Frequency of HLA-B27 and its alleles in patients with Reiter syndrome: comparison with the frequency in other spondyloarthropathies and a healthy control population

This retrospective study analyzed the HLA-B*27 alleles in a group of 20 consecutive patients with the diagnosis of Reiter syndrome (RS) followed in a tertiary referral university hospital in Brazil, during the period 1990-2006, and compared the data with that observed in other patients with spondyloarthropathies followed at the same institution. Eight cases were associated to gastrointestinal infection, eight cases to previous urethritis, and four cases presented no established preceding infection. HLA-B*27 alleles were typed by polymerase chain reaction-amplified DNA hybridized with sequence-specific oligonucleotide probes (HLA-B*2701 to HLA-B*2721). They were compared to a group of 108 patients with ankylosing spondylitis (AS), 40 with undifferentiated spondyloarthropathy (uSpA) and 111 healthy controls. Among the 20 patients, 17 were HLA-B*27 positive (85%). Two HLA-B*27 alleles were observed: HLA-B*2705 (65%) and HLA-B*2702 (35%). In the other spondyloarthropathies, the observed alleles were HLA-B*2705 (90% in AS and 92.5% in uSpA), HLA-B*2702 (8% in AS and 5% in uSpA), HLA-B*2704 (1% in AS and 2.5% in uSpA) and HLA-B*2713 (1% in AS). Among the 111 healthy controls, 80% presented HLA-B*2705, followed by HLA-B*2702 in 10%, HLA-B*2703 in 6%, HLA-B*2707 in 3% and HLA-B*2713 in 1%. Concluding, in the HLA-B*27 positive patients with RS in this study there was predominance of HLA-B*2705 allele, in a lower frequency than that observed in patients with other spondyloarthropathies and healthy controls.

Frequency of HLA-B27 alleles in Brazilian patients with psoriatic arthritis

This prospective study analyzed the frequency of HLA-B27 and its alleles in 102 Brazilian patients with psoriatic arthritis (PsA). The association of the HLA-B27 alleles with these variants was compared to a control healthy HLA-B27 positive group of 111 individuals. There was a predominance of male gender (59.8%), Caucasian race (89.2%), and negative HLA-B27 (79.4%) patients. Asymmetric oligoarthritis (62.7%) was the most frequently observed clinical PsA subgroup, followed by spondylitis (16.7%), and polyarthritis (15.7%). Male gender and the spondylitis subgroup were statistically associated to the positive HLA-B27, and the oligoarthritis subgroup was associated to the negative HLA-B27. Among the 21 HLA-B27-positive PsA patients, there was a significant prevalence of the HLA-B*2705 allele (90.5%), similar to that observed in the control group (80.2%); HLA-B*2703 and HLA-B*2707 were statistically associated to the control group.

Genotipagem de HLA de classe I e II para seleção de células precursoras dendríticas para estudo da imunobiologia do vírus associado ao Sarcoma de Kaposi (KSHV)

The Kaposi-associated Herpesvirus (KSHV) also known as Human Herpesvirus 8 (HHV-8) is associated with the development of Kaposi’s sarcoma (KS) and others limphoprolipheratives diseases such as Primary Effusion Lymphoma (PEL) and Multicentric Castleman Disease (MCD). Even though the virus is considered lymphotropic, it is able to infect others cell types such as macrophages, dendritic cells, endothelial cells, monocytes and fibroblasts. After infection, KSHV be latent expressing essential viral genes to its maintenance in a infected cell. However, in some circumstances may occur the reactivation of lytic cycle producing new viral particles. K1 protein of KSHV interferes in the cellular signaling inducing proliferation and supporting cellular transformation. K1 is encoded by viral ORF-K1, which shows high variability between different genotypes of KSHV. So far, it is not clear whether different isoforms of K1 have specific immunobiological features. The KSHV latency is maintained under strict control by the immune system supported by an adequate antigen presentation involving Human Leucocyte Antigen (HLA) class I and II. Polymorphisms of HLA class I and II genes confer an enormous variability in molecules that recognize a large amount of antigens, but also can increase the susceptibility to autoimmune diseases. Therefore, the present study aims to genotype HLA class I (A and B) and class II (DR and DQ) from volunteers to identify haplotypes that can provide better response to K1 epitopes of different KSHV genotypes. First of all, 20 volunteers were selected to genotype HLA genes. In our results we observed prevalence of certain HLA class I haplotypes as HLAA1, HLA-A2, HLA-A24, HLA-A26, HLA-B8, HLA-B18 e HLA-B44. After the in silico analysis using BIMAS and SYFPEITHI databases, we observed high scores for epitopes from the B genotype of KSHV, indicating...(Complete abstract click electronic access below)

The frequency of HLA-DRB1 polymorphisms in Brazilian Plasmodium vivax malaria patients and in blood donors from the Amazon Region

We evaluated the frequency of different HLA-DRB1 alleles in Plasmodium vivax-infected individuals and in healthy blood donors from malaria endemic areas of Brazil. Low-resolution human leukocyte antigen-DRB1 genotyping was performed for 73 malaria patients and 29 healthy blood donors. The most frequent alleles in individuals from northern Brazil were human leukocyte antigen-DRB1*04, *08, *07 and *13. The frequency of human leukocyte antigen-DRB1*07 was higher in malaria-infected individuals than in the control group, which reinforces the theory that this allele plays an important role in susceptibility to malaria. This study offers new information about a potential susceptibility factor for P. vivax malaria in a Brazilian population that is naturally exposed to malaria.

Efeito quimiopreventivo e modulador de HLA-G (Human Leukocyte Antigen - G) de Morelloflavona

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The role of HLA-G molecule and HLA-G gene polymorphisms in tumors, viral hepatitis, and parasitic diseases

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Balancing immunity and tolerance: genetic footprint of natural selection in the transcriptional regulatory region of HLA-G

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

MicroRNAs targeting the immunomodulatory HLA-G gene: a new survey searching for microRNAs with potential to regulate HLA-G

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A coupling technique for non-matching finite element meshes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Insights into HLA-G genetics provided by worldwide haplotype diversity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ridge-based fingerprint matching using hough transform

Despite the efficacy of minutia-based fingerprint matching techniques for good-quality images captured by optical sensors, minutia-based techniques do not often perform so well on poor-quality images or fingerprint images captured by small solid-state sensors. Solid-state fingerprint sensors are being increasingly deployed in a wide range of applications for user authentication purposes. Therefore, it is necessary to develop new fingerprint-matching techniques that utilize other features to deal with fingerprint images captured by solid-state sensors. This paper presents a new fingerprint matching technique based on fingerprint ridge features. This technique was assessed on the MSU-VERIDICOM database, which consists of fingerprint impressions obtained from 160 users (4 impressions per finger) using a solid-state sensor. The combination of ridge-based matching scores computed by the proposed ridge-based technique with minutia-based matching scores leads to a reduction of the false non-match rate by approximately 1.7% at a false match rate of 0.1%. © 2005 IEEE.

Expression of the classical and nonclassical HLA molecules in breast cancer

Considering that downregulation of HLA expression could represent a potential mechanism for breast carcinogenesis and metastasis, the aim of the present study was to use immunohistochemical methods to analyze the expression of HLA-Ia, HLA-DR, HLA-DQ, HLA-E, and HLA-G in invasive ductal carcinoma (IDC) of the breast and to relate this HLA profile to anatomopathological parameters. Fifty-two IDC from breast biopsies were stratified according to histological differentiation (well, moderately, and poorly differentiated) and to the presence of metastases in axillary lymph nodes. The expression of HLA molecules was assessed by immunohistochemistry, using a computer-assisted system. Overall, 31 (59.6%) out of the 52 IDC breast biopsies exhibited high expression of HLA-G, but only 14 (26.9%) showed high expression of HLA-E. A large number (41, 78.8%) of the biopsies showed low expression of HLA-Ia, while 45 (86.5%) showed high expression of HLA-DQ and 36 (69.2%) underexpressed HLA-DR. Moreover, 24 (41.2%) of 52 biopsies had both low HLA-Ia expression and high HLA-G expression, while 11 (21.2%) had low HLA-Ia expression and high HLA-E expression. These results suggest that, by different mechanisms, the downregulation of HLA-Ia, HLA-E, and HLA-DR and the upregulation of HLA-G and HLA-DQ are associated with immune response evasion and breast cancer aggressiveness.

HLA-E coding and 3' untranslated region variability determined by next-generation sequencing in two West-African population samples

HLA-E is a non-classical Human Leucocyte Antigen class I gene with immunomodulatory properties. Whereas HLA-E expression usually occurs at low levels, it is widely distributed amongst human tissues, has the ability to bind self and non-self antigens and to interact with NK cells and T lymphocytes, being important for immunosurveillance and also for fighting against infections. HLA-E is usually the most conserved locus among all class I genes. However, most of the previous studies evaluating HLA-E variability sequenced only a few exons or genotyped known polymorphisms. Here we report a strategy to evaluate HLA-E variability by next-generation sequencing (NGS) that might be used to other HLA loci and present the HLA-E haplotype diversity considering the segment encoding the entire HLA-E mRNA (including 5'UTR, introns and the 3'UTR) in two African population samples, Susu from Guinea-Conakry and Lobi from Burkina Faso. Our results indicate that (a) the HLA-E gene is indeed conserved, encoding mainly two different protein molecules; (b) Africans do present several unknown HLA-E alleles presenting synonymous mutations; (c) the HLA-E 3'UTR is quite polymorphic and (d) haplotypes in the HLA-E 3'UTR are in close association with HLA-E coding alleles. NGS has proved to be an important tool on data generation for future studies evaluating variability in non-classical MHC genes.

Greater expression of the human leukocyte antigen-G (HLA-G) and interleukin-17 (IL-17) in cervical intraepithelial neoplasia: analytical cross-sectional study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)