Skjelbred, a low frequency antigen in serum and on red cells

The Skjelbred (Sk) antigen has been studied in the donor population of South London and found to have a frequency of 0.0035%. Its presence in serum as well as on red cells, its transient nature and its absence in relatives of Sk(+) individuals are suggestive of a non-genetic background for Sk. The antibody is not uncommon in normal donor sera (3--12%).