Immune-hemolytic anemias

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Immune-hemolytic anemias are hemolytic anemias caused by antibodies and/or complement directed against red blood cells.

The exam pattern is:

anemia + jaundice + high reticulocytes + high lactate dehydrogenase + indirect bilirubin ↑ + haptoglobin ↓ + positive direct Coombs test → immune hemolysis.

The most important clinical split is:

Type	Antibody	Temperature	Main site of hemolysis
Warm autoimmune hemolytic anemia	IgG	37°C	spleen, mostly extravascular
Cold agglutinin disease/syndrome	IgM + complement	cold temperatures	liver/complement-mediated
Paroxysmal cold hemoglobinuria	biphasic IgG	cold binding, warm hemolysis	intravascular
Drug-induced immune hemolysis	drug-dependent or drug-independent antibodies	variable	variable
Alloimmune hemolysis	antibodies against foreign RBC antigens	transfusion/pregnancy	often severe

The Debrecen hematology textbook defines autoimmune hemolytic anemia as a rare acquired disorder where autoantibodies target RBC surface antigens, shortening RBC survival from 100–120 days to only a few days; diagnosis relies on hemolysis plus a positive direct antiglobulin test/direct Coombs test.

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