Maria Teresita Bendicho

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.

Porphyromonas gingivalis HmuY-induced production of interleukin-6 and IL-6 polymorphism in chronic periodontitis.

BACKGROUND In chronic periodontitis (CP), the gene polymorphism of interleukin-6 (IL-6) to 174C/G has been associated with the altered production of this cytokine. The aim of this pilot study is to compare the allelic and genotypic frequencies in patients with CP with control individuals without periodontitis (NP) and to measure the production of IL-6 by whole blood cells stimulated with Porphyromonas gingivalis HmuY protein. METHODS DNA was isolated from peripheral blood cells of 49 patients with CP and 60 control individuals classified as NP, and genotyping was performed by polymerase chain reaction using sequence-specific primers. Whole blood cells from 29 patients with CP and 30 control individuals were stimulated for 48 hours with HmuY, and IL-6 levels were measured using enzyme-linked immunosorbent assay. RESULTS The proportion of individuals carrying the G allele at position -174 of the IL-6 gene was higher in the group with CP (85.7%) than in the normal control group (73.3%; P <0.03). P. gingivalis HmuY-induced production of IL-6 was higher in the group with CP (P <0.05). CONCLUSIONS Our findings suggest that P. gingivalis HmuY may be associated with increased IL-6 production during CP. Furthermore, patients with periodontitis and individuals with higher HmuY-induced production of IL-6 show a high frequency of the G allele at position -174.

Ancestry informative markers and complete blood count parameters in Brazilian blood donors

O hemograma e muito util no diagnostico quando o intervalo de referencia e adequadamente estabelecido para populacao. Com o objetivo de verificar os valores hematologicos em populacao heterogenea foi analisado o hemograma e frequencias alelica de marcadores informativos de ancestralidade de brasileiros. Foi observada associacao positiva entre sexo e os valores de neutrofilos, monocitos, eosinofilos, eritrocitos, hemoglobina, hematocrito, MCV, MCHC e plaquetas (IC 95%; P 0,05). Os homens apresentaram valores maiores no eritrograma, enquanto no leucograma e plaquetograma foram as mulheres. Foi observado tambem que a populacao e altamente heterogenea e as medias proporcionais (±DP) de ancestralidade Africana, Europeia e Amerindia estimada foram: 49,0 ± 3,0 %, 44,0 ± 9,0% e 7,0 ± 9,0%, respectivamente. A contribuicao ancestral amerindia se demonstrou pequena, mas a estimativa de proporcoes ancestrais foi estatisticamente significante (r = 0,9838; P<0,001). Os valores hematologicos aqui descritos sao parecidos com os descritos em negros americanos, outra populacao heterogenea.

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.

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.

Lymphocyte subset reference intervals in blood donors from northeastern Brazil

UNLABELLED The reference intervals for leukocytes and lymphocytes currently used by most clinical laboratories present limitations as they are primarily derived from individuals of North American and European origin. The objective this study was to determine reference values for peripheral blood B lymphocytes, T lymphocyte subsets (CD4+, CD8+, naïve, memory, regulatory, TCRαβ and TCRγδ+) and NK cells from blood donors in Salvador-Bahia, Brazil. RESULTS The proportion of included male subjects was 73.7% and the median ages of males (34) and females (35) were found to be similar. Absolute counts total lymphocytes subsets to both gender was 1,956 (1,060-4,186) cells and relative values 34%. The T CD4+ and T CD8+ lymphocytes relative values was 51% (20-62) and 24% (9-28), respectively. The most statistically significant finding observed was a higher percentage of B lymphocytes (p=0.03) in females. Commonly cited subset reference intervals were found to be consistent with values in several populations from different geographic areas.

Interferon-gamma release assay performance in northeastern Brazil: influence of the IFNG + 874 A>T polymorphism

INTRODUCTION Latent tuberculosis infection diagnosis based on the release of interferon-gamma in cultures of peripheral blood cells stimulated with Mycobacterium tuberculosis antigens has replaced the tuberculin skin test in many countries with low tuberculosis prevalence. The IFN-γ production can be influenced by genetic polymorphisms, of which the IFNG+874 (rs62559044) locus is the most studied. We investigated the possible influence of the IFNG+874 A/T polymorphism on interferon-gamma test performance. METHODS Patients diagnosed with pulmonary tuberculosis (75), volunteers with positive tuberculin skin test (70) and healthy volunteers with negative tuberculin skin test and no history of contact with tuberculosis (57) were evaluated regarding the IFNG+874 genotype and the IFN-γ levels in whole blood cultures performed using an interferon-gamma commercial kit (QuantiFERON-TB® Gold In-Tube). RESULTS IFN-γ production was not influenced by the IFNG+874 genotype, regardless of antigen or mitogen-based stimulation, which suggests that other genes may influence IFN-γ production in response to mycobacteria. The IFNG+874 polymorphism was found to exert no influence over QFT-IT test sensitivity in our study. CONCLUSIONS The IFNG+874 polymorphism was not shown to influence QuantiFERON-TB® Gold In-Tube test performance in an admixed population from northeastern Brazil.