RESUMO
The aim of this study is to explore human leukocyte antigen (HLA)-DQ variability in two populations (Cayapas Amerindians and Afro-Ecuadorians) who live near one another along the Cayapa River and who are exposed to the same environmental stresses, such as infection by Onchocerca volvulus. HLA-DQA1 and HLA-DQB1 of 149 unrelated individuals (74 Cayapas and 75 Afro-Ecuadorians) have been analyzed. HLA high-resolution molecular typing was performed by sequence-based typing, sequence-specific oligonucleotides hybridization and sequence-specific primer (SSP) amplification. The comparison between affected (cases) and unaffected people (controls) in both populations shows the key role of several HLA-DQA1 alleles in susceptibility and protection against onchocerciasis. In both populations, there is strong evidence related to the protective role of DQA1*0401 against onchocerciasis. Alleles HLA-DQA1*0102 and *0103 seem to represent risk factors in Afro-Ecuadorians, while HLA-DQA1*0301 is only a suggestive susceptibility allele in Cayapas. These findings represent new positive/negative associations with onchocerciasis in South America, whereas previous findings pertained only to African populations.
Assuntos
Cadeias alfa de HLA-DQ/genética , Cadeias beta de HLA-DQ/genética , Onchocerca/imunologia , Oncocercose/genética , Adolescente , Adulto , Idoso , Alelos , Indígena Americano ou Nativo do Alasca , Animais , População Negra , Estudos de Casos e Controles , Criança , Primers do DNA , Suscetibilidade a Doenças , Equador/epidemiologia , Feminino , Frequência do Gene , Interação Gene-Ambiente , Cadeias alfa de HLA-DQ/imunologia , Cadeias beta de HLA-DQ/imunologia , Haplótipos , Teste de Histocompatibilidade , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Amplificação de Ácido Nucleico , Oncocercose/etnologia , Oncocercose/imunologia , Polimorfismo GenéticoRESUMO
OBJECTIVE: To determine the role of an immunodominant antigen OvPG-1 in human onchocerciasis. DESIGN: Cross-sectional study of subjects living in three onchocerciasis endemic areas. SETTING: Mbonge and Tubah divisions of Western Cameroon and in Esmeralda Province of Ecuador. SUBJECTS: There were 94 and 99 subjects from the Cameroon rain forest and savannah respectively, and 83 endemic residents from Ecuador. RESULTS: The IgG2 anti-OvPG-1 responses of visually impaired and microfiladermic patients were significantly higher than for their age and sex matched counterparts with normal vision and no microfiladermia (p=0.024). Furthermore, the isotype specificity of anti-OvPG-I responses varied for the various onchocerciasis endemic zones. IgG1, IgG2, IgG3 and IgE levels correlated with the presence of microfilariae in Cameroon, but not in Ecuador. CONCLUSION: Increased IgG and IgE levels to the antigen OvPG-1 seem to correlate with the development of onchocercal eye pathology. The present results suggest that the OvPG1 is a dominant antigen of Onchocerca volvulus with a significant role in the pathogenesis of onchocerciasis.
Assuntos
Proteoglicanas de Heparan Sulfato/genética , Onchocerca volvulus/genética , Oncocercose/parasitologia , Adolescente , Adulto , Idoso , Animais , Anticorpos Anti-Helmínticos/análise , Antígenos de Helmintos/genética , Antígenos de Helmintos/imunologia , Camarões , Criança , Estudos Transversais , Equador , Ensaio de Imunoadsorção Enzimática , Feminino , Proteoglicanas de Heparan Sulfato/imunologia , Humanos , Imunoglobulina E/análise , Imunoglobulina G/análise , Masculino , Pessoa de Meia-Idade , Onchocerca volvulus/imunologia , Oncocercose/genética , Oncocercose/imunologiaRESUMO
Se evaluó la importancia de los factores raciales en la epidemiología y las manifestaciones clínicas de la oncocercosis en la raza negra y la raza indígena Chachi, dos grupos étnicos diferentes del área hiperendémica del foco oncocercótico ecuatoriano. Los Chachi presentaron una significativa mayor densidad de microfilarias en la piel. De los negros, 72,2 por ciento presentaron lesiones oncocercóticas en la piel comparado con 56,4 por ciento en los Chachi. Se encontró mayor prevalencia de nódulos palpables en los Chachi (51,4 por ciento vs. 43,0 por ciento). La presencia de microfilarias en la cámara anterior del ojo fue más frecuente en los Chachi (51,9 por ciento vs. 34,2 por ciento), pero se evidenció una mayor prevalencia de corioretinitis y atrofia del nervio óptico en los negros (17,6 por ciento vs 11,2 por ciento y 8,5 por ciento vs. 0,5 por ciento, respectivamente)