HLA B27 and ankylosing spondylitis in the Israeli population.

The distribution of 24 HLA antigens of the A and B loci was investigated in 38 Israeli ankylosing spondylitis (AS) patients of various ethnic origins. This was compared with the distribution in rheumatoid arthritis (RA) and osteoarthritis (OA), as well as in 456 controls representing the Jewish population and 260 controls representing the Arab population. Included in the study were Ashkenazi Jews and non-Ashkenazi Jews, as well as Moslem and Christian Arabs. The frequency of HLA B27 among AS patients (79 per cent) was significantly greater (P less than 10(-10)) than among the controls (three per cent). Ashkenazi Jews showed a higher relative risk than non-Ashkenazi Jews and Arabs. Six of the AS patients were offspring of consanguineous marriages, but this was not higher than expected and therefore no indication for rare recessive genes contributing to the disease could be demonstrated. This study confirms the association between AS and B27, and extends our knowledge to the heterogeneous population of Israel not previously investigated. A significant but weak association of B27 with RA was noted. No correlation of other HLA antigens with RA or OA was observed.