SCYM Clinical Applications 4

Question 1

Which marker is used to distinguish T-cell large granular lymphocyte (T-LGL) leukemia from reactive CD8+ T-cell expansions?

Accepted Answer

TCR V-beta clonality by flow cytometry

Answer

TCR V-beta clonality analysis using a panel of V-beta-specific antibodies demonstrates clonal T-cell expansion, supporting LGL leukemia over reactive processes.

Question 2

In the context of solid organ transplantation, flow cytometry crossmatching (FCXM) detects which antibodies as clinically significant?

Accepted Answer

Donor-specific HLA antibodies binding to T and B lymphocytes

Answer

FCXM detects donor-specific antibodies (DSAs) by incubating recipient serum with donor T and B lymphocytes and measuring fluorescent anti-human IgG binding.

Question 3

Which immunophenotype best characterizes Sézary syndrome cells detected in peripheral blood?

Accepted Answer

CD4+/CD7-/CD26-/CD3+ T cells with high CD4:CD8 ratio

Answer

Sézary cells are neoplastic CD4+ T cells that characteristically lack CD7 and CD26, and are detected in blood with an elevated CD4:CD8 ratio.

Question 4

In diagnosing chronic lymphocytic leukemia (CLL), which score using CD5, CD23, CD22, FMC7, and surface Ig intensity is used?

Accepted Answer

Matutes/Moreau CLL immunophenotype scoring system

Answer

The Matutes score assigns points for CD5+, CD23+, weak CD22, FMC7-, and weak sIg; a score ≥4 is highly specific for CLL.

Question 5

In pediatric B-ALL, which antigen is most important for distinguishing normal hematogones from leukemic blasts?

Accepted Answer

CD38 and CD58 expression patterns relative to normal B-cell precursors

Answer

Leukemic B-ALL blasts typically show abnormal CD38 (bright) and CD58 (high) compared to normal hematogones, which follow predictable maturation-stage expression.

(SCYM) Specialist in Cytometry Practice Test

(SCYM) Specialist in Cytometry Practice Test

SCYM Clinical Applications 4