“…We tested the red cells of Weiner's pp donor and found H, I, and i antigen strengths to be normal. The ABO, H, I, i, and P systems are known to be interrelated (Allen et al, 1974;Bird, 1975), so that the specificity of some DL antibodies may well 'cut across' these systems. The DL antibody described by Engelfriet et al (1971) was possibly anti-p and, in retrospect, the antibody of Weiner et al (1964) was possibly an antibody with similar specificity.…”