Flow cytometry detection of cell differentiation antigens
Flow cytometry analysis: The specimen cells are labeled with fluorescent antibodies and prepared into a suspension so that the fluorescently labeled cells pass one by one through the capillary of the instrument to identify the morphological size and fluorescence characteristics of the cells respectively, called FACS (flow cytomatric cell sorting). The advantage is that tens of thousands of cells can be analyzed in a short period of time, and it can also be processed with computerized records for rapid multi-parameter quantitative analysis of individual cells. Our use of 4-color fluorescence analysis allows the identification of 4 colors of fluorescence present simultaneously on a single cell, which is very beneficial for the analysis of biphenotypic leukemia and microscopic residual disease.
Immunophenotyping features of leukemia proposed by EGIL Europe
1, ALL, including B-cell lineage type 4, T-cell lineage type 5 and ALL expressing 1-2 myeloid lineage markers (My+ALL).
2. AML includes 6 types, granulocytic; erythroid; megakaryocytic; hypofractionated myeloid (M0-AML); TdT-positive AML; AML expressing 1-2 lymphocytic lineage markers (Ly+AML).
3, Biphenotypic acute leukemia (BAL).
4, Undifferentiated acute leukemia. Immunophenotyping of ALL is proposed; AML immunophenotyping and biphenotypic ALL indicator system, respectively.
Immunophenotyping of acute lymphoblastic leukemia (ALL) in EGIL Europe
1. B-cell lineage ALL (a) (CD19+ and/or cCD79a+ and/or cCD22+)
pro-B-ALL (B-Ⅰ) (does not express other B-cell differentiation antigens)
Common ALL (B-II) CD10+
Pre-B-ALL (B-III) Cytoplasmic IgM+
Mature B-ALL (B-IV) with cytoplasmic or surface Igκ-, Igλ
2. T-cell lineage ALL (b) (cytoplasmic or membrane CD3+)
pro-T ALL (T-Ⅰ) CD7+
pre T ALL (T-II) CD2+ and/or CD5+ and/or CD8+
cortical T ALL (T-III) CD1a+
Mature T ALL (T-IV) Membrane CD3+, CD1a-
α/β+ T ALL (group a) Anti-T cell α/β+
γ/δ+ T ALL (group b) Anti-T cell γ/δ+
3, ALL with myeloid antigen expression (My+ALL) A
(a) Positive is positive for at least 2 of 3 markers. except B-IV TdT- Most cases TdT+, HLA DR+.
(b) TdT+, HLA DR-CD34- in most cases, but these markers are not considered in the typing
European EGIL acute granulocytic leukemia (AML) staging
1. Granulocyte series
Anti-MPO+, CD13+, CD33+, Cdw56+, and/or CD117+. Positive for at least 2 or more myeloid markers
2. Erythrocyte series (pure red, M6)
Early/immature: cannot be typed by markers
Late/mature: anti-blood group glycoprotein A+
3. Megakaryocyte series (M7)
CD41+, and/or CD61+ (membrane or cytoplasm)
4. early myeloid cells (M0) (can only be determined by immune markers)
Have other granulocytic AML phenotypes but cytochemical and lymphocyte-specific markers CD3, CD79a, CD22 negative
5, TdT+ AML
6, AML with expression of lymphocyte antigens (Ly+ AML) applying antisera and monoclonal antibodies
ALL cells can be divided into: pro-B cells (80%), T cells (10-15%), B cells with surface immunoglobulin (<5%) and CALLA (common ALL antigen) type (about 50%).
Dual phenotype leukemia
Some patients with ALL have primitive cells that also express granulocyte antigens
Terminal deoxynucleotidyl transferase (TdT): The expression of L3 terminal deoxynucleotidyl transferase (TdT) is increased in approximately 95% of ALL (except in B-cell ALL, which is often morphologically FAB typed). If the concentration of the enzyme is not elevated, the diagnosis of ALL is questionable. Twenty percent of AML also expresses TdT, which has a limited role as a specific marker of ALL.