Human leukocyte antigen–A, -B, -C, -DRB1 allele and haplotype frequencies in Americans originating from southern Europe: Contrasting patterns of population differentiation between Italian and Spanish Americans

Abstract

High resolution DNA sequencing was used to identify the HLA-A, -B, -C, and -DRB1 alleles found in 552 individuals from the United States indicating Southern European (Italian or Spanish) heritage. A total of 46 HLA-A, 80 HLA-B, 32 HLA-C, and 50 DRB1 alleles were identified. Frequent alleles included A*02:01:01G (allele frequency = 0.26 in Italian Americans; 0.22 in Spanish Americans); B*07:02:01G (Italian Americans allele frequency = 0.11); B*44:03 (Spanish Americans allele frequency = 0.07); C*04:01:01G and C*07:01:01G (allele frequency = 0.13 and 0.16, respectively, in Italian Americans; 0.15 and 0.12, respectively, in Spanish Americans); and DRB1*07:01:01 (allele frequency = 0.12 in each population). The action of balancing selection was inferred at the HLA-B and -C loci in both populations. The A*01:01:01G-C*07:01:01G-B*08:01:01G-DRB1*03:01:01 haplotype was the most frequent A-C-B-DRB1 haplotype in Italian Americans (haplotype frequency = 0.049), and was the second most frequent haplotype in Spanish Americans (haplotype frequency = 0.021). A*29:02:01-C*16:01:01-B*44:03-DRB1*07:01:01 was the most frequent A-C-B-DRB1 haplotype in Spanish Americans (haplotype frequency = 0.023), and was observed at a frequency of 0.015 in Italian Americans. Pairwise F’st values measuring the degree of differentiation between these Southern European-American populations and European and European-American populations suggest that Spanish Americans constitute a distinct subset of the European-American population, most similar to Mexican Americans, whereas Italian Americans cannot be distinguished from the larger European-American population.

Estimation of human leukocyte antigen class I and class II high-resolution allele and haplotype frequencies in the Italian population and comparison with other European populations

“…[15] 279 Uspa Austria [16] 200 Caus Croatia [16] 150 Scro Czech Republic [16] 106 Cczr England, Northwest [16] 298 Wenn France, Southeast [16] 130 Wfrs Germany pop 6 [16] 8862 Cge6 Ireland, Northern [16] 1000 Wirn Ireland, Southern [16] 250 Wirs ItaHR (this study)…”

“…The Italian population was compared with other 16 European, or with European origin, populations [15][16][17][18] typed at HR level for the most common alleles (58 in all) of the loci HLA-A, -B, -DRB1. Missing data (observed in seven populations and in a maximum of seven variables) were substituted with the allele mean frequencies.…”

Experimental Validation of Multi-Epitope Peptides Including Promising MHC Class I- and II-Restricted Epitopes of Four Known Leishmania infantum Proteins

“…Selection of HLA-A2 and HLA-DRB1 molecules was based on published data demonstrating high frequency of these supertypes in human population (54, 55). The ClusPro program was run to predict docked conformations presenting good surface complementarity with the two MHC molecules mentioned above.…”

High‐resolution characterization of 12 classical and non‐classical HLA loci in Southern Brazilians

“…The two most frequent HLA‐A~HLA‐B ~ HLA‐DRB1 haplotypes *29:02:01~*44:03:01~*07:01:01 ( f = 0.025) and *01:01:01~*08:01:01~*03:01:01 ( f = 0.02) were also reported as the most common in Italian Americans ( f = 0.015; P = 0.357 and f = 0.049%; P = 0.068, respectively) and in Spanish Americans ( f = 0.023; P = 0.922, and f = 0.021; P = 0.871, respectively) . The most frequent classical classes I and class II haplotypes corresponded to the most common haplotypes in other European populations, such as English and Spanish (data not shown) …”