Patients who present late to HIV care and associated risk factors in Nigeria.

OBJECTIVES: Our objectives were to assess trends in late presentation and advanced HIV disease (AHD) and determine associated risk factors. METHODS: We conducted a retrospective cohort analysis of patients who had received care and treatment at the AIDS Prevention Initiative Nigeria Plus (APIN)/Harvard School of Public Health-President's Emergency Plan for AIDS Relief (PEPFAR) programme at the Jos University Teaching Hospital, Jos, Nigeria from 2005 to 2010. We used the European Consensus Definition to assess trends in late presentation (CD4 count < 350 cells/µL or AIDS-defining illness) and AHD (CD4 count < 200 cells/µL or AIDS-defining illness) and evaluated associated risk factors using logistic regression methods. RESULTS: Among 14,487 eligible patients, 12,401 (85.6%) were late presenters and 9127 (63.0%) presented with AHD. Late presentation decreased from 88.9% in 2005 to 80.1% in 2010 (P < 0.001). Similarly, AHD decreased from 67.8% in 2005 to 53.6% in 2010 (P < 0.001). In logistic regression models adjusting for sociodemographic and biological variables, male sex [adjusted odds ratio (aOR) = 1.80; 95% confidence interval (CI) 1.60-2.04], older age (aOR = 1.37; 95% CI 1.22-1.54), civil service employment (aOR = 1.48; 95% CI 1.00-2.21), referral from out-patient (aOR = 2.18; 95% CI 1.53-3.08) and in-patient (aOR = 1.55; 95% CI 1.11-2.17) services, and hepatitis B virus (aOR = 1.43; 95% CI 1.26-1.63) and hepatitis C virus (aOR = 1.18; 95% CI 1.02-1.37) coinfections were associated with late presentation. Predictors of AHD were male sex (aOR = 1.67; 95% CI 1.54-1.82), older age (aOR = 1.26; 95% CI 1.16-1.36), unemployment (aOR = 1.34; 95% CI 1.00-1.79), referral from out-patient (aOR = 2.40; 95% CI 1.84-3.14) and in-patient (aOR = 1.97; 95% CI 1.51-2.57) services and hepatitis B virus coinfection (aOR = 1.30; 95% CI 1.19-1.42). CONCLUSIONS: Efforts to reduce the proportion of patients who first seek care at late stages of disease are needed. The identified risk factors should be utilized in formulating targeted public health interventions to improve early diagnosis and presentation for HIV care.

Isolation of T-lymphotropic retrovirus related to HTLV-III/LAV from wild-caught African green monkeys.

Present evidence suggests that the acquired immune deficiency syndrome (AIDS) emerged in Central Africa as a new disease in recent decades. This disease has recently approached epidemic proportions in many parts of the world. The etiologic agent of AIDS is believed to be the virus HTLV-III/LAV, which has been proposed as having originated from a recent simian-human transmission in Africa. This report describes the isolation of a designated STLV-IIIAGM retrovirus closely related to HTLV-III/LAV from seven healthy wild-caught African Green monkeys (Cercopithecus aethiops) that showed the presence of antibodies designated STLV-IIIAGM. In vitro growth characteristics, ultrastructural morphology, and major proteins of 160,000 kilodaltons (kD), 120 kD, 55 kD, and 24 kD are similar to and cross-reactive with the analogous antigens of HTLV-III/LAV. The use of these serologic markers in the detection of STLV-IIIAGM-infected monkeys may be important in assuring the continued safety of a variety of biologic reagents that are derived from these primate species. The existence of a retrovirus closely related to HTLV-III/LAV that naturally infects an African nonhuman primate in the apparent absence of disease may provide a unique model for the study of human AIDS and the development of an effective vaccine.

A new HTLV-III/LAV encoded antigen detected by antibodies from AIDS patients.

A newly identified protein from HTLV-III/LAV, the virus implicated as the etiologic agent of the acquired immune deficiency syndrome, was studied. This protein, which has a molecular weight of 27,000 (p27), was shown by amino acid sequencing to have a coding origin 3' to the env gene on the HTLV-III genome. The presence of antibodies to p27 in virus-exposed individuals indicated that this gene is functional in the natural host.

New human T-lymphotropic retrovirus related to simian T-lymphotropic virus type III (STLV-IIIAGM).

This report describes serologic evidence for a virus similar to that known as simian T-lymphotropic virus type III of African Green monkeys (STLV-IIIAGM) infecting apparently healthy people in Senegal, West Africa, and the isolation of virus from these individuals. Serum samples from selected healthy West African people showed unusual serologic profiles when tested with antigens of HTLV-III/LAV, the etiologic agent of AIDS, and of STLV-IIIAGM. The samples reacted strongly with all of the major viral antigens of STLV-IIIAGM but showed variable or no reactivity with the major viral antigens of HTLV-III/LAV by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A new human T-lymphotropic virus (HTLV-IV) isolated from these people was grown in vitro and shown to have retroviral type particles, growth characteristics, and major viral proteins similar to those of the STLV-III and HTLV-III/LAV group of retroviruses. The gp120/160, gp32, p64, p55, p53, p24, and p15 proteins precipitated were the same size as and reactive with STLV-IIIAGM proteins. The serologic data suggest that this virus shares more common epitopes with STLV-IIIAGM than with the prototype HTLV-III/LAV that infects people in the United States and Europe. Further study of this virus and of the origin of the HTLV-III/LAV group of viruses may expand our understanding of the human AIDS virus.

Human T-lymphotropic virus type 4 and the human immunodeficiency virus in West Africa.

A new human T-lymphotropic virus (HTLV-4) was recently described in healthy people from Senegal. This virus has many properties in common with members of the human T-lymphotropic viruses, particularly the human immunodeficiency virus or HIV, the etiologic agent of acquired immune deficiency syndrome (AIDS), but does not appear to be associated with immunodeficiency-related disorders. In the present study, serum samples were obtained from 4248 individuals from six West African countries, including Senegal, Guinea, Guinea Bissau, Mauritania, Burkina Faso, and Ivory Coast. These samples, collected during 1985-1987, were from people categorized as healthy control, sexually active risk, and disease populations. All samples were analyzed for reactivity to HTLV-4 and HIV by radioimmunoprecipitation-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Evidence for HTLV-4 infection was found in five of the six countries. The seroprevalence varied markedly from country to country. Healthy sexually active individuals in the risk category had the highest levels of HTLV-4 infection compared to individuals in the healthy control category and the disease category, the latter including AIDS patients. The seroprevalence of HIV infection in most of these countries was quite low, although tightly associated with the rare cases of AIDS. The biology of HTLV-4 infection thus differs from that of HIV in Central Africa or the United States and Europe. The presence of these viruses and their different pathogenicities in several countries of West Africa indicate the necessity for serologic assays that will distinguish between them. Further studies of their origin and distribution as well as of their biology will be important in advancing our understanding of AIDS.

Lymphoma in macaques: association with virus of human T lymphotrophic family.

Human T-cell leukemia virus has been linked with adult T-cell leukemia-lymphoma (ATLL), a tumor of mature T cells that occurs at elevated rates in southwestern Japan and in the Caribbean Basin. Human T-cell leukemia virus (HTLV) or a closely related virus, has also been found in varying proportions of healthy individuals of several species of Old World monkeys. In the present study, conducted with macaques from Taiwan and the New England Regional Primate Research Center, antibodies to membrane antigens of HTLV-infected cells (HTLV-MA) were found in 11 of 13 macaques with malignant lymphoma or lymphoproliferative disease but in only 7 of 95 of healthy macaques. This indicates that antibodies to HTLV are significantly associated with the development of naturally occurring lymphoid neoplasms in at least some species of nonhuman primates.

Serologic identification and characterization of a macaque T-lymphotropic retrovirus closely related to HTLV-III.

Human T-lymphotropic virus type III (HTLV-III) is thought to play an etiologic role in the development of the acquired immune deficiency syndrome (AIDS). In this study the serologic characterization of a new simian retrovirus that is related to HTLV-III is described. This new virus, here referred to as STLV-III, was isolated from sick macaques at the New England Regional Primate Research Center. Radioimmunoprecipitation analysis revealed STLV-III-specific proteins of 160, 120, 55, and 24 kilodaltons, all similar in size to the major gag and env proteins of HTLV-III. These antigens were recognized by representative macaque serum samples and human reference serum samples positive for HTLV-III antibodies. Monoclonal antibodies directed to p24, the major core protein of HTLV-III, also immunoprecipitated a 24-kilodalton species in lysates of cells infected with the macaque virus. This HTLV-III-related virus, which naturally infects a nonhuman primate species, may provide a useful model for the study of HTLV-III and the pathogenesis of AIDS.

Isolation of T-cell tropic HTLV-III-like retrovirus from macaques.

The isolation of a T-cell tropic retrovirus from three immunodeficient macaques and one macaque with lymphoma is described. The morphology, growth characteristics, and antigenic properties of this virus indicate that it is related to the causative agent of acquired immune deficiency syndrome in humans (HTLV-III or LAV). This virus is referred to as simian T-lymphotropic virus type III (STLV-III) of macaques. The existence of a cytopathic, T-cell tropic virus resembling HTLV-III in monkeys may facilitate study of disease induction and vaccine development in an animal model.

Immunological and Virological Outcomes of Patients Switched from LPV/r to ATV/r-Containing Second- Line Regimens.

BACKGROUND: Atazanavir/ritonavir (ATV/r) recently became the preferred protease inhibitor (PI) for use in Nigeria since it is dosed once daily, which may improve treatment adherence and has fewer side effects than lopinavir/ritonavir (LPV/r)--the most widely available PI in resource-limited settings. We, therefore, aimed to evaluate the immunologic and virologic effects of switching patients to an ATV/r-containing regimen. METHODS: In a large antiretroviral treatment programme at the Lagos University Teaching Hospital in Nigeria, 400 patients were switched to ATV/r-based second-line ART. We conducted a retrospective evaluation of immunologic and virologic outcomes following 24 months on the ATV/r regimens. RESULTS: Of the 400 patients switched to an ATV/r containing regimen, 255 were virologically suppressed on LPV/r prior to switch, 107 were switched due to failure on a first-line regimen, 28 were on saquinavir/ritonavir (SQV/r)-based regimen, while 10 were unintentionally switched while non-suppressed on a LPV/r-based regimen. Demonstrable and sustained immunological responses were documented as the median (IQR) CD4+ cell count increased steadily from 466 (323) cells/mm3 at the time of switch to 490 (346) cells/mm3 at 6 months, and 504 (360) cells/mm3 at 24 months. Of 99 patients evaluated 12 months after ATV/r switch, 2 (2%) had detectable viral load (VL). None of the 26 (0%) in this group evaluated at 24 months had detectable viral load. In a comparison group of 576 patients who were maintained on LPV/r-based second line regimens, 359 (62.3%) had undetectable viral loads. Of 318 patients with VL data 24 months later, 25 (7.9%) had detectable VL. There was no significant difference between the proportion of patients maintained on LPV/r (7.9%) and those switched to ATV/r (0%) in the development of virologic failure after 24 months of follow-up. CONCLUSION: Among patients that were switched to ATV/r-containing regimens, we found improvements in immunological responses and no increase in risk of virologic failure.

Virology of HIV-1 and HIV-2: implications for Africa.

PIP: Much has been learned over the past 2 decades about the virology of HIV-1 and HIV-2, with an accumulation of research findings leading to a better appreciation of the vast genetic diversity of the viruses, epidemiologic patterns, and host pathogenesis. To better understand the virologic properties of the viruses, efforts must now be made to link the observations from in-vitro and genetic analysis studies to studies in infected populations. New and innovative technologies will be needed to more readily diagnose subtypes and recombinants, and quantify viral burden. The current understanding of HIV-1 subtype epidemiology is evolving and future studies will likely provide better data upon subtype distribution and their epidemiology. The family of SIV/HIV-1/HIV-2 viruses and virologies of HIV-1 and HIV-2 are discussed.^ieng

Laboratory diagnosis of HIV-1 and HIV-2 in Africa.

PIP: It is well accepted that HIV is the cause of AIDS and that the virus is distributed widely throughout the world. Being able to diagnose infection with HIV through laboratory tests has done much to facilitate the early recognition of the severity and extent of the AIDS pandemic. Many laboratory techniques exist to detect infection with HIV-1 and HIV-2. In recent years, however, African countries have found it difficult to implement such diagnostic tests because the tests have been either ill-suited or too expensive for the developing country setting. This paper describes many of the HIV laboratory diagnostic techniques currently used in both diagnostic and research settings. The review of techniques is, however, neither all-inclusive nor globally applicable, but intended to be simply a view of available techniques from the African perspective. The opening general section on the detection of HIV-1 and HIV-2 is followed by discussion of screening tests, rapid tests, and confirmatory tests to detect HIV antibodies. Techniques to detect virus include viral isolation, the detection of viral antigen, and PCR. HIV testing algorithms are discussed. The authors stress in closing the importance of the effective laboratory diagnosis of HIV in the prevention and control of HIV/AIDS. Laboratory personnel must be trained, cost-effective laboratory techniques made available for the African setting, and test systems chosen which are best adapted to the prevailing epidemiologic, socioeconomic, and cultural contexts. These latter systems often will differ from the types of diagnostic tests and testing algorithms used in more developed countries.^ieng

Parallel Western blot analysis for HIV-1 and HIV-2 antibodies: absence of HIV-2 infection in Italian subjects at risk for AIDS.

Since HIV-2 infection has been identified in some European countries, we investigated whether HIV-2 infection is present in groups of Italian subjects at risk for AIDS. Our results clearly indicate that the parallel Western blot assay for HIV-1 and HIV-2 antibodies can detect HIV-2 infection, which is presently not epidemic in Italy. Careful examination of the serological data is mandatory before announcing the detection of HIV-2-infected patients.

Temporary expatriation is related to HIV-1 infection in rural Senegal.

OBJECTIVES: To assess temporary expatriation as a risk factor for HIV infection in a rural area of Senegal and to examine the transmission of HIV from expatriates to their families. DESIGN: Cross-sectional study in identified expatriates and in a representative cluster sample of the general population from the same geographical area in northern Senegal. METHODS: In 1989, a survey (including questionnaire and serological tests for HIV-1 and HIV-2) was conducted in all expatriates currently living in 11 villages in northern Senegal and spouses of all expatriates (present or not) from this area ('expatriate' group, n = 258). In parallel, a cluster sample of 600 adults was drawn from eight villages of the same area, of whom 414 were selected as the control group since they and their spouses had not travelled outside Senegal in the last 10 years. RESULTS: In the 'expatriate' group, sera from 39 subjects were confirmed as HIV-positive by Western blot [17 out of 63 men (27.0%) and 22 out of 195 women (11.3%)]. Of these subjects, 33 were infected by HIV-1, four by HIV-2 and two had a dual HIV-1/2 profile. In contrast, only two subjects (one man and one woman) from the control group were infected by HIV-2 and none by HIV-1. In men, HIV-1 seroprevalence was associated with age < 40 years [odds ratio (OR), 7.4; P = 0.03] and previous sexually transmitted disease (STD) symptoms (OR, 13.5; P = 0.03), whereas the risk factors in women were age < 25 years (OR, 3.7; P = 0.04), being a widow (OR, 30.4; P < 0.01) and presence of sexual activity over the last 2 years (OR, 21.3; P < 0.01). CONCLUSIONS: Penetration of HIV-1 infection in a country where HIV-2 is endemic shows that the HIV-1 epidemic is currently spreading to rural West Africa. Migrant workers appear to play a major role in this epidemic.

HIV-1 and HIV-2 dual infection: lack of HIV-2 provirus correlates with low CD4+ lymphocyte counts.

OBJECTIVE: We conducted this study to genetically characterize dual infection in individuals demonstrating a dual serological profile. METHODS: All subjects were first evaluated by immunoblot for antibody reactivity to the major viral antigens for HIV-1 and HIV-2. Sera were judged to be dual-seropositive if they reacted with strong and equal intensity with the envelope antigens of both HIV-1 and HIV-2 and were confirmed with type-specific recombinant env peptides. We used nested polymerase chain reaction (PCR) to amplify proviral gag and env sequence from peripheral blood mononuclear cell (PBMC) DNA from HIV-1- and HIV-2-infected individuals. Positive amplification was detected after Southern blot hybridization. RESULTS: Plasmid dilution and mixing showed equivalent sensitivity of HIV-1 and HIV-2 primers that was not altered by heterologous target sequences. The DNA PCR showed 100% sensitivity and specificity for detection of monotypic HIV infection. Serologically defined HIV-dual reactives were evaluated by this assay, with 100% detection in female sex workers (21 out of 21), but only 38.5% detection (five out of 13) in hospitalized patients; all being HIV-1 positive only. The lack of HIV-2 proviral signal was significantly correlated with low CD4+ lymphocyte counts (Pvalue = 0.04). CONCLUSION: The results suggest that HIV dual infection may not be a static condition. Levels of HIV-2 may decrease with disease progression or sequester in tissue reservoirs; our results may also suggest that HIV-1 effectively overgrows HIV-2 in the dually exposed host individual.

Genetic characterization of viral quasispecies in blood and cervical secretions of HIV-1- and HIV-2-infected women.

We evaluated cervical samples from 11 HIV-1- and 25 HIV-2-infected individuals. The rate of viral shedding was 36.4% for HIV-1 and 16% for HIV-2, after repeat PCRs. We sequenced multiple clones of the C2-C3 env region from cervical secretions and PBMC samples from three HIV-2-infected individuals, and the C2-V3 env region from four HIV-1-infected individuals. In most cases, phylogenetic analysis showed that the viral sequences from blood and genital secretions were intermingled and subclusters did not segregate according to sample site. In rare cases, however, tissue-specific sequences were observed, suggesting a complex relationship between quasispecies in the two sites where preferential transmission of HIV variants may be due to multiple factors.

The simian immunodeficiency virus envelope open reading frame located after the termination codon is expressed in vivo in infected animals.

Genetic comparison of SIVmac to the human retroviruses generally associated with AIDS revealed a closer relationship to HIV-2 than to HIV-1. A common feature differentiating SIV and HIV-2 from HIV-1 is the size of the transmembrane portion of the envelope, which is smaller (gp32) in SIVmac and HIV-2 than in HIV-1 (gp41). The presence of this truncated form of the transmembrane glycoprotein in SIVmac and HIV-2 virions is apparently related to the presence of a translation termination codon in the env gene of all SIV proviruses analyzed as well as in one HIV-2 provirus. Since the carboxy terminus of the envelope transmembrane protein has been implicated in the cytopathic effect of HIV-1 in vitro, we decided to investigate whether putative expression of the open reading frame located after the termination codon correlates with the pathogenicity of SIVmac in vivo. We generated two synthetic peptides from the inferred amino acid sequence of SIVmac and tested their reactivity by Western blot against the sera of naturally and experimentally infected monkeys as well as against sera of HIV-2-infected individuals. Our results indicate that the protein synthesized from this open reading frame is expressed in vivo, since an immunoresponse can be detected against the synthetic peptides in two of three experimentally SIVmac-infected animals. However, no correlation can be found between its expression and disease progression at this time. Furthermore, a rabbit immune serum raised against the synthetic peptide failed to identify any specific protein in SIVmac-infected cells.

Genetic analysis of HIV type 2 in monotypic and dual HIV infections.

A significant level of genetic variation among HIV-1 and HIV-2 has been described. The interaction of specific HIV-2 subtypes with HIV-1 may serve to identify potential biological properties associated with dual infection. To genetically characterize the HIV-2 strains circulating in Senegal and their relationship to coinfection with HIV-1, we sequenced the HIV-2 envelope C2-C3 region of 12 subjects coinfected with HIV-1 and HIV-2 and 9 subjects singly infected with HIV-2. The phylogenetic analysis showed that all subjects were infected with HIV-2 subtype A, confirming its predominance in West Africa. We did not observe specific sequences or genetic clustering based on coinfection status.

Bacterially produced HIV-2 env polypeptides specific for distinguishing HIV-2 from HIV-1 infections.

Five unique recombinant polypeptides, each encoded by a DNA segment representing a different region of the HIV-2 (NIH-Z strain) env gene, were produced at relatively high levels (greater than or equal to 5%) as cII-fusion products in Escherichia coli. These recombinant polypeptides were characterized serologically by the Western blot assay against a panel of HIV-2 and HIV-1 antibody-positive sera, and with normal human sera (HIV-1 and HIV-2 antibody negative). Only those polypeptides that are encoded by a segment of the env gene from the N-terminal region of the transmembrane protein gp35 (amino acids 537 to 707) were immunoreactive. Three polypeptides (921, 996, and 997), each encoding this immunoreactive region of the HIV-2 (NIH-Z) gp35, reacted strongly and specifically with antibodies in sera from HIV-2-positive individuals, but not with antibodies in sera from HIV-1-positive or HIV-uninfected individuals. These results show that the N-terminal region of the HIV-2 gp35 contains a highly antigenic determinant which is strongly immunogenic in HIV-2-infected individuals. The gp35-encoded recombinant env polypeptides can potentially be used in diagnostic assays to specifically differentiate between HIV-2 and HIV-1 infections.

Absence of antibodies to HIV-2/HTLV-4 in six central African nations.

We studied 1508 individuals from Zaire, Burundi, Tanzania, Zambia, Kenya, and Cameroon for antibodies to HIV-2/HTLV-4. AIDS, ARC, other disease or tumor patients and healthy people were sampled from 1984-1986. By radioimmunoprecipitation and SDS/PAGE analysis and/or Western blot we failed to find any samples with specific antibodies to HIV-2/HTLV-4 indicative of infection. In contrast, 363 of these 1508 individuals demonstrated antibodies to HIV-1/HTLV-3B by the same serologic assays. HIV-2/HTLV-4 infection appears to be quite rare in Central Africa. AIDS and related syndromes in this study were exclusively correlated with HIV-1 infection. Studies in West Africa have shown high rates of infection with HIV-2/HTLV-4 where cases of AIDS are still relatively uncommon. These results indicate that HIV-2/HTLV-4 has a distinct geographic distribution from that of HIV-1 in Africa. Further studies are necessary to better define the pathogenicity and natural history of this distinct new virus, HIV-2/HTLV-4.

Intrapatient variability of the human immunodeficiency virus type 2 envelope V3 loop.

Studies of HIV-2 infection have shown lower rates of sexual and perinatal transmission and a prolonged incubation period to AIDS as compared to HIV-1. To evaluate the role of genetic variation in HIV pathogenesis, we studied intrapatient variability in the V3 loop of the HIV-2 envelope gene over time in five seropositive individuals. Proviral sequences derived from uncultured PBMC DNA (n = 102) demonstrated an average sequence heterogeneity within a sample of 1.4% (0-4.1%). This was significantly lower than the V3 sequence heterogeneity observed in HIV-1, which can be as high as 6.1%. In HIV-2-seropositive healthy patients the average intrapatient nucleotide variability rate was 0.6% compared to 2.0% in patients with clinical AIDS. The lower rate of variability between HIV-2 and HIV-1 is compatible with differences in transmission and pathogenesis of these two related viruses.