HLA-DRB1 AND DQB TYPING OF HISPANIC AMERICAN PATIENTS WITH RHEUMATOID-ARTHRITIS - THE SHARED EPITOPE HYPOTHESIS MAY NOT APPLY

Objective. To determine whether the association of particular MHC clas s II alleles and the DRB1 ''shared epitope'' with disease susceptibili ty and severity in rheumatoid arthritis (RA) applies to ethnic groups other than Caucasian Americans. Methods. 67 Hispanic American patients with RA and a similar number of ethnically matched controls were type d for DRB1 using polymerase chain reaction methods. DR4 subtype and DQ B1 type were determined for the subjects positive for DR4, Disease sev erity in the patients with RA was assessed by clinical, radiographic a nd laboratory variables. Results. The frequency of DR4 was significant ly increased in the subjects with RA compared to the control group, Ho wever, the ''shared'' DRB1 amino acid sequence was relatively infreque nt in the Hispanic American patients with RA, and there was no associa tion of specific DR4 or DQ alleles with more. severe disease or extraa rticular manifestations. Conclusion. The HLA markers that predict poor prognosis and suggest that more aggressive clinical management may be appropriate in Caucasian American patients with RA may not be useful in other ethnic groups.