Establishment of Multi-Drug Resistance Functional Assay and Correlation of Multi-Drug Resistance Activity and Chemotherapeutic Outcomes in Patients with Acute Leukemia / 대한혈액학회지

BACKGROUND: Multi-drug resistance (MDR) is one of the most important obstacles in the chemotherapy of acute leukemia, so the modulators of MDR have been developed and tried. METHODS: We measured MDR function and expressoin (surface and cytoplasmic p-glycoprotein and cytoplasmic multidrug-resistance associated protein (MRP)) and inhibitory effects of MDR modulators (cyclosporine and verapamil) by flow cytometry with MDR positive cell line and bone marrow aspirates of patients with acute leukemia (128 specimen). We compared these methods, and tried to clarify the effects of MDR on chemotherapy in patients with acute leukemia. RESULTS: The MDR functional assay and the detection method for inhibitory effects of MDR modulators (cyclosporine and verapamil) by flow cytometry using rhodamine 123 were established. These MDR functional assay was more sensitive, accurate, relatively simple and very economic, compared with the immunofluorescence assays of surface and cytopla-smic p-glycoprotein and cytoplasmic MRP. The positivity of MDR functional assay was observed in about 60% of patients with acute leukemia, and MDR activity (%) was inversely correlated with the complete remission rate and mean survival time. About 60% of the patients showing positive MDR activity revealed MDR inhibitory responses by cyclosporine and/or verapamil, especially all cases of acute myeloid leukemia in persistence after chemotherapy showed MDR inhibitory effect of cyclosporine. CONCLUSION: The chemotherapeutic out- comes of acute leukemia can be expected by MDR functional assay. And it is possible to overcome MDR by the administration of MDR modulator selected according to the results of the functional assay for MDR inhibitory effect in acute leukemia patients with MDR positivity.

Detection of Minimal Residual Disease by IgH gene rearrangement-PCR in Childhood Acute Lymphoblastic Leukemia / 대한임상병리학회지

BACKGROUND: The IgH gene rearrangement (IgH GR) involving highly specific CDR3 region can be used as a minimal residual disease marker in ALL. The IgH GR-PCR has the advantages of the high positive rate in ALL and the detection of clonal evolution. METHODS: In 30 cases of childhood ALL, the DNA was extracted from the bone marrow aspirates at the diagnosis and during the chemotherapy. The 40 cycle polymerase chain reaction was performed with seven each VH family specific primer and common JH primer. The PCR products were electrophoresed on the agarose gel, and those showing specific bands were electrophoresed on 6M urea 6% polyacrylamide DNA sequencing gel. We compared and analyzed the IgH GR-PCR results, the morphologic diagnosis of the bone marrow and the clinical course. RESULTS: IgH GR was detected in 93.3% (28/30) at the diagnosis and the rest of two cases showed IgH GR during the therapy. IgH GR was detected in all specimens diagnosed as persistence, partial remission and relapse, the 80.0% of hypocellular marrow with persistence of blasts, the 72.7% of hypocellular marrow, and the 59.2% of complete remission. In the complete remission states the patients with IgH GR showed significantly higher relapse rate (26.2%) than those without IgH GR (7.1%) (p=0.019). Number of clones of IgH GR was from one to five. The more number of clones showed the shorter mean survival time (p=0.1172). The usage of VH3 was most frequent (70.0%). IgH GR had been detected average 3.5 months (range 1-12 months) earlier than the morphologic relapse appeared. During the chemotherapy the evolution of IgH GR was observed in the seven cases (23.3%). CONCLUSIONS: The IgH GR-PCR will help the understanding of biological characteristics of leukemic cells, the interpretation of the bone marrow studies after chemotherapy and the plans of further therapy, and can be used as a prognostic indicator in the morphologic complete remission state.