Examination of HLA-DR4 as a severity marker for rheumatoid arthritis in Greek patients

Previous reports have shown that HLA-DR4 may be a severity marker for rheumatoid arthritis (RA) in patients of northern European origin. The aim of the present study was to investigate this relation in Greek patients with RA, as RA in Greece differs from the RA described previously on clinical, serological, and immunological grounds.

Eighty four patients were studied in whom HLA-DR typing was performed by restriction fragment length polymorphism and the subtypes of HLA-DR4 were determined by the polymerase chain reaction. The absence or presence of HLA-DR4 and its subtypes was correlated with the clinical and serological characteristics of the patients and with the side effects due to disease modifying drugs.

Twenty one of the 84 (25%) patients with RA were DR4+. There was no difference between the DR4+ and DR4-patients with respect to duration of disease, severity of arthritis, functional grade, and joint erosion score. The DR4+ group were more likely to have side effects due to disease modifying drugs (43%) than DR4- patients (36%), but this difference was not statistically significant. DR4-patients had more extra-articular manifestations, including Sjögren's syndrome (47 v 19%). Analysis of the DR4 subtypes showed that Dw15 was the most common variant (9/21 patients; 43%). There was no statistical difference in the clinical manifestations among patients with different DR4 subtypes. The same was also true when the clinical picture was correlated with the 'shared RA epitope' (QKRAA/QRRAA/RRRAA), which is common to all HLA-DRB1 alleles positively associated with RA.

These results suggest that HLA-DR4 is not a severity marker in Greek patients with RA and further indicate differences in the clinical expression of RA in Greece.