HLA-DRB1* frequencies in Lombardy and Trentino valleys defined by high resolution typing methods

Population data on the HLA system are important to several areas of medicine and science. HLA-DRB1* allele frequencies found in 105 and 242 unrelated Italian healthy individuals from Lombardy and Trentino Valleys (from Alto Garda, Val di Ledro, Valli Giudicarie, Val Rendena, Val di Sole, Val di Non, Trento, Val di Fiemme, Val di Fassa, Valsugana, Vallagarina) were estimated, respectively. Sequencing Protrans S4 commercial kit and sequence-specific primers designed to match single alleles were used for specific primer polymerase chain reactions (PCR-SSP) to determine HLA-DRB1* alleles. A total of 30 DRB1* and 37 DRB1* alleles were identified at the 4-digit level in the Lombardy (LRP) and Trentino Valleys population (TrVP) respectively. A comparison between the allelic frequencies of DRB1* locus of the two populations shows that most of these frequencies are shared. One exception is the frequency of DRB1*11:04 allele in the TrVP characterized by a statistically significant lower frequency (3.09% vs. 14.3%, p <0.0138 ) than the LRP. Our data demonstrate that two populations are not genetically different for the DRB1* locus. The present findings as well as being useful for elucidating the genetic background of the populations, can also provide data for HLA matching in clinical transplantation, information about the distribution of HLA genotypes in different populations for the development of peptide-based vaccines and also for paternity diagnosis and evolutionary factors such as genetic drift, migration and selection.