Immuno-Hemolytic anemia Flashcards
Antibodies against person’s own red blood cells cause lysis leading to anemia
Autoimmune hemolytic anemia (AIHA)
Warm AIHA secondary to: 3 things
1) Lymphoproliferative disorders (Hodgkin Lymphoma)
2) Some rheumatic disorders (SLE)
3) Some non-lymphoid malignancies
Cold agglutinins secondary to:2 things
Mycoplasma pneumoniae infection or B cell malignancies
Mycoplasma pneumoniae infection
Cold agglutinins secondary cause
Cold AIHA has two types
Cold agglutinins
Cold Hemolysins
Cold agglutinins vs.
Cold Hemolysins
Compare and contrast
Both are COLD AIHA; both may be primary or idiopathic;
Cold agglutinins secondary to Mycoplasma pneumoniae infection or B cell malignancies;
Cold hemolysins secondary to Paroxysmal Cold Hemoglobinuria
Drug-induced hemolytic anemia (DIHA) causes:
- Penicillins
- Cephalosporins
- Levodopa and methyldopa
- NSAIDs
> 60% of infectious mono patients (exposed to EBV) suffer from:
COLD agglutinins type of Cold AIHA
May be aggravated or present at pregnancy
Warm AIHA syptoms
Chronic anemia ± jaundice
Cold AIHA symptoms
Periodic, acute hemolysis with hemoglobinuria induced by chilling
Cold AIHA symptoms
Warm AIHA: DAT test positive for:
anti-IgG, anti-C3, or both
COLD AIHA: DAT test positive for:
DAT negative for anti-IgG; positive for anti-C3
Draw the pts serum for 1)
Draw the pts WHOLE blood for 2)
1) INDIRECT coombs
2) DIRECT coombs
Positive test shows Antibodies are shown attached to antigens on the RBC surface;
DAT; direct coombs test;
AIHA–> IgG only OR IgG and Complement
Warm AIHA
AIHA–> Complement only; NO IgG;
Cold AIHA
Pathogenesis of ____:
B-cell is activated and secretes IgG and IgM;
- IgG does two things:
1) binds to RBC which activates Classical Complement Pathway; these complement fixed RBCs are phagocytosed by splenic macrophages;
2) complement fixation leading to MAC attack causing intravascular RBC lysis;
- IgM binds to RBCs leads to agglutination and formation of immune complex (antigen-antibody) complex and causes lysis (type III hypersenitivity)
AIHA; see image in lecture
pathogenesis of AIHA:
1) is activated and secretes 2)
1) B-cell
2) IgG and IgM
pathogenesis of AIHA:
IgG secreted from B-cell does:
binds to RBC and activates Class. compliment; these RBCs are then phagocytosed by splenic macrophages
pathogenesis of AIHA:
how does INTRAvascular RBC lysis occur?
Through complement fixation leading to MAC attack;
pathogenesis of AIHA:
what does IgM secreted from B-cell do?
-IgM binds to RBCs leads to agglutination and formation of immune complex (antigen-antibody) complex and causes lysis (type III hypersenitivity)
small molecule generates an immune response when attached to a larger molecule
Hapten mechanism (DIHA)
Helps the larger molecule elicit an immune response
Hapten mechanism (DIHA)
penicillins use 1) mechanism to cause
DIHA
1) hapten
Autoantibody mechanism of DIHA
Drug stimulates 1) against 2)
1) IgG production
2) RBCs
Immune complex mechanism of DIHA:
Drug stimulates 1) against RBCs, which leads to immune complex formation and complement activation
IgM production
direct coomb’s positive for IgG only; what mechanism caused the DIHA?
hapten drug adsorption type or autoantibody type
Direct Coomb’s positive for COMPLEMENT only; what mechanism caused the DIHA?
Immune complex mechanism aka ternary complex type: IgM production against RBCs, which leads to immune complex formation and complement activation
DIHA:
Ig production: Immune complex mechanism, autoantibody mechanism, hapten mechanism
IgM for Immune complex type
IgG for autoantibody and hapten;
Both are against RBCs, obviously
Mild to moderate hemolysis, with slow onset developing over days to weeks
DIHA symptoms due to:
Penicillin
Methyldopa
Sudden, severe hemolysis with hemoglobinuria
DIHA symptoms due to:
Ceohalosporin
DIHA symptoms due to:
Cephalosporin vs. Penicililn or methyldopa
Penicililn or methyldopa–> mild hemolysis slow onset over days or weeks;
Cephalosporin–> sudden, severe hemolysis
