 Gag p55-specific CD4(+) and CD8(+) T cells in a subset of participants. The magnitude and breadth of HIV-specific responses persisted in all group 1 subjects and in 5 of 11 (45%) group 2 subjects. Both of these parameters declined in 6 of 11 (55%) group 2 and in all group 3 and 4 individuals. All persons who maintained detectable numbers of HIV-1 Gag p55-specific CD4(+) and CD8(+) T cells after starting HAART preserved the intensity and breadth of their HIV-specific effector response. Our results show that HIV-specific immunity can be preserved even if HAART is initiated beyond the acute phase of infection.

Detection of an early HIV-1 infection by HIV RNA testing in an Italian blood donor during the preseroconversion window period

BACKGROUND

The implementation of NAT technologies for HIV screening has further reduced the diagnostic window in recent HIV infection. There is still a debate regarding the cost effectiveness of genomic screening of blood donations for transfusion-transmitted viruses (HBV, HCV, HIV).

STUDY DESIGN AND METHODS

Since October 2001, at the Transfusion Service of Verona, single-donation NAT testing for HCV and HIV-1 (Procleix TMA HIV-1/HCV Assay) of all blood donations has been performed.

CASE REPORT

A case of acute HIV-1 infection detected by HIV NAT in a repeat blood donor who donated during the preseroconversion window period is reported. All blood components donated were discarded, and the donor started antiretroviral therapy 2 weeks after blood donation. HIV-1 p24 antigen was still negative 10 days after the HIV-1 RNA-positive blood donation. Seroconversion was documented by Day 41 after donation.

CONCLUSION

This case report testifies that HIV NAT screening of blood donation is effective in preventing the transmission of HIV infection through blood components.

Transmission, acute HIV-1 infection and the quest for strategies to prevent infection

By the acute stage of HIV-1 infection, the immune system already faces daunting challenges. Research on mucosal barriers and the events immediately after heterosexual transmission that precede this acute stage could facilitate the development of effective microbicides and vaccines.