Km1 allotype association with one subgroup of alopecia areata.

The distribution of the immunoglobulin kappa light-chain determinant, Km1, was examined in 52 patients with alopecia areata, 22 of whom possessed serum antibodies to thyroid antigens. The allotype frequency was significantly higher than that found in a referent population of 105 healthy subjects. Furthermore, it was determined that within the patient population, the Km1 allotype was associated with the absence of detectable serum autoantibodies. In such patients, this association may be due to linkage disequilibrium between the chromosome 2 gene coding for Km1 and a chromosome 2 gene coding for susceptibility to alopecia areata.