Association of Gm allotypes with the occurrence of ankylosing spondylitis in HLA-B27-positive anterior uveitis.

We studied immunoglobulin Gm and Km allotypes in 54 patients with HLA-B27-positive anterior uveitis and in 204 healthy controls. No differences were noted between the two groups. Dividing the patients with anterior uveitis into those with ankylosing spondylitis (No. = 22) and those without it (No. = 32), produced interesting results. The Gm 1, 3, 17; 23; 5, 13, 21 phenotype was significantly (P = .007) increased in those within the ankylosing spondylitis and anterior uveitis group. Of these 22 patients, ten (45.5%) carried the Gm 1, 3, 17; 23; 5, 13, 21 phenotype compared to two of 32 (6.3%) in those with anterior uveitis alone and 33 of 204 (16.2%) normal controls. There were no significant differences between patients and controls in the frequencies of the other phenotypes tested.