Glutathione-S-transferase activity and multidrug resistance phenotype in chronic lymphocytic leukemia: do they have any clinical relevance?
BACKGROUND
Lymphocytes from patients affected by B-cell chronic lymphocytic leukemia (B-CLL) have frequently been shown to be positive for the multidrug resistance (MDR) phenotype. However, this phenotype does not seem to be responsible for the resistance to alkylating agents usually employed in the management of CLL.


METHODS
Lymphocytes from 42 patients were evaluated by flow cytometry for P-170 expression and by spectrophotometry for glutathione-S-transferase (GST) activity.


RESULTS
Our findings show that GST is not related to any clinical parameter but is increased in treated patients. Conversely, 85% of patients were positive for P-170 and this was related to the percentage of CD5/CD19-positive lymphocytes. CD5/CD19-negative patients were also negative for P-170. MDR was not related to any clinical parameter evaluated nor to GST activity in lymphocytes.


CONCLUSIONS
MDR is constitutively expressed in B-cell chronic lymphocytic leukemia and seems to be related to a CD5/CD19 B-CLL phenotype. The increase of GST activity in treated patients is statistically significant (p < 0.005).
Di Simone
D
D
Clinica Medica 1, Università di Pisa, Italy.
Testi
R
R
Caracciolo
F
F
Capochiani
E
E
Ambrogi
F
F
Grassi
B
B
Petrini
M
M
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000477:Alkylating Agents / Q000494:pharmacology / Q000627:therapeutic use; D015703:Antigens, CD / Q000032:analysis; D018941:Antigens, CD19; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D018956:CD5 Antigens; D002699:Chlorambucil / Q000494:pharmacology / Q000627:therapeutic use; D018432:Drug Resistance, Multiple / Q000235:genetics*; D005260:Female; D005982:Glutathione Transferase / Q000032:analysis*; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D014411:Neoplastic Stem Cells / Q000737:chemistry; D010641:Phenotype
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000477:Alkylating Agents; D015703:Antigens, CD; D018941:Antigens, CD19; D000944:Antigens, Differentiation, B-Lymphocyte; D018956:CD5 Antigens; D009363:Neoplasm Proteins; D002699:Chlorambucil; D005982:Glutathione Transferase