Another case of a lymphocytotoxic antibody with blood group A1 Leb and A Led associated specificity.

A lymphocytotoxic antibody with blood group A1 Leb, and A (A1 + A2) Led, associated specificity was found together with an anti-HLA-DR2 in the serum of a multiparous woman. The A1 Leb and A Led-antibodies could be absorbed with erythrocytes from persons with blood group A1 or A2, irrespective of their Lewis antigens, even if their lymphocytes reacted negatively in this antibody, leaving anti-HLA-DR2 in the serum. Lymphocytes of blood group A1 were able to absorb the anti-A1 Leb and -A Led, whereas those of A2 could only absorb the anti-A Led. Saliva from persons with blood groups A1 Le (a - b +), A2 Le (a- b +), A1 Le (a - b -), secretor, and A2 Le (a - b -), secretor, inhibited the anti-A1 Leb and -A Led when tested in the serum/saliva ratio 50:1, which was not the case with other ABO-Lewis combinations. The woman who produced this antibody has blood group O Le (a - b +) and secretes H, Lea and Leb substances in about the same amount as do other individuals with blood group O Le (a - b +) used as controls. The anti-A in her serum has equal titers against A1 Le (a + b -) and A1 Le (a - b +) red cells.