Immunoglobulin (Gm) allotype frequencies in patients with giant bell arteritis and polymyalgia rheumatica.

Fifty-five Caucasoid patients with polymyalgia rheumatica (PMR) or giant cell arteritis (GCA) were immunoglobulin (Gm) allotyped for this study. Forty-four of these patients had been previously HLA-A,B,C and DR locus allotyped. The incidence of the immunoglobulin allotypic marker Glm(2) was significantly increased in the GCA group (50.00% v. controls 18.75%, P equal less than 0.01). There was a similar but insignificant rise of this Gm marker in the PMR group (27.24% v. 18.75%, NS). The increase in Glm(2) in the GCA group was not accompanied by a corresponding rise in the number of people homozygous for Glm(2), i.e., all the increase could be attributed to patients with the Glm(1,2,3,):G3m(5,10,21)phenotype.