Prognostic significance of major histocompatibility complex class II antigens (HLA-DR) in normal colonic mucosa, tubulovillous adenoma, and invasive colonic carcinoma

The major histocompatibility complex is a series of genes that participate in the regulation of the immune response. This complex encodes two classes of cell-surface glycoprotein antigens: class I, found in all nucleated cells; and class II antigens, normally found only on a limited number of cells (B lymphocytes, macrophages, Langerhans’ cells, dendritic cells, vascular endothelial cells and someepithelial cells).1-3 Class II antigens control cellular interactions between lymphocytes. In man at least three class II antigens (DR, DQ, and DP), each consisting of a and b glycoproteins chains, are encoded by the HLA-D region of chromosome 6.