Allele and haplotype frequencies of HLA-DPA1 and-DPB1 in the population of Guadeloupe

Genetic polymorphism of human leukocyte antigen (HLA)-DPA1 and -DPB1 loci was studied in 154 unrelated individuals from Guadeloupe, an archipelago of five islands located in the Carribean Sea. Thirty different DPB1 and eight different DPA1 alleles were observed with a heterozygosity index of 0.87 and 0.78, respectively. This high degree of heterozygosity corresponds with those found in African populations. The DPB1* 01:01:01 allele was most frequent (0.260), followed by 02:01:02 (0.143) and 04:01:01 (0.127). The DPA1 alleles 01:03 (0.380), 02:01 (0.302), 02:02 (0.175) and 03:01 (0.123) were identified in >35 individuals each, whereas 01:04, 01:05 and 04:01 were present only once. Haplotype estimations revealed the presence of 39 different haplotypes, with DPB1*01:01:01-DPA1*02:02 and DPB1*02:01:02-DPA1*01:03 as the most frequent (0.143 and 0.140, respectively). A striking difference was observed in DPB1/DPA1 associations between DPB1*04:02 and *105:01, that have identical exon 2 sequences. DPB1*04:02 was exclusively associated with DPA1*01:03, whereas DPB1*105:01 was present with DPA1*03:01, *03:02 or *04:01. This implies that the DP molecules are actually different, and this difference is relevant to consider in studies on the function of HLA-DP molecules in transplantation. Overall, HLA-DPA1 and DPB1 allele frequencies and haplotypes of the population of Guadeloupe were most similar to African populations, with characteristic alleles and haplotypes that bespeaks the admixture with other ethnicities.