Autoimmune hemolytic anemia
- Acquired, antibody-mediated RBC destruction
Warm AIHA:
- IgG Abs opsonize RBCs at body temp → removal by spleen
- etiologies of warm autoimmune hemolytic anemia:
Cold AIHA
- IgM Ab binds to RBCs at temp <37°C → complement fixation → intravascular hemolysis and acrocyanosis on exposure to cold
- Etiologies of Cold autoimmune hemolytic anemia
Diagnosis
- spherocytes on smear,
- ⊕ Coombs’;
- ✓ cold agglutinin titer,
- splenomegaly
Treatment
(Blood 2017;129:2971): treat underlying disease
- Warm AIHA:
- corticosteroids ± splenectomy,
- IVIg,
- cytotoxic agents,
- rituximab
- Cold AIHA:
- avoid cold;
- steroids ineffective;
- rituximab (Blood 2004;103:2925);
- complement inhibitors
- (sutimlimab) approved for cold agglutinin disease
- (NEJM 2021;384:1323)