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7/28/2019 Hemolytic Anemia II

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Acquired Hemolytic Anemia

Immune hemolytic anemiaNone-immune hemolytic anemia


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Allo -immune hemolytic anemia

Autoimmune hemolytic anemia

Drug induced immune hemolytic anemia

Immune hemolytic anemia


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Allo-immune hemolytic anemia

1. Incompatible ABO blood transfusion

Donor Blood

Goup A

Recipient

Group O

Agglutination

Hemolysis

(cells contain A antigen) (cells contain neither A or B antigen)

Plasma contains Anti-A and Anti-B

(iso-antibody)


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Clinical and Pathological effects

Rigor : loin pain.hemoglobinuria

jaudice (after 12 hours)

SHOCK maybe DEATH

Perhaps laterHemostatic failure, Renal failure maybe DEATH


1. Incompatible ABO blood transfusion


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2. Incompatibilities with in the Rh blood group system

Incompatible blood transfusion

DONOR

(not previously transfused or pregnant)

Rh-ve (i.e. rbcs do not contain Rh antigen)

Plasma contains no Rh antibodies NO agglutination

Rh +ve

Later (months, years)Transfusion

of Rh +ve blood

to macrophage system for degradation

in usual way but Rh+ve cells

act as foreign antigens

Formation of

anti-Rh antibodies stimulated

Agglutination

and hemolysis

RECIPIENT


(rbcs contain Rh antigen)


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Hemolytic Disease of the New born (HDN)

First Pregnancy Rh+ve fetus in Rh-ve mother-no antibodies present.

Healthy Baby

Fetal circulation

Placenta

UterusMaternal

circulation

Damaged

chorionic villus

Rh+ve

fetal rbcs

into mother

(Rh-ve)

maternal

blood sinus

Trophoblast

Gradual elimination

by macrophage system

Iso-immunisation

Anti-Rh antibodies

formed (IgG type)




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Subsequent pregnancies

Maternal anti-Rh antibodies IgG type

Pass placental barrier

Enter fetal circulation and destroy fetal red cells

(agglutination and hemolysis)

Placenta

Uterus


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The effect are graded into 3 categories of severity:

1. Congenital hemolytic anemia

2. Icterus gravis neonatorum

3. Hydrops fetalis

severe anoxia in utero with cardiac failure and edema.

severe anemia and jaudice,

brain damage due to Kernicterus

mild anemia and jaundice


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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

= Antigenic determinant

Cell membrane

modified

Cell becomes

microspherocytes

With consequences similar tohereditary spherocytosis-

early sequestration in spleen (RE)


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Autoimmune hemolytic anemia : Cold antibody type

Reaction at temperatures usually below 30 Cthey occur in peripheral circulation and in cold weather.

Antibody

combineswith RBC

Reactions

= Antigenic determinant

Agglutination

Clinically present as painfulhand and feet

Amboceptor effect

Ag/Ab activates complement

Acute intravascular hemolysis

usually of IgM type


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Raynauds phenomenon

manifested by marked pallorof 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 cellSecond the drug must be able to elicit an antibody response

+ Drug (Ag) AntibodyB-Lymphocyte

RBC


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2. Immune Complex Mechanism : Innocent bystanderQuinidine and Phenacetin

Drug (Ag) Antibody

B-Lymphocyte

(IgG and/or IgM)

Extravascular

hemolysisIntravascular

hemolysis

RE Complement


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3. Methyldopa-Induced (Autoimmune) Mechanism

methyldopa and related drugs (Aldomet, L-dopa):

treatment of hypertension

Drug (Ag) Antibody

B-Lymphocyte

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