HLA-DRB1 ALLELES ASSOCIATED WITH RHEUMATOID-ARTHRITIS IN NORTHERN ITALY - CORRELATION WITH DISEASE SEVERITY

The aim of the study was to evaluate the relationship between the pres ence of the 'rheumatoid epitope', defined by a sequence motif in the H LA-DRB1 alleles, rheumatoid factor and disease severity in Northern It alian patients with rheumatoid arthritis (RA). Twenty-nine DR4-positiv e and 57 DR4-negative RA patients were studied. Each DR4-positive pati ent was matched with two DR4-negative controls of similar disease dura tion and sex. HLA-DRB1 alleles were determined in the 86 patients and 351 controls from the same geographical area. The patients were retros pectively evaluated for extra-articular features (EAF) and radiographi c damage. The rheumatoid epitope was expressed in 45% of patients. No significant differences in the presence of rheumatoid factor, EAF and articular damage were observed between patients with no, one or two do ses of epitope. However, the patients encoding the epitope by an HLA-D R4 allele had a higher number of eroded joints and a higher Larsen sco re compared to those without the epitope. No differences were present between patients expressing HLA-DRB101 alleles and those lacking the rheumatoid epitope. Even in the absence of expression of the rheumatoi d epitope, seropositive patients had more EAF and more erosive disease compared to those who were seronegative. Even if most Northern Italia n RA patients do not express the rheumatoid epitope, the radiological severity of disease is associated with HLA-DRB104 alleles.