Immune Hemolytic Anemias Autoimmune Hemolytic Anemias

Which technique is useful in determining if there are underlying alloantibodies in a WAIHA case where the patient has been recently transfused?

Allogeneic adsorption Feedback Allogeneic Adsorptions must be used in a recently transfused person. Autologous cells from a recently transfused individual would contain multiple cell populations of unknown phenotypes.

Which type of adsorption must be done if a patient has been recently transfused?

Allogeneic adsorption Feedback Allogeneic adsorptions are necessary when a patient has been recently transfused. If autologous cells are used after a recent transfusion, the transfused cells of different phenotypes could potentially remove alloantibody during the adsorption procedure.

Symptoms associated with autoimmune hemolytic anemias can include:

Anemia Jaundice Splenomegaly Hemoglobinuria

After an adsorption technique is complete, what is the next step in determining if any underlying alloantibody is present?

Antibody identification procedure using the adsorbed serum/plasma Feedback The adsorbed serum/plasma is tested against a panel of cells in order to determine if there are any underlying alloantibodies.

In which of these cases would an elution NOT be performed when investigating a warm autoimmune hemolytic anemia (WAIHA)?

Antibody screen positive, DAT (polyspecific) negative Feedback If the DAT is negative, an elution would not be performed. An elution is performed to remove RBC-bound antibody from the red cells to determine antibody specificity. A negative DAT would suggest that no antibody, or antibody below detectable limits, is bound to the red cells. Rare cases of WAIHA with a negative DAT have been documented.

Which autoimmune hemolytic anemia is associated with an IgM autoantibody that has a broad thermal range?

Cold hemagglutinin disease (CHD) Feedback CHD is caused by an IgM autoantibody that has the capability of binding at lower temperatures and causing hemolysis via complement at 37°C.

The direct antiglobulin test (DAT) is used most often for which of these purposes?

Detect in vivo sensitization of red blood cells. Feedback The DAT is used to detect in vivo sensitization of red blood cells. It is used primarily for the detection and differential diagnosis of various forms of immune hemolysis. The indirect antiglobulin test (IAT) detects the presence of antibody in a serum specimen. Adsorption is a procedure that is employed to remove antibodies from plasma using either autologous or allogeneic RBCs.

Diagnosis and medication history are of little value in the investigation of an autoimmune hemolytic anemia.

False Feedback This statement is false. In some situations the diagnosis and/or medications can be implicated or associated with an autoimmune hemolytic anemia.

The serological presentation of a mixed-type autoimmune hemolytic anemia would be serum/plasma reactions against a red cell panel only at the antiglobulin phase.

False Feedback This statement is false. Mixed-type reactions often present with reactivity at all phases tested due to the presence of both IgM and IgG autoantibodies.

Penicillin is one of the medications that may be responsible for the immune-complex mechanism of drug-induced hemolytic anemia.

False Feedback Penicillin is one of the more common medications that can cause a drug-induced hemolytic anemia by the drug adsorption mechanism.

The causative autoantibody in cold hemagglutinin disease (CHD), is IgG and usually has a P antigen specificity.

False Feedback This statement is false. In CHD, the causative autoantibody is IgM and usually has an I antigen specificity.

In a case of WAIHA , the production of IgG or IgG and complement that sensitizes the red blood cells leads to red blood cell destruction.

Feedback This statement is true. It is IgG (sometimes with complement association) autoantibody that is responsible for red blood cell sensitization.

Penicillin can potentially cause a drug-induced hemolytic anemia.

Feedback This statement is true. Penicillin may be implicated in red cell destruction via the drug adsorption mechanism. It is most likely to occur when high doses of penicillin are given intravenously.

Case Study One A 50-year-old female patient with systemic lupus erythematosus (SLE) is admitted to the hospital with evidence of hemolysis, including decreased hemoglobin and hematocrit, increased reticulocyte count, and increased indirect bilirubin. The patient has no recent history of transfusion. An antibody screen is ordered and 3+ agglutination is observed at the AHG phase for all cells. An autologous control (autocontrol) is also tested and 3+ agglutination is observed at the AHG phase in this test as well. Given the results of the antibody screen and other laboratory test results and the patient's medical and transfusion history, which of the following is the MOST likely cause of the positive screen results?

Feedback Given the diagnosis of SLE and the positive reactions at the AHG phase, including a positive autocontrol, the cause of the reactions is probably warm autoantibodies.

In which of these immune hemolytic anemias would complement NOT be suspected as the cause of a positive direct antiglobulin test (DAT)? You answered the question incorrectly. The correct answer is highlighted below A.Cold hemagglutinin disease (CHD) B.Hemolytic disease of the fetus and newborn (HDFN) C.Warm autoimmune hemolytic anemia (WAIHA) D.Drug-induced hemolytic anemia

Hemolytic disease of the fetus and newborn (HDFN) Feedback Complement would not be suspected as the cause of a positive DAT in HDFN. HDFN occurs when maternal IgG antibody binds to antigen on fetal red blood cells (RBCs); complement is not involved. In CHD, WAIHA, and drug-induced hemolytic anemia, complement coating the RBCs may be the cause of a positive DAT.

What is (are) the causative autoantibody(ies) in paroxysmal cold hemoglobinuria (PCH)?

IgG FEEDBACK The causative antibody in cases of PCH is always IgG. IgG cold autoantibody reacts with red cells in cold areas of the body such as the extremities when the individual is exposed to cold. Complement binds irreversibly to the red cells. When the cells circulate to warmer areas of the body, the cells undergo complement-mediated hemolysis.

Which mechanism of drug-induced hemolytic anemia closely resembles a warm autoimmune hemolytic anemia (WAIHA) as it has identical serological presentation.

Induction of autoimmunity Feedback The induction of autoimmunity mechanism is often indistinguisable from WAIHA. It is theorized that certain drugs can interfere with suppressor T-cell function. As a result, a proliferation of autoantibodies is produced by B-cells.

What is the goal of an adsorption when an autoantibody is present?

Remove autoantibody from the serum/plasma to determine if alloantibody is present Feedback The main goal of adsorptions when autoantibody is present is to remove the autoantibody from serum/plasma while preserving the alloantibody that may be present.

Which one of the following conditions may be associated with warm autoimmune hemolytic anemia (WAIHA)?

Systemic lupus erythematosus (SLE) Feedback WAIHA may be associated with SLE. A patient infected with Mycoplasma pneumoniae may experience cold hemagglutinin disease (CHD) secondary to infection. Usually the hemolytic episode is resolved when the infection subsides. HDFN causes an alloimmune hemolytic anemia that occurs before and/or after birth. Fetal red blood cell destruction occurs when maternal antibody reacts with an antigen or antigens present on the fetal red cells that were inherited from the father.

In an autologous adsorption procedure, aliquots of the patient's own red blood cells are chemically treated and used to remove autoantibody from serum/plasma.

TRUE Feedback This statement is true. An autologous adsorption is the use of chemically treated patient's cells in a suitable aliquot volume to remove autoantibody from serum/plasma, so that the presence of alloantibody can be determined.

in autoimmune hemolytic anemia DAT will be

positive because since it is detecting the presence of in vivo bound autoantibodies on a patient's red blood cells. The autoantibody that has sensitized the patient's red blood cells is causing the red blood cell destruction.