|  | Public Health Safety | Public Health

What Is a P Antibody?

P antibodies react against P antigens, which are sugar molecules on the outside of red blood cells. P antigens develop with age and are undeveloped at birth. P antibodies can cause hemolytic disease in certain sets of people.

  1. Red Blood Cell Antigens

    • The P system is similar to the familiar ABO blood classification system. P antigens are present on most people's red blood cells and on tissue cells. P, P1 and Pk (superscript k) are the three types of antigen, and in the rare case where someone has no P antigens, they are p type. 80 percent of people with P have both P1 and P antigens and are called the P1 group. 20 percent have only P antigen and are called the P2 group.

    Alloanti-P1

    • Alloanti-P1 is the most common form of P antibody and targets the P1 antigen. It occurs in the P2 group and is not clinically significant, as that group has no P1 antigen in their red blood cells.

    Auto Anti-P

    • Auto anti-P causes paroxysmal cold hemoglobinuria in people of the P1 and P2 groups, as the antibody attacks the P antibody present in their red blood cells. Auto anti-P is diagnosed by the Donath-Landsteiner test.

Public Health - Related Articles