Red blood cell-incompatible allogeneic hematopoietic progenitor cell transplantation

Transplantation of hematopoietic progenitor cells from red cell-incompatible donors occurs in 30-50% of patients. Immediate and delayed hemolytic transfusion reactions are expected complications of red cell-disparate transplantation and both ABO and other red cell systems such as Kidd and rhesus can be involved. The immunohematological consequences of red cell-incompatible transplantation include delayed red blood cell recovery, pure red cell aplasia and delayed hemolysis from viable lymphocytes carried in the graft ('passenger lymphocytes'). The risks of these reactions, which may be abrupt in onset and fatal, are ameliorated by graft processing and proper blood component support. Red blood cell antigens are expressed on endothelial and epithelial tissues in the body and could serve to increase the risk of GvHD. Mouse models indicate that blood cell antigens may function as minor histocompatibility antigens affecting engraftment. Similar observations have been found in early studies of human transplantation for transfused recipients, although current conditioning and immunosuppressive regimens appear to overcome this affect. No deleterious effects from the use of red cell-incompatible hematopoietic grafts on transplant outcomes, such as granulocyte and platelet engraftments, the incidences of acute or chronic GvHD, relapse risk or OS, have been consistently demonstrated. Most studies, however, include limited number of patients, varying diagnoses and differing treatment regimens, complicating the detection of an effect of ABO-incompatible transplantation. Classification of patients by ABO phenotype ignoring the allelic differences of these antigens also may obscure the effect of red cell-incompatible transplantation on transplant outcomes.     

An update on peripheral blood progenitor cell transplantation

High-dose therapy with stem cell rescue is increasingly being used as a salvage or consolidation therapy for patients with poor-risk malignant disease. The availability of peripheral blood progenitor cells (PBPC) has opened new therapeutic perspectives to alleviate the severe toxicity related to prolonged myelosuppression. The preferred method of collection is still a matter of much debate. PBPC can be collected in steady state and after chemotherapeutic conditioning, growth factor priming, or both. Usually a heterogeneous population containing both committed progenitors and pluripotent stem cells can be harvested. Studies comparing engraftment after mobilized PBPC with recovery after autologous bone marrow transplantation confirm the beneficial effect on neutrophil and platelet engraftment. The accelerated hematological recovery can be associated with a number of clinical benefits including a reduction of platelet transfusions and shorter hospital stay. Only a few randomized studies are currently available on the long-term outcome after PBPC transplantation. Recent findings on tumor cell mobilization stimulated the development of techniques for tumor cell reduction, based on negative selection (purging) of tumor cells or positive selection of CD34-positive progenitor cells. Positive CD34 selection is also imperative for successful ex vivo expansion of progenitor cells and gene transfer experiments. The value of PBPC in the field of allogeneic transplantation is currently being examined.     

Optimizing peripheral blood progenitor cell autologous transplantation in multiple myeloma.

As in other malignancies, peripheral blood progenitor cells (PBPC) have almost completely replaced bone marrow as the source of stem cells for autologous transplantation in multiple myeloma. PBPC collection could be optimized either by reducing contamination by the malignant clone or by increasing hematopoietic quality of the graft. Currently, the most promising technique for purifying the harvest is CD34 cell selection. Several pilot studies have shown the feasibility of this method in MM. However controlled studies are necessary to assess the clinical impact of CD34+ cell selection. In the IFM 94 study, CD34+ selection was optional. There was no significant difference between 50 patients receiving a CD34+ selected graft and 133 patients receiving non-selected PBPC, as regards duration of neutropenia, duration of thrombocytopenia, response rate, EFS or survival. Hematopoietic recovery after transplantation is related to the number of CD34+ cells infused. The optimal regimen for mobilizing the requested CD34+ yield is not yet known. We have completed a randomized study comparing the combination of SCF plus G-CSF and G-CSF alone after priming with cyclophosphamide 4 g/m2. The median number of leukaphereses to reach the target yield of 5x10(6) CD34+ cells/kg was 1 in the SCF group (N=55) versus 2 in the G-CSF group (N=47) (p=0.008). The median number of CD34+ cells collected in the first leukapheresis was 11. 6x10(6) in the SCF group versus 4x10(6) in the G-CSF group (p=0.003). These results are in line with those observed in other trials testing the combination of SCF and G-CSF to improve PBPC collection.     

Engraftment syndrome in children undergoing autologous peripheral blood progenitor cell transplantation

There is limited experience on engraftment syndrome (ES) in children. The present study analyzes the characteristics of ES in pediatric patients undergoing autologous peripheral blood progenitor cells transplantation (PBPCT). From 1993 to 2001, 30 of 156 patients (19.2%) who underwent PBPCT developed ES (skin rash which involved more than 27% of the body surface and temperature >38.3 degrees C with no compatible infectious disease etiology, during neutrophil recovery). Of the 30 patients who developed ES, 20 (66%) developed hypoxia and/or pulmonary infiltrates, seven (23%) had hepatic dysfunction, six (20%) developed renal insufficiency, 16 (53%) showed weight gain and three (10%) experienced transient encephalopathy. Multivariate analysis showed that the only positive predictive factor for developing ES was mobilization with high-dose G-CSF (12 microg/kg twice daily) (RR 3.88, CI 95% 1.73-8.67; P < 0.0005). The overall transplant-related mortality (TRM) was 8.33% and this was significantly higher in the patients who developed ES than in those who did not (23% vs 4.76%; P < 0.0001). We also found a higher morbidity in patients who developed ES, expressed as a statistically significant increase in supportive care (transfusion requirement, parenteral nutrition) and increase in the length of hospital stay. In summary, we have found ES to be the most important cause of morbidity and mortality in children undergoing autologous PBPCT.     

Autologous peripheral blood progenitor cell transplantation for multiple myeloma.

Autologous stem cell transplantation (ASCT) is increasingly used in the treatment of cases of multiple myeloma (MM) where there has been no significant improvement in the patient's condition following conventional chemotherapy. Peripheral blood progenitor cells (PBPC) have replaced bone marrow as a source of stem cells and offer easier accessibility and availability, faster haematopoietic recovery and possibly lower tumour contamination. The IFM 90 randomized trial has shown that autologous bone marrow transplantation significantly improves response rate, event-free survival (EFS) and overall survival (OS) in younger patients with MM. For MM, this review discusses the role of ASCT, the use of PBPC for autologous transplantation, and current developments of ASCT.     

Kinetics of serum cytokines in adults undergoing peripheral blood progenitor cell transplantation

Summary. We investigated the serum cytokine levels (G-CSF, GM-CSF, IL-l/?, IL-3 and IL-6) using an ELISA in 14 patients with haematological malignancies undergoing peripheral blood progenitor cell transplantation (PBPCT). Serum G-CSF levels in all patients rose immediately after PBPCT, then gradually decreased as the neutrophil counts began to rise. No detectable serum levels of GM-CSF or IL-lp were observed, but serum levels of IL-3 rose transiently immediately following PBPCT. Serum levels of JL-6 rose transiently during a fever in four patients. These observations suggest that G-CSF and L 3 may contribute to the early haemopoietic reconstitution in PBPCT.     

G-CSF-stimulated BM progenitor cells supplement suboptimal peripheral blood hematopoietic progenitor cell collections for auto transplantation

Peripheral blood hematopoietic progenitor cells (PBHC) are the standard source of support for high-dose chemotherapy because of faster recovery of marrow function. Unfortunately, a proportion of patients are unable to mobilize adequate progenitors to proceed to autologous hematopoietic cell transplant (AHCT). Granulocyte-CSF-stimulated BM-derived hematopoietic progenitor cells (BMHC) may circumvent this problem. From 1999 to 2006, 52 patients (cases) with AML, Hodgkin (HL) or non-Hodgkin's lymphoma (NHL) in whom PBHC mobilization failed underwent a G-CSF-stimulated bone marrow harvest and proceeded to AHCT. Their outcome was compared with 422 patients (controls) with AML, HL and NHL undergoing AHCT using only PBHC. Twenty-three patients received BMHC alone and 29 patients received a combination of PBHC and BMHC. Median engraftment time for neutrophils (>0.5 x 10(9)/l) and platelets (>20 x 10(9)/l) were 14 and 27 days, but significantly longer when compared with controls (11 days, 11 days, P<0.0001). Patients receiving both PBHC and BMHC had faster engraftment, when compared with those receiving BMHC alone (P<0.001). In conclusion, performing an AHCT using G-CSF-stimulated BMHC in patients failing PBHC collection is feasible with faster engraftment seen in patients receiving both BMHC and PBHC over BMHC alone.     

Peripheral blood progenitor cell transplantation in lymphoma and leukemia using a single apheresis

Myeloablative treatment and peripheral blood progenitor cell (PBPC) transplantation are increasingly used for lymphomas and leukemias. We have sought to optimize conditions for priming, collection, and engraftment of the leukapheresis product. Fifty-four consecutive adult patients were eligible, 31 with high-grade non-Hodgkin's lymphoma of poor prognosis, 12 with Hodgkin's disease in chemosensitive relapse, and 11 with poor prognosis acute lymphoblastic leukemia. Filgrastim was administered after routine chemotherapy with VAPEC-B or HiCCOM to mobilize PBPC. A rapidly increasing white blood cell count was used to predict the time of peak PBPC release and plan leukapheresis. Forty- five patients underwent leukapheresis. A median of 14 L of blood was processed at a single apheresis. A median of 2.4 x 10(8)/kg mononuclear cells (MNCs), 1.04 x 10(6)/kg granulocyte-macrophage colony-forming cells (GM-CFCs), and 10.6 x 10(6)/kg CD34+ cells were obtained. Slightly fewer MNCs were obtained from the heavily pretreated Hodgkin's disease group. There were no other significant differences in the size or composition of the leukapheresis harvest in the three patient groups. Forty patients underwent high-dose therapy and PBPC transplantation. Filgrastim was administered by daily subcutaneous injection until the absolute neutrophil count was > or = 1 x 10(9)/L for 2 consecutive days. Rapid and sustained hematopoietic engraftment occurred in all patients. The median time to achieve a neutrophil count > or = 0.5 x 10(9)/L was 9 days (range, 8 to 16 days); to achieve a platelet count > or = 20 x 10(9)/L was 10 days (range, 6 to 88 days); and to achieve a platelet count > or = 50 x 10(9)/L was 15.5 days (range, 10 to 100 days). Neutrophil recovery was faster than that of a historical control group treated with autologous bone marrow transplantation and filgrastim, but platelet recovery times were halved in the PBPC group. There was no secondary engraftment failure. Requirements for blood and platelet transfusions, antibiotic use, and parenteral nutrition were similar in the three patient groups. The median number of days in the hospital was 13 (range, 10 to 55) in the PBPC patients, compared with 19 (range, 14 to 51) in the historical controls. Leukapheresis yields (MNC, GM-CFC, and CD34+ cell numbers) were not useful for predicting the times to engraftment. We have shown that sufficient PBPC for transplantation can be obtained at a single leukapheresis after mobilization with routine chemotherapy and filgrastim in patients with non-Hodgkin's lymphoma, Hodgkin's disease, and acute lymphoblastic leukemia, even those heavily pretreated.(ABSTRACT TRUNCATED AT 400 WORDS)     

Infectious complications after autologous peripheral blood progenitor cell transplantation followed by G-CSF

Infectious complications after autologous peripheral blood progenitor cell transplantation (PBPCT) have been reported in a few studies including small patient numbers. The present study was performed to assess the incidence, types, outcome and factors affecting early and late infections in 150 patients aged 18 to 68 years (median 46.5) who underwent high-dose therapy, with G-CSF. Patients were kept in reverse isolation rooms and received antimicrobial chemoprophylaxis with oral quinolone and fluconazole. One hundred and fifteen patients (76.7%) developed fever (median 3 days, range 1-29); 20 patients (55.5%) had Gram-positive and 13 (36. 2%) Gram-negative bacterial infections. There were no fungal infections or infection-related deaths. Mucositis grade II-IV (P = 0. 0001; odds ratio 3.4) and >5 days on ANC <100/microl (P = 0.0001; odds ratio 2.3) correlated with development of infection. Only days with ANC <100/microl affected infection outcome (P = 0.0024) whereas the antibiotic regimen did not. After day +30 there were four cases of bacterial pneumonitis (2.7%), one case of fatal CMV pneumonia (0. 8%) and 20 of localized VZV infection (13.3%). Reduction of neutropenia duration with PBPCT and G-CSF is not enough to prevent early infectious complications since only a few days of severe neutropenia and mucositis are related to development of early infections. However, no infection-related deaths were seen. Although Gram-positive organisms were the major cause of bacteremia, a glycopeptide in the empirical antibiotic regimen did not affect infection outcome. In PBPCT recipients, early and late opportunistic infections were notably absent, which was at variance with what was seen with bone marrow recipients. Efforts should be made to prevent mucositis and neutropenia and identify new strategies of antibacterial prophylaxis.     

Analysis of circulating hematopoietic progenitor cells after peripheral blood stem cell transplantation

We investigated the kinetics of posttransplant circulating progenitor cells (PTCPC) in the early phase after autologous (auto-) and allogeneic (allo-) peripheral blood stem cell transplantation (PBSCT). We analyzed the number of myeloid progenitor cells (CFU-GM) per 10 ml of peripheral blood (PB) on days 0 (just prior to transplantation), 1 (12-15 hours after completion of first transplantation), 2, 3, 5, 7, 10, 14, 17, 21 and 28 (after auto-PBSCT), and also additionally on day 35 after allo-PBSCT. A standard methylcellulose colony assay was used for analysing the number of CFU-GGM and BFU-E on all of the days. In addition, high proliferative potential-colony forming cells (HPP-CFC) of the harvested PBSC from donors and day 1 PB from recipients were assayed in 5 allo-PBSCT patients. Furthermore, a proportion of CD38- cells among CD34+ cells in the harvested PBSC and day 1 PB was evaluated by two-color flow cytometric analysis in 5 allo-PBSCT patients. The number of CFU-GM on day 1 ranged from 7 to 119 per 10 ml PB after auto-PBSCT, and from 15 to 61 per 10 ml PB after allo-PBSCT. After these transient increases, PTCPC diminished rapidly. Then, PTCPC emerged again on day 7 after auto-PBSCT and on day 10 or 14 after allo-PBSCT along with neutrophil recovery. A proportion of HPP-CFC among myeloid colonies from day 1 PB of recipients was significantly higher than that from the harvested PBSC from donors (65.6 +/- 12.7% vs. 17.4 +/- 13.0%, respectively, n = 5, P = 0.0013). In addition, two-color flow cytometric analysis revealed that the proportion of CD34+CD38- cells was significantly higher in day 1 PB of recipients than in the harvested PBSC from donors (57.5 +/- 17.6% vs. 11.7 +/- 4.9%, n = 5, P = 0.005). These observations suggest that both primitive and committed transplanted myeloid progenitor cells may circulate in the very early period following PBSCT.     

Post-transplantation cyclophosphamide to facilitate HLA-haploidentical hematopoietic cell transplantation: Mechanisms and results

Allogeneic blood or marrow transplantation (BMT) is a curative therapy for a number of high-risk hematologic malignancies. Historically, only patients with a human leukocyte antigen (HLA)-matched sibling or unrelated donor were able to receive this therapy, thus excluding many potential transplant recipients. In recent years, partially mismatched related donor, or human leukocyte antigen-haploidentical (haplo) BMT has expanded the donor pool to nearly every patient in need of a transplant, particularly when using post-transplantation cyclophosphamide to promote immune tolerance and prevent graft-versus-host disease. With now over 15 years of clinical experience using this platform, long terms outcomes are well understood. We review the clinical literature and highlight the advantages and disadvantages of haplo BMT with post-transplantation cyclophosphamide.     

T cell receptor diversity in severe combined immunodeficiency following HLA-haploidentical bone marrow transplantation.

We have studied T cell receptor (TCR) diversity in a group of six patients with severe combined immunodeficiency (SCID) previously treated by HLA-haploidentical bone marrow transplantation (BMT). At the time of study, all patients had developed stable T cell chimerism and full reconstitution of T cell functions in the absence of acute or chronic graft-versus-host disease. Peripheral blood lymphocytes (PBL) were analysed by immunofluorescence using a panel of monoclonal antibodies (MoAb) against TCR variable (V) region epitopes including V beta 5, V beta 6, V beta 8, V beta 12, and V alpha 2. Our results showed that in each patient studied a low but significant portion of PBL reacted with each anti-TCR V region epitope MoAb used, in a manner that was, on statistical grounds, indistinguishable from results obtained with PBL from healthy controls. We conclude that within the experimental resolution of a limited number of anti-TCR V region epitope MoAb, T cell reconstitution following BMT for SCID, even when performed across a full HLA-haplotype barrier, leads to an apparently normal TCR diversity. These novel findings may be relevant in the evaluation of functional capacities of T cells that have differentiated from transplanted precursor cells in an HLA-haplodifferent environment.     

Secondary acute myeloid leukemia and myelodysplasia after autologous peripheral blood progenitor cell transplantation

Secondary myelodysplastic syndrome (MDS) and acute leukemia (AL) are well-known complications of antineoplastic therapy. The incidence of these serious complications after autologous hematopoietic transplantation ranges from 1.1% to 24%. Prior chemotherapy is its most likely cause, but other variables related to these long-term complications are seriously discussed. There is evidence that priming of progenitor cells isolated from peripheral blood with chemotherapy is also related to a higher risk of secondary MDS/AL. Whether progenitor cells isolated from bone marrow or peripheral blood after mobilization only with cytokines are related to higher risk is a controversial issue. In this paper, we analyze the incidence and variables related to these complications in a series of 99 patients diagnosed with lymphoma or multiple myeloma who underwent autologous transplantation using hematopoietic progenitors isolated from peripheral blood mobilized with granulocyte colony-stimulating factor (G-CSF). The probability of MDS/AL in patients alive 5 years after transplant in our series is 8.58%, similar to that reported in other series using bone marrow grafts. The total dose of cyclophosphamide ( p=0.099), the number of chemotherapy cycles ( p=0.04) received before transplant, and the total dose of mononuclear cells infused at the time of transplant were the only variables associated with secondary MDS/AL. Autologous transplantation with progenitor cells isolated from peripheral blood after mobilization with cytokines has probability and risk factors for secondary MDS/AL development similar to bone marrow grafts when compared with other published series.     

Immune reconstitution after T-cell replete HLA-haploidentical transplantation

Impaired immune reconstitution has been one of the perceived limitations of alternative donor transplantation. However, modern transplantation platforms such as HLA-haploidentical transplantation with either post-transplantation cyclophosphamide or with anti-thymocyte globulin combined with intense immunosuppression may be associated with robust immune recovery as inferred by low rate of infectious mortality and post-transplantation lymphoproliferative disease. Here, we review the data on immune reconstitution including individual cell subsets, the effect of reconstitution on outcomes, and comparative studies using these commonly utilized T-cell replete HLA-haploidentical platforms. We find robust recovery of neutrophils, natural killer cells, CD8⁺ T-cells, and B-cells, with delayed CD4⁺ T-cell recovery comparable to that after HLA-matched transplantation. In addition, while viral reactivations and infections appear more common after HLA-haploidentical when compared with HLA-matched transplantation, infectious mortality remains low likely due to modern cytomegalovirus monitoring, preemptive treatment, as well as relative frequency of nonlethal viral infections like polyomavirus hominis 1 (BK virus). Higher graft cell doses also appear to be associated with faster recovery without concomitant increases in lethal graft-vs-host disease. Finally, despite rapid numerical return of natural killer cells post-transplant, phenotypically they retain immaturity markers till day 180 or more after transplantation, which suggests an avenue for future research to improve outcomes further.