RESUMO
KIR2DL4 is an important immune modulator expressed in natural killer cells; HLA-G is its main ligand. We have characterized the KIR2DL4 genetic diversity by considering the promoter, all exons, and all introns in a highly admixed Brazilian population sample and by using massively parallel sequencing. We introduce a molecular method to amplify and to sequence the complete KIR2DL4 gene. To avoid the mapping bias and genotype errors commonly observed in gene families, we have developed and validated a bioinformatic pipeline designed to minimize these errors and applied it to survey the variability of 220 individuals from the State of São Paulo, southeastern Brazil. We have also compared the KIR2DL4 genetic diversity in the Brazilian cohort with the diversity previously reported by the 1000Genomes consortium. KIR2DL4 presents high linkage disequilibrium throughout the gene, with coding sequences associated with specific promoters. There are few but divergent promoter haplotypes. We have also detected many new KIR2DL4 sequences, all bearing nucleotide exchanges in introns and encoding previously described proteins. Exons 3 and 4, which encode the external domains, are the most variable. The ancestry background influences the KIR2DL4 allele frequencies and must be considered for association studies regarding KIR2DL4.
Assuntos
Etnicidade/genética , Regulação da Expressão Gênica , Predisposição Genética para Doença , Haplótipos , Polimorfismo de Nucleotídeo Único , Receptores KIR2DL4/genética , Receptores KIR2DL4/metabolismo , Adulto , Brasil , Estudos de Coortes , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Desequilíbrio de Ligação , Masculino , Regiões Promotoras GenéticasRESUMO
BACKGROUND: Tuberculosis (TB) and AIDS are the leading causes of infectious disease death worldwide. In some TB-HIV co-infected individuals treated for both diseases simultaneously, a pathological inflammatory reaction termed immune reconstitution inflammatory syndrome (IRIS) may occur. The risk factors for IRIS are not fully defined. We investigated the association of HLA-B, HLA-C, and KIR genotypes with TB, HIV-1 infection, and IRIS onset. METHODS: Patients were divided into four groups: Group 1- TB+/HIV+ (n = 88; 11 of them with IRIS), Group 2- HIV+ (n = 24), Group 3- TB+ (n = 24) and Group 4- healthy volunteers (n = 26). Patients were followed up at INI/FIOCRUZ and HGNI (Rio de Janeiro/Brazil) from 2006 to 2016. The HLA-B and HLA-C loci were typed using SBT, NGS, and KIR genes by PCR-SSP. Unconditional logistic regression models were performed for Protection/risk estimation. RESULTS: Among the individuals with TB as the outcome, KIR2DS2 was associated with increased risk for TB onset (aOR = 2.39, P = 0.04), whereas HLA-B*08 and female gender were associated with protection against TB onset (aOR = 0.23, P = 0.03, and aOR = 0.33, P = 0.01, respectively). Not carrying KIR2DL3 (aOR = 0.18, P = 0.03) and carrying HLA-C*07 (aOR = 0.32, P = 0.04) were associated with protection against TB onset among HIV-infected patients. An increased risk for IRIS onset was associated with having a CD8 count ≤500 cells/mm3 (aOR = 18.23, P = 0.016); carrying the KIR2DS2 gene (aOR = 27.22, P = 0.032), the HLA-B*41 allele (aOR = 68.84, P = 0.033), the KIR2DS1 + HLA-C2 pair (aOR = 28.58, P = 0.024); and not carrying the KIR2DL3 + HLA-C1/C2 pair (aOR = 43.04, P = 0.034), and the KIR2DL1 + HLA-C1/C2 pair (aOR = 43.04, P = 0.034), CONCLUSIONS: These results suggest the participation of these genes in the immunopathogenic mechanisms related to the conditions studied. This is the first study demonstrating an association of HLA-B*41, KIR2DS2, and KIR + HLA-C pairs with IRIS onset among TB-HIV co-infected individuals.
Assuntos
Infecções por HIV/complicações , Infecções por HIV/genética , HIV-1 , Síndrome Inflamatória da Reconstituição Imune/etiologia , Síndrome Inflamatória da Reconstituição Imune/genética , Tuberculose/complicações , Tuberculose/genética , Brasil , Coinfecção/tratamento farmacológico , Coinfecção/genética , Coinfecção/patologia , Feminino , Seguimentos , Frequência do Gene/genética , Marcadores Genéticos , Genótipo , Infecções por HIV/tratamento farmacológico , Infecções por HIV/patologia , Antígenos HLA-B/genética , Antígenos HLA-C/genética , Humanos , Síndrome Inflamatória da Reconstituição Imune/patologia , Masculino , Receptores KIR/genética , Fatores Sexuais , Tuberculose/tratamento farmacológico , Tuberculose/patologiaRESUMO
BACKGROUND: The objective of this study was to investigate the association between KIR genes and the immunopathogenesis of leprosy. METHODS: The types of KIR and HLA genes were evaluated by PCR-SSOP-Luminex in 408 patients with leprosy and 413 healthy individuals. Statistical analysis was performed using the Chi-square or Fisher's exact test and stepwise multivariate analysis. RESULTS: There was a higher frequency of activating KIR genes (KIR2DS1, 2DS2 and 3DS1) together with their HLA ligands in the tuberculoid (TT) group as compared to the lepromatous leprosy (LL) group. KIR2DL2/2DL2-C1 was more frequent in the patient, TT and LL groups than in the control group. Borderline patients presented a higher frequency of inhibitory pairs when compared to the control group, and a higher frequency of activating pairs as compared to the LL group. Multivariate analysis confirmed the associations and demonstrated that being a female is a protective factor against the development of the disease per se and the more severe clinical form. CONCLUSIONS: This study showed that activating and inhibitory KIR genes may influence the development of leprosy - in particular, activating genes may protect against the more aggressive form of the disease - thereby demonstrating the role of NK cells in the immunopathology of the disease.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Fenótipo , Brasil , Genes MHC Classe I , Células Matadoras Naturais/citologia , Estudos de Casos e Controles , Receptores KIR/genética , Genótipo , Hanseníase/genética , Hanseníase/patologia , LigantesRESUMO
Killer cell immunoglobulin-like receptors (KIR) form a group of regulatory molecules that specifically recognise human leukocyte antigen (HLA) class I molecules, modulating the cytolytic activity of natural killer cells. The purpose of this study was to investigate the influence of KIR genes and their class I HLA ligands in susceptibility to dengue fever in a population from southern Brazil through a case-control study. One hundred four subjects with confirmed diagnoses of dengue participated in this study, along with a control group of 172 individuals from the same geographic area. HLA and KIR genotyping was performed by polymerase chain reaction with sequence-specific oligonucleotide probes (PCR-SSOP) and with sequence-specific primer (PCR-SSP) techniques, respectively. Data analysis showed significant differences for the KIR2DS1 (54.8% vs 40.7%, P = 0.03), KIR2DS5 (50.0% vs 36.0%, P = 0.03) and KIR2DL5 (76.0% vs 56.4%, P = 0.001) genes. With regard to KIR-ligand pairs, positive associations with dengue were observed in KIR3DS1-Bw4 (45.2% vs 29.7%, P = 0.01), KIR3DL1-Bw4 (80.7% vs 65.1%, P < 0.001), KIR2DL1-C2 (75.0% vs 62.2%, P = 0.03) and KIR2DS1-C2 (40.4% vs 25.6%, P = 0.01) interactions, and a negative association in KIR2DL3-C1/C1 (18.2% vs 33.1%, P = 0.01). Furthermore, the analysis of KIR haplogroups showed a possible protective factor against dengue fever in individuals with the AA genotype. Taken together, these results suggest the existence of genetic predisposition to dengue fever in the population from southern Brazil.
Assuntos
Dengue/imunologia , Antígenos HLA/genética , Receptores KIR/genética , Adolescente , Adulto , Brasil , Estudos de Casos e Controles , Dengue/genética , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Teste de Histocompatibilidade , Humanos , Masculino , Polimorfismo Genético , Ligação Proteica , Adulto JovemRESUMO
OBJETIVOS: Analisar a importância das células natural killer, de seus receptores killer immunoglobulin-like receptors e correspondentes genes (KIR) na vigilância imunológica do organismo contra agentes infecciosos, transplantes de células-tronco hematopoiéticas, assim como sua participação na auto-imunidade. As características e o polimorfismo dos genes e receptores KIR na população brasileira serão descritos. FONTES DOS DADOS: Livros, artigos de revisão e artigos científicos recentes são citados e listados na bibliografia. A experiência pessoal é também apresentada. SÍNTESE DOS DADOS: Identificamos o perfil de genes e haplótipos KIR na população caucasóide brasileira, sendo de importância esse conhecimento para a análise da relação desse sistema com doenças. Examinamos 116 indivíduos doadores voluntários de medula óssea, identificando-se 32 genótipos e a presença de 51 e 49 por cento de haplótipos A e B, respectivamente. Foi realizado estudo comparativo entre os nossos genótipos e os de outras populações. CONCLUSÕES: A imunidade inata é uma barreira antiinfecciosa de importância em pediatria. Ela atua de maneira independente da imunidade celular e humoral, sendo mais rápida que as demais fontes de proteção do organismo. Ao mesmo tempo, ela estimula os linfócitos T CD8 a agirem e amplificarem a rede de proteção imunológica. Entretanto, como na maioria das vezes em que a imunidade atua, ela também pode ser prejudicial, agredindo o organismo por mecanismos auto-imunes ou mesmo, na sua ausência, oferecer espaço aos agentes infecciosos para agirem de forma impune.
OBJECTIVES: To analyze the importance of natural killer cells, their killer immunoglobulin-like receptors (KIR) and genes in autoimmunity and in the immune surveillance against infectious agents and stem cells transplantation. The characteristics and polymorphisms of the KIR genes and receptors in the Brazilian population is described. SOURCES: Textbooks, review articles and recent scientific articles are cited and listed in the references. SUMMARY OF THE FINDINGS: KIR genes and haplotypes within a Brazilian Caucasian population were surveyed and analyzed to assess the future relationship of this system with diseases. Of 116 voluntary bone marrow donors, we identified 32 genotypes with frequencies of A and B haplotypes of 51 and 49 percent, respectively. A comparative analysis was performed between these genotypes and those from other populations. CONCLUSIONS: Innate immunity is an important anti-infectious barrier in newborns. It is independent of both cellular and humoral immunity, can be faster and confers great advantage in early age. At the same time, it stimulates CD8 T lymphocytes to act and amplify the immunological protection network. Nevertheless, as in the majority of situations in which immunity is activated, it can also be harmful, damaging the body through autoimmune mechanisms or even, through its absence, creating space for infectious agents to act free. Our study of a control group for KIR genotype and haplotypes in Brazilian Caucasoids could be used in future analyse of diseases related to these genes.