Rheumatoid arthritis in south-east Europe.

The clinical, serological and immunogenetic studies of RA in mediterranean countries and other small tribal groups have added some more information that is valuable in understanding the pathogenesis of RA. However, the immunogenetic studies seem to be more helpful in understanding the mechanisms of initiation of disease and its dissimilarities in different ethnic groups than in discovering its cause. It should also be stressed that, in addition to genetic factors, other factors may influence disease expression. This proposal was supported by a study from Africa which revealed an increasing incidence and severity of RA in rural compared with urbanized African populations (Brighton, 1987). Thus, the variability factor influencing disease expression may lie in the environment (Woodrow, 1988).