Denise Carneiro Lemaire

IL28B polymorphisms are markers of therapy response and are influenced by genetic ancestry in chronic hepatitis C patients from an admixed population.

IL28B polymorphisms are predictors of therapy response in hepatitis C virus (HCV) patients. We do not know whether they are markers of treatment response in admixed populations or not.

Comparison between enzyme-linked immunosorbent assay, indirect fluorescent antibody and rapid conglutination tests in detecting antibodies against Babesia bovis

The performance of an enzyme-linked immunosorbent assay (ELISA), an indirect fluorescent antibody test (IFAT) and a rapid conglutination test (RCT) for the detection of antibodies against Babesia bovis, was evaluated with 462 cattle sera from Bahia State; Brazil. The results showed a concordance of 96.6% between the ELISA and IFAT, 90.5% between the ELISA and RCT, and 91.8% between the IFAT and RCT. Although the prevalence rates determined by ELISA (97.2%) and IFAT (96.8%) were higher than that indicated by the RCT (92.9%), performances of the three serological tests were very similar and characterized the region studied as enzootically stable to B. bovis.

Coassociations between IL10 polymorphisms, IL-10 production, helminth infection, and asthma/wheeze in an urban tropical population in Brazil

BACKGROUND Helminth infections are associated with protection against allergies. It is postulated that IL-10 production after helminth infection suppresses skin hypersensitivity and increases IgG₄ production, protecting against allergies. OBJECTIVE We aimed to determine whether IL10 polymorphisms are associated with helminth infection and the risk of wheeze and allergy. METHODS Twelve IL10 single nucleotide polymorphisms were genotyped in 1353 children aged 4 to 11 years living in a poor urban area in Salvador, Brazil. Wheezing status, Ascaris lumbricoides and Trichuris trichiura infection, IL-10 production by peripheral blood leukocytes stimulated with A lumbricoides extract, serum total IgE levels, specific IgE levels, skin prick test responses to common aeroallergens, and IgG4 and IgE anti-A lumbricoides antibody levels were measured in all children. Association tests were performed by using logistic or linear regression when appropriate, including sex, age, helminth infection, and principal components for ancestry informative markers as covariates by using PLINK. RESULTS Allele G of marker rs3024496 was associated with the decreased production of IL-10 by peripheral blood leukocytes in response to A lumbricoides stimulation. Allele C of marker rs3024498 was negatively associated with helminth infection or its markers. Marker rs3024492 was positively associated with the risk of atopic wheeze, total IgE levels, and skin prick test responses to cockroach. CONCLUSIONS Our findings suggest that IL10 polymorphisms might play a role in the production of IL-10, helminth infection, and allergy. We hypothesize that polymorphisms related to protection against helminths, which would offer an evolutionary advantage to subjects in the past, might be associated with increased risk of allergic diseases.

Natural killer cell receptor and HLA-C gene polymorphisms among patients with hepatitis C: a comparison between sustained virological responders and non-responders.

Background/Aims: Killer cell immunoglobulin‐like receptors (KIR) are involved in the activation/inhibition of NK cells through an interaction with HLA class I molecules on target cells. Our study aimed to evaluate the association between KIR gene polymorphisms and the response of patients with CHC to antiviral therapy.

Distribuição e freqüência de alelos e haplotipos HLA em brasileiros com diabetes melito tipo 1

The genetic predisposition to type 1 diabetes (DM1) is associated with genes of the human leukocyte antigen (HLA) system, specially the HLA-DR and -DQ. In Caucasians, the HLA-DR3 and -DR4 antigens are associated with susceptibility and the -DR2, with protection. In Brazil, a country with a large miscegenation of Europeans Caucasians, Native Amerindians and African Blacks, the genetic basis of DM1 has not been adequately studied. The aim of this paper is to present a critical review of articles indexed in the MEDLINE and LILACS-BIREME data basis about the association of HLA with DM1 in Brazilians. Eight papers, all of them from the Southeast region, were found. Immunogenetic susceptibility to DM1 in Brazilians was associated with HLA-DRB1*03, -DRB*04, -DQB1*0201, -DQB1*0302 alleles, and protection against DM1 was associated with HLA-DQB1*0602, -DQB1*0301 alleles and -DR2 and -DR7 antigens. Since the Brazilian population is not racially homogeneous, it is not possible to extrapolate studies from a single region to the remaining of the country. It is necessary to study populations from different regions to identify new associations or to strengthen associations with the ones already identified. This knowledge will contribute to future prophylactic or therapeutic interventions in the group of Brazilians at risk of developing DM1.

Myxovirus resistance, osteopontin and suppressor of cytokine signaling 3 polymorphisms predict hepatitis C virus therapy response in an admixed patient population: comparison with IL28B

OBJECTIVES: Suppressor of cytokine signaling 3, myxovirus resistance protein and osteopontin gene polymorphisms may influence the therapeutic response in patients with chronic hepatitis C, and an association with IL28 might increase the power to predict sustained virologic response. Our aims were to evaluate the association between myxovirus resistance protein, osteopontin and suppressor of cytokine signaling 3 gene polymorphisms in combination with IL28B and to assess the therapy response in hepatitis C patients treated with pegylated-interferon plus ribavirin. METHOD: Myxovirus resistance protein, osteopontin, suppressor of cytokine signaling 3 and IL28B polymorphisms were analyzed by PCR-restriction fragment length polymorphism, direct sequencing and real-time PCR. Ancestry was determined using genetic markers. RESULTS: We analyzed 181 individuals, including 52 who were sustained virologic responders. The protective genotype frequencies among the sustained virologic response group were as follows: the G/G suppressor of cytokine signaling 3 (rs4969170) (62.2%); T/T osteopontin (rs2853744) (60%); T/T osteopontin (rs11730582) (64.3%); and the G/T myxovirus resistance protein (rs2071430) genotype (54%). The patients who had ≥3 of the protective genotypes from the myxovirus resistance protein, the suppressor of cytokine signaling 3 and osteopontin had a greater than 90% probability of achieving a sustained response (p<0.0001). The C/C IL28B genotype was present in 58.8% of the subjects in this group. The sustained virological response rates increased to 85.7% and 91.7% by analyzing C/C IL28B with the T/T osteopontin genotype at rs11730582 and the G/G suppressor of cytokine signaling 3 genotype, respectively. Genetic ancestry analysis revealed an admixed population. CONCLUSION: Hepatitis C genotype 1 patients who were responders to interferon-based therapy had a high frequency of multiple protective polymorphisms in the myxovirus resistance protein, osteopontin and suppressor of cytokine signaling 3 genes. The combined analysis of the suppressor of cytokine signaling 3 and IL28B genotypes more effectively predicted sustained virologic response than IL28B analysis alone.

HLA-Bw4-B*57 and Cw*18 alleles are associated with plasma viral load modulation in HIV-1 infected individuals in Salvador, Brazil.

UNLABELLED Host genetic factors play an important role in mediating resistance to HIV-1 infection and may modify the course of infection. HLA-B alleles (Bw4 epitope; B*27 and B*57) as well as killer cell immunoglobulin-like receptors have been associated with slow progression of HIV-1 infection. OBJECTIVE To evaluate the association between serological epitopes HLA-Bw4 and HLA-Bw6 and prognostic markers in AIDS. METHODS 147 HIV-infected individuals in Bahia, Northeast Brazil, were genotyped for HLA class I locus. HLA class I genotyping was performed by hybridization with sequence-specific oligonucleotide probes following amplification of the corresponding HLA-A, HLA-B and HLA-C genes. Statistical analysis was performed using Fishers exact and ANOVA tests for categorical and continuous variables, respectively. RESULTS We detected a significant association (χ2 = 4.856; p = 0.018) between the presence of HLA-Bw4 and low levels of viremia. Eighteen out of the 147 HIV-infected individuals presented viremia <1,800 copies/mL and 129 presented viremia > 2,000 copies/mL. Ninety and four percent (17/18) of all individuals with viremia < 1,800 copies/mL carried HLA-Bw4, compared to 67.4% (87/129) of individuals with viremia > 2,000 copies/mL. Additionally, we found a significantly higher frequency of B*57 (OR = 13.94; 95% CI = 4.19-46.38; p < 0.0001) and Cw*18 (OR = 16.15; 95% CI = 3.46-75.43; p < 0.0001) alleles, favoring the group with lower viremia levels, in comparison with those with higher viral load. CONCLUSION HLA-Bw4-B*57 and Cw*18 alleles are associated with lower level of viral load in HIV-infected Brazilian patients. These findings may help us in understanding the determinants of HIV evolution in Brazilian patients, as well as in providing important information on immune response correlates of protection for such population.

Coping with genetic diversity: the contribution of pathogen and human genomics to modern vaccinology

Vaccine development faces major difficulties partly because of genetic variation in both infectious organisms and humans. This causes antigenic variation in infectious agents and a high interindividual variability in the human response to the vaccine. The exponential growth of genome sequence information has induced a shift from conventional culture-based to genome-based vaccinology, and allows the tackling of challenges in vaccine development due to pathogen genetic variability. Additionally, recent advances in immunogenetics and genomics should help in the understanding of the influence of genetic factors on the interindividual and interpopulation variations in immune responses to vaccines, and could be useful for developing new vaccine strategies. Accumulating results provide evidence for the existence of a number of genes involved in protective immune responses that are induced either by natural infections or vaccines. Variation in immune responses could be viewed as the result of a perturbation of gene networks; this should help in understanding how a particular polymorphism or a combination thereof could affect protective immune responses. Here we will present: i) the first genome-based vaccines that served as proof of concept, and that provided new critical insights into vaccine development strategies; ii) an overview of genetic predisposition in infectious diseases and genetic control in responses to vaccines; iii) population genetic differences that are a rationale behind group-targeted vaccines; iv) an outlook for genetic control in infectious diseases, with special emphasis on the concept of molecular networks that will provide a structure to the huge amount of genomic data.

The TNF-α -308 polymorphism may affect the severity of Crohn's disease

OBJECTIVE: The goal of this project was to analyze the association between Crohns disease, its clinical features, and the tumor necrosis factor alpha (TNF-α) -308 polymorphism. METHODS: This is a case-control and cross-sectional study that enrolled 91 patients with Crohns disease and 91 controls. Patients with Crohns disease were characterized according to the Montreal Classification, along with their clinical and surgical treatment history. Analysis of the TNF-α -308 polymorphism was performed using a commercial kit. A stratified analysis was applied using an OR (odds ratio) with a 95% confidence interval. The chi-square and Fishers exact tests were utilized for analysis of the association between the polymorphism and the clinical features of Crohns disease. RESULTS: The low producer predicted phenotype was present in 76.9% of Crohns disease cases and 75.8% of controls (OR 0.94 [0.45-1.97]). The TNF2 allele and the high producer predicted phenotype were more frequent among patients with Crohns disease penetrating behavior (p = 0.004). The TNF2 allele and the high producer predicted phenotype were also associated with a history of colectomy (p = 0.02), and the TNF2 allele was associated with small bowel resection (p = 0.03). CONCLUSIONS: The TNF-α -308 polymorphism appears to affect the severity of the disease. However, TNF-α -308 polymorphism does not appear to be important for the susceptibility in the development of Crohns disease.

Factors Associated with Insulin Resistance in Patients with Chronic HCV Genotype 1 Infection without Obesity or Type 2 Diabetes.

Objective: To investigate the prevalence of insulin resistance (IR) and its association with clinical parameters in patients with hepatitis C virus (HCV) genotype 1 without obesity or type 2 diabetes. Methods: One hundred and twenty-seven HCV-infected patients admitted to the Nutrition and Hepatology Clinic were included. Statistical analysis was performed using the Mann-Whitney test, Fishers exact test, and Poisson regression analysis. Results: The prevalence of IR (homeostasis model assessment [HOMA]-IR ≥ 3.0) was 37.0%. The independent predictors for IR included the following: aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 1.5 times the upper normal limit (odds ratio [PR] = 2.06, 95% CI, 1.16–3.66; PR = 2.32, 95% CI, 1.26–4.49, respectively); gamma glutamyl transferase (γGT) ≥ 85 U/L (PR = 2.09, 95% CI, 1.12–4.12); increased waist circumference (PR = 2.24, 95% CI, 1.25–4.17); increased waist : hip ratio (PR = 2.24, 95% CI, 1.11–5.17); increased body fat percentage (PR = 2.21, 95% CI, 1.01–5.79); overweight (PR = 2.54, 95% CI, 1.40–4.82); and metabolic syndrome (PR = 3.05, 95% CI, 1.69–5.44). High ALT levels and anthropometric parameters remained in the model of multivariate regression analysis. Conclusions: Our findings showed a significantly high prevalence of insulin resistance in nondiabetic, nonobese patients with hepatitis C genotype 1. High ALT levels and anthropometric parameters were significantly associated with IR after multivariate regression analysis. Our data show the importance of monitoring IR, weight, and body composition in patients with chronic hepatitis C. Nutritional management seems to be important in the control of comorbidities related to excess weight and the enhancement of therapeutic responses.