SUSCEPTIBILITY TO RELAPSING POLYCHONDRITIS IS ASSOCIATED WITH HLA-DR4

Objective. To determine the frequency of HLA class II antigens in Cauc asian central European patients with relapsing polychondritis (RP). Me thods. HLA class I, DR, and DQ specificities were identified in 41 pat ients with RP, and the frequencies were compared with those in 204 hea lthy, unrelated control subjects. HLA typing was performed using the s tandard complement-dependent microcytotoxicity assay. HLA-DR genotypin g of 12 DR4-positive RP patients and 57 controls was performed by alle le-specific oligonucleotide probing after amplification of genomic DNA by polymerase chain reaction. Results. A significant increase in DR4 antigen frequency was found in the patients (56.1%) as compared with t hat in healthy controls (25.5%) (P(corr) < 0.001). Genotyping of DR4-p ositive patients and controls revealed no predominance of any DR4 subt ype. Conclusion. There are important clinical similarities and overlap s between RP and rheumatoid arthritis (RA). In RA, the association wit h DR4 has been well established. Our findings show that although there is a DR4 association with RP, the situation is sufficiently distinct from that of RA to imply considerable differences in pathogenesis of t he two conditions.