ABO antigens not found in (AIIMS NOV 2009)
I.Although the ABO blood group antigens are regarded as RBC antigens, they are actually expressed on a wide variety of human tissues and are present on most epithelial and endothelial cells.
II.Each human RBC expresses about 2 million ABO blood group antigens. Other blood cells, such as T cells, B cells, and platelets, have ABO blood group antigens that have been adsorbed from the plasma.
- In individuals who are "secretors" Q, a soluble form of the ABO blood group antigens is found in saliva Q and in all bodily fluids (Semen, Sweat Q, Saliva) except for the cerebrospinal fluid.