Bone marrow transplantation for chronic myeloid leukemia (CML) from unrelated and sibling donors: single center experience

Higher therapeutic CsA levels early post transplantation reduce risk of acute GVHD and improves survival

We studied whether early CsA trough levels were associated with the risk of acute GVHD in 337 patients after either sibling PBSC or double umbilical cord blood transplantation. All patients, regardless of donor type, started CsA at a dose of 5 mg/kg i.v. divided twice daily, targeting trough concentrations 200-400 ng/mL. The CsA level was studied by a weighted average method calculated by giving 70% of the weight to the level that was measured just before the onset of the event or day +30. We found that higher weighted average CsA trough levels early post transplantation contributed to lower risk of acute GVHD, and lower non-relapse and overall mortality. Thus, our data support close monitoring with active adjustments of CsA dosing to maintain therapeutic CsA levels in the first weeks of allo-HCT. In patients who are near or even modestly above the CsA target trough level, in the absence of CsA-related toxicity, dose reduction should be cautious to avoid subtherapeutic drug levels resulting in higher risk of acute GVHD.

Mobilization of hematopoietic progenitors from normal donors using the combination of granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor results in fewer plasmacytoid dendritic cells in the graft and enhanced donor T cell engraftment with Th1 polarization: results from a randomized clinical trial

Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) both mobilize CD34(+) stem cells into the blood when administered before apheresis but have distinct effects on dendritic cell (DC) differentiation. We previously demonstrated that the combination of GM+G-CSF results in fewer plasmacytoid DCs (pDCs) when used to mobilize peripheral blood stem cells for autologous transplantation. To test the hypothesis that the content of pDCs in an allograft can be modulated with the cytokines used for mobilization, we randomized the human leukocyte antigen-matched sibling donors of 50 patients with hematological malignancies to a mobilization regimen of either GM+G-CSF (n = 25) or G-CSF alone (n = 25). Primary and secondary endpoints included the cellular constituents of the mobilized grafts, the kinetics of posttransplantation immune reconstitution, and clinical outcomes of the transplantation recipients. Grafts from donors receiving GM+G-CSF contained equivalent numbers of CD34(+) cells with fewer pDCs and T cells, with a higher fraction of Th1-polarized donor T cells than G-CSF mobilized grafts. Immune recovery was enhanced among recipients of GM+G-CSF. Survival was not significantly different between transplantation recipients in the two arms. The use of GM+G-CSF modulates immune function and recovery after allogeneic transplantation and should be explored in larger studies powered to evaluate clinical outcomes.

Effect of once-a-day fractionated total body irradiation on the risk of relapse after non-T-cell-depleted HLA-matched sibling transplantation

PURPOSE

The aim of this study was to assess the impact of fractionated total body irradiation (F-TBI) on treatment-related mortality (TRM) and relapse in patients who received a non-T-cell-depleted allogeneic stem cell transplantation (ASCT) for hematological malignancies.

MATERIALS AND METHODS

Between March 2003 and December 2004, a total of 24 patients with HLA-identical sibling donors entered this study and received three doses of 3.33 Gy F-TBI separated by 24 h and cyclophosphamide or etoposide.

RESULTS

At a median follow-up of 37 months (range 29-47 months), 4 of the 24 patients (16.6%) died of TRM. Relapse occurred in 10 patients at a median of 9 months (range 2-18 months). Overall, 13 of 24 patients (54%) died. Relapse was the most common cause of death (9/13). The 2-year actuarial survival rate was 46% (+/-11%).

CONCLUSION

In our experience, ASCT conditioned with F-TBI was associated with low TRM but a high early relapse rate in patients with hematological malignancies.

Autotransplantation versus HLA-matched unrelated donor transplantation for acute myeloid leukaemia: a retrospective analysis from the Center for International Blood and Marrow Transplant Research

Most acute myeloid leukaemia (AML) patients lack human leucocyte antigen-identical sibling donors for transplantation. Autotransplants and unrelated donor (URD) transplants are therapeutic options. To compare autologous versus URD transplantation for AML in first (CR1) or second complete remission (CR2), we studied the outcomes of 668 autotransplants were compared with 476 URD transplants reported to the Center for International Blood and Marrow Transplant Research. Proportional hazards regression adjusted for differences in prognostic variables. In multivariate analyses transplant-related mortality (TRM) was significantly higher and relapse lower with URD transplantation. Adjusted 3-year survival probabilities were: in CR1 57 (53-61)% with autotransplants and 44 (37-51)% URD (P = 0.002), in CR2 46 (39-53)% and 33 (28-38)% respectively (P = 0.006). Adjusted 3-year leukaemia-free survival (LFS) probabilities were: CR1 53 (48-57)% with autotransplants and 43 (36-50)% with URD (P = 0.021), CR2 39 (32-46)% and 33 (27-38)% respectively (P = 0.169). Both autologous and URD transplantation produced prolonged LFS. High TRM offsets the superior antileukaemia effect of URD transplantation. This retrospective, observational database study showed that autotransplantation, in general, offered higher 3-year survival for AML patients in CR1 and CR2. Cytogenetics, however, were known in only two-thirds of patients and treatment bias cannot be eliminated.

Donor age and degree of HLA matching have a major impact on the outcome of unrelated donor haematopoietic cell transplantation for chronic myeloid leukaemia

We analysed the outcome of 92 consecutive unrelated donor haematopoietic cell transplantations (UD-HCTs) performed in Spain to treat adult patients with CML in the first chronic phase (1CP). Patients' and donors' median age was 32 (15-49) and 36 (22-56) years, respectively. In all, 73 pairs (79%) matched for A, B+/-C and DRB1+/-DQB1 loci and 19 had > or =1 mismatch. Their probability of survival and disease-free survival at 4 years were 50 and 46%, respectively. Pretransplant factors associated with a better survival were patient age <25 years (P=0.035), donor age < or =36 years (P=0.012), use of cyclosporine since day -7 (P=0.001), and matching 8/8, 9/10 or 10/10 loci at allele level (P=0.003). In multivariate analysis only donor age (P=0.003; RR=3.1 (95% CI: 1.3-7.1)) and degree of HLA-matching (P=0.009; RR: 7.7 (95% CI: 1.8-33)) maintained their significance. The addition of these two variables to the EBMT prognostic score allowed an adequate risk assessment for patients receiving a UD-HCT during 1CP. Our analysis shows that in patients with a young and fully allele-matched donor, UD-HCT should be considered in the initial therapeutic algorithm due to its excellent outcome (92% survival at 2 years).

A revised day +7 predictive score for transplant-related mortality: serum cholinesterase, total protein, blood urea nitrogen, gamma glutamyl transferase, donor type and cell dose

We have previously described a scoring system for patients undergoing hemopoietic stem cell transplantation (HSCT) based on day +7 blood urea nitrogen (BUN) and serum bilirubin levels. We have revised that scoring system using a formal multivariate approach based on a training phase (305 patients) and a validation phase (217 patients). Day +7 BUN, serum cholinesterase (CHE), total proteins (TP), gamma glutamyl transferase (gammaGT), donor type and cell dose at transplant were included in the new score. The score distribution identified three groups of patients in the training set (<25, 25-75, >75 percentile of the score) which were classified as low, intermediate and high risk. Their actuarial risk of transplant-related mortality (TRM) at 6 years was, respectively, 12, 38 and 60%. In the validation set the 6 year actuarial TRM was, respectively, 15, 40 and 69%. High risk patients had more graft-versus-host disease (GvHD) (P <0.0001) and lower platelet counts (P <0.0001). This study confirms that GvHD and TRM can be predicted on day +7 after HSCT: pre-emptive GvHD therapy may be one option for high-risk patients and is being tested in a prospective randomized trial. The score for single patients can be calculated on the web site http://213.26.110.20/lrm/day_seven_score.html.

Low-dose fractionated total body irradiation (TBI) adversely affects prognosis of patients with leukemia receiving an HLA-matched allogeneic bone marrow transplant from an unrelated donor (UD-BMT)

The optimal total body irradiation (TBI) regimen for unrelated donor bone marrow transplant (UD-BMT) is unknown. In the present study we analyze the outcomes of two different TBI regimens used in our center for patients with leukemia undergoing an UD-BMT. Between January 1994 and August 2001, 99 consecutive UD-BMT patients entered this comparative study. The conditioning regimen consisted of cyclophosphamide, 120 mg/kg followed by TBI on days -3, -2 and -1. Forty-six patients received TBI 12 Gy (2 Gy, twice a day) in six fractions (HF-TBI) and 53 patients received TBI 9.90 Gy (3.30 Gy per day) fractionated over 3 days (F-TBI). End-points were transplanted-related mortality (TRM), leukemia relapse rate (LRR) and overall survival (OS). At median follow-up of 22 months (58 months for HF-TBI and 17 for F-TBI, respectively), 60 patients were alive (32 in HF-TBI sub-group and 28 in F-TBI one). The actuarial 5-year TRM was 31% for HF-TBI and 41% for F-TBI (P = 0.1), whereas the 5-year LRR was 13% for HF-TBI and 31% for F-TBI (P = 0.04). The actuarial 5-year OS was 68% for patients treated with HF-TBI and 51% for those treated with F-TBI (P = 0.02). At multivariate analysis F-TBI schedule emerged as an adverse predictor for OS (P = 0.04) and LRR (P = 0.03). These data indicate that a lower total dose of TBI appears significantly less effective in leukemia eradication and associated with worse overall survival when compared with a higher dose of radiation.

Dynamics of CD34+ progenitor cells following allogeneic bone marrow transplantation in Ph1+CML--an immunohistochemical study on 113 patients with sequential trephine biopsies

A retrospective immunohistological and morphometric study was performed on bone marrow trephine biopsies derived from 113 patients with Philadelphia chromosome-positive chronic myeloid leukemia (Ph(1+)-CML) before and at standardized intervals following allogeneic transplantation (BMT) with full unmanipulated marrow specimens. The purpose of this investigation was to quantify CD34+ progenitor cells and to determine their dynamics during the post-transplant period. Moreover, we tried to correlate their number with corresponding changes in the amount of nucleated erythroid precursors and megakaryocytes including pro- and megakaryoblasts and the fiber content. Monitoring the quantity of precursors after BMT revealed a very rapid recovery in comparison to a control group. However, a more detailed evaluation showed that at day 22 +/- 6 a higher number of progenitor cells was significantly associated with an earlier independence for platelet transfusion and also with a more pronounced growth of erythro- and megakaryopoiesis including their precursor cells. Furthermore, a slight increase in the density of the fibrous matrix (reticulin fibers) was present in these patients that were characterized by a more favorable engraftment. The latter feature sheds some light on the complex pathomechanisms of homing and differentiation of progenitors. In confirmation with in vitro findings, this phenomenon is dependent on proper anchoring sites to the fibrous bone marrow stroma. Finally, the size of a full BM graft exerted a distinctive influence on the number of CD34+ precursors in the early post-transplant period. In conclusion, the present study has validated a number of BM features by focusing on the CD34+ progenitor cells and associated hematopoietic reconstitution including reticulin fibers and precursor cells of the erythroid and megakaryocyte lineage, which are not readily evaluable by fluorescence-activated cell sorting (FACS) analysis.

Long-term medical outcomes and quality-of-life assessment of patients with chronic myeloid leukemia followed at least 10 years after allogeneic bone marrow transplantation

PURPOSE

Benchmark analysis of patients with chronic myeloid leukemia (CML) alive for more than 10 years after allogeneic bone marrow transplantation (BMT) including data on disease status, bone marrow reserve, long-term complications, and quality of life (QOL).

PATIENTS AND METHODS

Eighty-nine patients (46 in first chronic phase, 43 in advanced phase) received an allogeneic BMT for CML during the study period. Medical outcomes and QOL of patients were analyzed retrospectively.

RESULTS

Twenty-eight (31.5%) of 89 patients were alive at 10 years and included in this analysis. Thirteen (46.4%) of 28 long-term survivors never relapsed. Fifteen patients relapsed between 0.5 and 16 years after transplantation. Ten patients showed a hematologic relapse and received salvage treatment. Five patients showed transient low levels of BCR-ABL-positive cells by Southern blot with no subsequent hematologic relapse. One of the 28 patients died in blast crisis at 12 years. The most frequent long-term complications were chronic graft-versus-host disease, osteoporosis, and cataracts. Frequency of clonogenic progenitors remained persistently decreased. QOL assessment yielded lower scores in physical performance as compared with an age-matched normative population, whereas social functioning was equivalent. A high degree of satisfaction was noted with interpersonal relationships.

CONCLUSION

Patients with CML surviving their BMT long term do well in terms of medical outcomes. A constant rate of relapse was noted, with a high salvage rate of affected patients, suggesting the need for lifelong monitoring. QOL is perceived as good, particularly as related to social functioning; however, it is inferior to a normative population with regard to physical performance.

Improved disease-free–survival after transplantation of peripheral blood stem cells as compared with bone marrow from HLA-identical unrelated donors in patients with first chronic phase chronic myeloid leukemia

Outcomes after peripheral blood stem cell transplantation (PBSCT) for chronic phase chronic myeloid leukemia (n = 37) were compared with outcomes after bone marrow transplantation (BMT) (n = 54) in the HLA-compatible unrelated donor setting. Median follow-up was 17 months after PBSCT and 29 months after BMT. Both neutrophil and platelet recovery were faster after PBSCT (P &lt; .05). PBSCT was associated with improved immune reconstitution, with higher peripheral blood naive (CD4+CD45RA+) and memory (CD4+ CD45RO+) helper T cells at 3 months and 12 months after transplantation (P &lt; .03). The cumulative incidence of acute (grades II-IV) and chronic graft-versus-host disease (GVHD) were similar, but BMT was associated with a higher cumulative incidence of severe, acute (grade III-IV) GVHD at 24% as compared with 8% with PBSCT (P &lt; .05). Molecular relapse, defined by 2 consecutive positive polymerase chain reaction assays for bcr-abl within a 4-week interval, occurred in 12 of 45 evaluable patients (27%) after BMT and in 4 of 37 (11%) after PBSCT (not significant). Cytogenetic relapse occurred in 5 of 54 patients after BMT (9%) and in 1 of the 37 (3%) patients after PBSCT (not significant). Seventeen of the 54 patients died after BMT (31%), as compared with 2 of 37 patients after PBSCT (5%). Deaths in the BMT group were associated mainly with infections and severe, acute GVHD. The estimated probability of transplant-related mortality (TRM) and disease-free survival at 1000 days after receiving the transplant were 30% and 64% in the BMT group and 5% and 91% in the PBSCT group (P &lt; .03). Overall survival 1000 days after receiving the transplant was 66% after BMT and 94% after PBSCT (P &lt; .02). In the multivariate analysis, only acute GVHD significantly influenced TRM (P &lt; .01).

Pre-emptive therapy of acute graft-versus-host disease: a pilot study with antithymocyte globulin (ATG)

We have previously shown that patients at high risk of graft-versus-host disease (GVHD) and transplant-related mortality (TRM) can be identified on day +7 following an allogeneic bone marrow transplant (BMT), based on serum bilirubin and blood urea nitrogen levels. One possible approach to reduce the risk of GVHD and TRM, is pre-emptive treatment with T cell antibodies. We report a pilot study testing the feasibility of this approach in 18 high risk patients, with a median age of 41, 83% of whom had advanced disease, undergoing an alternative donor BMT (family mismatched in five and unrelated in 13). The patients received three doses of rabbit antithymocyte globulin (ATG) (Thymoglobuline; Sangstat) 1.25 mg/kg on alternate days, starting at a median interval of 11 days (range 7-13) after BMT. Controls were 20 historical unrelated donor transplants (median age 35, 63% with advanced disease), with a high score from our original publication in 1999. The actuarial 1 year TRM of the ATG-treated patients was 40% compared to 60% for untreated controls (P = 0.06). Severe grade III-IV aGVHD developed in 27% of the ATG-treated patients, and in 55% of the controls (P = 0.08). This study indicates that early pre-emptive treatment of aGVHD in day +7 high risk patients is feasible and may lead to a reduction of aGVHD and TRM. This approach is being tested in a prospective randomized trial.

Larger numbers of CD4(bright) dendritic cells in donor bone marrow are associated with increased relapse after allogeneic bone marrow transplantation

Relapse is the major cause of death after allogeneic bone marrow transplantation (BMT). This study tested the hypothesis that the numbers of donor mononuclear cells, lymphocytes, and CD34(+) cells influence relapse and event-free survival (EFS) after BMT. The study population consisted of 113 consecutive patients with hematologic malignancies who underwent non-T-cell-depleted BMT from HLA-matched siblings. Sixty-four patients had low-risk diagnoses (ALL/AML CR1, MDS RA/RARS, and CML CP1); 49 patients had high-risk diagnoses (all others). CD34(+) cells, T cells, B cells, natural killer cells, monocytes, and a rare population of CD3(-), CD4(bright) cells in the allografts were measured by flow cytometry. The CD3(-), CD4(bright) cells in bone marrow had the same frequency and phenotype as CD123(bright) type 2 dendritic cell (DC) progenitors, and they differentiated into typical DCs after short-term culture. Cox regression analyses evaluated risk strata, age, gender, and the numbers of nucleated cells, CD3(+) T cells, CD34(+) hematopoietic cells, and CD4(bright) cells as covariates for EFS, relapse, and nonrelapse mortality. Recipients of larger numbers of CD4(bright) cells had significantly lower EFS, a lower incidence of chronic graft-versus-host disease (cGVHD), and an increased incidence of relapse. Recipients of larger numbers of CD34(+) cells had improved EFS; recipients of fewer CD34(+) cells had delayed hematopoietic engraftment and increased death from infections. In conclusion, the content of donor CD4(bright) cells was associated with decreased cGVHD and graft-versus-leukemia effects in recipients of allogeneic bone marrow transplantation, consistent with a role for donor DCs in determining immune responses after allogeneic BMT.

Genetically haploidentical stem cell transplantation for acute leukemia

Genetically haploidentical stem cell transplants have been performed for several decades, mostly for patients with advanced acute leukemia. Such transplants are an option for those patients who do not have a histocompatible sibling donor. The historical data have been disappointing due to graft-versus-host disease, engraftment failure and delayed immune reconstitution. Recent modifications and new technological developments have led to more encouraging clinical results. Haploidentical transplantation is immediately available to the majority of patients with acute leukemia and is an acceptable alternative to matched unrelated donor transplantation.

Allogeneic transplantation for patients with advanced acute leukemia: a single center retrospective study of 92 patients

Allogeneic transplantation is a well recognized treatment strategy of leukemia. However, its use in advanced leukemia patients is a subject of some debate especially when donors are not HLA-identical siblings because of the toxicity and cost of the procedure. We reviewed retrospectively the outcome of patients (pts) who received allogeneic transplantation for advanced acute leukemia in our center between 09/86 and 11/97. Thirty-six pts (study group) who lacked a matched sibling donor received partially matched related donor (n=14: PMRD group) or matched unrelated donor transplantation (n=22: MUD group). Fifteen pts had AML and 21 ALL. Seventeen pts (47%) were in CR>1, 13 pts (36%) had refractory disease and six pts (17.7%) were in untreated relapse. The outcome was compared to that of 56 patients (AML: 45.5 %, ALL: 55.5 %, CR>1: 49.9 %, refractory disease: 37.5 %, untreated relapse 19.6 %) who received allogeneic transplantation from a matched sibling donor (control group). Various conditioning regimens and GVHD prophylaxis were used. The actuarial incidence of grade II to IV acute GVHD was significantly higher in the study group (57%) than in the control group (34%) (p=0.047). The actuarial risk of relapse at three years was 21% +/- 22% in the study group versus 65% +/- 16% in the control group (p= 0.04). The actuarial probability of transplant-related mortality at 3 years is 64 +/- 16% for the study group and 25 +/- 11% for the control group (p=0.001). The leading cause of death in the study group was infection (30%) followed by acute GVHD and relapse. Relapse was the major cause of death in the control group (54%), followed by infection, interstitial pneumonia, veno-occlusive disease and GVHD. The OS and probability of leukemia-free survival at 3 years were 28 % +/- 15% (95% CI) and 27% +/- 15% (95% CI) in the study group. The overall survival and probability of LFS at 3 years were respectively 28 +/- 12% (95% CI) and 23 +/- 12% (95% CI) in the control group (p = 0.08 and p=0.11 respectively). In multivariate analysis, transplant-related mortality was higher in the study group (p=0.04) and lower if both donor and recipient were seronegative for CMV (p=0.007). OS was significantly higher for seronegative couples (p=0.0001), and when CR was achieved before BMT (p=0.0022). These results suggest that all efforts in this field should be directed on lowering the transplant related mortality for non geno-identical transplants and the relapse rate in geno-identical transplants.

CD6+ donor marrow T-cell depletion as the sole form of graft-versus-host disease prophylaxis in patients undergoing allogeneic bone marrow transplant from unrelated donors

PURPOSE

The role of donor marrow T-cell depletion (TCD) in preventing graft-versus-host disease (GVHD) after transplantation of unrelated allogeneic marrow remains undefined. Because different TCD methodologies differ in the degree and specificity with which T cells are removed, it is likely that transplant outcomes would depend on which technique is used. Herein, we report results in the first 48 recipients of unrelated marrow using CD6+ TCD as the sole form of GVHD prophylaxis.

PATIENTS AND METHODS

Median age of patients was 46 years (20 to 58 years). Donors were matched at A/B HLA loci. Ablation consisted of cyclophosphamide and fractionated total-body irradiation (TBI; 14 Gy). To facilitate engraftment, patients also received 7.5 Gy (22 patients) [corrected] or 4.5 Gy (26 patients) [corrected] of total lymphoid irradiation (TLI) before admission. No additional immune suppressive prophylaxis was administered. Granulocyte colony-stimulating factor was administered daily from day +1 to engraftment.

RESULTS

All 48 patients demonstrated neutrophil engraftment. An absolute neutrophil count of 500 x 10(6)/L was achieved at a median of 12 days (range, 9 to 23 days). There were no cases of late graft failure. The number of CD34+ cells infused/kg was associated with speed of platelet and neutrophil recovery. The dose of TLI did not influence engraftment. Grades 2-4 acute GVHD occurred in 42% of patients (95% confidence interval [CI], 0.28 to 0.57). Mortality at day 100 was 19%. There have been only five relapses. Estimated 2-year survival was 44% (95% CI, 0.28 to 0.59) for the entire group, 58% for patients less than 50 years of age. In multivariable analysis, age less than 50 years (P =.002), cytomegalovirus seronegative status (P =.04), and early disease status at bone marrow transplant (P =.05) were associated with superior survival.

CONCLUSION

CD6+ TCD does not impede engraftment of unrelated bone marrow after low-dose TLI, cyclophosphamide, and TBI. CD6+ TCD as the sole form of GVHD prophylaxis results in an incidence of GVHD that compares favorably with many adult studies of unrelated transplantation using unmanipulated marrow and immune-suppressive medications, especially in light of the median age of our patients (46 years). Although event-free survival in patients less than 50 years of age is very encouraging, older patients experience frequent transplantation-related complications despite TCD.

Megakaryopoiesis and myelofibrosis in chronic myeloid leukemia after allogeneic bone marrow transplantation: an immunohistochemical study of 127 patients

An immunohistochemical and morphometric study was performed on 363 trephine biopsies of the bone marrow derived from 127 patients with chronic myeloid leukemia at standardized end points before and after allogeneic bone marrow transplantation (BMT). The purpose of this investigation was to evaluate features of CD61+ megakaryopoiesis related to successful engraftment. Further, we tried to elucidate possible associations of this lineage, including precursor cells, with the platelet count and reticulin fibrosis during the pretransplant and, specifically, post-transplant periods. A significant correlation was recognizable between the quantity of CD61+ megakaryocytes and the platelet values before BMT and also after completed hematopoietic recovery. In the very early post-transplant period, which is associated with severe thrombocytopenia, patchy regeneration of disarranged hematopoiesis occurred, including dysplastic megakaryocytes. According to planimetric measurements after BMT, the atypical micromegakaryocytes characteristic for chronic myeloid leukemia disappeared, and the engrafted donor bone marrow revealed a prevalence of normal-size cells of this lineage. On the other hand, normalization of megakaryocyte size was absent in sequential examinations of the few patients with a leukemic relapse who had a predominance of atypical dwarf forms comparable with chronic myeloid leukemia. Before BMT occurred, reticulin fiber density was significantly correlated with the number of CD61+ megakaryocytes and its precursor cell population. In 34 patients with myelofibrosis that occurred after myelo-ablative therapy and BMT, an initial regression was followed by an insidious recurrence of fibers concentrated in the areas of regenerating hematopoiesis. This postgraft reappearance of reticulin fibrosis was significantly associated with the quantity of megakaryocytes. Regarding engraftment parameters, pretransplant presence of (reticulin) myelofibrosis exerted a distinctive impact because of a delayed hematopoietic reconstitution according to standard clinical criteria. In line with this finding, slowed engraftment was also significantly related with higher pretransplant megakaryocyte and platelet counts.

Reconstitution of the CD45RO(+) and CD20(+) lymphoid marrow population following allogeneic bone marrow transplantation for Ph(+) CML

Following bone marrow transplantation (BMT) investigations on the recovery of the B and T lymphocyte populations have focused on the peripheral blood and only marginally regard the bone marrow. An immunohistochemical and morphometric study was performed on 352 trephine biopsies derived from 123 patients with chronic myelogenous leukemia (CML) at standardized endpoints before and after allogeneic BMT and compared to a control group. The purpose of this investigation was to quantify the B-CD20(+) and T-CD45RO(+) lymphocyte subsets and to determine possible relationships with the occurrence of acute and chronic GVHD. Moreover, we studied the dynamics of lymphocyte repopulation in the post-transplant period, correlations with the total peripheral lymphocyte count and differences associated with sibling vs alternate HLA-compatible (unmanipulated) marrow grafts. Morphometric analysis revealed a very fast regeneration of CD45RO(+) and CD20(+) marrow lymphocytes in the first 2 weeks following BMT. In less than 2 months, in most patients, the post-transplant quantity of lymphocytes was comparable to that of the normal bone marrow. This finding was opposed to the profound depression of the absolute lymphocyte count in the peripheral blood. No relevant relationships could be calculated between engraftment status and the lymphocyte repopulation in the bone marrow. On the other hand, significant correlations were calculable between the development of (chronic and acute) GVHD including severity with the number of CD45RO(+) lymphocytes. In non-related graft constellations a more frequent evolution of acute grade III + IV GVHD was detectable. This complication was accompanied by an increased quantity of CD45RO(+) lymphocytes in the marrow.

Allogeneic bone marrow transplantation from unrelated donors using in vivo anti-T-cell globulin

Despite improvements in HLA typing, graft-versus-host disease (GVHD) continues to impair the results after volunteer unrelated donor bone marrow transplantation (VUD-BMT) in adult patients compared with matched sibling BMT. Here, the outcome after VUD-BMT using a specific regimen with high-dose anti-T-lymphocyte globulin (ATG) was analysed. Fifty-five adult patients, median age 34 years (range 17-55 years), with acute or chronic leukaemia or myelodysplastic syndrome (MDS) were transplanted in first complete remission (CR1)/first chronic phase (CP1) (early disease) (n = 21) or in advanced (CR2/CP2, no remission) disease (n = 34) from an unrelated marrow donor. GVHD prophylaxis consisted of ATG-S (Fresenius) 60-90 mg/kg b.w. prior to transplantation, in addition to cyclosporin A and short-course methotrexate. Graft failure did not occur and white blood cell count (WBC) > 1.0 x 10(9)/l was reached at median day +16. The cumulative incidence of acute (a)GVHD grade II-IV was 15% [95% CI (8%, 28%)] and of chronic GVHD was 51% [95% CI (38%, 68%)]. The cumulative incidence of relapse within 1 year was 0% [95% CI (0%, 19%)] and 21% [95% CI (11%, 40%)] for patients with early and advanced disease respectively. With a median follow-up of 28 months (range 16-45 months), 2-year disease-free and overall survival for patients transplanted in CR1/CP1 was 81% and 81% [95% CI (64%, 98%)], respectively, and for patients with advanced disease was 33% [95% CI (17%, 50%)] and 40% [95% CI (23%, 57%)] respectively. Complete and persistent donor chimaerism was seen in 77.5% of 40 patients evaluated. All 14 chronic myeloid leukaemia (CML)-CP1 patients became bcr-abl negative within 250 d. High-dose ATG pretransplant results in a low incidence of severe aGVHD without compromising donor chimaerism or elimination of minimal residual disease. Our results are similar to data obtained after matched sibling donor transplantation.

Unrelated donor marrow transplantation for acute myeloid leukemia: an update of the Seattle experience

Between 1985 and 1998, 161 patients with primary acute myeloid leukemia (AML) received T-replete bone marrow transplantation (BMT) from unrelated donors in Seattle. Median age was 30 (range 1-55) years. Conditioning for BMT consisted of cyclophosphamide and total body irradiation in 154 (96%) cases and graft-versus-host disease prophylaxis was the standard methotrexate and cyclosporine combination in 134 (83%) cases. Median post-transplant follow-up was 2.9 years. Leukemia-free survival (LFS) at 5 years was 50+/-12% for transplants during first complete remission (n = 16), 28+/-8% during second CR (n = 40), 27+/-17% during subsequent CR (n = 8), 7+/-3% during relapse (n = 81) and 19+/-10% during primary induction failure (n = 16). The cumulative incidences of relapse were 19%, 23%, 25%, 44% and 63%, for the five groups, respectively. Transplantation during remission, a marrow cell dose above 3.5 x 10(8)/kg, and cytomegalovirus seronegative status before BMT in both patient and donor were favorable prognostic factors. Adults in any CR who received a marrow cell dose above 3.5 x 10(8)/mg had a LFS of 54+/-9% at 5 years. These data extend our previous findings on the association between a high marrow cell dose and improved survival and support the use of unrelated donor BMT for treatment of patients with high risk AML when a family match is not available.

Relevance and dynamics of myelofibrosis regarding hematopoietic reconstitution after allogeneic bone marrow transplantation in chronic myelogenous leukemia--a single center experience on 160 patients

A retrospective single center study was performed on 516 trephine biopsies derived from 160 patients with stable phase Ph+-CML and allogeneic BMT. Following morphometric quantification of reticulin-collagen fibers we tried to elucidate (1) the dynamics of bone marrow fibrosis in the post-transplant period; and (2) the influence of manifest myelofibrosis on relevant engraftment parameters. An evaluation of fiber density at standardized endpoints after BMT was carried out on a selected cohort of 124 patients (399 biopsy specimens). A manifest myelofibrosis (more than a three-fold increase compared to the normal fiber content) before BMT was found in 26% of our patients. Concentrating on bone marrow areas with reconstituting hematopoiesis, several findings emerged. Pretransplant myelofibrosis was associated with an initial regression following BMT, but insidiously recurred in the areas of regenerating hematopoiesis or developed in a few patients without increased pregraft fibers during the post-transplant period (mean observation time more than 4 months). Severe acute GVHD (grades III and IV) was significantly correlated with a greater amount of reticulin fibers in the early post-transplant period (9 to 30 days after BMT). Regarding engraftment parameters, a significant delay was detectable in the time to achieve transfusion independence for the patients with manifest myelofibrosis compared to those without pre-transplant fiber increase.

Erythropoietic reconstitution, macrophages and reticulin fibrosis in bone marrow specimens of CML patients following allogeneic transplantation

A clinicopathological study was conducted on 351 bone marrow trephine biopsies derived from 124 patients with chronic myeloid leukemia (CML) at standardized endpoints before and after allogeneic bone marrow transplantation (BMT). The purpose was to investigate quantitative changes of the nucleated erythroid precursor cell population and other associated features such as resident bone marrow macrophages and myelofibrosis and to elucidate their relevance on engraftment parameters. Monoclonal antibodies were applied for the identification of erythroid precursors and the labeling of mature macrophages; argyrophilic (reticulin-collagen) fibers were demonstrated by a silver impregnation technique. Following morphometric analysis of the pregraft bone marrow specimens statistical evaluation was in line with an adverse correlation between early to moderate reticulin fibrosis and amount of erythropoiesis. Moreover, a significant relationship was calculable between numbers of erythroid precursors and CD68+ macrophages. After myelo-ablative therapy and BMT a pronounced decrease in cellularity and in the quantity of erythropoiesis was found. Comparable with the pregraft samples, a significant association between erythroid precursors and macrophages could be determined in the regenerating donor bone marrow. A pretransplant relevant reduction of the red cell lineage and a manifest (reticulin) myelofibrosis indicating an advanced stage of disease were accompanied by a significant delay to reach transfusion independence. This result was further supported by comparable findings in trephine biopsies performed in the early post-transplant period (second month after BMT). Corresponding examinations revealed an enhancement of fiber density and a decrease in erythropoiesis in those patients who did not conform with the usually accepted criteria for successful engraftment. In conclusion, compelling evidence has been produced that a significantly reduced amount of erythroid precursors, which is usually associated with myelofibrosis in the pretransplant bone marrow, exerts an impairment to undisturbed hematopoietic reconstitution. Moreover, a close spatial and numerical relationship between the erythroid lineage and resident (mature) macrophages is observable, in particular in the state of regeneration after BMT.

Th2 and Tc2 cells in the regulation of GVHD, GVL, and graft rejection: considerations for the allogeneic transplantation therapy of leukemia and lymphoma

Allogeneic stem cell transplantation (SCT) represents a curative treatment option for patients with leukemia and lymphoma. T lymphocytes contained in the allograft mediate a graft-versus-leukemia (GVL) effect and prevent graft rejection; however, T cells also initiate graft-versus-host disease (GVHD). Identification of T cell populations which mediate a GVL effect and prevent rejection with reduced GVHD will likely improve transplantation outcome. T cells exist in four functionally-defined populations, the CD4+, Th1/Th2 and CD8+, Tc1/Tc2 subsets. Th1-type CD4 cells primarily secrete type I cytokines (IL-2 and IFN-gamma), whereas Th2 cells secrete type II cytokines (IL-4, IL-5, and IL-10). Similarly, the CD8+ Tc1 and Tc2 cells differentially secrete the type I and type II cytokines, respectively. In addition to cytokine secretion, Tc1 and Tc2 populations mediate cytolytic effects, with Tc1 cells utilizing both perforin- and fas-based killing pathways, whereas Tc2 cells primarily utilize perforin-mediated cytolysis. In murine transplantation models of graft rejection, GVHD, and GVL effects, we have evaluated such functional T cell subsets for their ability to differentially mediate and regulate transplantation responses. These studies demonstrate that donor Th2 cells do not initiate acute GVHD, and can regulate the GVHD mediated by unmanipulated donor T cells without impairing alloengraftment. Additional experiments have shown that allospecific donor Tc2 cells result in reduced GVHD, and mediate a significant GVL effect. Thirdly, we have demonstrated that non-host reactive Tc2 cells with veto-like activity can potently abrogate marrow rejection independent of GVHD. Together, these results demonstrate that functionally-defined donor Th2 and Tc2 populations play an important role in the regulation of GVHD, the prevention of graft rejection, and the mediation of GVL effects, and suggest that utilization of Th2 and Tc2 cells in clinical allogeneic SCT may have potential for improving treatment outcome.

Foscarnet prophylaxis of cytomegalovirus infections in patients undergoing allogeneic bone marrow transplantation (BMT): a dose-finding study

This is a dose-finding study using foscarnet for CMV prophylaxis after allogeneic bone marrow transplantation (BMT) in 20 high risk patients (unrelated donors, or T cell depleted, and/or advanced disease). Foscarnet was started on day +1 after BMT and continued until day +100. We explored four different dose levels, patients being entered at the lowest dose level until one patient experiences CMV-reactivation, identified as two consecutive positive CMV antigenemias (CMVAg-emia). The four dose levels expressed as mg/kg/day between days 1 and 30 (induction) and between days 31 and 100 (maintenance) were respectively: dose level I = 60/30 (n = 5); dose level II = 120/60 (n = 4); dose level III = 120/90 (n = 5) and dose level IV = 120/120 (n = 6). All patients showed engraftment: PMN > or =0.5 x 109/l at a median interval of 16, 21, 17, 15 days after BMT, and Plt > or =30x10(9)/l on days 19, 16, 17, 17 respectively. CMVAg-emia was seen in 10 patients at a median interval of 53 days post-BMT (range 33-89) with a median of 10 CMV antigen+ cells (range 1-16). There was a dose effect of foscarnet on CMVAg-emia: respectively 4/5 patients (80%), 2/4 (50%), 3/5 (60%) and 1/6 (18%) at dose levels I, II, III, IV (P = 0.1). CMV disease was seen in 3/9 (33%) at dose levels I, II and 0/11 at dose levels III, IV (P = 0. 07). The median number of CMV antigen-positive cells at diagnosis of CMV infection was different: 13 in dose levels I-II and two in dose levels III-IV (P = 0.01). Increased creatininine was seen in 15 patients with a mean of 1.8 mg% (range 1.5-5.7) and was the cause of discontinuation in nine patients (45%). Renal toxicity was reversible in all nine patients. Overall actuarial TRM at 2 years was 31%: 47% for patients at dose levels I-II and 19% for patients at dose levels III-IV. In conclusion, foscarnet exhibits a dose-dependent prophylactic effect on CMVAg-emia, CMV disease and transplant-related mortality with acceptable and reversible renal toxicity.

The North American experience with photopheresis

Photopheresis or extracorporeal photochemotherapy (ECP) is a novel immunomodulatory therapy based upon pheresis of light-sensitive cells. Whole blood is removed from patients who have previously ingested the photosensitizing agent 8-methoxypsoralen (8-MOP) followed by leukapheresis and exposure of the 8-MOP containing white blood cells (WBCs) extracorporeally to an ultraviolet A (UVA) light source prior to their return to the patient. In 1988, the Food and Drug Administration (FDA) approved photopheresis for the treatment of cutaneous T-cell lymphoma (CTCL). Treatment of CTCL with photopheresis has been reported in over 300 patients worldwide. Photopheresis has also demonstrated encouraging results in the treatment of solid organ transplant rejection, graft versus host disease, scleroderma, and other autoimmune diseases although fewer patients have been studied. This review will focus on the North American experience with photopheresis.

Treatment of high-risk acute leukemia with T-cell-depleted stem cells from related donors with one fully mismatched HLA haplotype

BACKGROUND

In this study we tried to achieve successful transplantation in patients with acute leukemia with the use of hematopoietic stem cells from donors who shared only one HLA haplotype with the recipient (a "full-haplotype mismatch"). To prevent graft failure, large doses of T-cell-depleted hematopoietic stem cells were transplanted after a conditioning regimen of enhanced myeloablation and immunosuppression was administered to the recipient.

METHODS

Forty-three patients with high-risk acute leukemia who were scheduled for transplantation received total-body irradiation, thiotepa, fludarabine, and antithymocyte globulin. The graft consisted of peripheral-blood progenitor cells that had been mobilized in the donor with recombinant granulocyte colony-stimulating factor and also, in 28 cases, bone marrow. Bone marrow from the donor was depleted of T lymphocytes by processing with soybean agglutinin and E-rosetting. T-cell depletion of peripheral-blood mononuclear cells was achieved by E-rosetting followed by positive selection of CD34+ cells. No post-transplantation prophylaxis against graft-versus-host disease (GVHD) was administered.

RESULTS

In all the patients, full donor-type engraftment was achieved. In none of the patients who could be evaluated did acute or chronic GVHD develop. Regimen-related toxicity was minimal. Eleven of the 23 patients with acute lymphoblastic leukemia had a relapse, as did 2 of the 20 patients with acute myeloid leukemia. Transplantation-related mortality was 40 percent. After a median follow-up of 18 months (range, 8 to 30), 12 of the 43 patients were alive and free of disease. All surviving patients had a good quality of life.

CONCLUSIONS

The main limitations of transplantation of bone marrow from donors who are matched with the recipient for only one HLA haplotype GVHD and graft failure - can be overcome. Since most patients have a relative with one haplotype mismatch, advances in this method will increase the availability of hematopoietic-cell transplantation as curative therapy for acute leukemia.

Unrelated donor marrow transplantation for chronic myelogenous leukaemia

Between January 1989 and July 1995 the search for an unrelated donor (UD) was started for 379 consecutive Italian patients with Philadelphia positive (Ph+) chronic myelogenous leukaemia (CML). 89 (23%) were transplanted. The overall probability of transplant before and after December 1991 was 16% and 49%, respectively (P=0.0001), and average interval between search activation and graft was 23 months and 13 months, respectively (P=0.0001). Disease-free survival (DFS) following 60 consecutive transplants performed before February 1996 was 41.5% at 48 months and was 64% for patients grafted after January 1993. In univariate analysis, five variables had a favourable effect on DFS: year of bone marrow transplantation (BMT) after 1993 (P=0.0002), HLA-DRB1 donor/recipient (D/R) match (P=0.0006), total body irradiation (TBI) containing regimen (P=0.0006), graft-versus-host disease (GvHD) prophylaxis including 'early' cyclosporin before the transplant, and a marrow cell dose > 3 x 10(8)/kg of recipient body weight (P=0.04). Multivariate analysis confirmed that HLA identity (P=0.006), TBI-containing regimen (P=0.0001) and 'early cyclosporin' (P=0.04) were associated with higher DFS. Transplant-related mortality (TRM) was 67% in patients grafted before January 1993 and 30% in patients grafted subsequently (P=0.002). Multivariate analysis confirmed DRB1 identity (P=0.03) and TBI-containing regimen (P=0.0005) to be independent factors predictive of low TRM. This suggests that the outcome of patients transplanted from an HLA DRB1 matched donor, after a TBI-containing preparative regimen, is similar to results recently reported in patients transplanted from geno-identical siblings. These results indicate that the search should be initiated at diagnosis for patients < 45 years of age and UD BMT should be considered early in the disease course for those with an available DRB1-matched unrelated donor.