ALLELIC DISTRIBUTION OF HLA-B*5 IN HLA-B5 POSITIVE BEHCET PATIENTS IN ISRAEL.
R Narinsky, T Klein, M Paul, I Krause, Y Molad, and A Weinberger, Rabin Medical Center, Petah Tikva and Sackler School of Medicine, Tel Aviv University, Israel.

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Behcet’s disease (BD) has been strongly associated with HLA-B51 in several ethnic groups. Subtyping of the B51 antigen has revealed a strong correlation between BD and allel B*5101 in different populations. We determined allelic distribution of Israeli Arab and Jewish HLA-B5-positive BD patients compared to the allelic distribution in HLA-B5 positive healthy controls. HLA-B*5 allele genotyping was performed by the PCR-Olerup SSP HLA B5 by Genovision identifying the HLAB*5101 to B*5121 alleles and the HLAB*5201, B*5202 alleles. Twenty-four HLA-B5 serologically positive patients all fulfilling the International Study Group criteria for BD, were compared to 18 HLA-B5 positive, ethnically matched, healthy controls. HLA B*51 was found in 54% of the patients: 30.7% Arab and 69.3% Jewish, while HLA B*52 was found in 46% of the them: 54.6% Arab and 45.4% Jewish. The allele B*51011-51012 was dominant among both Arab and Jewish patients (77%) as well as among the B*5 controls (94%). Both Arab and Jewish B*52 positive Behcet patients had the B*52011-52012 allele as well as in the B*52 controls. We conclude that BD in Israeli-Arab patients is associated mainly with the HLA B*52011-52012 allele while the Jewish BD is associated mainly with the allele B*51011-51012.