Phenotypic Characteristics of Tumor Cells in Patients with Chronic Lymphocytic Leukemia into Different Prognostic Groups

Background. The presence or absence of certain cluster of differentiation on the tumor cells of chronic lymphocytic leukemia may affect the course of the disease. Influence of genetic abnormalities on the prognosis of the disease was also proved.

Aim. To determine the relationship of the phenotype of tumor cells with genetic prognostic groups of patients with chronic lymphocytic leukemia (CLL).

Methods. Thirty-five adult pts (median age 61 year, range 44 - 82; male 24, female 11) with diagnosed CLL were included in the study. The CLL was diagnosed according to the standard basic examination (complete blood count with differential, multicolor flow cytometry (MFC) of blood and bone marrow (BM), lymph node and BM immunohistochemistry (IHC), computered tomography). Cytogenetic studies were performed on blood samples using standard GTG-method. Interphase FISH analyses were performed according to the manufacturer's protocol using DNA probes: LSI 13(RB1)13q14, LSI ATM (11q22), CEP12, LSI TP53 (17p13.1) (Abbott). Immunophenotype (IFT) of CLL cells assessed with combinations: CD3/CD19, CD19/CD5, CD19/CD11c, CD19/CD20, CD19/CD22, CD19/CD23, CD19/CD25, CD19/CD38, CD19/CD43, CD19/CD81, CD19/HLA-DR, and CD19/CD5/CD23.

Results. Stratification of patients into prognostic groups was performed based on identified GA. Favorable prognosis - patients with del(13q) (n = 9); neutral prognosis - normal karyotype (n = 14) or trisomy of chromosome 12 (n = 4); unfavorable prognosis - del(17p) (n = 3), del(11q) (n = 3) and the complex karyotype (n = 2).

Expression of CD20 was lower, and CD38 - higher in adverse group (51.0±16.31 % and 36.02±10.35 %, respectively) versus neutral or favorable groups (CD20+ - 83.17±5.52 % and 84.41±4.7 %; CD38 - 10.46±4.8 %, and 12.44±4.1 %, respectively, p <0.05). The expression level of CD20 and CD38 did not differ between the neutral and favorable groups.

The number of patients with CD38 expression more than 10% was higher in the unfavorable group (7/8) versus favorable (4/8) (p <0.05). At the same time overexpression of CD38 was observed more frequently in patients with a lack of expression of CD23 on CD5 tumor cells (CD5+CD23-) (p<0.05).

Expression of HLA-DR was higher in patients with MRD-negative remissions (3/4) versus patients with MRD-positive remissions (1/8) (p<0.05).

Conclusions. The study of the influence of various factors on the prognosis and course of CLL requires a comprehensive approach. Further researches are needed to determine the relationship between CLL affecting factors like genetic abnormalities, phenotypic characteristics of the tumor cells and MRD.