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#199
STUDY OF THE HLA-DQB1 IN NAHUA FAMILIES WITH Helicobacter pylori INFECTION.
M. Perez-Rodriguez BSc,MSc,PhD , E. Hernandez BSc , I. Mendoza Camarillo BSc,MSc , M. Camorlinga BSc,MSc , G. Gonzalez-Valencia BSc,MSc , J. Torres BSc,MSc,PhD and R. Kretschmer MD . Mexico D.F., Mexico, CMN-SXXI, IMSS, 06720, Biomedical Research Unit in Immunology and Mexico D.F., Mexico, CMN-SXXI, IMSS, 06720, Biomedical Research Unit in Infectious and Parasitic Diseases .

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The DQB1*0401 allele is associated with atrophic gastritis in the Japanese population, and DQB1*0301 and DQB1*0501 are related to gastric cancer in Caucasian and Mexican populations respectively. A 25% to 65% seroprevalence to Helicobacter pylori (H. pylori) has been reported in Mexican Mestizo children. We analysed HLA-DQB1 to help define the development of infections with H. pylori in a Nahua population. Twenty-three Nahua families (n = 73, comprising one, two o three generations), with 67% seropositivity to H. pylori by ELISA were studied. At least one member of the family had gastro duodenal symptoms. Exon 2 of DQB1 was analysed using RSCA. Ninety % of Nahua families had Amerindian alleles, DQB1*030101 (29.5% vs 16.7%), DQB1*0302 (28.1% vs 12.1%) and DQB1*0402 (32.2% vs 15.8%) when compared with the Mexican Mestizo population. The DQB1*030101 (22% vs 7.5%) and DQB1*0402 (24.7% vs 7.5%) alleles were found more frequently in seropositive individuals than in their seronegative relatives. DQB1*030101-DQB1*0402 (16.4% vs 4.1%) and DQB1*0402-DQB1*0402 (11.0% vs 0%) haplotypes were present in the seropositive Nahua population. These alleles were analysed by the transmission disequilibrium test. However, due to the size of the small sample no significant association was observed. Nevertheless, based on this tendency DQB1*030101 and DQB1*0402 alleles, and DQB1*030101-DQB1*0402 and DQB1*0402-DQB1*0402 haplotypes may be associated with H. pylori infections. Studies with a larger population seem to be in place.