HLA antigens and IgG allotypes on the Island of Barra (Outer Hebrides).

The distribution of HLA antigens and IgG allotypes in a group of nearly 200 adults on the Island of Barra, shows some unusual features. The sample tested included only people age 65 and over. Marked differences in the frequency of some HLA antigens were noted, compared to those previously determined for the northern island of Lewis and Harris, with increase in the frequency of HLA-A5 and B7. The latter antigen was present in over 40% of the group, compared with a frequency of 27% in the Northern islands. The high frequencies of HLA-A2, the Aw19 group and B12 previously noted in Scottish populations were also present. The IgG allotype, Gm (f;b4) was markedly increased, being present in 67% of the group, in comparison with frequencies of 40--45% in previous Scottish studies. These results either suggest a sampling phenomenon, or may be an indicator of selective forces related to immunological mechanisms or the age distribution of the population studied.