title: Distribution of class I and class III MHC antigens in the Tarasco Amerindians.
abstract: Class I and class III major histocompatibility complex (MHC) antigen frequencies were analyzed in 130 haplotypes from 33 families belonging to a group of Amerindians culturally and linguistically isolated for more than 12 centuries in Mexico: the Tarascos. The most frequent antigens in this ethnic group of the HLA-A locus are: A2 (gf 0.353), A24 (gf = 0.223), A31 (gf = 0.184), and A28 (gf = 0.161); and the most frequent of the HLA-B locus are: B35 (gf = 0.230), B39 (gf = 0.192), B15 (gf = 0.146), and B5 (gf = 0.123). On the other hand, class III antigens demonstrated relatively high frequencies of the SC31 (frequency = 0.561), SC01 (frequency = 0.076), and SC42 (frequency = 0.069) complotypes. Also important was the relatively high frequency of the HLA-B27 antigen (gf 0.061) and the SC33 complotype (frequency = 0.046), which are either absent or found infrequently in other Amerindian groups. Analysis of MHC haplotypes revealed that four of them have relatively high frequencies, these were the following: [B39;SC31] (11.6%), [B35;SC31] (11.6%), [B15;SC31] (8.0%), and [B5;SC31] (5.8%). Other MHC haplotypes had frequencies lower than 5.0%. The decreased frequency of BF alleles other than BF*S and the presence of the SC33 and SC32 complotypes suggest long time preservation from genetic admixture. This information withstands the basis for population genetic analysis and disease association studies in Mexican mestizos.
authors.affiliation: Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México.
authors.forename: Francisco
authors.initials: F
authors.lastname: Loeza
authors.forename: Gilberto
authors.initials: G
authors.lastname: Vargas-Alarcón
authors.forename: Felipe
authors.initials: F
authors.lastname: Andrade
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Vergara
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Rodríguez-Pérez
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Ruiz-Morales
authors.forename: Donato
authors.initials: D
authors.lastname: Alarcón-Segovia
authors.forename: Julio
authors.initials: J
authors.lastname: Granados
mesh_terms: D003175:Complement C2 / Q000032:analysis*; D003181:Complement C4 / Q000032:analysis*; D005787:Gene Frequency; D005805:Genes, MHC Class I; D015234:HLA-A Antigens / Q000032:analysis*; D015235:HLA-B Antigens / Q000032:analysis*; D006650:Histocompatibility Testing; D006801:Humans; D007197:Indians, Central American / Q000235:genetics*; D008285:Major Histocompatibility Complex / Q000235:genetics*; D008800:Mexico / Q000208:ethnology
chemical_list: D003175:Complement C2; D003181:Complement C4; D015234:HLA-A Antigens; D015235:HLA-B Antigens