Autoimmune hemolytic anemias

Immune hemolytic anemia definition

Shortened RBC survival mediated through the immune response by humoral antibody

Three types of IHAs

Allo immune, auto immune, and drug induced

Alloimmune antibody production

In response to foreign or non self antigens from transfusion, transplant, or pregnancy

Intravascular alloimmune response

Complement fixation or damage to RBC by mechanical issue (ABO)

Extravascular alloimmune response

Antibody coated or irregular shape removed out of circulation by liver and spleen

Most auto-antibodies react with

High incidence RBCs antigens (react w most random donors or own cells)

Auto-antibody theory

Loss of suppressor T-cell function which regulates B cells

An elution is necessary when

Monoclonal IgG test is positive

Drug dependent antibodies

Require presence of drug in the test system

Drug independent antibodies

Do not require drug in the test system

Benign cold reactive auto

Performed at 4°

No reaction at greater than 22

Low titer less than 64

Pathological autoantibody

Performed at 4 but can react at 32

Titer greater than 1000

Disease associated w pathological cold auto I

viral infections or M. pneumo

Labs affected by cold agglutinins

ABO forward, reverse, IAT, phenotyping

Auto adsorption

Sample goes in fridge for 8-12 hours to help settle cold ab into the red cells (equal parts RBC and plasma). Remove the adsorbed plasma using pre warm method

Pre warm method

Prewarm serum, screen cells, saline, and enhancement media for cold agglutinin

Specificity of a cold agglutinin is

Associated with patient diagnosis

Most common cold auto

Anti-I because it’s fully expressed on adult cells

Anti-H, and IH found

In sera of A1 and A1B individuals

H and IH reactivity

O >A2> B >A2B >A1 >A1B >Oh

Infectious mono associated antibody

Anti-i

Signs and symptoms of CHD

Acrocyanosis, numbness in extremities, hemoglobinuria

Lab findings of CHD

Reticulocytosis, DAT+ only complement, WBC and platelets normal, rouleaux, poly, aniso, and poikilo, HCT ~40

Sore throat, high fever, weakness, jaundice, anemia, lymphadenopathy, and hepatosplenomegaly

High titer anti-i w IM

PCH incidence

Least common AIHA

PCH seen in

Kids with measles, mumps, chickenpox, IM, or flu

PCH antibody

IgG anti-P biphasic hemolysin

Signs of intravascular hemolysis in PCH

Fever, shaking chills, malaise, cramps, back pain, hemoglobinemia, hemoglobinuria, and bilirubinemia

Many of the true AIHAs are

Warm autos

Warm autos react like

High frequency antibody

Significant % of warm auto

Require transfusion but crossmatch is incompatible

Onset of WAIHA

Secondary to infection, trauma, surgery, pregnancy, or disease

Signs and symptoms of warm auto

Significant anemia, pall, weakness, dizzy, dyspnea, jaundice, and fever

Warm auto peripheral observation

Poly, macro, retics, nRBCs, spheros, fragments (extravascular hemolysis)

WAIHA treatment

Blood, corticosteroids, splenectomy, immunosuppressive drugs, plasma exchange, filter plasma

Disorders associated with WAIHA

Cancer cells, SLE, viral syndromes, hypogammaglobulinemia, ulcerative colitis, ovarian cysts

Tests affected by warm auto

Rh (false positive), DAT+, Antibody detection, elution (all +)

Most concern when working up an autoantibody

Possibility of masked alloantibody

When is it appropriate to determine pt phenotype and auto-adsorption

No transfusion w/in 3 months (if they have then test retics)

If it is not possible to phenotype then

Do alloadsorption on R1Rq, R2R2, and rr

Adsorption

Using or plasma to remove as much auto antibody as possible

Performing adsorptions will

Leave alloantibody in plasma

Adsorption contraindications

Transfusion, severely anemic, diluted by wash