FREQUENCY OF HLA-DPB1 ALLELES IN A SPANISH POPULATION - THEIR CONTRIBUTION TO RHEUMATOID-ARTHRITIS SUSCEPTIBILITY

HLA-DPB1 allele frequencies in 181 unrelated control individuals and 7 0 rheumatoid factor-positive RA patients from Seville (Spain) were det ermined using oligonucleotide typing methods. All frequencies shown co ncern the percentage of individuals positive for a certain allele. HLA -DPBl0401 was the most common DPB1 allele in the healthy individuals, possessed by 65.7% of them. In addition to HLA-DPB10401, only the fo llowing alleles were found in normal subjects at frequencies greater t han 10%: DPB10101 (15.5%), DPB1*0201 (12.2%), DPB1*0301 (16.6), and D PB10402 (29.3%). When HLA-DPB1 allelic frequencies were compared betw een seropositive RA patients and controls, a negative association for DPB10301 and DPB1*0401 was found in RA patients, although it failed t o reach statistical significance after correction for the number of co mparisons made. The other DPB1 alleles exhibited almost identical freq uencies in both groups. However, when only DR4+ patients and controls were considered, the decrease in the frequency of the DPB10301 and DP B10401 alleles lacked statistical significance. On the other hand, wh en DR4- RA patients and controls were compared, the frequency of DPB1 0301 was found decreased significantly again, even more than in the wh ole group of patients.