Edward Kanfer

When to harvest peripheral-blood stem cells after mobilization therapy: prediction of CD34-positive cell yield by preceding day CD34-positive concentration in peripheral blood.

PURPOSE To evaluate whether the CD34+ yield from a single peripheral-blood stem-cell (PBSC) harvest could be predicted by measurement of the patients circulating WBC and CD34+ cell concentrations on the day before harvest. PATIENTS AND METHODS Thirty-nine patients with hematologic or nonhematologic malignancy underwent 41 stem-cell mobilization episodes with cytotoxic chemotherapy and/or granulocyte colony-stimulating factor (G-CSF), and a total of 63 leukapheresis procedures were performed. Peripheral-blood samples were analyzed for WBC and CD34+ cell concentration both on the day before and the day of leukapheresis. RESULTS The median WBC and CD34+ concentrations on the day preceding leukapheresis were 10.0 x 10(9)/L (range, 0.4 to 44.4) and 24.9 x 10(6)/L (range, 0.1 to 349.4), respectively. On the day of harvest, the corresponding figures were 15.1 x 10(9)/L (range, 1.5 to 52.6) and 29.3 x 10(6)/L (range, 0.1 to 543.1), respectively. The median CD34+ cell number collected in a single leukapheresis was 2.6 x 10(6)/kg body weight (range, 0.1 to 26.1). Both the preceding day (r = .84, P < .001) and harvest day (r = .95, P < .001) CD34+ circulating concentrations correlated significantly with the number of CD34+ cells per kilogram collected at leukapheresis. The correlation between CD34+ cells per kilogram collected and harvest day WBC count was also significant (r = .43, P <.001), but with the preceding day WBC count was nonsignificant. CONCLUSION The number of CD34+ cells harvested in a single leukapheresis can be predicted by measurement of the preceding day peripheral-blood circulating CD34+ concentration, and on the basis of these data a table of probable CD34+ cell yield has been constructed. This correlation may facilitate the efficient organization of leukapheresis procedures.

CYTOMEGALOVIRUS SEROPOSITIVITY ADVERSELY INFLUENCES OUTCOME AFTER T-DEPLETED UNRELATED DONOR TRANSPLANT IN PATIENTS WITH CHRONIC MYELOID LEUKAEMIA: THE CASE FOR TAILORED GRAFT-VERSUS-HOST DISEASE PROPHYLAXIS

Graft‐versus‐host disease (GVHD) remains a major cause of morbidity and mortality after haematopoietic stem cell transplantation from matched unrelated donors (MUD). The role of T‐cell depletion (TCD) as a strategy to prevent GVHD is controversial because of the associated increased risk of leukaemic relapse, graft failure and delayed immune reconstitution. The demonstration that donor lymphocyte infusion (DLI) is effective salvage therapy if patients relapse after transplantation for chronic myeloid leukaemia (CML) prompted us to examine the proposal that TCD may be a form of GVHD prophylaxis particularly suited to this disease in patients undergoing MUD transplantation. We analysed the outcome of 106 consecutive patients with CML in first chronic phase who underwent MUD transplantation. Patients were conditioned with cyclophosphamide and total body irradiation (TBI), and received in vivo TCD, using CD52 monoclonal antibody, as GVHD prophylaxis. Donor lymphocytes were infused at the time of leukaemic relapse. The projected survival at 5 years for all patients was 52·6%. The probability of developing severe acute GVHD (grade 3 or 4) was 14·5%. The only significant predictor of overall survival in univariate and multivariate analysis was patient cytomegalovirus (CMV) serostatus: in CMV‐negative patients survival at 5 years was 60% vs. 42% in CMV‐positive patients (P = 0·006). The use of TCD was associated with an increased risk of relapse (62% probability at 5 years after transplant), but 80% of patients who received DLI achieved molecular remission that was durable in all but two cases. In vivo TCD, in conjunction with DLI at relapse, is a valuable GVHD prophylactic regimen in CMV‐seronegative recipients of MUD allografts, but in CMV‐seropositive patients this approach is associated with an increased non‐relapse mortality. Consequently, GVHD prophylactic regimens in MUD transplantation should be tailored according to the patient and donor pretransplant characteristics.

CD34 counts to predict the adequate collection of peripheral blood progenitor cells

An essential prerequisite for successful procurement of sufficient autologous peripheral blood progenitor cells (PBPC) for engraftment is the optimal timing of collection. A number of surrogate markers of peripheral blood progenitor cells were analysed to identify a single test which could predict the optimum time to harvest, providing at least 2 × 106 CD34+ cells/kg patient body weight. The study comprised 95 patients undergoing varied mobilisation regimens with chemotherapy and G-CSF for both solid tumours and haematological malignancies. One hundred and fifty-seven PBPC harvests were collected. Full blood counts (FBC) and CD34+ cell enumeration was performed on blood samples taken during the mobilisation period and immediately prior to leucapheresis (pre-harvest). All PBPC collections were assayed for colony-forming cells and CD34+ cells in addition to a FBC. The white cell count on the day of harvest showed only weak correlation with the total number of CD34+ cells in the collection (r = 0.30). In contrast, the absolute number of circulating CD34+ cells strongly correlated with the CD34+ cell and CFU-GM yield of the corresponding apheresis product. Provided the mobilisation sample contained ⩾20 × 106 CD34+ cells/ml, 94% of single collections, performed the following day, contained ⩾2 × 106 CD34+ cells/kg.

Monitoring patients in complete cytogenetic remission after treatment of CML in chronic phase with imatinib: patterns of residual leukaemia and prognostic factors for cytogenetic relapse

We monitored BCR–ABL transcript levels by quantitative real-time PCR in 103 patients treated with imatinib for chronic myeloid leukaemia in chronic phase for a median of 30.3 months (range 5.5–49.9) after they achieved complete cytogenetic remission (CCyR). The patients could be divided into three groups: (1) in 32 patients transcript levels continued to decline during the period of observation (nadir BCR–ABL/ABL ratio 0.015%); in five of these patients BCR–ABL transcripts became undetectable on repeated testing, (2) in 42 patients the transcript levels reached a plateau and (3) in 26 patients transcript numbers increased and the initial CCyR was lost. Three patients were not evaluable. Patients who remained in CCyR for at least 24 months appeared to have a low risk of subsequent cytogenetic relapse. We conclude that the pattern of ‘residual’ disease after achieving CCyR on imatinib is variable: some patients in CCyR show a progressive reduction in the level of residual disease, some reach a plateau where transcript numbers are relatively stable and others relapse with Ph-positive metaphases.

Predictive factors for survival in myeloma patients who undergo autologous stem cell transplantation: a single-centre experience in 211 patients.

High-dose therapy with autologous stem cell therapy (ASCT) has become the treatment of choice for eligible patients with myeloma. We analysed retrospectively the prognostic influence of pre-transplant characteristics and transplant modalities on response and survival in 211 myeloma patients who were transplanted in our centre between 1994 and 2004. All patients received peripheral blood stem cell support after conditioning with melphalan alone (183 patients), or melphalan and total blood irradiation (28 patients). We evaluated the influence of age, type of multiple myeloma, status prior and post ASCT, previous treatment regimens, time of ASCT from diagnosis, year of autograft, dose of re-infused CD34+ cells, plasma cell infiltration and β2-microglobulin at diagnosis on overall survival (OS) and event-free survival (EFS) to define patients with better prognosis. Median OS and EFS from transplantation were 50.9 and 20.1 months, respectively. Median OS from diagnosis was 68.8 months. Transplant-related mortality was 1.4%. Lower β2-microglobulin levels, achievement of complete remission (CR) post transplant and lower plasma cell infiltration at diagnosis and transplant correlated with longer EFS and OS, whereas CR at transplant and low international prognostic index at transplant correlated with better EFS. Higher CD34+ cell dose correlated with improved OS. We conclude that ASCT is safe and effective and the outcome is independent of age, time from diagnosis, previous treatment and conditioning regimen.

Graft invariant natural killer T-cell dose predicts risk of acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation

Invariant natural killer T (iNKT) cells are powerful immunomodulatory cells that in mice regulate a variety of immune responses, including acute GVHD (aGVHD). However, their clinical relevance and in particular their role in clinical aGVHD are not known. We studied whether peripheral blood stem cell (PBSC) graft iNKT-cell dose affects on the occurrence of clinically significant grade II-IV aGVHD in patients (n = 57) undergoing sibling, HLA-identical allogeneic HSCT. In multivariate analysis, CD4(-) iNKT-cell dose was the only graft parameter to predict clinically significant aGVHD. The cumulative incidence of grade II-IV aGVHD in patients receiving CD4(-) iNKT-cell doses above and below the median were 24.2% and 71.4%, respectively (P = .0008); low CD4(-) iNKT-cell dose was associated with a relative risk of grade II-IV aGVHD of 4.27 (P = .0023; 95% CI, 1.68-10.85). Consistent with a role of iNKT cells in regulating aGVHD, in mixed lymphocyte reaction assays, CD4(-) iNKT cells effectively suppressed T-cell proliferation and IFN-γ secretion in a contact-dependent manner. In conclusion, higher doses of CD4(-) iNKT cells in PBSC grafts are associated with protection from aGVHD. This effect could be harnessed for prevention of aGVHD.

Autologous stem cell transplantation in multiple myeloma: improved survival in nonsecretory multiple myeloma but lack of influence of age, status at transplant, previous treatment and conditioning regimen. A single-centre experience in 127 patients

Summary:High-dose therapy with autologous stem cell transplantation (ASCT) has become the treatment of choice for symptomatic eligible patients with multiple myeloma (MM). We report our centre experience and analyse retrospectively the prognostic influence of pretransplant characteristics and transplant modalities on response and survival. A total of 127 MM patients (median age: 55.2 years) were transplanted between 1994 and 2001. In all, 69 patients had IgG, 28 IgA, 23 light chain, one IgD and six non secretory MM. At the time of autograft, 6% of patients were in complete remission (CR), 73% in partial remission (PR), 12% showed minor response to previous treatment and 9% had stable or refractory disease. Prior to autograft, 79% of cases had received only one line of chemotherapy and 21% two or more lines. All patients received PBSC support after conditioning with 200 mg/m2 melphalan alone (100 patients) or melphalan and TBI (27 patients). We evaluated the influence of age (using as cutoff value the ages of 55, 60 and 65 years), type of MM, status pre- and post-ASCT, number of lines of previous regimens, time of ASCT from diagnosis, year of autograft, dose of reinfused CD34+ cells, plasma cell infiltration and β2-microglobulin at diagnosis on overall (OS) and progression-free survivals (PFS) to define patients with better prognosis. Following ASCT, 15% of patients were in CR and 81% in PR, while only two patients progressed. Median OS and PFS from transplantation were 50.4 and 23.5 months, respectively. Median OS from diagnosis was 79.7 months. Transplant-related mortality was 2.3%. Low levels of β2-microglobulin and the achievement of CR post-transplant correlated with longer PFS (P<0.03 and <0.01, respectively). The median PFS was 36.1, 23.9, 21.1 and 16.4 months for nonsecretory, IgG, IgA and light chain subtypes, respectively. Age was not an important prognostic factor at a cutoff value of 55 or 60 years. We conclude that ASCT is a safe and effective procedure even in resistant cases. The outcome was independent of age, time from diagnosis, previous treatment and conditioning regimen, but there was a tendency for better survival in the nonsecretory patients.

Autologous stem cell transplantation normalizes abnormal bone remodeling and sRANKL/osteoprotegerin ratio in patients with multiple myeloma

The osteoprotegerin (OPG)/receptor activator of NF-kappa B ligand (RANKL) system has a major role in the pathogenesis of bone disease in myeloma (MM). The effect of autologous stem cell transplantation (ASCT) on bone turnover in MM was evaluated in 51 patients (35M/16F). Markers of bone resorption (NTX, TRACP-5b), bone formation (bone-alkaline phosphatase (bALP), osteocalcin), OPG and sRANKL were measured pre- and every month post-ASCT. The median follow-up period was 12 months. Four patients were transplanted in CR, 44 were transplanted in PR and three patients had progressive/resistant disease. All patients received bisphosphonates both pre- and post-ASCT. At baseline the majority of patients had increased NTX, TRACP-5b levels, and sRANKL/OPG ratio, while markers of bone formation were strongly suppressed. ASCT produced a significant reduction of sRANKL/OPG ratio, with a concomitant decrease of NTX, and TRACP-5b levels, starting the second month post-ASCT. Bone formation markers, osteocalcin and bALP, started to increase after the 9th and 11th month post-ASCT, respectively, while the increase of OPG preceded this. These results provide biochemical evidence that ASCT normalizes the abnormal bone resorption in MM patients possibly through the decrease of RANKL/OPG ratio, while bone formation requires a longer period to return to normal.

Optimizing patient selection for myeloablative allogeneic hematopoietic cell transplantation in chronic myeloid leukemia in chronic phase

Outstanding results have been obtained in the treatment of chronic myeloid leukemia (CML) with first-line imatinib therapy. However, approximately 35% of patients will not obtain long-term benefit with this approach. Allogeneic hematopoietic stem cell transplantation (HCT) is a valuable second- and third-line therapy for appropriately selected patients. To identify useful prognostic indicators of transplantation outcome in postimatinib therapeutic interventions, we investigated the role of the HCT comorbidity index (HCT-CI) together with levels of C-reactive protein (CRP) before HCT in 271 patients who underwent myeloablative HCT for CML in first chronic phase. Multivariate analysis showed both an HCT-CI score higher than 0 and CRP levels higher than 9 mg/L independently predict inferior survival and increased nonrelapse mortality at 100 days after HCT. CML patients without comorbidities (HCT-CI score 0) with normal CRP levels (0-9 mg/L) may therefore be candidates for early allogeneic HCT after failing imatinib.

CD34+-selected peripheral blood progenitor cell transplantation in patients with multiple myeloma: tumour cell contamination and outcome.

Thirty‐six patients with multiple myeloma (23 PR1, nine PR2, four stable disease) were entered into a pilot study evaluating the use of CD34+‐selected peripheral blood progenitor cell transplantation (PBPCT) following high‐dose melphalan alone or high‐dose melphalan and total body irradiation. Peripheral blood progenitor cells (PBPCs) were mobilized with cyclophosphamide and granulocyte colony stimulating factor (G‐CSF). CD34+ selection using the Cellpro Ceprate‐SC system was performed in 22 cases with an adequate yield in 20. 10 patients failed to mobilize sufficient cells to permit selection and in four cases selection was not performed for other reasons. 16 patients therefore received unselected PBPC. Tumour cell contamination was evaluated by IgH gene fingerprinting (fpPCR). Harvested PBPC were fpPCR positive in 13/20 CD34+‐selected cases and remained positive after selection in seven. Harvested PBPC were studied in 9/16 patients receiving unselected cells; fpPCR was positive in five and negative in four. There was no difference in event‐free survival (EFS) between the CD34+‐selected group and the unselected group (median 21 and 26 months, respectively, P=ns). The CD34+‐selection process therefore reduced contamination but did not eliminate it completely, and in this small non‐randomized study there was no apparent clinical benefit of CD34+selection.