RESUMO
The increase of HLA-DR3 and complotype SCO1 previously found in Mexican mestizo adults with E. histolytica amoebic abscess of the liver, was also found in Mexican mestizo children of either sex with the same disease, when compared to the healthy control population (adults and/or children) of the same ethnic and socioeconomic background. This HLA and complotype pattern was not found in Mexican Mestizo patients with amoebic rectocolitis. No linkage disequilibrium was found between these and the other MHC determinants tested in this survey. Thus, HLA-DR3 and SCO1 may constitute primary, independent risk factors, not for any kind of amoebic tissue invasion (i.e. amoebic rectocolitis), but specifically for amoebic liver abscess, irrespective of age or sex. The possibility of linkage disequilibrium with other factors (i.e. the TNF family) within or close to the MHC that were not tested in this study, is discussed. Children with amoebic liver abscess revealed a significant increase in HLA-DR5, and the absence of HLA-DR6 when compared to adults with amoebic liver abscess, suggesting that at least in this ethnic group these class II HLA traits may contribute to some of the peculiarities of pediatric amoebic liver abscess as opposed to the adult version of this disease. HLA-DR3, SCO1, but also HLA-DR5 and HLA-DR6 have all been associated with certain forms of immune-dysfunction, and may thus contribute to some of the clinical and immunological features of this parasitic disease.
Assuntos
Antígeno HLA-DR3 , Abscesso Hepático Amebiano/imunologia , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Estudos de Coortes , Disenteria Amebiana/genética , Disenteria Amebiana/imunologia , Etnicidade/genética , Feminino , Frequência do Gene , Antígeno HLA-DR3/genética , Antígeno HLA-DR5/genética , Antígeno HLA-DR6/genética , Humanos , Indígenas Norte-Americanos/genética , Lactente , Desequilíbrio de Ligação , Abscesso Hepático Amebiano/genética , Masculino , México , Fatores de Risco , População Branca/genéticaRESUMO
Some strains of mice are known to be relatively resistant to hepatic or intestinal amebic infections. In order to know if the intestinal resistance is expressed few hours after infection, we inoculated axenic amebae in three inbred strains of mice either by direct intracecal injection or by infection of a washed-closed cecal loop. We found that amebae do not survive in conventional animals but they colonize longer in animals with the cecal loop. However, the survival was low after 24 hours postinfection. Balb/c mice were more susceptible and CBA mice more resistant. Our results suggest that genetic resistance to intestinal amebiasis is expressed in mice in the early phases of infection.