CHAPTER 26: EXTRINSIC DEFECTS LEADING TO INCREASED ERYTHROCYTE DESTRUCTION - IMMUNE CAUSES

Question 1

(1) Immune hemolytic anemia is due to a(n):

a. Structural defect in the RBC membrane
b. Allo- or autoantibody against an RBC antigen
c. T cell immune response against an RBC antigen
d. Obstruction of blood flow by intravascular thrombi

Answer 1

b. Allo- or autoantibody against an RBC antigen

Question 2

(2) The pathophysiology of immune hemolysis with IgM antibodies always involves:

a. Complement
b. Autoantibodies
c. Abnormal hemoglobin molecules
d. Alloantibodies

Answer 2

a. Complement

Question 3

(3) In hemolysis mediated by IgG antibodies, which abnormal RBC morphology is typically observed on the peripheral blood film?

a. Spherocytes
b. Nucleated RBCs
c. RBC agglutination
d. Macrocytes

Answer 3

a. Spherocytes

Question 4

(4) The most important finding in the diagnostic investigation of a suspected autoimmune hemolytic anemia is:

a. Detection of a low hemoglobin and hematocrit
b. Observation of hemoglobinemia in a specimen
c. Recognition of a low reticulocyte count
d. Demonstration of IgG and/or C3d on the RBC surface

Answer 4

d. Demonstration of IgG and/or C3d on the RBC surface

Question 5

(5) In autoimmune hemolytic anemia, a positive DAT is evidence that an:

a. IgM antibody is in the patient’s serum
b. IgG antibody is in the patient’s serum
c. IgM antibody is sensitizing the patient’s red blood cells
d. IgG antibody is sensitizing the patient’s red blood cell

Answer 5

d. IgG antibody is sensitizing the patient’s red blood cell

Question 6

(6) Which of the following is NOT a mechanism of drug-induced hemolytic anemia?

a. Drug adsorption on red blood cell membrane
b. Drug–RBC membrane protein immunogenic complex
c. RBC autoantibody induction
d. IgM autoantibody sensitization of RBCs after exposure to the cold

Answer 6

d. IgM autoantibody sensitization of RBCs after exposure to the cold

Question 7

(7) Which of the following describes a penicillin-induced AIHA?

a. Extravascular hemolysis, positive DAT with IgG, gradual anemia
b. Intravascular, possible renal failure, positive DAT with C3d
c. Rare hemolysis, positive DAT with IgG
d. Intravascular hemolysis, positive DAT with IgG

Answer 7

a. Extravascular hemolysis, positive DAT with IgG, gradual anemia

Question 8

(8) Which one of the following statements is true about DHTR:

a. It is usually due to an ABO incompatibility
b. Hemoglobinemia and hemoglobinuria frequently occur
c. It is due to an anamnestic response after repeat exposure to a blood group antigen
d. The DAT yields a positive result for C3d only

Answer 8

c. It is due to an anamnestic response after repeat exposure to a blood group antigen

Question 9

(9) Chronic secondary CAD is most often associated with:

a. Antibiotic therapy
b. M. pneumoniae infection
c. B cell malignancies
d. Infectious mononucleosis

Answer 9

c. B cell malignancies

Question 10

(10) A 63-year-old man is being evaluated because of a decrease in hemoglobin of 5 gm/dL after a second cycle of fludarabine for treatment of chronic lymphocytic leukemia. The patient’s DAT result is strongly positive for IgG only, and antibody testing on his serum and an eluate of his RBCs yield positive results with all panel cells and the patient’s own cells. This suggests which mechanism of immune hemolysis for this patient?

a. Drug-RBC membrane protein complex
b. Drug adsorption
c. RBC autoantibody induction
d. Drug-induced nonimmunologic protein adsorption

Answer 10

c. RBC autoantibody induction

Question 11

(11) A Group A Rh-negative mother gave birth to a Group O Rh-positive baby. The baby is at risk for HDFN if:

a. This was the mother’s first pregnancy
b. The mother has IgG ABO antibodies
c. The mother was previously immunized to the D antigen
d. The mother received Rh immune globulin prior to delivery

Answer 11

c. The mother was previously immunized to the D antigen