[CD43 in B-cell chronic lymphocytic leukemia]

CD43 (other names: sialophorin, leukosialin, sialoglycoprotein of white blood cells) is an integral cell membrane mucin. In population of peripheral B cells CD43 occurs only on activated B cells and CD5 positive B cells. These last cells create neoplasm population in patients with B-cell chronic lymphocytic leukemia (B-CLL). Anti-CD43 monoclonal antibodies are used routinely in investigations of tissue fragments in cases of non-Hodgkin's lymphoma, whereas we did not find publication on theme of CD43 expression on peripheral blood B cells in patients with B-cell chronic lymphocytic leukemia. Wherefore advisable appeared estimation CD43 expression on B-CLL cells and comparison it with expression of typical B-CLL markers--such as CD5 and CD6. Immunological phenotype of peripheral blood and bone marrow lymphocytes has been evaluated using flow cytometry (Cytoron Absolute Ortho-Diagnostic Systems) and two-color staining. Twenty six untreated patients with B-CLL were studied. Because on well-known correlations between CD43 expression and metastasis potential of tumor, patients were divided on two groups differing score of total tumor mass (score TTM). Score TTM was evaluated according to criterion of Jaksic and Vitale. Twelve patients whose TTM score was equal or lower than 9 and median lymphocytosis was 24.6 x 10(9) in microliter were included in group I. 14 patients whose TTM score was higher than 9 were included in group II. Median lymphocytosis in these patients was 152.6 x 10(9) in microliter. The median percentage of CD43+/CD19+ cells in peripheral blood was 62.6% in the group I, and 75% in the group II (p < 0.05). Median fluorescence intensity (MFI) of CD43 antigen was 87.7 in the I group comparing to 77.4 in the group II. So one observed tendency to lowering MFI during tumor growing but the difference was not significant (p = 0.25). In peripheral blood during progression of disease more clearly than CD43+ cells increased percentage of CD5+ and CD6+ cells. The median percentage of CD19+/CD5+ cells was 62.7% in the group I, 82.4% in the group II and the difference was significant (p < 0.002). The difference in the median percentages CD6+/CD19+ cell 71.8% in group I and 84.3% in the II one were also significant (p < 0.03). MFI of CD5 and also CD6 antigens did not change in course of disease. Moreover, examination of CD43 and CD5 expression in marrow additionally to blood study were performed in 12 cases (6 from group I, 2 from group II and 4 new not included). The median percentage of CD43+/CD19+ cell was 35.1% in blood and 43.7% In marrow, in contrast to these results was the median percentage of CD19+/CD5+ cell, which was higher in peripheral blood (70.4%) than in bone marrow (60.9%). The results of this study indicate that CD43 is present on peripheral blood B-CLL cells. Moreover, percentage of these cell increases during progression of disease however more weakly than percentage of CD5 and CD6 positive cells. Expression of CD43 is independent from expression CD5 and CD6 and diminishes during tumor mass increasing, what can depended from releases exocellular domains of CD43. CD43+ cell from B-CLL patients have a tendency to accumulation in tissues what is illustrated by higher percentage of CD43+ cell in bone marrow than in peripheral blood.