Three different HLA-B27 structures and hypotheses as to how they might induce disease processes in ankylosing spondylitis

HLA-B27 are first generated as free heavy chains, which inside the cells become associated and folded with the beta-2-microglobulin and antigenic peptide, and then become expressed on the cell surface as a trimolecular complex. It can also be expressed on the cell surface as homodimers of heavy chains without the beta-2-microglobulin.