AB0 incompatibility/comments

Why is the incompatibility of AB0 "worst" in transfusions?
Blood groups are many - AB0,  Rh, MN, Duffy, Lewis, Kell… So why transfusion incompatibility is the most dramatic in the AB0 system? This is because (naturally occurring) antibodies ( anti-A  and  anti-B ) occur in the blood in high titers.

Natural antibodies

 * Antibodies that each individual begins to produce soon after birth (and often create a lifetime) without obviously immunizing,
 * antibodies against common environmental antigens, which (perhaps surprisingly) include AB0 antigens (of course, the individual does not produce antibodies against his group),
 * In other systems, antibodies are produced only after specific immunization (typically with blood), which is quite rare in the population.

In case of incompatibility
Incompatible erythrocytes AB0 are immediately attacked by the recipient's highly excited immune system. The result is often death in tens of minutes. The immune system, which conducts open war throughout the body (after circulating blood directly into the circulation), has enough arsenal to kill its owner - cytokines, immunocomplexes, vasoactive substances, activation complement, circulatory failure etc.

In the other groups, immunization takes place first - activation of antibody production (hours to days). The reaction of the immune system is not so stormy, so it is not lethal.

CAVE: With repeated transfusions, the recipient may be gradually immunized against other groups (other than AB0) with an increased risk of transfusion reaction.

Related Articles

 * Transfusion
 * Pre-transfusion examination