Characterization of anti-lymphocyte antibodies in inflammatory bowel disease.

Sera from patients with inflammatory bowel disease (IBD) showing broad lymphocytotoxic or lymphocyte-binding activity were subjected to additional analysis to further characterize their properties. Lymphocytotoxins appear to be antibodies predominantly of IgM class as determined by [1] 2-mercaptoethanol sensitivity, [2] serum fractionation by sucrose density gradient sedimentation, Sephadex G-200 filtration, and DEAE ion exchange chromatography, and [3] absorption by anti-Ig immunoadsorbent columns. Lymphocyte-binding antibody was found to be IgG, IgA, and IgM, as determined by indirect immunofluorescent staining of acetone-fixed lymphocytes. Individual IBD sera showed marked variability in occurrence of cytotoxic and binding antibodies when tested against the same donor panel of lymphocytes. These studies emphasize the marked heterogeneity of anti-lymphocyte antibodies occurring in IBD.