An antiserum to a disease-associated factor from the cells of an HLA-B27 positive patient with ankylosing spondylitis specifically recognizes an HLA-B27 associated determinant

Antiserum raised to a factor elaborated by a lymphoblastoid cell line derived from the peripheral blood cells of an HLA-B27 positive patient with ankylosing spondylitis specifically lyses the B27 positive, but not the B27 negative, cells of ankylosing spondylitis patients. The cells of B27 positive and B27 negative normal controls are not lysed. This serum has similar specificity to antisera against cross-reactive bacteria.