Compare and contrast typically cold- reactive autoantibodies with warm- reactive autoantibodies:
1) Briefly list the immunoglobulin class and optimal temperature of reactivity, DAT profile results, and serologic specificity of the autoantibodies involved with each type. How does each type of autoantibody affect routine ABO/Rh and antibody screening tests.?
2) Discuss the techniques used in the lab to detect underlying, clinically significant alloantibody(ies) that may also be present together with the cold or warm autoantibodies.
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1. Ig class- cold rxt ab are generally IgM, warm rxt Ab are generally IgG.
DAT profile- Cold-Ab rxt best at 4C but pathological cold Ab will have a greater thermal range, rxt at
higher temp (~30). Warm-Ab react best at 37C. Both cold and warm tend to cause DAT(+) rxt with
polyspecific Ab but cold are DAT(+) with C3 monospecific rgt, as they activate complement, while warm
Ab are DAT(+) with monospecific IgG.
Since routine ABO/Rh tests are performed at RT cold-Ab will cause ABO/Rh discrepancy, while warm-Ab
will not effect ABO/Rh routine testing. With the XM panel cold-Ab will cause rxns with all panel cells at IS
and RT, being generaaly IgM. Warm-Ab are Rh specific and will cause panel rxns with most donor cells at
the 37C and AHG phases.
2. With a cold rxt auto-Ab you could Pre-warm the serum perform the washes with warm saline to prevent
cold-Ab rxt and complement activation but this can only be done if a cold-Ab is obvious, ex: AC(+),
DAT(+)C3 and rxns at IS or RT. Cold adsortion is also an option, using pt cells and serum if they have not
been recently transfused (txn). This method is enhanced with enzymes like ficin and incubatons done at
4C. Allows detection of underlying allo-Ab.
Warm auto-Ab can be removed from RBCs via ZZAP auto adsorption. This process also requires that the
pt has not been txn recently. Auto-Ab are removed allowing allo-Ab detection. The method destroys Kell
antigens be aware.
In a patient who has NOT been recently transfused, the presence of a positive DAT or a positive autocontrol:
1) confirms a diagnosis of autoimmune hemolytic anemia
2) could be due to a drug-related cause
3) verifies the presence of immune-mediated RBC destruction
4) can indicate the presence of autoantibody
B) 2 and 4
Reactions caused by a cold autoantibody can mask the presence of clinically significant alloantibodies. Inorder to differentiate these:
A) All of the above
Paroxysmal cold hemoglobinuria (PCH) is:
C) Caused by a biphasic IgG antibody and confirmed by the Donath-Landsteiner test
(T/F) Harmless warm autoantibodies are NOT serologically distinguishable from harmful ones.
True
Diseases reported to be frequently associated with warm autoimmune hemolytic anemia (WAIHA) include:
A) All of the above
(T/F) ABO grouping is frequently affected by warm reactive autoantibodies because they are direct agglutinins.
False
(T/F) In the drug-induced immune complex mechanism, the patient presenting with acute intravascularhemolysis can recover rapidly once the drug is withdrawn.
True
Problems in routine serologic testing caused by cold- reactive autoantibodies can usually be resolved by all of the following EXCEPT:
B) Collecting clotted blood specimens
Most warm reactive autoantibodies have a broad specificity within which of the following blood groups?
A) Rh
One method that can be used to separate patient's red cells from recently transfused donor cells is:
C) Reticulocyte harvesting
Autoadsorption to remove either warm or cold autoantibodies should not be used with a recentlytransfused patient. Recently means:
D) 3 months
Hemoglobin 7.4g/dL
HCT 22%
Retic Count 10%
Direct Ag Test: Poly=3+, IgG=3+, C3=0
Antibody Screen: SCI=3+, SCII=3+, Auto=3+
Which clinical condition is consistent with the lab results shown above for a patient who has NOT been recently transfused?
-IgG autoantibody, reacts with R
-Drug and anti-drug antibody lo
-Penicillin and cephalosporin in
-Warm autoantibody reacts aga
-Acrocyanosis, autoagglutination
Cold Agglutinin Disease: Acrocyanosis, autoagg
Drug adsorption (Hapten): Penicillin and cephalosporin
Aldomet, L-dopa: Warm autoantibody reacts
PCH: IgG autoantibody reacts with R
Immune complex Mechanism: Drug and anti-drug
A patient exhibits hemoglobinemia and decreased haptoglobin 2 hours after transfusion of 2 units packed RBCs. Post-transfusion testing reconfirms his ABO type is A positive: the transfused donor units also reconfirmed as A positive. His post-transfusion antibody screen and DAT are negative. The patient has no physical symptoms of discomfort and his temperature is normal. Which of the following would most probably be associated with this clinical picture?
A) nonimmune hemolysis
The process of separation of anti-RBC antibody from its antigen is known as:
D) elution
Which of the following can be used to remove antibodies from the surface of RBCs?
a) organic solvents (ether)
b) heat
c) acid
d) all of the above
d all of the above
(T/F) IgA deficient patients who have anti-IgA antibodies can suffer anaphylactic reactions when transfused with blood products. One way to avoid this reaction is to transfuse washed RBCs.
True
(T/F) Graft versus host disease (GVHD) occurs when donor lymphocytes attack foreign antigens of tissues in immunocompromised recipients.
True
(T/F) The only effective way to prevent transfusion-associated GVHD is to irradiate the units.
True
Possible cause(s) of a non-immune hemolytic event following transfusion:
A) Incompatible intravenous solution
Anti-HLA and anti-leukocyte antibodies in transfused donor plasma are thought to initiate antibody mediatedpulmonary edema in which condition?
A) TRALI
Examples of non-immune RBC abnormalities that may cause hemolytic anemia include all of the following except:
A) Aldomet-Induced Hemolytic Anemia
Which of the following is NOT associated with mild or severe Allergic Transfusion Reactions:
D) Fever and increased blood pressure (hypertension)
Match the type of transfusion reactions on the left with the characteristics listed on the right.
