1.5 Hematology: Qualitative and Quantitative White Blood Cell Disorders

Which of the following is an unusual complication that may occur in infectious mononucleosis?

A. Splenic infarctions

B. Dactylitis

C. Hemolytic anemia

D. Giant platelets

C. Hemolytic anemia

C Occasionally patients with infectious mononucleosis develop a potent cold agglutinin with anti-I specificity. This cold autoantibody can cause strong hemolysis and a hemolytic anemia.

In a patient with human immunodeficiency virus (HIV) infection, one should expect to see:

A. Shift to the left in WBCs

B. Target cells

C. Reactive lymphocytes

D. Pelgeroid cells

C. Reactive lymphocytes

C HIV infection brings about several hematological abnormalities seen on peripheral smear examination; most patients demonstrate reactive lymphocytes and have granulocytopenia.

Which inclusions may be seen in leukocytes?

A. Döhle bodies

B. Basophilic stippling

C. Malarial parasites

D. Howell-Jolly bodies

A. Döhle bodies

A Döhle bodies are RNA-rich areas within polymorphonuclear neutrophils (PMNs) that are oval and light blue in color. Although often associated with infectious states, they are seen in a wide range of conditions and toxic reactions, including hemolytic and pernicious anemias, chronic granulocytic leukemia, and therapy with antineoplastic drugs. The other inclusions are associated with erythrocytes.

Which of the following is contained in the primary granules of the neutrophil?

A. Lactoferrin

B. Myeloperoxidase

C. Histamine

D. Alkaline phosphatase

B. Myeloperoxidase

B Myeloperoxidase, lysozyme, and acid phosphatase are enzymes that are contained in the primary granules of neutrophils. The contents of secondary and tertiary granules include lactoferrin, collagenase, NADPH oxidase, and alkaline phosphatase.

What is the typical range of relative lymphocyte percentage in the peripheral blood smear of a 1-year-old child?

A. 1%-6%

B. 27%-33%

C. 35%-58%

D. 50%-70%

D. 50%-70%

D The mean relative lymphocyte percentage for a 1-year-old child is 61% compared to the mean lymphocyte percentage of 35% for an adult.

Qualitative and quantitative neutrophil changes noted in response to infection include all of the following except:

A. Neutrophilia

B. Pelgeroid hyposegmentation

C. Toxic granulation

D. Vacuolization

B. Pelgeroid hyposegmentation

B Neutrophil changes associated with infection may include neutrophilia, shift to the left, toxic granulation, Döhle bodies, and vacuolization. Pelgeroid hyposegmentation is noted in neutrophils from individuals with the congenital Pelger-Huët anomaly and as an acquired anomaly induced by drug ingestion or secondary to conditions such as leukemia.

Neutropenia is present in patients with which absolute neutrophil counts?

A. <1.5 × 109/L

B. <5.0 × 109/L

C. <10.0 × 109/L

D. <15.0 × 109/L

A. <1.5 × 109/L

A Neutropenia is defined as an absolute decrease in the number of circulating neutrophils. This condition is present in patients having neutrophil counts of less than 1.5 × 109/L.

The morphological characteristic(s) associated with the Chédiak-Higashi syndrome is (are):

A. Pale blue cytoplasmic inclusions

B. Giant lysosomal granules

C. Small, dark-staining granules and condensed

nuclei

D. Nuclear hyposegmentation

B. Giant lysosomal granules

B Chédiak-Higashi syndrome is a disorder of neutrophil phagocytic dysfunction caused by depressed chemotaxis and delayed degranulation. The degranulation disturbance is attributed to interference from the giant lysosomal granules characteristic of this disorder.

The familial condition of Pelger-Huët anomaly is important to recognize because this disorder must be differentiated from:

A. Infectious mononucleosis

B. May-Hegglin anomaly

C. A shift-to-the-left increase in immature granulocytes

D. G6PD deficiency

C. A shift-to-the-left increase in immature granulocytes

C Pelger-Huët anomaly is a benign familial condition reported in 1 out of 6,000 individuals. Care must be taken to differentiate Pelger-Huët cells from the numerous band neutrophils and metamyelocytes that may be observed during severe infection or a shift-to-the-left of immaturity in granulocyte stages.

SITUATION: A differential shows reactive lymphocytes, and the physician suspects a viral infection is the cause. What is the expected laboratory finding in a patient with a cytomegalovirus (CMV) infection?

A. Heterophile antibody: positive

B. Epstein-Barr virus (EBV)-immunoglobulin (IgM): positive

C. Direct antiglobulin test (DAT): positive

D. CMV-IgM: positive

D. CMV-IgM: positive

D If both the heterophile antibody test and the EBV-IgM tests are negative in a patient with reactive lymphocytosis and a suspected viral infection, the serum should be analyzed for IgM antibodies to CMV. CMV belongs to the herpes virus family and is endemic worldwide. CMV infection is the most common cause of heterophile negative infectious mononucleosis.

Neutrophil phagocytosis and particle ingestion are associated with an increase in oxygen utilization called respiratory burst. What are the two most important products of this biochemical reaction?

A. Hydrogen peroxide and superoxide anion

B. Lactoferrin and NADPH oxidase

C. Cytochrome b and collagenase

D. Alkaline phosphatase and ascorbic acid

A. Hydrogen peroxide and superoxide anion

A The biochemical products of the respiratory burst that are involved with neutrophil particle ingestion during phagocytosis are hydrogen peroxide and superoxide anion. The activated neutrophil discharges the enzyme NADPH oxidase into the phagolysosome, where it converts O2 to superoxide anion (O2 -), which is then reduced to hydrogen peroxide (H2O2).

Which of the morphological findings are characteristic of reactive lymphocytes?

A. High nuclear:cytoplasmic ratio

B. Prominent nucleoli

C. Basophilic cytoplasm

D. All of these options

D. All of these options

D Both reactive lymphocytes and blasts may have basophilic cytoplasm, a high N:C ratio, and the presence of prominent nucleoli. Blasts, however, have an extremely fine nuclear chromatin staining pattern as viewed on a Wright's-Giemsa's—stained smear.