engleski

COMPLEXITY AND DIVERSITY OF HLADRB1*04~DQB1 HAPLOTYPES IN THE CROATIAN POPULATION

Information on the precise content of HLA haplotypes is needed for transplantation, disease association, anthropological and epidemiological studies. In this study we aimed to analyse HLA- DRB1*04~DQB1 haplotype diversity at a high- resolution level in DRB1*04-positive individuals (N=734). The high-resolution level typing of HLA- DRB1 and DQB1 loci was performed using the Polymerase Chain Reaction - Sequence Specific Primers (PCR-SSP) method. A total of 10 different DRB1*04 alleles (DRB1*04:01- 08, DRB1*04:15 and DRB1*04:50) and nine different DQB1 alleles (DQB1*03:01-05, DQB1*03:07, DQB1*02:02, *04:01-02) have been determined, composing 29 different haplotypes. The most common DRB1*04 alleles were DRB1*04:01 (30.6%), DRB1*04.02 (25.2%), DRB1*04:04 (19.7%) and DRB1*04:03 (13.5%). The most prevalent DQB1 allele was DQB1*03:02 (85%), followed by DQB1*03:01 (7.5%). The two most frequent haplotypes were DRB1*04:01~DQB1*03:02 and DRB1*04:02~ DQB1*03:02 (35.2% and 27.4%, respectively). The haplotype analysis performed for each respective HLA-DRB1*04 allele revealed the most prevalent association with DQB1*03:02 for most of them. The most striking one was exclusive association of DRB1*04:02 with DQB1*03:02, as it was observed in all DRB1*04:02 positive cases (N=201). On the other side, DRB1*04:07 was most commonly found with DQB1*03:01 (83% of DRB1*04:07 positive cases) while DRB1*04:08 was most commonly found with DQB1*03:04 (82% of DRB1*04:08 positive cases). The analysis also showed DRB1*04:03~DQB1*03:05 as an exclusive haplotype association, as it was found on all DQB1*03:05 positive haplotypes (N=9). DRB1*04:05 was the most frequent allele found in an unusual association with DQB1*02:02 (85 % of DQB1*02:02 positive haplotypes). These results provide information on HLA-DRB1*04~ DQB1 haplotype diversity in the Croatian population that can be implemented in the strategic planning in unrelated hematopoietic stem cell transplantation increasing the likelihood of finding a suitable donor.

HLA-DRB1*04, haplotypes, Croatian population

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