HLA typing done in 10 Mexican mestizo patients with Behcet's syndrome revealed that 7 of them had HLA-B5 antigen as compared to a frequency of 31% in a Mexican mestizo control population. These findings are akin to those made in Japan and Turkey but differ from those made in Caucasian populations in the United States and Great Britain. Ethnic groups with a high frequency of HLA-B5 in Asia and America may belong to the same ancestral trunk. The occurrence of Behcet's syndrome in them may be more frequently HLA-B5 positive than in other ethnic groups.
