Acquired Hemolytic Anemia

1
Acquired Hemolytic Anemia

• Immune hemolytic anemia
• None-immune hemolytic anemia

2
Immune hemolytic anemia

• Allo -immune hemolytic anemia
• Autoimmune hemolytic anemia
• Drug induced immune hemolytic anemia

3
Allo-immune hemolytic anemia
1. Incompatible ABO blood transfusion
Donor Blood
Recipient
Group O
Goup A
(cells contain neither A or B antigen) Plasma
contains Anti-A and Anti-B (iso-antibody)
(cells contain A antigen)
Agglutination
Hemolysis
4
Allo-immune hemolytic anemia
1. Incompatible ABO blood transfusion
Clinical and Pathological effects Rigor loin
pain. hemoglobinuria jaudice (after 12
hours) SHOCK ? maybe DEATH Perhaps
later Hemostatic failure, Renal failure ? maybe
DEATH
5
Allo-immune hemolytic anemia
2. Incompatibilities with in the Rh blood group
system
Incompatible blood transfusion
DONOR
RECIPIENT
(not previously transfused or pregnant) Rh-ve
(i.e. rbcs do not contain Rh antigen) Plasma
contains no Rh antibodies ? NO
agglutination
Rh ve
(rbcs contain Rh antigen)
to macrophage system for degradation in usual way
but Rhve cells act as foreign antigens
Later (months, years) Transfusion of Rh ve blood
Formation of anti-Rh antibodies stimulated
Agglutination and hemolysis
6
Allo-immune hemolytic anemia
2. Incompatibilities with in the Rh blood group
system
Hemolytic Disease of the New born (HDN)
First Pregnancy Rhve fetus in Rh-ve mother-no
antibodies present.
?Healthy Baby
Gradual elimination by macrophage system
Rhve fetal rbcs into mother (Rh-ve)
Fetal circulation
Iso-immunisation
Placenta
maternal blood sinus
Anti-Rh antibodies formed (IgG type)
Damaged chorionic villus
Maternal circulation
Trophoblast
Uterus
7
Allo-immune hemolytic anemia
2. Incompatibilities with in the Rh blood group
system
Hemolytic Disease of the New born (HDN)
Subsequent pregnancies
Maternal anti-Rh antibodies IgG type
Uterus
Placenta
Pass placental barrier
Enter fetal circulation and destroy fetal red
cells (agglutination and hemolysis)
8
Allo-immune hemolytic anemia
2. Incompatibilities with in the Rh blood group
system
Hemolytic Disease of the New born (HDN)
The effect are graded into 3 categories of
severity
1. Congenital hemolytic anemia
mild anemia and jaundice
2. Icterus gravis neonatorum
severe anemia and jaudice, brain damage due to
Kernicterus
3. Hydrops fetalis
severe anoxia in utero with cardiac failure and
edema.
9
Autoimmune Hemolytic Anemia (AIHA)
1. Warm autoimmune hemolytic anemia (WAIHA)
2. Cold autoimmune hemolytic anemia (cold AIHA)
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Autoimmune hemolytic anemia Warm antibody type
(WAIHA)
Reaction at normal temperature (37 ?C)
Antibody usually IgG type
Cell becomes microspherocytes
Cell membrane modified
Antigenic determinant
With consequences similar to hereditary
spherocytosis- early sequestration in spleen (RE)
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Autoimmune hemolytic anemia Cold antibody type
Reaction at temperatures usually below 30
?C ?they occur in peripheral circulation and in
cold weather.
Antibody
usually of IgM type
Antigenic determinant
combines with RBC
Reactions
Agglutination
Amboceptor effect
Ag/Ab activates complement
Clinically present as painful
hand and feet
Acute intravascular hemolysis
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Raynauds phenomenon manifested by marked pallor
of the fingers, in the cold type
Peripheral blood film showing a neutrophil/red
cell rosette
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Drug-Induced Immune Hemolytic Anemia
1. Drug Adsorption Mechanism
Penicillins, Cephalosporin and Streptomycins
mechanism First the drug is nonspecifically
adsorbed to the patients red cell Second the
drug must be able to elicit an antibody response
B-Lymphocyte
Drug (Ag)
Antibody
RBC
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Drug-Induced Immune Hemolytic Anemia
2. Immune Complex Mechanism Innocent bystander
Quinidine and Phenacetin
B-Lymphocyte
Drug (Ag)
Antibody
RE
Complement
Extravascular hemolysis
Intravascular hemolysis
(IgG and/or IgM)
15
Drug-Induced Immune Hemolytic Anemia
3. Methyldopa-Induced (Autoimmune) Mechanism
methyldopa and related drugs (Aldomet, L-dopa)
treatment of hypertension
B-Lymphocyte
Drug (Ag)
Antibody
Hemolysis
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Direct Coombs test
Indirect Coombs test
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• None-immune hemolytic anemia
• Red cell fragment syndrome
• Microangiopathic hemolytic anemia
• Macroangiopathic hemolytic anemia
• March hemoglobinuria
• Hypersplenism
• Paroxymal Nocturnal Hemoglobinuria

the bone marrow produces red cells with defective
cell membrane which are particular sensitive to
lysis by complement
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PNH Acid lysis test. The affected red cells
(on left) show marked complement-dependent lysis
in acidified fresh serum at 37 ?C. Preheating
the acidified serum inactivates
complement, preventing lysis of the affected cells