Expression of some ATP-binding cassette transporters in Acute Myeloid Leukemia.

Hematopoietic cells express ATP binding cassette (ABC) transporters in relation to different degrees of differentiation. One of the known multidrug resistance mechanisms in acute myeloid leukemia (AML) is the overexpression of efflux pumps belonging to the superfamily of ABC transporters such as ABCB1, ABCG2 and ABCC1. Although several studies were carried out to correlate ABC transporters expression with drug resistance, little is known about their role as markers of diagnosis and progression of the disease. For this purpose we investigated the expression, by real-time PCR, of some ABC genes in bone marrow samples of AML patients at diagnosis and after induction therapy. At diagnosis, ABCG2 was always down-regulated, while an up regulated trend for ABCC1 was observed. After therapy the examined genes showed a different expression trend and approached the values of healthy subjects suggesting that this event could be considered as a marker of AML regression. The expression levels of some ABC transporters such as ABCC6, seems to be related to gender, age and to the presence of FLT3/ITD gene mutation

Plerixafor Added to Chemotherapy Plus G-CSF Is Safe and Allows Adequate PBSC Collection in Predicted Poor Mobilizer Patients with Multiple Myeloma or Lymphoma

We evaluated the safety and efficacy of plerixafor, subsequent to disease-specific chemotherapy followed by granulocyte-colony stimulating factor (G-CSF), in 37 multiple myeloma (MM) or lymphoma patients, who were candidates for autologous stem cell transplantation (ASCT) predicted as poor mobilizers (PMs). Patients were identified as predicted PMs according to the history of a previously failed mobilization attempt or the presence of ≥1 factors predicting an unsuccessful harvest, such as advanced disease, prior extensive radiotherapy, or prolonged treatment, with stem cell poisons, advanced age, or extensive bone marrow involvement. Plerixafor (0.24 mg/kg) was administered subcutaneously for up to 3 consecutive days while continuing G-CSF for 9 to 11 hours before the planned apheresis. Plerixafor administration was safe and no significant adverse events were recorded. We observed a median 4-fold increase (range: 1.4-32) in the number of circulating CD34+ cells following plerixafor compared with baseline CD34+ cell concentration (from a median of 5 cells/μL, range: 1-32, to a median of 32 cells/μL, range: 6-201). Twenty-seven of the 37 patients (14 of 17 with MM and 13 of 20 with lymphoma) had ≥2×106 CD34+ cells/kg collected in 1-3 apheretic procedures. Of the 27 patients rescued with plerixafor, 24 (13 MM, 11 lymphoma) have been transplanted with plerixafor-mobilized peripheral blood stem cells, showing a rapid and durable hematologic recovery. Our results suggest that the addition of plerixafor to G-CSF after disease-oriented chemotherapy is safe and allows for a satisfactory harvest in order to perform a safe ASCT, in a relevant proportion of lymphoma and MM patients considered to be PMs

Long-term outcome and prospective validation of NIH response criteria in 39 patients receiving imatinib for steroid-refractory chronic GVHD

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Predicting failure of hematopoietic stem cell mobilization before it starts: the predicted poor mobilizer (pPM) score

Predicting mobilization failure before it starts may enable patient-tailored strategies. Although consensus criteria for predicted PM (pPM) are available, their predictive performance has never been measured on real data. We retrospectively collected and analyzed 1318 mobilization procedures performed for MM and lymphoma patients in the plerixafor era. In our sample, 180/1318 (13.7%) were PM. The score resulting from published pPM criteria had sufficient performance for predicting PM, as measured by AUC (0.67, 95%CI: 0.63â\u80\u930.72). We developed a new prediction model from multivariate analysis whose score (pPM-score) resulted in better AUC (0.80, 95%CI: 0.76â\u80\u930.84, p < 0001). pPM-score included as risk factors: increasing age, diagnosis of NHL, positive bone marrow biopsy or cytopenias before mobilization, previous mobilization failure, priming strategy with G-CSF alone, or without upfront plerixafor. A simplified version of pPM-score was categorized using a cut-off to maximize positive likelihood ratio (15.7, 95%CI: 9.9â\u80\u9324.8); specificity was 98% (95%CI: 97â\u80\u9398.7%), sensitivity 31.7% (95%CI: 24.9â\u80\u9339%); positive predictive value in our sample was 71.3% (95%CI: 60â\u80\u9380.8%). Simplified pPM-score can â\u80\u9crule inâ\u80\u9d patients at very high risk for PM before starting mobilization, allowing changes in clinical management, such as choice of alternative priming strategies, to avoid highly likely mobilization failure