Association of the HLA-B*52 allele with non-progression to AIDS in Brazilian HIV-1-infected individuals.

Several human leukocyte antigen (HLA) class I alleles are associated with the susceptibility to human immunodeficiency virus-1 (HIV-1) infection and/or AIDS progression. Of these, the HLA-B alleles are considered the strongest genetic determinant of disease outcome. We evaluated the influence of the HLA-B alleles on AIDS progression among HIV-1-positive individuals from Rio de Janeiro, Brazil, who were categorized as rapid progressors (RPs), typical progressors (TPs) or long-term non-progressors (LTNPs). In this study, significant differences in HLA-B allele frequencies were observed among the three progression groups for the B*48, B*49 and B*52 alleles. After controlling for other factors associated with AIDS progression, the presence of the B*52 allele was shown to be a significant protective factor (hazard ratio (HR) 0.49 (95% confidence interval (CI) 0.27-0.90) P<0.03). Although no direct association was observed between the presence of the B*27 or B*57 allele and the LTNP profile compared with the TP or RP groups, the adjusted model confirmed that these alleles are protective factors against AIDS progression (HR 0.62 (95% CI 0.38-0.99) P<0.05), as previously described. These data corroborate the existence of significant differences in HLA-B allele frequencies among the distinct AIDS progression profiles and further elucidate the role of HLA alleles in the outcome of HIV infections in diverse populations.

Polymorphism of the Human Immunodeficiency Virus Type 1 in Brazil: genetic characterization of the nef gene and implications for vaccine design.

Most of the Brazilian HIV-1 samples have been characterized based on the structural genes (env, gag and pol) and no data concerning the variability of the accessory genes such as nef have been available so far. Considering the role of the nef on virus biology and the inclusion of this region in some HIV/AIDS vaccine products under testing, the purpose of this study was to document the genetic diversity of the nef gene in third-four HIV-1 Brazilian samples previously subtyped based on the env C2-V3 region. Although only few non-subtype B samples have already been analyzed so far, the cytotoxic Tlymphocyte epitopes encoded in this region were relatively conserved among the subtypes, with some amino acid signatures mainly in the subtype C samples. Considering the increasing of the non-B HIV-1 subtypes worldwide, in special the subtype C, more data should be generated concerning the genetic and antigenic variability of these subtypes, as well as the study of the impact of such polymorphism in HIV/AIDS vaccine design and testing.

Polymorphism of the human immunodeficiency virus type 1 in Brazil: genetic characterization of the nef gene and implications for vaccine design

Most of the Brazilian HIV-1 samples have been characterized based on the structural genes (env, gag and pol) and no data concerning the variability of the accessory genes such as nef have been available so far. Considering the role of the nef on virus biology and the inclusion of this region in some HIV/AIDS vaccine products under testing, the purpose of this study was to document the genetic diversity of the nef gene in third-four HIV-1 Brazilian samples previously subtyped based on the env C2-V3 region. Although only few non-subtype B samples have already been analyzed so far, the cytotoxic Tlymphocyte epitopes encoded in this region were relatively conserved among the subtypes, with some amino acid signatures mainly in the subtype C samples. Considering the increasing of the non-B HIV-1 subtypes worldwide, in special the subtype C, more data should be generated concerning the genetic and antigenic variability of these subtypes, as well as the study of the impact of such polymorphism in HIV/AIDS vaccine design and testing

HIV-1 polymorphism: a challenge for vaccine development - a review.

The perspective for the development of anti-HIV/AIDS vaccines became a target sought by several research groups and pharmaceutical companies. However, the complex virus biology in addition to a striking genetic variability and the limited understanding of the immunological correlates of protection have made this an enormous scientific challenge not overcome so far. In this review we presented an updating of HIV-1 subtypes and recombinant viruses circulating in South American countries, focusing mainly on Brazil, as one of the challenges for HIV vaccine development. Moreover, we discussed the importance of stimulating developing countries to participate in the process of vaccine evaluation, not only testing vaccines according to already defined protocols, but also working together with them, in order to take into consideration their local information on virus diversity and host genetic background relevant for the vaccine development and testing, as well as including local virus based reagents to evaluate the immunogenicity of the candidate vaccines.

HIV-1 polymorphism: a challenge for vaccine development - a review

The perspective for the development of anti-HIV/AIDS vaccines became a target sought by several research groups and pharmaceutical companies. However, the complex virus biology in addition to a striking genetic variability and the limited understanding of the immunological correlates of protection have made this an enormous scientific challenge not overcome so far. In this review we presented an updating of HIV-1 subtypes and recombinant viruses circulating in South American countries, focusing mainly on Brazil, as one of the challenges for HIV vaccine development. Moreover, we discussed the importance of stimulating developing countries to participate in the process of vaccine evaluation, not only testing vaccines according to already defined protocols, but also working together with them, in order to take into consideration their local information on virus diversity and host genetic background relevant for the vaccine development and testing, as well as including local virus based reagents to evaluate the immunogenicity of the candidate vaccines

Retrovirus infections in a sample of injecting drug users in Rio de Janeiro City, Brazil: prevalence of HIV-1 subtypes, and co-infection with HTLV-I/II.

BACKGROUND: Retrovirus infections among injecting drug users (IDUs), a core at-risk population for both HIV-1 and HTLV-I/II infections in Brazil, were assessed within an ongoing cooperative research. OBJECTIVE: The study assessed the seroprevalences of HIV-1 and HTLV-I/II infections, as well as the prevalence of HIV-1 subtypes in a sample of IDUs from Rio de Janeiro, Brazil. An attempt to evaluate HIV incidence was carried out using a dual 'sensitive/less sensitive' testing strategy. STUDY DESIGN: Cross-sectional evaluation of 175 IDUs. Serostatus for HIV-1 and HTLV-I/II were established by enzyme-linked immunosorbent assays, and confirmed by western blot. The dual testing strategy aimed to estimate HIV-1 incidence rates. Differentiation between HTLV-I and -II was performed by western blot. DNA samples were polymerase chain reaction amplified by a nested protocol, and HIV-1 subtyping was determined by heteroduplex mobility assay. RESULTS: Forty-six and 29 samples were found to be, respectively, positive for HIV-1 and HTLV-I/II, 15 of them co-infected by both viruses. Among HTLV-I/II-infected patients, 75.9% were infected by HTLV-I. Thirty-one HIV samples were identified as B subtype, with seven of them showing the typical "Brazilian B" pattern in the gp120 V3 loop, and ten were identified as F subtype. The use of less sensitive assays for HIV infection wrongly identified a deeply immunocompromised patient as an incident case. CONCLUSION: Moderately high seroprevalences were found for both HIV-1 and HTLV-I/II infections, HIV-1/HTLV-I co-infections being of special concern. A non-statistically significant higher prevalence of F subtype was observed, when compared with the distribution of F/B subtypes among Brazilian patients from other exposure categories. No recent HIV-1 infections were detected, but a limitation of the "sensitive/less-sensitive" testing strategy was made evident.

Vertical HIV-1 transmission: importance of neutralizing antibody titer and specificity.

Neutralization analyses were carried out with plasma from 132 volunteer human immunodeficiency virus (HIV)-1 infected women (76% pregnant, 24% with infants suspected for HIV-1 infection) collected between 1994 and 1998, against autologous and heterologous primary- and the reference HIV-1 MN isolates. A significantly lower percentage of HIV-1 transmissions was observed after 1996, parallel to a more intense antiretroviral treatment of infected pregnant women. HIV-1 isolation was significantly more frequent from peripheral blood mononuclear cells of mothers of infected children than mothers of uninfected children (P = 0.0065). Neutralization of autologous HIV-1 isolates was comparable for HIV-1 transmitters and nontransmitters' plasma, whereas neutralization of the reference isolate HIV-1 MN was more frequent at high titers for pregnant women who did not transmit HIV to their offspring compared to pregnant women who did. Although neutralization of heterologous primary HIV-1 isolates from HIV transmitters and non transmitters by transmitter plasma occurred with similar frequency, neutralization of isolates from transmitters was much more frequent when heterologous plasma from nontransmitters were used. Macrophage-tropic heterologous HIV-1 isolates were neutralized more frequently at higher titers by plasma from nontransmitters than from transmitters. The results obtained indicate that antiretroviral treatment, lack of success of HIV-1 isolation and high titers of antibodies able to neutralize macrophage-tropic viruses appear to be of importance for protection against HIV-1 vertical transmission for the group of patients studied.

Molecular characterization of human immunodeficiency virus type 1-infected individuals from bolivia reveals the presence of two distinct genetic subtypes B and F.

Thirty HIV-1-positive samples from Bolivia were genetically characterized on the basis of HMA and DNA sequencing, revealing the presence of B and F subtypes, in accordance with the molecular epidemiology pattern already described for other South American countries such as Brazil and Argentina. The interpatient divergence of subtype B Bolivian specimens was on average 14.2% (4.3-19.8%) at the nucleotide level, whereas the two unlinked subtype F samples (BO23 and BO29) were only 8.2% divergent, suggesting a more recent introduction of this subtype in the country. In our study group, which represents 13% of the HIV/AIDS cases already described in Bolivia as of May 1996, the transmission occurred more frequently through heterosexual exposures (46.7%), followed by homosexual (23.3%), bisexual (10%), intravenous drug use (3.3%), and vertical (3.3%); in one case the potential exposure category could not be defined (3.3%). No association could be established between exposure categories, gender, or clinical classification and subtype distribution in the Bolivian HIV/AIDS patients.

HIV-1 diversity in Brazil: genetic, biologic, and immunologic characterization of HIV-1 strains in three potential HIV vaccine evaluation sites. Brazilian Network for HIV Isolation and Characterization.

The Brazilian Network for HIV Isolation and Characterization was established for the surveillance of HIV variability in Brazil. Here, we report characterization of HIV strains and virus-specific immune responses from 35 clinical samples collected from three potential HIV vaccine sites. Three genetic subtypes of HIV-1 were identified by heteroduplex mobility assay (HMA) B (in 82.9% of the samples), F (14.3%), and C (2.9%). Phylogenetic analysis based on the C2V3/env DNA sequence from all 25 specimens examined was 100% concordant with HMA results. Four variants of subtype B with different tetrapeptides at the tip of the V3 loop were found: the GPGR motif (North American), GWGR motif (Brazilian B"), and two minor variants, GFGR and GPGS, as previously detected. No significant association was found between HIV-1 subtypes and the mode of transmission or biologic properties of HIV-1 isolates (derived from 88.6% of the specimens). Only 5 of 16 isolates studied were neutralized by the autologous sera. Consistent with previous results, no relation between viral subtype and peptide enzyme-linked immunosorbent assay (ELISA) seroreactivity or neutralization was evident. This study also demonstrated the effectiveness of the collaborative approach followed by Brazilian scientists when addressing a complex subject such as HIV variability.

Lamotrigine as add-on therapy in treatment-resistant epilepsy. Portuguese Lamotrigine as Add-on Therapy in Treatment-resistant Epilepsy Study Group.

The efficacy and safety of lamotrigine as add-on therapy in treatment-resistant epilepsy were evaluated in an open prospective study carried out at five centres in Portugal and involving 61 patients. Daily seizure diaries were kept by patients, and used by the investigators to give a rating of response to therapy. Assessments were recorded after 1, 2, 3, 6, 9, 12, 18 and 24 months. Overall, seizure control was improved in 57% of patients, remained unchanged in 34% and deteriorated in 9%. There were some indications that efficacy was greatest in patients with generalized seizures and in those taking concomitant valproate. Efficacy was maintained throughout the 2-year study. It was possible to reduce the dose of concomitant antiepileptic drug in 56% of patients, and seven patients no longer needed a concomitant antiepileptic drug. Although 75% of patients reported an adverse experience, most of these were mild or moderate in intensity, did not require treatment and were not judged to be serious. A total of 13 patients withdrew from the study (four due to adverse events, four due to lack of efficacy and five for other reasons).

Anti-HIV-1 seroreactivity and HIV transmission route[R1]. The HEC/FIOCRUZ AIDS Clinical Research Group.

BACKGROUND: Antibody binding assays carried out by our group have consistently indicated a higher reactivity of sera from male HIV-1 infected individuals. This study was carried out in order to analyze the importance of gender, route of transmission, disease progression and HIV-1 genotype in seroreactivity assays. STUDY DESIGN: Specificity of antibody binding was studied in plasma of 247 HIV-1 seropositive individuals belonging to patient groups of pregnant women, injecting drug users (IDUs) and recent seroconvertors, resident in Rio de Janeiro, RJ. Recognition of synthetic peptides corresponding to antigenically important epitopes in the envelope of HIV-1 (gp41 immunodominant epitope, V3 loop, V2 loop and gp41 735-752 epitope) was determined. RESULTS: The immunodominant gp41 peptide (amino acids 594-613, HIV-1 MN sequence) was recognized by 85% of all plasma tested. Reactivity with the gp41 735-752 peptide and gp120 V2 loop peptides was low but quite variable, being generally more often specific to a Brazilian V2 peptide used than to the HIV-1 MN derived V2 peptide. The overall recognition of the different V3 peptides tested varied from 41 to 76%. Patients with more advanced disease showed a more frequent reactivity with the peptides studied than did asymptomatic patients. Statistically significant differences in peptide recognition were observed by multiple logistic analyses comparing plasma derived from individuals infected by blood or sexual HIV transmission, adjusting for disease progression and gender. Plasma from individuals infected by sexual transmission showed lower peptide recognition than did plasma from individuals infected through HIV positive blood. Association attempts between seroreactivity and genotype indicated that plasma derived from patients infected with HIV-1 of the F subtype showed highest recognition of heterologous V3 peptides, as well as a slightly more frequent recognition of the non-V3 peptides tested. Recognition of homologous peptides was generally higher than recognition of heterologous peptides. Differences were most pronounced between the prototypical HIV-1 B subtype and the Brazilian B" variant of this subtype but almost non-existent between the HIV-1 B and F subtypes. CONCLUSIONS: Individual gender was shown to be a confounder when investigating the relationships of peptide reaction to HIV-1 route of transmission through multivariate statistical methods: patients infected by blood transmission (IDU) present higher frequency of peptide recognition than individuals infected by sexual HIV-1 transmission. Plasma from individuals infected with the B" variant (GWG) of B subtype HIV-1 showed lower heterologous peptide recognition than that from HIV-1 B (GPG) or F infected individuals.

Reduction in temporal N-acetylaspartate and creatine (or choline) ratio in temporal lobe epilepsy: does this 1H-magnetic resonance spectroscopy finding mean poor seizure control?

BACKGROUND: Proton magnetic resonance spectroscopy (1H-MRS) is a potentially useful tool in the in vivo investigation of brain metabolites in intractable temporal lobe epilepsy (TLE). Focal N-acetylaspartate (NAA) reductions have been correlated with mesial temporal sclerosis (MTS) in surgically resected epileptogenic foci. OBJECTIVE: To evaluate the abnormalities in the metabolites NAA, creatine+ phosphocreatine (Cr), and choline containing compounds (Cho) in the temporal lobe of medically refractory patients with temporal lobe epilepsy, seizure free patients with temporal lobe epilepsy, and normal controls. PATIENTS AND METHODS: Ten refractory patients, 12 seizure free patients with temporal lobe epilepsy, and 10 age matched normal controls were studied by 1H-magnetic resonance spectroscopy. All patients had consistently unilateral temporal EEG abnormalities and a normal brain MRI. Proton MR spectra were obtained from an 8 ml volume in the medial temporal lobes in patients with temporal lobe epilepsy (ipsilateral to EEG foci) and the normal controls. The signals measured were expressed in terms of NAA/Cr, NAA/Cho, and Cho/Cr. RESULTS: When compared with seizure free patients with temporal lobe epilepsy and normal controls, the 10 refractory patients with temporal lobe epilepsy had a lower mean (SEM) NAA/Cr ratio (1.65 (0.53) v 2.62 (0.60), and 2.66 (0.73); p<0.002 and p<0.006) and a lower mean NAA/Cho ratio (1.59 (0.79) v 2.83 (1.33) and 2.58 (0.67); p<0.02 and p<0.007). Furthermore, the two patients showing the lowest NAA/Cr ratios (1.47 and 1.73) in the seizure free group had had a past period of poor seizure control. CONCLUSIONS: There were reduced temporal NAA/Cr and NAA/Cho ratios, suggesting neuronal loss or damage, associated with past or present poor seizure control in the patients with temporal lobe epilepsy, but it does not exclude the possibility of a future complete seizure control (seizure free patients with temporal lobe epilepsy at the time of 1H-MRS). This study warrants further 1H-MRS investigation with a larger series of patients with temporal lobe epilepsy.

HIV specific humoral immune response in Rio de Janeiro, Brazil. The HEC/Fiocruz AIDS Clinical Research Group.

Efforts to characterize HIV-1 polymorphism and anti-HIV immune response are being made in areas where anti-HIV/AIDS vaccines are to be employed. Anti-HIV-1 humoral immune response is being studied in infected individuals residents in Rio de Janeiro, in distinct cohorts involving recent seroconvertors, pregnant women or intravenous drug users (IDU). Comparative analyses of specificity of antibody response towards epitopes important for anti-HIV-1 immune response indicate quantitative differences between cohorts, with an exceptionally strong response in IDUs and weakest response in pregnant women. However, a comparative analysis between pregnant women cohorts from Rio de Janeiro and Rio Grande do Sul indicated an even lower response (with exception of the anti-V3-C clade peptide recognition) for the southern cohort. Studies analysing the immune function of the humoral response indicate a quite elevated occurrence of antibodies capable for neutralizing heterologous primary HIV-1 isolates from Rio de Janeiro. Attempts to correlate seroreactivity with HIV-1 neutralization with respect to HIV-1 polymorphism were not very successful: while the Brazilian B clade B " variant could be recognized by binding assays, no significant distinction of HIV-1 clades/variants was observed in viral neutralization assays.

Molecular epidemiology of HIV-1 in Brazil: high prevalence of HIV-1 subtype B and identification of an HIV-1 subtype D infection in the city of Rio de Janeiro, Brazil. Evandro Chagas Hospital AIDS Clinical Research Group.

HIV-1-positive individuals were recruited from January 1993 to December 1996 from several cohorts receiving follow-up in the city of Rio de Janeiro, Brazil, to evaluate HIV-1 genetic variability and the potential association with modes of transmission. HIV-1 subtyping was carried out using the heteroduplex mobility assay (HMA), and those samples corresponding to the typical Brazilian subtype B variant were further identified based on the Fok I restriction fragment length polymorphism (RFLP). DNA sequencing was performed to evaluate one case of subtype D infection. From the 131 HIV-1-positive individuals analyzed, 106 (80.9%) could be identified as infected by subtype B and 20 (15.3%) by subtype F. One of the samples (0.8%) was classified as subtype D. DNA samples from 4 patients (3.0%) did not yield polymerase chain reaction (PCR)-amplified products to be typed. Based on the Fok I RFLP, 39 of the 106 subtype B samples (37%) were identified as corresponding to the typical Brazilian subtype B variant containing the GWGR motif at the tip of the V3 loop. No statistically significant association could be detected between HIV-I subtypes and modes of transmission, exposure categories, or gender. This is the first reported case of HIV-1 subtype D infection in Brazil.

Neutralization susceptibility of B subtype variant B" primary HIV-1 isolates. The HEC/FIOCRUZ AIDS Clinical Research Group.

Susceptibility to autologous and heterologous neutralization of primary human immunodeficiency virus (HIV)-1 isolates belonging to subtype B, to the B"-variant of subtype B or to subtype F from infected individuals residing in Rio de Janeiro was assayed. A lower infectivity of the B"- and F isolates when compared to the classical B-subtype HIV-1 isolates was observed. Comparisons of neutralization susceptibilities were carried out for 19 B-subtype, 11 B"-variant and two F-subtype HIV-1 isolates with plasma from autologous and heterologous samples. Frequency of autologous neutralization was slightly lower for B-subtype isolates in comparison to B"-variant isolates. Heterologous intra-subtype neutralization was significantly lower for B-subtype than for the B"-variant or the F-subtype isolates. While B-subtype isolates were neutralized by most anti-F-subtype plasma, F-subtype isolates, although most susceptible to F-subtype antibodies, were highly susceptible to neutralization by anti-B-subtype antibodies. Cross-neutralization for B"-variant and B-subtype isolates was not as extensive as observed for B- and F-subtype isolates. However, the results presented indicate a quite extensive cross-neutralization between Brazilian HIV-1 isolates.

HIV specific humoral immune response in Rio de Janeiro, Brazil

Efforts to characterize HIV-1 polymorphism and anti-HIV immune response are being made in areas where anti-HIV/AIDS vaccines are to be employed. Anti-HIV-1 humoral immune response is being studied in infected individuals resident in Rio de Janeiro, in distinct cohorts involving recent seroconvertors, pregnant women or intravenous drug users (IDU). Comparative analysis of specificity of antibody response towards epitopes important for anti-HIV-1 immune response indicate quantitative differences between cohorts, with an exceptionally strong response in IDUs and weakest response in pregnant women. However, a comparative analysis between pregnant women cohorts from Rio de Janeiro and Rio Grande do Sul indicated an even lower response (with exception of the anti-V3-C clade peptide recognition) for the southern cohort. Studied analysing the immune function of the humoral response indicate a quite elevated occurrence of antibodies capable of neutralizing heterologous primary HIV-1 isolates from Rio de Janeiro. Attempts to correlate seroreactivity with HIV-1 neutralization with respect to HIV-1 polymorphism were not very successfull: while the Brazilian B clade B" variant could be recognized by binding assays, no significant distinction of HIV-1 clades/variants was observed in viral neutralization assays.