CLASS-II ALLELES IN JUVENILE ARTHRITIS IN CZECH CHILDREN

Objective. Patients with pauciarticular and polyarticular onset rheuma toid factor (RF) negative juvenile arthritis (JA) have been reported t o have a variety of HLA associations. The reason for the differences f ound in several recent studies is not known. We compare a new series o f patients investigated in Prague, Czechoslovakia with those we report ed from Dallas. Methods. Czech patients with JA (N = 153) were classif ied clinically using the same criteria as in our studies in Dallas. Th e RF negative group included 56 patients that had persistent pauciarti cular disease, 42 pauciarticular with polyarticular course and 39 with polyarticular onset. RF was present in 13 additional patients. HLA cl ass II alleles were determined by oligotyping as previously described from our laboratory. Results. DRB10801 was increased and DRB1*0701 wa s decreased in all the RF negative groups. The persistent pauciarticul ar group was associated with DRB111 and DPB1*0201 and lacked the asso ciation with DRB11301 seen in Dallas. Also found in Prague and not in Dallas were an increase in the frequency of DR2 in pauciarticular pat ients with early conversion and of DRB11201 in patients with iritis. Certain HLA associations (DRB10801, DPB1*0201) appear to be present i n patients with JA in most studies; others DRB11301, DPB1*0301) are m ore variable. Conclusion. The reason for differences in the HLA risk f actors observed in our 2 populations is not known. Clinical heterogene ity not detected by our method seems the most likely explanation. Gene tic and environmental factors may also play a role.