Multidrug resistance in B-cell chronic lymphocytic leukemia

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• B cell chronic lymphocytic leukemia (B-CLL) is a heterogeneous lymphoid malignancy.
• Understanding multidrug resistance (MDR) mechanisms is crucial for B-CLL treatment efficacy.
• P-glycoprotein (P-gp) is a key transporter implicated in MDR.

Purpose of the Study:

• To investigate the prevalence and level of MDR in B-CLL patients.
• To compare MDR activity between B-CLL cells and normal B lymphocytes.
• To explore potential correlations between MDR and clinical parameters in B-CLL.

Main Methods:

• Peripheral blood cells from 40 B-CLL patients and 7 healthy volunteers were analyzed.
• Flow cytometry was used to detect rhodamine 123 (Rh 123) efflux, a marker for P-gp activity.
• The proportion of cells actively effluxing Rh 123 indicated MDR levels.

Main Results:

• B-CLL cells showed low MDR activity, with only 14% +/- 17% of leukemic cells effluxing Rh 123.
• In most B-CLL cases, the percentage of MDR-positive cells was below 30%.
• Normal B lymphocytes displayed significantly higher MDR activity (44% +/- 13%) compared to B-CLL cells.

Conclusions:

• MDR activity, mediated by P-gp, is generally low in B-CLL peripheral blood cells.
• Normal B lymphocytes exhibit a higher capacity for Rh 123 efflux than B-CLL cells.
• No correlation was found between MDR levels and clinical status or prior treatment in B-CLL patients.