RESUMO
Amebiasis is an endemic disease and a public health problem throughout Mexico, although the incidence rates of amebic liver abscess (ALA) vary among the geographic regions of the country. Notably, incidence rates are high in the northwestern states (especially Sonora with a rate of 12.57/100,000 inhabitants) compared with the central region (Mexico City with a rate of 0.69/100,000 inhabitants). These data may be related to host genetic factors that are partially responsible for resistance or susceptibility. Therefore, we studied the association of the HLA-DRB1 and HLA-DQB1 alleles with resistance or susceptibility to ALA in two Mexican populations, one each from Mexico City and Sonora. Ninety ALA patients were clinically diagnosed by serology and sonography. Genomic DNA was extracted from peripheral blood mononuclear cells. To establish the genetic identity of both populations, 15 short tandem repeats (STRs) were analyzed with multiplexed PCR, and the allelic frequencies of HLA were studied by PCR-SSO using LUMINEX technology. The allele frequencies obtained were compared to an ethnically matched healthy control group (146 individuals). We observed that both affected populations differed genetically from the control group. We also found interesting trends in the population from Mexico City. HLA-DQB1*02 allele frequencies were higher in ALA patients compared to the control group (0.127 vs 0.047; p= 0.01; pc= NS; OR= 2.9, 95% CI= 1.09-8.3). The less frequent alleles in ALA patients were HLA-DRB1*08 (0.118 vs 0.238 in controls; p= 0.01; pc= NS; OR= 0.42, 95% CI= 0.19-0.87) and HLA-DQB1*04 (0.109 vs 0.214; p= 0.02; pc= NS; OR= 0.40, 95% CI= 0.20-0.94). The haplotype HLA-DRB1*08/-DQB1*04 also demonstrated a protective trend against the development of this disease (0.081 vs. 0.178; p=0.02; pc=NS; OR= 0.40, 95% CI= 0.16-0.93). These trends suggest that the prevalent alleles in the population of Mexico City may be associated with protection against the development of ALA.
Assuntos
Alelos , Resistência à Doença/genética , Antígenos de Histocompatibilidade Classe II/genética , Abscesso Hepático Amebiano/genética , Estudos de Casos e Controles , Feminino , Frequência do Gene , Predisposição Genética para Doença , Geografia , Antígenos de Histocompatibilidade Classe I/genética , Teste de Histocompatibilidade , Humanos , Abscesso Hepático Amebiano/epidemiologia , Masculino , México , PrevalênciaRESUMO
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
Mexican mestizo pediatric patients with ALA revealed a significantly increased frequency of HLA-DR3 alone, or in its haplotype form HLA-A2, DR3, which confirms our previous observation in adult patients with ALA in the same ethnic group. However, the relative increase in these HLA specificities in pediatric ALA patients when compared to adult patients was not statistically significant, and calls for an enlargement of the population studied.
Assuntos
Antígeno HLA-DR3/análise , Abscesso Hepático Amebiano/genética , Adolescente , Adulto , Criança , Pré-Escolar , Suscetibilidade a Doenças/imunologia , Feminino , Predisposição Genética para Doença , Antígenos HLA/análise , Antígeno HLA-A2/análise , Haplótipos/genética , Humanos , Abscesso Hepático Amebiano/epidemiologia , Abscesso Hepático Amebiano/imunologia , Masculino , Casamento , México , Prevalência , Fatores de RiscoRESUMO
The association between parasitic diseases, and antigens of the major histocompatibility complex in man (HLA) has been poorly studied. The only study of the association between the HLA system and amebic abscess of the liver was performed by our group, and revealed a significant increase in HLA-BI6 and HLA-DR3 in patients with amebic abscess of the liver. The present study covered a larger number of patients and controls (110 of each) and it confirmed the association with HLA-DR3, it failed to confirm the association with HLA-BI6.
Assuntos
Proteínas do Sistema Complemento/análise , Etnicidade , Antígenos HLA/análise , Abscesso Hepático Amebiano/imunologia , Adulto , Proteínas do Sistema Complemento/genética , Suscetibilidade a Doenças/imunologia , Feminino , Predisposição Genética para Doença , Antígenos HLA/genética , Antígenos HLA-B/análise , Antígeno HLA-DR3/análise , Haplótipos , Humanos , Abscesso Hepático Amebiano/epidemiologia , Abscesso Hepático Amebiano/genética , Complexo Principal de Histocompatibilidade , Masculino , México/epidemiologia , FenótipoRESUMO
Amebiasis, that is, infection with Entameba histolytica, continues to be endemic in the United States, with liver abscess occurring as an infrequent but constant complication. Seven cases are reported, with epidemiologic investigation of two. Reliable findings in hepatic abscess include fever, abdominal pain, respiratory distress, tender abdomen, and large, tender liver. Anemia, elevated white count with left shift, and the radiographic findings of an elevated right hemidiaphragm are constant. Epidemiologically, amebiasis occurs in clusters in the United States with person-to-person transmission predominant in spread. Infection is associated with poor sanitation and crowding. Investigation of the families of two patients documented 9/21 carriers and an additional 3/21 who were seropositive, as well as crowding and poor sanitation. In this country, treatment of a patient with amebic disease should include investigation of his home and family.