Natural IgM and IgG antibodies to Thomsen-Friedenreich (T) antigen in serum of patients with gastric cancer and blood donors - Relation to Lewis (a,b) histo-blood group phenotype

A possible association of serum anti-T IgM and IgG antibody levels with Lew is blood-group phenotype was investigated in 168 blood donors and 132 gastr ic cancer patients using ELISA with synthetic T-disaccharide-polyacrylamide conjugate as antigen. The donors of Le(a - b +) phenotype showed the highe st anti-T IgM level irrespective of ABO(H) blood group. A significant decre ase in anti-T IgM in serum was observed among cancer patients of Le(a - b ) phenotype: 95% of weak responders versus 17.5% for related groups of dono rs (p < 10(-6)). In contrast, no significant difference between patients an d donors was found for Le(b -) individuals. Thus, a level of natural anti-T antibodies in serum of blood donors and its decrease in patients with gast ric cancer are related to Le(a,b) phenotype. This should be taken into acco unt where anti-T antibody level in thr serum is used as a tumour marker or for monitoring patients during cancer immunotherapy with mucin-type vaccine s.