Saliva from which of the following individuals would neutralize an auto anti-H in the serum of a group A, Le(a-b+) patient?

To understand why saliva from an individual with blood type group O and Le(a-b+) would neutralize an auto anti-H in the serum of a group A, Le(a-b+) patient, it's essential to look at the compatibility of the Lewis antigens and the presence of H antigen in the blood groups.

The auto anti-H antibodies are directed against the H antigen, which is present on red blood cells of individuals with blood type O and A. Group A individuals express the A antigen but still have the H antigen. The Lewis antigen status (Lea and Leb) can impact how antibodies function, especially in terms of neutralization.

In this scenario, a group A, Le(a-b+) patient has auto anti-H, which means their antibodies are reacting against the H antigen. The person with a blood type group O and Le(a-b+) would have abundant H antigen in their saliva, which can neutralize the auto anti-H present in the serum of the group A patient. The presence of the Le(b+) antigen indicates that this individual can provide additional binding sites for the auto anti-H antibodies, enhancing the neutralization effect.

Therefore, the saliva of the group O, Le(a-b+) individual contains both the H antigen and the Lewis antigens that