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PubMed2003

Persistently biased T-cell receptor repertoires in HIV-1-infected combination antiretroviral therapy-treated patients despite sustained suppression of viral replication.

In most HIV-1-infected patients, highly active antiretroviral therapy (HAART) reduces plasma viral load to <50 copies/mL and increases CD4+ T-cell number and function. However, it is still unclear whether alterations of T-cell receptor (TCR) beta-chain variable region (BV) repertoire, tightly related to disease progression, can be fully recovered by long-term treatment with HAART. This study analyzed the evolution of both T-cell subset composition and TCRBV perturbations in chronically HIV-1-infected patients with moderate immunodeficiency during 36 months of HAART. Despite persistently suppressed HIV replication, the rate of CD4+ T-cell repopulation, after an initial burst, progressively declined throughout the study period, resulting in a mean CD4+ T-cell count at the end of follow-up that was still significantly lower in HIV patients than in HIV-seronegative controls. This was seen in association with an incomplete restitution of both CD4 and CD8 TCRBV repertoire disruptions and was also demonstrated by the appearance of new TCRBV oligoclonal expansions occurring during HAART. In conclusion, these data indicate that 3 years of fully suppressive HAART may be not adequate to normalize CD4 counts and TCRBV repertoires in patients starting HAART with moderately advanced disease.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Evolution of pathogens towards low R0 in heterogeneous populations.

Maximization of the basic reproduction ratio or R(0) is widely believed to drive the emergence of novel pathogens. The presence of exploitable heterogeneities in a population, such as high variance in the number of potentially infectious contacts, increases R(0) and thus pathogens that can exploit heterogeneities in the contact structure have an advantage over those that do not. However, exploitation of heterogeneities results in a more rapid depletion of the potentially susceptible neighbourhood for an infected host. Here a simple model of pathogen evolution in a heterogeneous environment is developed and placed in the context of HIV transmission. In this model, it is shown that pathogens may evolve towards lower R(0), even if this results in pathogen extinction. For sufficiently high transmissibility, two locally stable strategies exist for an evolving pathogen, one that exploits heterogeneities and results in higher R(0), and one that does not, and results in lower R(0). While the low R(0) strategy is never evolutionarily stable, invading strains with higher R(0) will also converge to the low R(0) strategy if not sufficiently different from the resident strain. Heterogenous transmission is increasingly recognized as fundamental to epidemiological dynamics and the evolution of pathogens; here, it is shown that the ability to exploit heterogeneity is a strategy that can itself evolve.

Disease Outbreaks↗
PubMed1996

HIV viral dynamics.

BACKGROUND: Elucidation of the underlying rapid turnover of virus and HIV infected cells in vivo was perhaps the most informative and exciting discovery in HIV and AIDS research in the last few years. This observation, based on the rapid drop in virus load following antiviral drug therapy promises to change significantly the way we view important aspects of interaction of the virus and its host. As a result, the paradigm for HIV infection has shifted from considering the long period of clinical latency as one of viral inactivity, to viewing it as an active steady state of constant virus replication and cell death. This period should also be viewed as an integral part of the disease process, not simply a prolog to frank AIDS. METHODS: Here, I discuss the theoretical basis of the steady state model of HIV infection as well as its important consequences for understanding and controlling HIV pathogenesis. These include the significance of genetic variation and the establishment and evolution of the virus quasispecies, the evolution of resistance of the virus to antiviral therapy, and the theoretical and practical significance of virus load measurements. Emphasis is on discussion of recent developments as well as areas where our understanding still has significant gaps.

Antiviral Agents↗
PubMed1994

Evolution of the human immunodeficiency virus type 2 envelope gene in preimmunized and persistently infected rhesus macaques.

The V3 and V4 domains of human immunodeficiency virus type 2 (HIV-2) env genes from 14 rhesus macaques experimentally infected by HIV-2 SBL6669/H5 were sequenced. No variation was observed in viral sequences from sera and from uncultured peripheral blood mononuclear cells during primary infection. The first mutations were detected 17 months after infection; they mainly concerned the region between the V3 and V4 domains and not those domains themselves, which are known to be hypervariable, suggesting that variation of V3 is a late event of HIV infection.

AIDS Vaccines↗
PubMed1990

[Correlation of viral replication activity, the clinical phase of the disease and immunologic deterioration in HIV infection].

The authors have studied the relationship among HIV replicative activity, expressed by HIV isolation from peripheral blood lymphocytes and p24 antigenemia detection, and the evolution of infection, in terms of stage of disease and T4 cells absolute number, in a group of 120 infected subjects. Data presented indicate that the expression of viral gene products is related both to clinical and immunological deterioration and suggest that viral replication plays a central role in the progression of the disease.

AIDS-Related Complex↗
PubMed2003

Multiple viral genetic analyses detect low-level human immunodeficiency virus type 1 replication during effective highly active antiretroviral therapy.

To evaluate human immunodeficiency virus type 1 (HIV-1) replication and selection of drug-resistant viruses during seemingly effective highly active antiretroviral therapy (HAART), multiple HIV-1 env and pol sequences were analyzed and viral DNA levels were quantified from nucleoside analog-experienced children prior to and during a median of 5.1 (range, 1.8 to 6.4) years of HAART. Viral replication was detected at different rates, with apparently increasing sensitivity: 1 of 10 by phylogenetic analysis; 2 of 10 by viral evolution with increasing genetic distances from the most recent common ancestor (MRCA) of infection; 3 of 10 by selection of drug-resistant mutants; and 6 of 10 by maintenance of genetic distances from the MRCA. When four- or five-drug antiretroviral regimens were given to these children, persistent plasma viral rebound did not occur despite the accumulation of highly drug-resistant genotypes. Among the four children without genetic evidence of viral replication, a statistically significant decrease in the genetic distance to the MRCA was detected in three, indicating the persistence of a greater number of early compared to recent viruses, and their HIV-1 DNA decreased by > or =0.9 log(10), resulting in lower absolute DNA levels (P = 0.007). This study demonstrates the variable rates of viral replication when HAART has suppressed plasma HIV-1 RNA for years to a median of <50 copies/ml and that combinations of four or five antiretroviral drugs suppress viral replication even after short-term virologic failure of three-drug HAART and despite ongoing accumulation of drug-resistant mutants. Furthermore, the decrease of cellular HIV-1 DNA to low absolute levels in those without genetic evidence of viral replication suggests that monitoring viral DNA during HAART may gauge low-level replication.

Antiretroviral Therapy, Highly Active↗
PubMed1996

Oxidative stress in blood of HIV infected patients.

The oxidative stress in human erythrocytes was studied in asymptomatic and symptomatic patients infected by the human immunodeficiency virus (HIV), and patients with the acquired immunodeficiency syndrome (AIDS). tert-Butyl hydroperoxide initiated chemiluminescence, superoxide dismutase and catalase activities, and total glutathione were evaluated in the erythrocytes and the total antioxidant capacity in the plasma of control, patients infected with HIV that have not yet developed acquired immunodeficiency syndrome, and patients in the later stage of AIDS. tert-Butyl hydroperoxide initiated chemiluminescence was increased by 33% in asymptomatic (stage A1) and symptomatic patients (stage B2) infected with HIV and 82% for patients with AIDS (stage B3) (P < 0.05). While catalase activity did not show any difference between patients and controls, other indices showed differences that, in some cases, reached statistical significance. Superoxide dismutase activity was increased by 24% in stages A1 and B2 of HIV infection and 65% in patients in stage B3 (P < 0.05). Glutathione was decreased by 20% in stages A1 and B2, and by 32% in stage B3 patients (P < 0.05). Total plasma antioxidant capacity was increased in 30 and 57% for the asymptomatic and AIDS patients groups, respectively (P < 0.05). The data indicate that erythrocyte's oxidative stress is associated with the progressive development of HIV disease. Parameters indicating oxidative stress could be an interesting form to screen the evolution of these patients and their response to anti-oxidant therapies.

Adult↗
PubMed1995

[Changes in heroin administration route and frequency of human immunodeficiency virus infection].

BACKGROUND: Self-administration of drugs by different intravenous routes may induce a reduction in the organic complications of drug addiction (DA). The aim of this study was to evaluate the changes in the way of drug administration in a series of DA individuals in the province of Cádiz, Spain, and the evolution of the frequency of infection by the human immunodeficiency virus (HIV) in these patients. METHODS: The reports of all the drug users from the province of Cádiz admitted to the Detoxication Unit of the Hospital Punta de Europa in Algeciras, from January, 1989 to July, 1993 were reviewed. At the time of admission many data were evaluated, fundamentally the main route of drug administration, and anti-HIV seropositivity. RESULTS: Seven hundred ten drug users were included in the study. Ninety-seven percent used mainly heroin. The route of drug administration on admission was intravenous in 56.1%, pulmonary in 39.7%, inhalatory in 3.2% and oral in 0.8%. Forty-one point seven percent patients were seropositive for HIV. The frequency of the use of the intravenous route throughout the semesters analyzed was I/89: 85.7%, II/89: 89.6%, I/90: 80%, II/90: 80.8%, I/91: 59.8%, II/91: 50%, I/92: 44.9%, II/92: 39%, I/93: 34.3% (p < 0.00001). The use of the respiratory route significantly increased. The percentage of anti HIV positivity in the drug users evaluated was 67.4, 80.8, 56.4, 46.9, 40.7, 34.1, 30.6, 36.3, 23.2% (p < 0.00001), respectively for the same periods. The decrease in the use of the intravenous route and the reduction in anti HIV seropositivity demonstrated a correlation coefficient of 0.91 with a confidence interval from 0.62 to 0.98 (p < 0.05). CONCLUSIONS: The decrease, over time, in the use of the intravenous route for heroin administration in the collective analyzed was significantly associated with a decrease in HIV infection in these patients.

Adult↗
PubMed1996

[Neurological impairment in children with HIV infection].

We retrospectively checked 53 paediatric patients suffering from infection with human immunodeficiency virus (HIV) registered in our Centre between the years 1987 and 1993, and evaluated the appearance of HIV encephalopathy. We noted important neurological signs in eleven patients (20.7%) ten of whom had HIV infection via vertical transmission and one as a result of contamination from haemoderivatives. In this review we give a detailed description of neurological signs, the moment of onset of these signs and their possible relationship with the state of the HIV infection. We also analyzed the resulting neuroradiological findings as well as any abnormalities in cerebrospinal fluid. Follow-up period ranged from one month to two and a half years from the moment of onset of the appearance of encephalopathy. Although most of our patients showed a clear improvement after oral or intravenous treatment with zidovudine, this improvement generally proved to be short-lived. The mortality rate in our HIV encephalopathy series was 81.8%, this figure being reached two and a half years after encephalopathy. The appearance of neurological signs in HIV patients therefore represents a very gloomy prognostic factor in the evolution of the disease.

AIDS Dementia Complex↗
PubMed1999

Variants from the diverse virus population identified at seroconversion of a clade A human immunodeficiency virus type 1-infected woman have distinct biological properties.

Development of effective therapeutics to prevent new infections with human immunodeficiency type 1 (HIV-1) is predicated on an understanding of the properties that provide a selective advantage to a transmitted viral population. In contrast to the homogeneous virus population that typifies early HIV-1 infection of men, the viral population in women recently infected with clade A HIV-1 is genetically diverse, based on evaluation of the envelope gene. A longitudinal study of viral envelope evolution in several women suggested that representative envelope variants detected at seroconversion had distinct biological properties that affected viral fitness. To test this hypothesis, a full-length, infectious molecular clone, Q23-17, was obtained from an infected woman 1 year following seroconversion, and chimeric viruses containing envelope genes representative of seroconversion and 27-month-postseroconversion populations were constructed. Dendritic cells (DC) could transfer infection of seroconversion variant Q23ScA, which dominated the viral population in the year following seroconversion, and the closely related 1-year isolate Q23-17 to resting peripheral blood mononuclear cells (PBMC). In contrast, resting PBMC exposed to DC pulsed with Q23ScB, which was detected infrequently in samples after seroconversion, or the 27-month chimeras were inconsistently infected. Additionally, quiescent PBMC infected with Q23ScA or Q23-17 proliferated more robustly than uninfected cells or cells infected with the other envelope chimeras in response to immobilized anti-CD3. Stimulation with tetanus toxoid led to an increased proportion of CD45RA+ cells and a decreased expression of CD28 on CD45RO+ cells in cultures of Q23-17-infected PBMC. These data demonstrate that variants from the heterogeneous seroconversion clade A HIV-1 population in a Kenyan woman have distinct biological features that may influence viral pathogenesis.

Amino Acid Sequence↗
PubMed2004

Epidemiology of HIV-associated cryptococcosis in France (1985-2001): comparison of the pre- and post-HAART eras.

OBJECTIVE: To analyse the epidemiological evolution of cryptococcosis in France after the introduction of highly active antiretroviral therapy (HAART). DESIGN: Retrospective study of cryptococcosis cases recorded at the National Reference Center for Mycoses in France since 1985. METHODS: Using the national surveillance data, we reviewed 1644 cases of HIV-associated cryptococcosis diagnosed in France (population, 59 million) between 1985 and 2001 and compared them to 335 cases recorded in HIV-negative patients. RESULTS: The total number of cryptococcosis cases evolved in parallel to that recorded for HIV-infected patients. Changes occurring after HAART introduction were analysed. A negative binomial regression model established a 46% decrease of the incidence of cryptococcosis during the post-HAART era (1997-2001, n = 292) compared to the pre-HAART era (1985-1996, n = 1352). According to multivariate analysis, African origin, older age, heterosexual HIV contamination, no previous AIDS-defining illness, and no previous HIV infection diagnosis were variables independently associated with an increased risk of cryptococcosis during the post-HAART era. During the same period, the characteristics of the HIV-negative population did not change. CONCLUSIONS: Our analysis of the national surveillance identified demographic factors associated with an increased risk of cryptococcosis in the post-HAART era suggesting that failure to consult and considering oneself not at risk were determinant in the current epidemiology of HIV-related cryptococcosis in France.

AIDS-Related Opportunistic Infections↗
PubMed2003

Adaptation in the env gene of HIV-1 and evolutionary theories of disease progression.

The exact mechanisms by which HIV overwhelms the immune system remain poorly understood. Among the several explanations of HIV disease progression, most include adaptation of the viral genome to the host environment as a causal factor. Therefore, quantifying the rate and pattern of adaptive evolution within infected patients is critical to understanding the development of AIDS. Using sequence data from infected individuals sampled at multiple time points, I estimate the within-host adaptation rate of the HIV-1 env gene for viral populations from 50 different patients. I find that, averaging across patients, one adaptive substitution occurs every 3.3 months. Also, one adaptive mutation is driven to a high frequency (>50% but <100%) every 2.5 months. Taken together, such adaptive events occur once every 25 viral generations, which is the fastest adaptation rate ever recorded for a single protein-coding gene. Within the entire env gene, I estimate that a majority ( approximately 55%) of both nonsynonymous substitutions and high-frequency polymorphisms are adaptive. Further, in the C2-V5 region of env, I find that patients with longer asymptomatic periods have virus populations with higher adaptation rates, corroborating the notion that a broad, strong immune response against epitopes in the env gene product leads to longer asymptomatic periods. I conclude by discussing the distribution of nonsynonymous changes over the env gene.

Adult↗
PubMedDate not supplied

Rapid full-length genomic sequencing of two cytopathically heterogeneous Australian primary HIV-1 isolates.

Two Australian HIV-1 isolates, derived from patient blood (HIV(MBC200)) and cerebrospinal fluid (HIV(MBC925)), were characterized after in vitro culture in peripheral blood mononuclear cells (PBMC). Although virus replication was similar, as measured by cell-free reverse transcriptase activity, only one of the two isolates (HIV-1(MCB200)) consistently induced cell syncytia and depleted the PBMC population of CD4+ cells by cell killing. A novel technique, devised for rapidly obtaining high-quality viral sequence data and the full-length genomic sequence of these two isolates, is presented. Analysis of the predicted sequence of the viral Env proteins provides correlates of the observed phenotypes. Phylogenetic analysis derived using near full-length sequence of these and other HIV-1 subtype B genomic sequences (including two other Australian isolates) shows a star-shaped phylogeny with each member having a similar genetic diversity. These data expand the database of genomic sequence available from well-characterized primary clinical isolates of HIV-1 using a novel rapid technique.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Squamous intraepithelial lesions in cervical smears of human immunodeficiency virus-seropositive adolescents.

Various authors have reported a high rate of human papillomavirus (HPV) infection and HPV-related neoplasias in human immunodeficiency virus (HIV)-seropositive women. On the other hand, young women are most susceptible to cervical infection because of immaturity of the cervix, as it appears that HPV has more access to the basal cells of the differentiating epithelium. The purpose of the present work was to study cervical smears of 82 adolescent HIV-seropositive women (13-21 years of age) to search for cytological evidence of cervical intraepithelial neoplasias. Twenty-one cases showed characteristic features of HPV infection and squamous intraepithelial lesions (SIL; 25.6%). Sixteen cases aged from 17 to 21 years (mean age 19.5 years) had low-grade SIL (LSIL; 19.5%) and five cases aged from 18 to 21 years (mean age 20.2 years) had high-grade SIL (HSIL; 6.1%). There was no significant difference between the mean age of patients with LSIL and HSIL. Two cases had atypical squamous cells of undetermined significance (ASCUS). In the present work it was found that HIV-seropositive adolescents have a high risk for preneoplastic lesions of the cervix (25.6%) as well as a high incidence of more aggressive lesions (6.1% of HSIL) when compared to the general population of adolescents. As it can be assumed that, if the age of acquisition of the infection in both groups (in the general population and HIV-seropositive women) is the same, it is probable that HIV infection in adolescents not only increases the frequency of HPV infections but also facilitates the evolution to more aggressive preneoplastic lesions of the cervix due to HPV.

Adolescent↗
PubMed1992

Supporting health care workers in the treatment of HIV-infected patients.

The care of HIV-infected patients is demanding, raising concerns among health care workers regarding safety, competence, and emotional endurance. Many health care workers are reluctant to undertake this challenging work. For many professions within health care, for example nursing, there is a clearly articulated responsibility to treat all ill individuals. Less unanimity on this point continues among physicians. Clearly, a first issue is to continue the discussion of the nature of physicians' professional responsibilities and to convey an understanding of the duties of physicians to medical students and to those considering careers as doctors. Meanwhile, efforts must continue to recruit individuals in all areas of health care to work with HIV-infected people. To some extent, this process will happen as a natural consequence of the evolution of the epidemic and its decreasing geographic and demographic restriction. "Mainstreaming" AIDS care will also require continuing attention to important issues, such as acquiring and maintaining the requisite professional competence in the management of HIV-related illnesses, ensuring the availability of support services that are required for the comprehensive care of HIV complications, and continuing education on and proactive monitoring of infection control practices. All of these activities assist in the creation of a positive environment for the care of AIDS patients. In addition, the emotional consequences of caring for HIV-infected people should be directly addressed, although there is less information on which strategies are useful. A supportive working environment, characterized by some meaningful element of control by all health care workers not just the medical staff, nonauthoritarian management, explicit and responsive processes for approaching the inevitable ethical dilemmas that arise in the care of HIV-infected patients, and a recognition of the emotional, psychological, and technical aspects of medical care are essential. In such an environment, health care providers will be able to develop and institute programs that address their particular needs. Strategies that have been helpful are diverse and include support groups, rotation of clinical assignments, part-time work, social activities away from the workplace, and collective spiritual activities.

Attitude of Health Personnel↗
PubMed2005

The role of Vpr in HIV-1 pathogenesis.

The HIV-1 vpr gene is conserved among the human (HIV-1, HIV-2) and simian immunodeficiency viruses (SIV). HIV-1 vpr encodes a 96-amino acid, 14 kDa protein (Vpr). Research from a number of laboratories in the last decade has shown that Vpr performs multiple functions, including the induction of cell cycle arrest in the G(2) phase, transactivation of the viral promoter, nuclear import of preintegration complexes, and induction of apoptosis in the infected cell. More recent studies have attempted to elucidate the cellular targets that Vpr utilizes in order to perform the above functions. This review presents the latest findings about the pathogenic events triggered by Vpr, the cellular pathways involved, and the molecular and cellular consequences of the action of Vpr in the context of HIV-1 infection.

Active Transport, Cell Nucleus↗
PubMed2004

Liver transplantation without steroid induction in HIV-infected patients.

Until recently, human immunodeficiency virus (HIV) infection was considered an absolute contraindication for liver transplantation in Spain. We present the first 4 cases of liver transplantation (LT) carried out in our center in patients infected with HIV and coinfected by the hepatitis C virus (HCV), immunosuppressed with cyclosporine A (CyA) and basiliximab, but without steroids. The 4 patients were male, with a mean age of 38.25 +/- 4.5 years. Mean time of HIV infection was 114 +/- 62.3 months and all patients were receiving highly active antiretroviral therapy (HAART). HCV genotypes of the 4 patients were 4, 1b, 1b, and 1a. Two patients were classified as Child-Turcotte-Pugh C (10 and 11 points), 1 was B (8 points), and the patient with hepatocellular carcinoma was A (5 points). Immunosuppression consisted of basiliximab and monotherapy with CyA. There were no postoperative infections. With a follow-up of 17 +/- 8 months, all patients are alive. There was only 1 acute rejection episode, and this was solved with steroid pulses. Three patients showed HCV recurrence with enzymatic and histological changes and were treated with interferon and ribavirin. One patient had negative HCV-ribonucleic acid after 6 months of treatment. In conclusion, HIV infection should not be considered an absolute contraindication for liver transplantation. The evolution of this type of patients will probably depend on the HCV infection. Immunosuppression without steroids may reduce opportunistic infection.

AIDS-Related Opportunistic Infections↗