Higher doses of CD34+ peripheral blood stem cells are associated with increased mortality from chronic graft-versus-host disease after allogeneic HLA-identical sibling transplantation

Predictors of the yield of mobilized peripheral blood CD34+ cells in HLA-matched sibling donor

We examined the donor factors that may affect the yield of peripheral blood stem cell (PBSC) mobilized from healthy donors. Pre-apheresis PB-CD34(+) cell count was the only factor that correlated with PBSC yield. Leukocyte count (LC) and monocyte count (MC) correlated with PB-CD34(+) cell. Male gender and PB-CD34(+) cell count of at least 87.1/μL and 69.8/μL on day-4 and -5 of G-CSF were associated with the ability to harvest at least 5×10(6)/kg CD34(+) cells after one apheresis. We concluded that gender and PB-CD34(+) cell count are important predictors of PBSC yield. LC and MC may serve as surrogate markers for estimating the PB-CD34(+) cell count.

Risk factors for invasive fungal disease after allogeneic hematopoietic stem cell transplantation: a single center experience

Invasive fungal disease (IFD) is a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HCT). We performed a retrospective review of 271 adults with a hematologic malignancy undergoing allogeneic HCT to determine the incidence of and risk factors for IFD and to examine the impact of IFD on nonrelapse mortality and overall survival. We defined IFD using standard criteria and selected proven and probable cases for analysis. Diagnoses in the study group included acute leukemia (42%), non-Hodgkin lymphoma (24%), myelodysplastic syndrome (15%), chronic lymphocytic leukemia (5%), and other hematologic disorders (14%). Conditioning included reduced-intensity (64%) and myeloablative (36%) regimens. Donor sources were HLA-matched sibling (60%), matched unrelated (20%), haploidentical (12%), and cord blood (8%). A total of 51 episodes of IFD were observed in 42 subjects (15%). Aspergillus spp (47%) was the most frequent causative organism, followed by Candida spp (43%). The majority of IFD cases (67%) were reported after day +100 post-HCT. In multivariate analysis, haploidentical donor transplantation (hazard ratio [HR], 3.82; 95% confidence interval [CI], 1.49-9.77; P = .005) and grade II-IV acute graft-versus-host disease (HR, 2.55; 95% CI, 1.07-6.10; P = .03) were risk factors for the development of IFD. Conversely, higher infused CD34(+) cell dose was associated with a lower risk of IFD (HR, 0.80; 95% CI, 0.68-0.94; P = .006, per 1 × 10(6) cells/kg increase in CD34(+) cell infusion). IFD-related mortality was 33.3%. Nonrelapse mortality was significantly higher in patients who developed IFD compared with those without IFD (P < .001, log-rank test). Patients with IFD had lower overall survival (5.8 months versus 76.1 months; P < .001, log-rank test). Further studies exploring strategies to increase the infused cell dose and determine adequate prophylaxis, especially against aspergillus, beyond day +100 are needed.

Advances in stem cell mobilization

The use of mobilized peripheral blood stem cells (PBSCs) has largely replaced the use of bone marrow as a source of stem cells for both allogeneic and autologous stem cell transplantation. G-CSF with or without chemotherapy is the most commonly used regimen for stem cell mobilization. Some donors or patients, especially the heavily pretreated patients, fail to mobilize the targeted number of stem cells with this regimen. A better understanding of the mechanisms involved in hematopoietic stem cell (HSC) trafficking could lead to the development of newer mobilizing agents and therapeutic approaches. This review will cover the current methods for stem cell mobilization and recent developments in the understanding of the biology of stem cells and the bone marrow microenvironment.

Extensive chronic GVHD is associated with donor blood CD34+ cell count after G-CSF mobilization in non-myeloablative allogeneic PBSC transplantation

The correlation between the incidence of GVHD and the number of infused CD34(+) cells remains controversial for PBSC transplantation after a reduced-intensity-conditioning (RIC) regimen. We evaluated 99 patients transplanted with an HLA-identical sibling after the same RIC (2-Gy-TBI/fludarabine). Donor and recipient characteristics, donor's blood G-CSF-mobilized CD34(+) cell count, and number of infused CD34(+) and CD3(+) cells were analyzed as risk factors for acute and chronic GVHD There was a trend for an increased incidence of extensive chronic GVHD in the quartile of patients receiving more than 10 × 10(6) CD34(+) cells/kg (P = 0.05). Interestingly, the number of donor's blood CD34(+) cells at day 5 of G-CSF mobilization was closely associated with the incidence of extensive chronic GVHD, that is, 48% (95% CI: 28-68) at 24-months in the quartile of patients whose donors had the highest CD34(+) cell counts versus 24.3% (95% CI: 14-34) in the other patients (P = 0.007). In multivariate analysis, the only factor correlating with extensive chronic GVHD (cGVHD) was the donor's blood CD34(+) cell count after G-CSF (HR 2.49; 95% CI: 1.16-5.35, P = 0.019). This study shows that the incidence of cGVHD is more strongly associated with the donor's ability to mobilize CD34(+) cells than with the number of infused CD34(+) cells.

Cellular therapies supplement: strategies for improving transplant efficiency in the context of cellular therapeutics

The field of hematopoietic stem cell transplantation (HSCT) has overcome many obstacles that have led to our current clinical ability to utilize cells collected from marrow, mobilized peripheral blood, or umbilical cord blood for the treatment of malignant and nonmalignant hematologic diseases. It is in this context that it becomes evident that future progress will lie in our development of an understanding of the biology by which the process of HSCT is regulated. By understanding the cellular components and the mechanisms by which HSCT is either enhanced or suppressed it will then be possible to design therapeutic strategies to improve rates of engraftment that will have a positive impact on immune reconstitution post-HSCT. In this review we focus primarily on allogeneic hematopoietic stem cell transplantation (allo-HSCT), the current challenges associated with allo-HSCT, and some developing strategies to improve engraftment in this setting.

Low incidence and severity of graft-versus-host disease after outpatient allogeneic peripheral blood stem cell transplantation employing a reduced-intensity conditioning

BACKGROUND

The prevalence and features of graft-versus-host disease (GVHD) in patients receiving allografts using peripheral blood stem cells (PBSCs) after a reduced-intensity conditioning (RIC) regimen are not well known. Several features of GVHD in patients at two institutions using RIC were assessed.

METHODS

We analysed the overall survival (OS) and prevalence of GVHD in patients who underwent outpatient allogeneic PBSC transplantation after RIC between October 1998 and July 2008.

RESULTS

We included 301 patients with a median age of 30 yrs (range, 1-71 yrs). In 37 cases, allogeneic peripheral blood stem cell transplantation was indicated for non-malignant disease, and in 264 for malignant disease. The median OS was 35 months. The estimated 3-yr OS was 48%. A total of 154 patients developed GVHD: there were 64 acute, 50 chronic and 40 cases that progressed from acute to chronic. Of the 104 patients with acute GVHD (aGVHD), 40% had grade I and 60% had grades II-IV. Of the 90 patients with chronic GVHD (cGVHD), 67% had limited and 33% had extensive forms. A total of 160 patients died, 40 as a result of GVHD (24 from aGVHD and 16 from cGVHD), 50 as a result of progressive disease and 70 from diverse causes.

CONCLUSIONS

The incidence of GVHD was lower than in other series using conventional myeloablative preparative regimens. Most importantly, the severity of GVHD did not significantly affect the long-term survival.

Long-term complications and side effects after allogeneic hematopoietic stem cell transplantation: an update

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective therapy for various malignant and non-malignant diseases. Many patients have now been followed for two or three decades posttransplant and are presumed to be cured. With the tremendous advances achieved in terms of supportive care, it is reasonable to expect outcomes to improve steadily and consequently increasing numbers of transplant survivors will be facing life after the initial transplant experience. Although long-term allo-HSCT survivors generally enjoy good health, for many others, cure or control of the underlying disease is not accompanied by full restoration of health. The burden of long-term morbidity borne by allo-HSCT survivors is substantial, and long-term follow-up of patients who received allo-HSCT is now widely recommended. Immediate survival is no longer the sole concern after allo-HSCT. The goals should also include complete recovery of the overall health status with normal physical and psychological functioning. Long-term side effects after allo-HSCT include non-malignant organ or tissue dysfunction, changes in quality of life, infections related to abnormal immune reconstitution and secondary cancers. Many of these can be attributed to the deleterious effects of chronic graft-versus-host disease. The aims of this review are to provide an update on the recent research evidence in the field.

A retrospective comparison of allogeneic peripheral blood stem cell versus bone marrow transplantation

BACKGROUND AND OBJECTIVES

Disease evolution depends in part on the source of transplanted cells. Therefore, we compared outcomes after allogeneic bone marrow (BM) and peripheral blood stem cell (PBSC) transplantation in patients who underwent transplant at Hospital das Clinicas of the Federal University of Minas Gerais, Brazil.

PATIENTS AND METHODS

We studied 364 patients who received allogeneic BM (n = 142) or PBSC transplantation (n = 222) between July 1995 and May 2005. The median age of the patients was 31 years (range, 3.1-58 years). Chronic myeloid leukemia was the predominant diagnosis (41.2%). A conditioning regimen with cyclosphosphamide and busulfan was used in 79.4% (n = 289) and graft-versus-host disease (GVHD) prophylaxis was cyclosporine/methotrexate in 95.9% (n = 349) of cases.

RESULTS

The patients in the PBSC group had faster neutrophil (P < .001) and platelet engraftment (P = .03) but increased rates of acute GVHD (P < .001) vs. those in the BM group. There was no significant difference between the groups in chronic GVHD, transplant-related mortality, relapse and survival rates.

CONCLUSIONS

Although allogeneic PBSC transplant results in a faster hematopoietic engraftment, there was an increase in acute GVHD. There was no clear benefit in relapse rate and no evidence that transplantation with PBSC benefits patient survival in our institution.

Long-term physiological side effects after allogeneic bone marrow transplantation

Allogeneic bone marrow transplantation (allo-BMT) or stem cell transplantation has the potential to cure a significant proportion of patients with otherwise fatal diseases. At present, immediate survival is no longer the sole concern after allo-BMT, because many patients can survive the acute complications of the procedure and remain free of their original disease for several years. Although long-term allo-BMT survivors generally enjoy good health, for many others cure or control of the underlying disease is not accompanied by full restoration of health. The long-term physiologic effects after allo-BMT include nonmalignant organ or tissue dysfunction; changes in quality of life; infections related to delayed, or abnormal, immune reconstitution; and secondary cancers. These long-term complications and the features of chronic graft-versus-host disease (GVHD) symptoms are heterogeneous in nature, time of onset, duration, and severity. The underlying origin of these complications is often multifactorial, with chronic GVHD being the most challenging risk factor. The main aims of this review are to present transplant physicians and health care providers with an overview of these malignant and nonmalignant late complications, with a special focus on chronic GVHD. A close partnership between the transplant center, organ-specific specialties, and local primary care providers is a key component of preventive medicine. The patient can play a major role through engagement in health maintenance behaviors.

GVHD prophylaxis using low-dose cyclosporine improves survival in leukaemic recipients of HLA-identical sibling transplants

Graft-versus-host disease (GVHD) prophylaxis of short duration (6 months) with low-dose cyclosporine A (CsA) starting at 1 mg/kg per day i.v. and four doses of methotrexate (MTX) were given to 171 consecutive leukaemic recipients of HLA-identical sibling transplants. In contrast, apart from MTX, retrospective controls received high-dose CsA, starting at 5-7.5 mg/kg per day i.v. and discontinued 1 yr post-transplant. In the low-dose CsA group, the probability of acute GVHD grades I-II (70% vs. 53%, P < 0.01), and chronic GVHD were increased (58% vs. 25%, P < 0.01), whereas the incidences of acute GVHD grades III-IV (9% vs. 5%, P = 0.62), and non-relapse mortality (20% vs. 22%, P = 0.58) were similar. Moreover, the probability of relapse was decreased (31% vs. 54%, P < 0.01), and both relapse-free (56% vs. 38%, P = 0.04) and overall survival (61% vs. 40%, P = 0.04) were markedly improved using the low-dose CsA regimen. In multivariate analyses, low-dose CsA was strongly associated with chronic GVHD [relative hazard (RH) 2.56, P < 0.01], which decreased the risk of relapse (RH 0.46, P < 0.01) and improved the probability of survival (RH 1.84, P < 0.01). In conclusion, a low-dose CsA regimen in leukaemic recipients of HLA-identical sibling transplants increases the rate of chronic GVHD, which seems to attenuate the risk of relapse, thereby improving patient survival owing to enhanced graft-versus-leukaemia effect.

The number of infused CD34+ cells does not influence the incidence of GVHD or the outcome of allogeneic PBSC transplantation, using reduced-intensity conditioning and antithymocyte globulin

The influence of graft composition on the outcome of reduced-intensity (RIC) allogeneic PBSC transplantation (allo-PBSC) remains controversial. In this study, we analyzed the impact of CD34+ cell dose on the incidence of GVHD, and on the outcome after allo-PBSC, in 103 patients with hematological malignancies, using a uniform RIC regimen. The following variables were included in statistical analysis: (1) number of C34+ cells, (2) high-risk vs low-risk disease status, (3) matched related vs matched unrelated donor, (4) female donor to male recipient vs any other combination, (5) age of recipient (above vs below the median). Univariate and multivariate analysis did not reveal any association between CD34+ cell dose and acute grade-2 to grade-4, cGVHD, non-relapse mortality (NRM), relapse rate (RR) and OS. High-risk disease status was the only variable independently associated with increased NRM (P=0.001), increased RR (P=0.012) and decreased OS (P<0.001). The same results were obtained when analysis was restricted to a subgroup of 55 patients with myeloid neoplasms. The influence of graft composition on the outcome of RIC allo-PBSC should be further investigated via well-controlled randomized prospective studies.

Donor, recipient, and transplant characteristics as risk factors after unrelated donor PBSC transplantation: beneficial effects of higher CD34+ cell dose

We report outcomes of 932 recipients of unrelated donor peripheral blood stem cell hematopoietic cell transplantation (URD-PBSC HCT) for acute myeloid leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia, and myelodysplastic syndrome enrolled on a prospective National Marrow Donor Program trial from 1999 through 2003. Preparative regimens included myeloablative (MA; N = 611), reduced-intensity (RI; N = 160), and nonmyeloablative (NMA; N = 161). For MA recipients, CD34(+) counts greater than 3.8 x 10(6)/kg improved neutrophil and platelet engraftment, whereas improved overall survival (OS) and reduced transplant-related mortality (TRM) were seen for all preparative regimens when CD34(+) cell doses exceeded 4.5 x 10(6)/kg. Higher infused doses of CD34(+) cell dose did not result in increased rates of either acute or chronic graft-versus-host disease (GVHD). Three-year OS and disease-free survival (DFS) of recipients of MA, RI, and NMA approaches were similar (33%, 35%, and 32% OS; 33%, 30%, and 29% DFS, respectively). In summary, recipients of URD-PBSC HCT receiving preparative regimens differing in intensity experienced similar survival. Higher CD34(+) cell doses resulted in more rapid engraftment, less TRM, and better 3-year OS (39% versus 25%, MA, P = .004; 38% versus 21% RI/NMA, P = .004) but did not increase the risk of GVHD. This trial was registered at www.clinicaltrials.gov as #NCT00785525.

CD34?+ cell dose and outcome of patients undergoing reduced-intensity-conditioning allogeneic peripheral blood stem cell transplantation

While in bone marrow allogeneic transplantation the infusion of high doses of progenitor stem cells has a favourable impact on outcome, due to a faster hematopoietic and immune recovery, in the peripheral blood allo-setting the infusion of a high number of CD34 cells increases the risk of extensive chronic graft vs. host disease (cGVHD). This higher incidence of extensive cGVHD has an adverse impact on outcome due to a higher transplant related mortality, specially among patients receiving T-cell depleted allogeneic transplantation with myeloablative conditioning. By contrast, patients undergoing reduced intensity conditioning regimen may benefit from increasing higher CD34 + cell doses, especially those categorized as high risk according to disease status at transplant. Thus, the source of progenitors cells, type of conditioning and GVHD prophylaxis, among other factors, may influence the effect of the progenitor cell dose on outcome after allogeneic transplant.

International myeloma working group (IMWG) consensus statement and guidelines regarding the current status of stem cell collection and high-dose therapy for multiple myeloma and the role of plerixafor (AMD 3100)

Multiple myeloma is the most common indication for high-dose chemotherapy with autologous stem cell support (ASCT) in North America today. Stem cell procurement for ASCT has most commonly been performed with stem cell mobilization using colony-stimulating factors with or without prior chemotherapy. The target CD34+ cell dose to be collected as well as the number of apheresis performed varies throughout the country, but a minimum of 2 million CD34+ cells/kg has been traditionally used for the support of one cycle of high-dose therapy. With the advent of plerixafor (AMD3100) (a novel stem cell mobilization agent), it is pertinent to review the current status of stem cell mobilization for myeloma as well as the role of autologous stem cell transplantation in this disease. On June 1, 2008, a panel of experts was convened by the International Myeloma Foundation to address issues regarding stem cell mobilization and autologous transplantation in myeloma in the context of new therapies. The panel was asked to discuss a variety of issues regarding stem cell collection and transplantation in myeloma especially with the arrival of plerixafor. Herein, is a summary of their deliberations and conclusions.

TBI with lung dose reduction does not improve hematopoietic cell homing to BM during allogeneic transplantation

Purpose

To determine the effects of total body irradiation (TBI) dose, fractionation, and lung shielding on hematopoietic stem cell homing to the bone marrow.

Material and Methods

Bone marrow (BM) cells were extracted from tibiae and femurs of B6-GFP mice and were transplanted into B6 mice. Recipient mice had either: 1) no radiation, 2) single dose TBI at 13.6 Gray (Gy), 3) single dose TBI at 13.6 Gy with reduced lung exposure to 0.4 Gy by shielding, 4) split dose TBI at 12 Gy to twice/day over four days, or 5) split dose TBI at 12 Gy to twice/day over four days with reduced lung exposure to 0.36 Gy by shielding. The last radiation exposure preceded tail vein injection by 4–6 hours. Mice were sacrificed after 18 hours.

Results

Homing of GFP positive, lineage negative cells was not significantly improved in any irradiated group compared to control. Homing of GFP positive, lineage negative, Kit positive cells was significantly worse in all irradiated groups.

Conclusion

TBI does not improve the homing of lineage negative donor BM cells to the recipient marrow. Homing of lineage negative, Kit positive donor BM cells was significantly worse following TBI, with or without lung dose reduction.

Peripheral blood stem cell mobilization: new regimens, new cells, where do we stand

PURPOSE OF REVIEW

Granulocyte colony-stimulating factor-mobilized peripheral blood stem cells are widely used to reconstitute hematopoiesis; however, preclinical and clinical studies show that improvements to this mobilization can be achieved. We discuss the development of new mobilizing regimens and evaluation of new findings on mobilized stem cell populations that may improve the utility and convenience of peripheral blood stem cell transplant.

RECENT FINDINGS

Chemokines and their receptors regulate leukocyte trafficking, and altering chemokine signaling pathways mobilizes stem cells. In recent trials, combination use of the chemokine (C-X-C motif) receptor 4 antagonist AMD3100 and granulocyte colony-stimulating factor mobilized more CD34 cells in fewer days than granulocyte colony-stimulating factor alone and allowed more patients to proceed to autotransplant. In preclinical studies the chemokine GRObeta synergizes with granulocyte colony-stimulating factor and when used alone or with granulocyte colony-stimulating factor mobilizes more primitive hematopoietic stem cells with less apoptosis, higher integrin activation, lower CD26 expression and enhanced marrow homing compared with granulocyte colony-stimulating factor. Hematopoietic stem cells mobilized by GRObeta or AMD3100 demonstrate superior engraftment and contribution to chimerism in primary and secondary transplant studies in mice, and peripheral blood stem cells mobilized by AMD3100 and granulocyte colony-stimulating factor in patients demonstrate enhanced engraftment capabilities in immunodeficient mice.

SUMMARY

Alternate regimens differentially mobilize stem cell populations with unique intrinsic properties with the potential to expand the utility of hematopoietic transplantation. Continued mechanistic evaluation will be critical to our understanding of mechanisms of mobilization and their use in regenerative medicine.

Impact of graft cell dose on transplant outcomes following unrelated donor allogeneic peripheral blood stem cell transplantation: higher CD34+ cell doses are associated with decreased relapse rates

Peripheral blood stem cells (PBSC) have been increasingly used in the matched unrelated donor (MUD) transplant setting, but the impact of CD34(+) cell dose on outcomes in this setting have not been well characterized. We analyzed 181 consecutive patients who underwent MUD-PBSC transplantation at the City of Hope between August 2000 to December 2004. Patients were conditioned with either full-intensity regimen or reduced-intensity regimen. There was a significant inverse relationship between higher CD34(+) cell dose and faster neutrophil engraftment (r = -0.16, P = .035). By univariate analysis, a CD34(+) cell dose > or =4.2 x 10(6)/kg (above the lowest quartile) was associated with significantly lower relapse risk (hazard ratio [HR] = 0.67, P = .0126), with a trend for corresponding improvement for disease-free survival (HR = 0.84, P = .12) but not overall survival (HR = 0.91, P = .46). The impact of the CD34(+) cell dose remained significant in multivariate analysis. The higher CD34(+) cell dose was significantly associated with faster recovery of absolute lymphocyte counts on day +30 posttransplant. Subset analysis demonstrated that the higher CD34(+) cell dose was associated with (1) greater reduction in relapse in myeloid malignancies than that in lymphoid malignancies, (2) greater reduction in reduced-intensity conditioning than in full-intensity conditioning, (3) greater reduction in relapse when there is a inhibitory killer-cell immunoglobulin-like receptor ligand (iKIRL)-mismatch in the gravft-versus-host (GVH) direction, and (4) greater reduction in relapse when there is a lack of iKIRL, suggesting that the protective effect of CD34(+) cell dose against relapse may be immune-mediated, possibly through NK cell recovery.

B-cell concentration in the apheretic product predicts acute graft-versus-host disease and treatment-related mortality of allogeneic peripheral blood stem cell transplantation

BACKGROUND

The influence of the graft composition on the clinical outcome after allogeneic peripheral blood stem cell (PBSC) transplantation is not well established.

METHODS

The cellular composition of the apheretic products obtained from 63 human leukocyte antigen-identical siblings was prospectively correlated with the outcome of patients with hematological malignancies undergoing an allogeneic PBSC transplant after myeloablative conditioning. The concentration of nuclear, mononuclear, CD34+, T-cell subsets, B cells, and natural killer cells in the graft has been analyzed.

RESULTS

In univariate analysis, acute graft-versus-host disease (GVHD) correlated with the disease (P=0.002), with the phase of disease at transplant (P=0.01), and with the number of CD20+ cells infused (P=0.05). In multivariate analysis, a dose of CD20+ cells in the graft higher than the median dose remained the only factor negatively affecting the incidence of acute GVHD (P=0.01; 95% confidence interval [CI]: 0.12-0.78). In univariate analysis, treatment-related mortality (TRM) correlated with the disease (P=0.04) and was negatively affected by a dose of infused B cells greater than the median value (28% versus 50%; P=0.02). In multivariate analysis, TRM was close to statistical correlation with the dose of CD20+ cells (P=0.06; 95% CI: 0.02-1.05). No other clinical parameter was influenced by the composition of the graft.

CONCLUSIONS

Our results suggest that the concentration of B cells in the apheretic product may predict the incidence of acute GVHD and TRM in patients undergoing an allogeneic PBSC transplantation and open the way to the new preventive and therapeutic strategies for the management of GVHD.

Impact of natural killer cell dose and donor killer-cell immunoglobulin-like receptor (KIR) genotype on outcome following human leucocyte antigen-identical haematopoietic stem cell transplantation

To define the role of quantitative graft composition and donor killer-cell immunoglobulin-like receptor (KIR) genotype in clinical outcome following unmanipulated peripheral blood stem cell transplantation (PBSCT) from human leucocyte antigen (HLA)-identical siblings, 43 consecutive transplants for haematological malignancies were analysed retrospectively. Twenty-four patients underwent myeloablative conditioning and 19 received busulphan/fludarabine-based reduced intensity conditioning (RIC). In patients with acute myelogenous leukaemia or myelodysplastic syndrome (AML/MDS; n = 18), no relapse occurred following transplants meeting both a high (above median) natural killer (NK) cell count and missing HLA-ligand(s) to donor's KIR(s), compared to all other AML/MDS patients (0% versus 44%; P = 0.049). Missing HLA-B and/or HLA-C ligand combined with missing HLA-A3/11 (KIR3DL2 unblocked) predicted for reduced relapse incidence regardless of diagnosis or conditioning type (P = 0.028). Moreover, in AML/MDS patients, this constellation predicted superior overall survival (OS) (P = 0.046). Transplants with more than two different activating donor KIRs were associated with an increased risk for non-relapse mortality (NRM), both by univariate and multivariate analysis. Quantitative graft composition had a significant impact exclusively in RIC transplants. Here, a trend towards reduced relapse incidence was found in patients receiving high numbers of NK cells (16% versus 54%; P = 0.09). In patients receiving high versus low T cell numbers, OS was superior (83% versus 37%; P = 0.01), due mainly to reduced NRM (0% versus 33%; P = 0.046). By multivariate analysis, relapse risk was decreased significantly in patients receiving high NK cell numbers (P = 0.039). These data suggest that both the number of transplanted NK cells and the donor KIR genotype play a role in graft-versus-malignancy mechanisms in HLA-identical PBSCT.

Allogeneic stem cell transplantation following reduced-intensity conditioning can induce durable clinical and molecular remissions in relapsed lymphomas: pre-transplant disease status and histotype heavily influence outcome

The safety and efficacy of reduced-intensity conditioning (RIC) followed by allogeneic stem cell transplantation (SCT) for relapsed lymphomas remains unresolved. We conducted a prospective, multicentered, phase II trial. A total of 170 relapsed/refractory lymphomas received a RIC regimen followed by SCT from sibling donors. The primary study end point was non-relapse mortality (NRM). Histologies were non-Hodgkin's lymphomas (NHL) (indolent (LG-NHL), n=63; aggressive (HG-NHL), n=61; mantle cell lymphoma (MCL), n=14) and Hodgkin's disease (HD, n=32). Median follow-up was 33 months (range, 12-82). The results show that frequencies were as follows: cumulative NRM at 3 years, 14%; acute and chronic graft-versus-host disease (GVHD) 35 and 52%, respectively; 3-year overall survival (OS), 69% for LG-NHL, 69% for HG-NHL, 45% for MCL and 32% for HD (P=0.058); and 3-year relapse incidence, 29, 31, 35 and 81%, respectively (P<0.001). Relapse risk differed significantly at 3 years between follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL) (14 versus 46%, P=0.04). Molecular remission occurred in 94 and 40% (P=0.002) of patients with FL and CLL, respectively. On multivariate analysis, OS was influenced by chemorefractory disease (hazard ratio (HR)=3.6), diagnosis of HD (HR=3.5), and acute GVHD (HR=5.9). RIC allogeneic SCT is a feasible and effective salvage strategy in both indolent and aggressive NHL.

Efficacy of CD34+ stem cell dose in patients undergoing allogeneic peripheral blood stem cell transplantation after total body irradiation

We estimated the effect of CD34(+) stem cell dose during peripheral blood stem cell transplantation (PBSCT) in predicting mortality after total body irradiation (TBI). Between 1997 and 2004, 146 consecutive patients with hematologic malignancies received fractionated TBI (12-13.6 Gy) in 8 fractions over 4 days before undergoing PBSCT; 61 patients received TBI with reduced radiation dose to the lung (6-9 Gy). The number of CD34(+) cells transplanted was recorded for all patients. A cubic spline representation for CD34(+) dose within a Cox proportional hazards model was used to model the relationship between the CD34(+) dose and mortality. Median follow-up was 44 months (range, 12-90 months). The CD34(+) cell dose ranged from 2.45 to 15.90 x 10(6) cells/kg (median, 5.15 x 10(6) cells/kg). Risk of mortality decreased with CD34(+) doses between 4-8 x 10(6) cells/kg and then began to increase. For all patients, CD34(+) doses of 5.1-12.9 x 10(6)/kg resulted in at least a doubling of median survival associated with the lowest CD34(+) value. In patients treated with lung dose reduction, a similar range of CD34(+) dose (4.3-10.2 x 10(6) cells/kg) produced at least a 5-fold improvement from the survival associated with the lowest CD34(+) dose; however, the relationship between CD34(+) dose and mortality was not statistically different when analyzed by lung dose reduction. A method for assessing risk of mortality by CD34(+) dose as a continuous variable is presented. Risk of mortality decreased with CD34(+) doses between 4-8 x 10(6) cells/kg and then began to increase.

Risk assessment in haematopoietic stem cell transplantation: Stem cell source

Bone marrow (BM) has been used for many years as the unique source of progenitor cells for allogeneic transplantation. However, two other sources of progenitor cells, peripheral blood (PB) and umbilical cord (UC), are being increasingly used. The type of graft is one of the most important factors in determining the speed and robustness of the reconstitution after the transplant of monocytes, T lymphocytes, B lymphocytes, NK cells, and dendritic cells. This fact is of especial relevance since the most important reactions after allogeneic transplants - e.g. graft-versus-host disease (GVHD), graft-versus-leukaemia effect (GvL), achievement of full donor chimerism, and fight against infections - are strongly influenced by a rapid and robust reconstitution of these cells. For this reason, the choice of the type of graft for allogeneic transplantation will influence the clinical outcome.

The Graft Content of Donor T Cells Expressing γδTCR+ and CD4+foxp3+ Predicts the Risk of Acute Graft versus Host Disease after Transplantation of Allogeneic Peripheral Blood Stem Cells from Unrelated Donors

PURPOSE

Recently, high numbers of regulatory T cells within the stem cell graft were described to be associated with less graft-versus-host disease (GVHD) after related peripheral blood stem cell transplantation (PBSCT). Studies in mice also suggest a distinct role of gamma delta TCR(+) T cells in mediating GVHD. Therefore, the aim of this study was to define the yet-unknown role of regulatory and gamma delta TCR(+) T cells in human PBSCT from unrelated donors.

EXPERIMENTAL DESIGN

The frequency of both T-cell subsets within the graft was analyzed in 63 patients receiving unrelated allogeneic PBSCT. The respective amounts were quantified by flow cytometry and PCR and further correlated with clinical outcome.

RESULTS

The grafts contained a median of 11.2 x 10(6)/kg CD4(+)foxp3(+) and 9.8 x 10(6)/kg gamma delta TCR(+) T cells, respectively. Patients receiving more CD4(+)foxp3(+) cells had a lower cumulative incidence of acute GVHD II-IV (44% versus 65%, P=0.03). Interestingly, in patients who received higher concentrations of donor gamma delta TCR(+) T cells, acute GVHD II-IV was more frequent (66% versus 40%, P=0.02). In multivariate analysis, only the graft concentration of gamma delta TCR(+) T cells (P=0.002) and a positive cytomegalovirus status of the recipient (P = 0.03) were significantly associated with the occurrence of acute GVHD II-IV.

CONCLUSION

Graft composition of T-cell subsets seems to affect the outcome of patients receiving allogeneic PBSCT from unrelated donors. Therefore, selective manipulation or add-back of particular subsets might be a promising strategy to reduce the incidence of GVHD.

Mobilizing stem cells from normal donors: is it possible to improve upon G-CSF?

Currently, granulocyte colony stimulating factor (G-CSF) remains the standard mobilizing agent for peripheral blood stem cell (PBSC) donors, allowing the safe collection of adequate PBSCs from the vast majority of donors. However, G-CSF mobilization can be associated with some significant side effects and requires a multi-day dosing regimen. The other cytokine approved for stem cell mobilization, granulocyte-macrophage colony stimulating factor (GM-CSF), alters graft composition and may reduce the development of graft-versus-host disease, but a significant minority of donors fails to provide sufficient CD34+ cells with GM-CSF and some experience unacceptable toxicity. AMD3100 is a promising new mobilizing agent, which may have several advantages over G-CSF for donor mobilization. As it is a direct antagonist of the interaction between the chemokine stromal-derived factor-1 and its receptor CXCR4, AMD3100 mobilizes PBSCs within hours rather than days. It is also well tolerated, with no significant side effects reported in any of the clinical trials to date. Studies of autologous and allogeneic transplantation of AMD3100 mobilized grafts have demonstrated prompt and stable engraftment. Here, we review the current state of stem cell mobilization in normal donors and discuss novel strategies for donor stem cell mobilization.

Non-CD34+ cells, especially CD8+ cytotoxic T cells and CD56+ natural killer cells, rather than CD34 cells, predict early engraftment and better transplantation outcomes in patients with hematologic malignancies after allogeneic peripheral stem cell transplantation

The effect of the transplant dose of each cell subset on engraftment kinetics and transplantation outcomes was evaluated in HLA-identical allogeneic peripheral blood stem cell transplantation (PBSCT). Sixty-nine patients were included in this retrospective study. Engraftment kinetics, transplantation outcomes, and immune reconstitution up to 1 year after transplantation were analyzed according to the transplant dose of CD34+ and non-CD34+ cells, including natural killer (NK) cells and CD8+ cytotoxic T (Tc) cells. An accelerated neutrophil engraftment was strongly associated with a higher transplant dose of NK cells (12 versus 16 days, P < .001) and Tc cells (13 versus 16 days, P < .001) but not CD34+ cells (P = .442). Survival analyses revealed a favorable prognosis for patients who received a higher dose of non-CD34+ cell subsets, rather than CD34+ cells, in terms of overall survival (OS; P = .024 for NK cells and .050 for Tc cells) and nonrelapse mortality (NRM; P = .005 for NK cells, .060 for Tc cells). In addition, a higher transplant dose of NK and Tc cells was correlated with a faster lymphoid reconstitution. In multivariate analyses, rapid neutrophil engraftment was correlated with a higher transplant dose of NK cells (P = .001) and Tc cells (P = .004). Moreover, an increased OS was associated with the NK cell dose (P = .007) and chronic graft-versus-host disease (P = .009), whereas a decreased NRM was associated with the NK dose (P = .024). In conclusion, in a PBSCT setting, a higher transplant dose of NK and Tc cells accelerated neutrophil engraftment, improved the immune reconstitution, and decreased NRM, thereby increasing OS after allogeneic PBSCT.

G-CSF increases the number of peripheral blood dendritic cells CD16+ and modifies the expression of the costimulatory molecule CD86+

Dendritic cells (DC) play a key role in initiating immune reactions after allogeneic stem cell transplantation. The two main peripheral blood DC populations are myeloid (DC1) and lymphoplasmacytoid (DC2). A new subset of myeloid DC, expressing CD16, has been identified. We analyzed the number and CD86 expression of DC subsets in peripheral blood of 18 healthy donors, before and after granulocyte colony-stimulating factor (G-CSF) and in the inoculum of allogeneic peripheral blood transplants (allo-PBT; n=100) and allogeneic bone marrow transplants (allo-BMT; n=22). Granulocyte colony-stimulating factor administration increased the median number of DC1 (P=0.0007), of DC2 (P<0.0001) and of DC CD16+ (P=0.0001). Granulocyte colony-stimulating factor administration was also associated with a significant decrease of CD86 expression on DC1 (P=0.0003) and with a trend for an increase on DC CD16+ (P=0.07). Recipients of allo-PBT received similar quantities of DC1 and higher doses of DC2 and DC CD16+ than recipients of allo-BMT (P=0.5; P=0.0001; P<0.0001, respectively). Granulocyte colony-stimulating factor modifies the number of DC in peripheral blood and the expression of the costimulatory molecule CD86. This resulted in a different composition of DC2 and especially of DC CD16+ in the harvests, which might explain some of the differences observed in allogeneic reactions after allo-PBT with respect to allo-BMT.

Evidence that donor intrinsic response to G-CSF is the best predictor of acute graft-vs-host disease following allogeneic peripheral blood stem cell transplantation

OBJECTIVE

Risk factors of acute graft-vs-host disease (GVHD) following allogeneic bone marrow transplantation have been well described before. In this study, we tested the hypothesis that acute GVHD after allogeneic peripheral blood stem cell (PBSC) transplant might be associated with donors' responsiveness to granulocyte colony-stimulating factor (G-CSF), rather than the dose of CD34(+) cells infused.

PATIENTS AND METHODS

We retrospectively analyzed mobilization and transplant data (demographic characteristics, donor blood cell subsets after G-CSF, graft composition) in 149 consecutive HLA-identical donor/recipient pairs in order to identify acute GVHD risk factors.

RESULTS

In 25% of donors, G-CSF mobilization led to an outstanding response, defined as greater than 117 x 10(6) CD34(+) cells/L. Overall, incidence of grades II-IV acute GVHD was 20.1% (95% CI: 16.6-23.6). Following univariate analysis, the incidence increased significantly in recipients receiving greater than 10 x 10(6) CD34(+) cells/kg (35% vs 15%; p = 0.007), and those transplanted from outstanding mobilizers (41% vs 12%, p < 0.0001). In multivariate analysis, only transplantation from outstanding mobilizers remained significant (p = 0.02). Donor or recipient demographic characteristics and lymphocyte subsets reinfused in the graft had no impact.

CONCLUSIONS

We demonstrate for the first time that donor responsiveness to G-CSF is associated with acute GVHD following PBSC transplantation. If confirmed, this correlation will help to identify recipients who could potentially benefit from improved prophylaxis. As further corollary, decreasing the dose of CD34(+) cells infused is unlikely to prevent acute GVHD. Future studies should focus on the molecular bases of interindividual discrepancies in response to G-CSF.

Unrelated donor or partially matched related donor peripheral stem cell transplant with CD34+ selection and CD3+ addback for pediatric patients with leukemias

Unmodified peripheral stem cell transplants are associated with an increased risk of extensive chronic GVHD. T depletion may reduce this risk, but the risk of graft failure or relapse may increase. To decrease the risks of both extensive chronic GVHD and graft failure, we added back a defined dose of CD3+ cells to CD34+ selected PSCs. Twenty-four patients were evaluable for outcome analysis. Donors were unrelated (23) or related (1). Conditioning was thiotepa, cyclophosphamide, and total body irradiation. Cyclosporine was used post transplant. Following CD34+ selection, a total of 5 x 10(5)/kg CD3+ cells were infused. Donors were matched for 12 patients. The median CD34+ dose infused was 7.1 x 10(6)/kg. Engraftment occurred in all patients at a median of 14 days (10-19). Twelve patients are alive in remission 15-34 months (median, 25) post PSCT. GVHD occurred in 17 patients, but was >grade II in only 2. Chronic GVHD occurred in 61.5% of evaluable patients, but was limited to skin and perioral cavity. Two patients relapsed, and 10 patients died of non-relapse causes. This study demonstrates that PSCT with CD34+ selection and a defined dose of CD3+ results in prompt engraftment and may limit development of extensive chronic GVHD.

Transplantation with higher dose of natural killer cells associated with better outcomes in terms of non-relapse mortality and infectious events after allogeneic peripheral blood stem cell transplantation from HLA-matched sibling donors

BACKGROUND

Little is known about the role of the CD56+ natural killer (NK) cell dose on the outcome of allogeneic peripheral blood stem cell transplantation (PBSCT). Recently, higher dose of NK cells has been associated with a lower incidence of severe graft-versus-host disease (GVHD). The current study attempted to evaluate the effect of the NK cell dose on transplant outcomes in allogeneic PBSCT setting.

METHODS AND MATERIALS

Sixty-one cytokine mobilized PBSC recipients were analyzed according to the infused dose of CD34+ cells and NK cells in relation to overall survival (OS), non-relapse mortality (NRM), GVHD, and infectious events.

RESULTS

The group received a higher dose of NK cells (> or =5 x 10(7)/kg) showed a lower incidence of NRM (P = 0.0186) and infectious events (P = 0.0107). In a multivariate analysis, a higher dose of NK cells was correlated to better transplant outcomes for NRM (P = 0.042) with CD34+ cell dose (P = 0.018), and for infectious events (P = 0.013) with CD34+ cell dose (P = 0.016). Higher NK cell infusion group also showed a faster immune recovery in serial measurements at days +90, +180, and +365.

CONCLUSIONS

High dose of NK cells may play an important role in improving transplant outcomes, in terms of reducing NRM and infectious events together with CD34+ cells.

Influence of T-cell depletion on chronic graft-versus-host disease: results of a multicenter randomized trial in unrelated marrow donor transplantation

Donor-derived T cells have been proposed to play a role in pathogenesis of chronic graft-versus-host disease (cGVHD). The impact of ex vivo T-cell depletion (TCD) on cGVHD was analyzed in a randomized multicenter trial involving unrelated donor marrow transplants. A total of 404 patients diagnosed with hematologic malignancies received a total body irradiation-based myeloablative conditioning regimen. GVHD prophylaxis included TCD plus cyclosporine (CSA) or unmodified grafts with CSA plus methotrexate (M/C). Median recipient age was 31.2 years (range, 0.5-55.6 years); median follow-up time since randomization was 4.2 years. The mean number of T cells infused was 1 log lower on the TCD arm. The incidence of cGVHD at 2 years was similar between the TCD and M/C arms, 29% versus 34% (P = .27), respectively. Survival at 3 years from diagnosis of cGVHD was also similar, (TCD 51% versus M/C 58%; P = .29). The proportion of patients with cGVHD who discontinued immunosuppression at 5 years was not different (TCD 72% versus M/C 63%; P = .27), and incidence of serious infections and leukemia relapse were similar on both treatment arms. In spite of a significant reduction of acute GVHD, TCD did not reduce the incidence of cGVHD or improve survival in patients who developed cGVHD.

Reduced risk of acute GVHD following mobilization of HLA-identical sibling donors with GM-CSF alone

We retrospectively reviewed the results of transplanting peripheral blood progenitor cell (PBPC) allografts from HLA-matched sibling donors mobilized using various hematopoietic cytokines. Patients had received allografts mobilized with Granulocyte colony-stimulating factor (G-CSF) (G, N = 65) alone, G plus Granulocyte-macrophage colony stimulating factor (GM-CSF) (G/GM, N = 70), or GM-CSF alone at 10 or 15 microg/kg/day (GM, N = 10 at 10 microg/kg/day and 21 at 15 microg/kg/day). The CD34+ and CD3+ cell content of grafts were significantly lower following GM alone compared to G alone (P < 0.001 and 0.04, respectively). Nonhematopoietic toxicity observed in donors precluded dose escalation of GM-CSF beyond 10 microg/kg/day. Hematopoietic recovery was similar among all three groups. Grades II-IV acute graft-versus-host disease (GVHD) was observed in only 13% of patients in the GM alone group compared to 49 and 69% in the G alone or G/GM groups, respectively (P < 0.001). In a multivariate analysis, receipt of PBPC mobilized with GM alone was associated with a lower risk of grades II-IV acute GVHD (hazard ratio 0.21; 95% CI 0.073, 0.58) compared to G alone or G/GM. There were no differences in relapse risk or overall survival among the groups. Donor PBPC grafts mobilized with GM-CSF alone result in prompt hematopoietic engraftment despite lower CD34+ cell doses and may reduce the risk of grades II-IV acute GVHD following HLA-matched PBPC transplantation.

High doses of transplanted CD34+ cells are associated with rapid T-cell engraftment and lessened risk of graft rejection, but not more graft-versus-host disease after nonmyeloablative conditioning and unrelated hematopoietic cell transplantation

This report examines the impact of graft composition on outcomes in 130 patients with hematological malignancies given unrelated donor granulocyte-colony-stimulating-factor-mobilized peripheral blood mononuclear cells (G-PBMC) (n = 116) or marrow (n = 14) transplantation after nonmyeloablative conditioning with 90 mg/m(2) fludarabine and 2 Gy TBI. The median number of CD34(+) cells transplanted was 6.5 x 10(6)/kg. Higher numbers of grafted CD14(+) (P = 0.0008), CD3(+) (P = 0.0007), CD4(+) (P = 0.001), CD8(+) (P = 0.004), CD3(-)CD56(+) (P = 0.003), and CD34(+) (P = 0.0001) cells were associated with higher levels of day 28 donor T-cell chimerism. Higher numbers of CD14(+) (P = 0.01) and CD34(+) (P = 0.0003) cells were associated with rapid achievement of complete donor T-cell chimerism, while high numbers of CD8(+) (P = 0.005) and CD34(+) (P = 0.01) cells were associated with low probabilities of graft rejection. When analyses were restricted to G-PBMC recipients, higher numbers of grafted CD34(+) cells were associated with higher levels of day 28 donor T-cell chimerism (P = 0.01), rapid achievement of complete donor T-cell chimerism (P = 0.02), and a trend for lower risk for graft rejection (P = 0.14). There were no associations between any cell subsets and acute or chronic GVHD nor relapse/progression. These data suggest more rapid engraftment of donor T cells and reduced rejection rates could be achieved by increasing the doses of CD34(+) cells in unrelated grafts administered after nonmyeloablative conditioning.

Mobilization and collection of peripheral blood progenitor cells for transplantation

Bone marrow transplantation gradually expanded as a treatment modality for various malignant and non malignant disease conditions. Since the discoveries of the potential of Peripheral Blood Progenitor Cells (PBPC) in the hematopoietic reconstitution mid 1980s and early 1990s PBPC gradually replaced bone marrow as the preferred source of stem cells. The introduction of hematopoietic cytokines that can mobilize large number of progenitors into circulation accelerated PBPC usage. Technological advancements in the apheresis instrumentation greatly helped in the conversion from marrow to PBPC. PBPC collection is less painful, less expensive and transplant with PBPC results in faster hematological recovery than with marrow. Almost all of the autologous transplants are currently performed with PBPC and a similar trend is seen with the allogeneic transplants. The progenitor cell mobilization regimen for autologous patients can be cytokines alone or cytokines combined with chemotherapy. In the majority of the patients the required minimal cell dose of 2.5-5.0 x 10(6)/kg CD34+ cells can be collected in one or two apheresis collections. A few of autologous transplant patients who mobilize poorly require several collections. Allogeneic donors are generally mobilized with daily subcutaneous injections of G-CSF 10 microg/kg for 5 days. The PBPC are collected in one or two apheresis procedures. The side effects of G-CSF are generally mild to moderate; however rare serious reactions including rupture of the spleen have been reported. The collection of PBPC in pediatric patients poses additional challenges yet an adequate dose of cells can be collected with the available apheresis instrumentation. The apheresis collection procedures are safe with no serious adverse consequences. Future scientific advancements may expand the use of PBPC for other clinical application in addition to the current use for hematological reconstitution.

CD34, CD4, and CD8 cell doses do not influence engraftment, graft-versus-host disease, or survival following myeloablative human leukocyte antigen-identical peripheral blood allografting for hematologic malignancies

OBJECTIVES

Optimal granulocyte colony-stimulating factor-mobilized peripheral blood progenitor cell (G-PBMC) graft compositions for myeloablative allogeneic hematopoietic cell transplantation (AHCT) have not been identified. G-PBMC cell contents were analyzed for influence on outcomes.

PATIENTS AND METHODS

Human leukocyte antigen(HLA)-identical related donor AHCT was used to treat 101 patients with hematologic malignancies at a single institution between 1995 and 2002. CD34+, CD3+, CD4+, and CD8+ cell doses were enumerated by flow cytometry and evaluated by univariate analysis.

RESULTS

Categorized by the median of cell doses infused, no G-PBMC cell dose significantly correlated with neutrophil and platelet engraftment. Incidence of grade II to IV acute graft-versus-host disease (GVHD) was 24.6% (95% confidence interval [CI]: 15.9-33.3) and was not significantly influenced by evaluated G-PBMC cell doses. With a median follow-up time of 18 months for surviving patients, estimates for extensive chronic GVHD was 43.8% (95% CI: 31.4-56.2), for freedom from progression was 69.5% (95% CI: 58.1-80.9), and for overall survival was 46.9% (95% CI: 35.5-58.3). CD34+, CD3+, CD4+, and CD8+ cell doses were not significantly predictive of extensive chronic GVHD, freedom from progression or overall survival. Additionally, comparing patients receiving the upper versus lower 33rd percentiles of CD34+ cell dose, associations with extensive chronic GVHD remained insignificant (p=0.21; relative risk (RR)=1.7; 95% CI: 0.7-3.9).

CONCLUSIONS

G-PBMC graft content does not influence outcomes after myeloablative AHCT. In particular, no significant association between extensive chronic GVHD was identified with any G-PBMC cell dose, including CD34.

NK-KIR Transcript Kinetics Correlate With Acute Graft-Versus-Host Disease Occurrence After Allogeneic Bone Marrow Transplantation

Natural killer (NK) cell alloreactivity observed during stem cell transplantation (SCT) can be either beneficial (graft-versus-leukemia effect) or detrimental to the host (graft-versus-host disease). Killer immunoglobulin-like receptors (KIRs), expressed on NK and CD8 memory T cells, are regulated at a posttranscriptional level and, because there are currently no KIR-specific antibodies available, the analysis of these receptors remains elusive. To better define the role of cells expressing KIR after SCT, we studied KIR transcript repertoires in 29 grafted patients who received myeloablative or nonmyeloablative regimens. We restricted our analysis to 3DL1, 3DL2, 2DL4, 2DS3, and 2DS4 KIR transcripts 6 months after SCT. Absolute counts of NK and CD8 T cells were determined by flow cytometry, and KIR transcripts were quantified by real-time reverse transcription polymerase chain reaction at days 14, 28, 60, 100, and 180 after transplantation. Three groups of patients were identified. Groups I and III were characterized by the absence or a delayed appearance of KIR transcripts, which correlated with the highest risk of acute graft-versus-host disease (aGvHD). In contrast, in group II, a significant transcript peak was observed early, and only one patient suffered from aGvHD (p = 0.025). Thus determining the kinetics of KIR transcription should make it possible to identify transplanted patients at a high risk of developing aGvHD.

Infused CD34+ cell dose predicts long-term survival in acute myelogenous leukemia patients who received allogeneic bone marrow transplantation from matched sibling donors in first complete remission

Allogeneic stem cell transplantation (ASCT) has improved the outcome of acute myelogenous leukemia (AML). To further improve the treatment outcome of ASCT in AML, finding a modifiable prognostic factor is mandatory. We evaluated the effect of CD34(+) cell dose on survival in allogeneic bone marrow transplantation (BMT) from HLA-matched sibling donors for AML patients in first complete remission (CR1). The 99 patients included in our analysis were classified into high CD34(+) cell dose group (CD34(+) cells > or = 2.5 x 10(6)/kg) and low CD34(+) cell dose group (CD34(+) cells < 2.5 x 10(6)/kg). The high CD34(+) cell dose patients had better overall survival (5-year overall survival rate, 75% +/- 6% vs 52% +/- 9%; P = .01) and leukemia-free survival (5-year leukemia-free survival rate, 70% +/- 6% vs 44% +/- 9%; P = .04). CD34(+) cell dose was the only independent prognostic factor in overall survival and leukemia-free survival. The high CD34(+) cell dose group had a lower relapse incidence with a borderline statistical significance (5-year relapse rate, 27% +/- 6% vs 50% +/- 10%; P = .09). There were no differences in the engraftment of neutrophil and platelet, grade II-IV acute graft-versus-host disease (GVHD), extensive-stage chronic GVHD, and transplant-related mortality between the high and low CD34(+) cell dose groups. We confirmed that high CD34(+) cell dose favorably affects the outcomes in allogeneic BMT for AML. The effort to attain a high CD34(+) cell dose should be pursued during bone marrow harvest in allogeneic BMT for AML in CR1.

CD8+ T cell dose affects development of acute graft-vs-host disease following reduced-intensity conditioning allogeneic peripheral blood stem cell transplantation

OBJECTIVE

Acute graft-vs-host disease (aGVHD) remains an important cause of morbidity after reduced-intensity conditioning (RIC) allogeneic transplantation (allo-SCT). It has been shown that antithymocyte globulin (ATG) dose infused during RIC is a major determinant for the likelihood of developing aGVHD. The ATG modulation on aGVHD is likely related to in vivo T-cell depletion.

PATIENTS AND METHODS

We therefore investigated the relationship between the cellular composition of the allograft and clinical outcome in 57 patients who received allogeneic peripheral blood stem cells from HLA-identical siblings following an ATG-based RIC.

RESULTS

In a multivariate analysis, the CD8+ T cell dose infused was the only parameter associated with the risk of aGVHD (p=0.031; RR=1.96; 95% CI, 1.1-3.6). When looking at the extremes, patients experiencing grade III-IV aGVHD received a median of 143 x 10(6)/kg CD8+ T cells, while patients without aGVHD received a median of 96 x 10(6)/kg CD8+ T cells (p=0.021). None of the different cell subtypes contained in the allograft was associated with a significant probability of developing chronic GVHD. Patients with grade II aGVHD who received an intermediate dose of CD8+ T cells (median, 111 x 10(6)/kg) had a significantly better overall survival in comparison to patients with grade 0-I or grade III-IV aGVHD (p=0.009).

CONCLUSION

In comparison to myeloablative allo-SCT, these results demonstrate that a cautious monitoring of the number of cells infused, at least in the context of ATG-based RIC, may represent an important predictive indicator of early transplant-related events and outcome after RIC allo-SCT.