Appearance of dextrans and antidextran antibodies in human sera

The serologically active moiety of an antigen detected occasionally in pathologic sera by double-diffusion gel precipitation tests, referred to in earlier studies as ubiquitous tissue antigen, was identified as a dextran composed predominantly, if not exclusively, of a(1 leads to 6)-linked glycopyranoses. By means of an enzyme immunoassay, dextran or dextran-like material, which inhibited the binding of antidextran serum to dextran, was detected in sera of several patients with various gastrointestinal (GI) diseases, especially GI ulcers (7/10), and also often in sera of aged people (9/21). However, 2 of 50 normal blood donor sera and a few sera from almost every disease group studied contained low quantities of dextran-like material. The levels of antidextran antibodies of the IgG class were also often elevated among patients with GI diseases and aged people as demonstrated by enzyme immunoassay with dextran T-500 as the solid phase antigen. OD values exceeding the mean plus 2.5 SD of 106 normal blood donor sera were recorded in ;69% of patients with gastric and duodenal ulcers, 40% with ulcerative colitis, 29% with Crohn's disease, 20% with colorectal carcinomas, and in 21% with rheumatoid arthritis. None of 23 children, but 9 of 23 aged people (35%) had elevated antibody levels. It is suggested that absorption of dextrans from food or their production by intestinal bacteria may be facilitated in various GI diseases.