Flow cytometry immunophenotyping evaluation in acute lymphoblastic leukemia: correlation to factors affecting clinic outcome

Abstract

The authors conducted a flow cytometry immunophenotyping study in patients with acute lymphoblastic leukemia (ALL) from Natal, Rio Grande do Norte, Brazil. The patients (n = 126) were newly diagnosed using a panel of monoclonal antibodies: CD1a, CD2, CD3, CD4, CD7, CD8, CD10, CD13, CD33, CD14, CD19, CD22, CD79a, CD117, CD34, anti-IgM, anti-TdT, anti-HLA-Dr, and anti-human kappa and lambda light chains. Additional data, such as patients' age and gender, clinical and laboratory findings such as presence of tumor masses, lymphadenopathy, hepatomegaly, splenomegaly, leukemic infiltration in the central nervous system (CNS) were also investigated. Results showed that 56.7% of the cases were B-lineage ALL and 55% were T-cell ALL. Also, we found that males were more affected by the disease, regardless of immunological classification. The correlation between age and immunological subtypes showed that the B-lineage ALL occurred more frequently in patients aged under 15 while the T-cell ALL subtype was more frequent in adults. Immunophenotypic profiles and morphological subtypes showed a direct correlation between L3 subtype and B-lineage ALL, while L1 and L2 subtypes correlated more often with B-cell lineage and T-cell ALL, respectively. Correlation analysis between immunophenotypic and clinical profiles showed that T-cell ALL was more associated with a higher incidence of lymphadenopathy, hepatomegaly, splenomegaly and CNS leukemic infiltration, also showing a greater blast cell count in peripheral blood than the other subgroups. The presented data suggest that immunophenotyping is an important method in the diagnosis, monitoring and prognostic assessment in determining the pathological mechanisms of evolution of ALL.

Figure 1

Immunophenotyping profile of one case of Common ALL. (A) FSC and SSC, morphologic characteristic of blood cells in especially blastic cells in the recessed area (gate); (B) CD19 and CD3 expressed in 80% and 10% of blastic cells, respectively; (C) CD10/CD22 co‐expression in 68% of blastic cells; (D) negative expression of CD7 antigen; (E) cytoplasmic CD79a expression in 70% and cytoplasmic CD13 in blastic cells; (F) MoAb against Terminal deoxynucleotidyl Transferase (TdT) expression in 80% of blastic cells and negative expression of myeloperoxidase antigen (MPO).

Figure 2

Immunophenotyping profile of one case of Pre‐B cμ+ ALL. (A) FSC and SSC, morphologic characteristic of blood cells in especially blastic cells in the recessed area (gate); (B) CD19 and CD3 expressed in 70% and 1% of blastic cells, respectively; (C) CD10 expression in 30% of blastic cells and negative in CD20; (D) negative expression of cytoplasmic CD3 antigen and cytoplasmatic expression of mü chain of immunoglobulin in 85% of blastic cells; (E) negative expression of CD41 and CD33 antigens; (F) negative expression of MoAb against myeloperoxidase antigen (MPO) and positive expression of cytoplasmatic expression of CD22 in 90% of blastic cells.

Figure 3

Immunophenotyping profile of one case of T‐cell ALL. (A) FSC and SSC, morphologic characteristic of blood cells in especially blastic cells in the recessed area (gate); (B) CD19 and surface CD3 expressed in 1% and 96% of blastic cells, respectively; (C) CD10 and CD22 negative; (D) CD22 and CD20 expression in 1% of blastic cells; (E) Terminal deoxynucleotidyl Transferase (TdT) expression in 90% of blastic cells; (F) cytoplasmic expression of CD3 antigen in 99% of blastic cells and negative expression of cytoplasmatic mü chain of immunoglobulin.