Comparison of Three Graft-versus-Host Disease Prophylaxis Strategies after T Cell-Replete Haploidentical Hematopoietic Transplantation: Tacrolimus versus Calcineurin Inhibitors + Mycophenolate Mofetil versus Sirolimus + Mycophenolate Mofetil.

Since the introduction of post-transplantation cyclophosphamide (PTCy), haploidentical hematopoietic stem cell transplantation (haploSCT) has become a real alternative for patients who lack other eligible donors. The standard graft-versus-host disease (GVHD) prophylaxis after PTCy has been a calcineurin inhibitor (CNI) plus mycophenolate mofetil (MMF) (up to day +35), but promising results with sirolimus (with or without MMF) and single-agent tacrolimus have been published recently. This multicenter retrospective study compared the outcomes of 372 adult haploSCT recipients who received conditioning with thiotepa, busulfan, and fludarabine (TBF), PTCy, and additional GVHD prophylaxis with 1 of 3 strategies: cohort A, single-agent tacrolimus (n = 222); cohort B, CNI + MMF (n = 49); or cohort C, sirolimus + MMF (n = 101). No differences among the 3 cohorts were found in terms of grade II-IV acute GVHD (20% in cohort A, 25% in cohort B, and 30% in cohort C) or grade III-IV acute GVHD (9%, 6%, and 15%, respectively) at 100 days; however, cohort A had the lowest incidence of overall chronic GVHD (24%, 47%, and 52%, respectively; P = .001) and moderate-severe chronic GVHD (13%, 35%, and 33%, respectively; P = .001). There were no differences in 3-year overall survival, progression-free survival, nonrelapse mortality, or relapse among the 3 cohorts. Overall, our study suggests that single-agent tacrolimus, CNI + MMF, and sirolimus + MMF GVHD prophylaxis lead to similar outcomes following haploSCT with TBF and PTCy, with a low incidence of grade III-IV acute GVHD, although possible differences in chronic GVHD require further investigation.

Effects of the installation of offshore pipelines on macrozoobenthic communities (northern and central Adriatic Sea).

Macrozoobenthos living around several pipelines placed at different depths and sediment types in the Western Adriatic Sea was investigated for three years after structures' deployment to detect possible effects due to their installation and presence. Three environmental habitats were considered based on the grain size (silty clay, clayey silt and sand). Samplings were taken within a radius of 100 m from the pipelines and at control sites. Multivariate and univariate analysis showed peculiarities of the three habitats due to the different sediment type, without differences between pipelines and controls inside each group. Silty clay and clayey silt communities appeared quite similar, being mainly represented by opportunistic species typical of the Adriatic coastal area. Benthic populations found at the offshore relict sand were characterized by a higher percentage of sensitive species. Independently of sediment typology, pipelines' installation seems to not affect the benthic populations that appear more influenced by environmental features.

Single-agent GvHD prophylaxis with tacrolimus after post-transplant high-dose cyclophosphamide is a valid option for haploidentical transplantation in adults with hematological malignancies.

Eighty-one patients with high-risk hematological malignancies received unmanipulated haploidentical stem cell transplants (haploSCT) using the same protocol at four Spanish institutions. The conditioning regimen was thiotepa, busulfan and fludarabine; following bone marrow or peripheral blood infusion. GvHD prophylaxis with high-dose cyclophosphamide on days +3 and +4, and IV tacrolimus from day +5 was administered. 62% were in complete remission, 17% had received previous allogeneic SCT and 44% had a high-very high refined disease risk index. One patient had primary graft failure and three more died before +21. The median days to neutrophil and platelet recoveries were +18 and +23, respectively, and 93% achieved a full donor chimerism on day +30. At 1 year, cumulative incidences (CumInc) of non-relapse mortality and relapse were 27 and 19%. One-year overall survival and PFS were 61 and 51%. CumInc of grade II-IV and III-IV were 23 and 14%. At 30 months, CumInc of limited and extensive GvHD were 20 and 22%. In conclusion, patients with hematological malignancies who receive an unmanipulated haploSCT with post-transplant cyclophosphamide may benefit from less intense pharmacological prophylaxis for GvHD prophylaxis. Whether this approach potentiates the graft-versus-tumor effect and decreases relapses requires further investigation.

Busulfan-based reduced intensity conditioning regimens for haploidentical transplantation in relapsed/refractory Hodgkin lymphoma: Spanish multicenter experience.

Relapsed or refractory Hodgkin lymphoma (advanced HL) still remains a therapeutic challenge. Recently, unmanipulated haploidentical related donor transplant with reduced conditioning regimen (HAPLO-RIC) and post-transplant cyclophosphamide (PT-Cy) as GvHD prophylaxis has became a promising rescue strategy potentially available to almost every patient. This paper reports our multicenter experience using an IV busulfan-based HAPLO-RIC regimen and PT-Cy in the treatment of 43 patients with advanced HL. Engraftment occurred in 42 patients (97.5%), with a median time to neutrophil and platelet recovery of 18 and 26 days. Cumulative incidences of grades II-IV acute GvHD and chronic GvHD were 39% and 19%, respectively. With a median follow-up of 25.5 months for survivors, 27 patients are alive, with 22 of them disease free. Cumulative incidences of 1-year non-relapse mortality and relapse at 2 years were 21% and 24%, respectively. The estimated 2-year event-free survival (EFS) and overall survival (OS) were 48% and 58%, respectively. CR prior to HAPLO-RIC correlated with better EFS (78.5% vs 33.5%; P=0.015) and OS (86% vs 46%; P=0.044). Our findings further confirm prior reports using HAPLO-RIC in advanced HL in a multicenter approach employing an IV busulfan-based conditioning regimen.

UGT2B17 minor histocompatibility mismatch and clinical outcome after HLA-identical sibling donor stem cell transplantation.

Minor histocompatibility Ags (mHags) have been implicated in the pathogenesis of GVHD after allogeneic hematopoietic stem cell transplantation (HSCT). Uridine diphospho-glucuronosyltransferase 2B17 (UGT2B17) gene deletion may act as a mHag and its association with acute GVHD (aGVHD) has been described. We retrospectively studied the clinical impact of a UGT2B17 mismatch in a cohort of 1127 patients receiving a HSCT from an HLA-identical sibling donor. UGT2B17 mismatch was present in 69 cases (6.1%). Incidence of severe aGVHD was higher in the UGT2B17 mismatched pairs (22.7% vs 14.6%), but this difference was not statistically significant (P: 0.098). We did not detect differences in chronic GVHD, overall survival, relapse-free survival, transplant-related mortality or relapse. Nevertheless, when we analyzed only those patients receiving grafts from a male donor (616 cases), aGVHD was significantly higher in the UGT2B17 mismatched group (25.1% vs 12.8%; P: 0.005) and this association was confirmed by the multivariate analysis (P: 0.043; hazard ratio: 2.16, 95% confidence interval: 1.03-4.57). Overall survival was worse for patients mismatched for UGT2B17 (P: 0.005). We conclude that UGT2B17 mismatch has a negative clinical impact in allogeneic HSCT from HLA-identical sibling donors only when a male donor is used. These results should be confirmed by other studies.

Single-unit umbilical cord blood transplantation from unrelated donors in patients with hematological malignancy using busulfan, thiotepa, fludarabine and ATG as myeloablative conditioning regimen.

Attempts to optimize outcomes in cord blood transplantation (CBT) by using new conditioning regimens and standardization of cord blood unit selection are warranted. In all, 88 patients (18 children and 70 adults) with hematological malignancy from nine Spanish institutions underwent a single-unit CBT after an i.v. BU-based myeloablative conditioning regimen. All evaluable patients except one engrafted. The overall cumulative incidence (CI) of myeloid engraftment was 94% at a median time of 19 days. In multivariate analysis, nonadvanced disease stage was the only factor with a favorable impact on myeloid engraftment. The CI of acute GVHD grades II-IV and chronic extensive GVHD were 24% each. The CI of nonrelapse mortality at 100 days, 180 days and 5 years was 14, 23 and 44%, respectively. The 5-year CI of relapse was 18%, whereas disease-free survival (DFS) was 46%, 39% and 11% for patients transplanted in early, intermediate and advanced stages of the disease, respectively. Our study shows high rates of engraftment with fast neutrophil recovery in patients undergoing single-unit CBT using a BU-based conditioning regimen. Long-term DFS can be achieved in a substantial number of patients with high-risk hematological malignancies, particularly when transplanted in an early stage of the disease.

KIR-ligand incompatibility in the graft-versus-host direction improves outcomes after umbilical cord blood transplantation for acute leukemia.

Donor killer cell immunoglobulin-like receptor (KIR)-ligand incompatibility is associated with decreased relapse incidence (RI) and improved leukemia-free survival (LFS) after haploidentical and HLA-mismatched unrelated hematopoietic stem cell transplantation. We assessed outcomes of 218 patients with acute myeloid leukemia (AML n=94) or acute lymphoblastic leukemia (n=124) in complete remission (CR) who had received a single-unit unrelated cord blood transplant (UCBT) from a KIR-ligand-compatible or -incompatible donor. Grafts were HLA-A, -B or -DRB1 matched (n=21) or mismatched (n=197). Patients and donors were categorized according to their degree of KIR-ligand compatibility in the graft-versus-host direction by determining whether or not they expressed HLA-C group 1 or 2, HLA-Bw4 or HLA-A3/-A11. Both HLA-C/-B KIR-ligand- and HLA-A-A3/-A11 KIR-ligand-incompatible UCBT showed a trend to improved LFS (P=0.09 and P=0.13, respectively). Sixty-nine donor-patient pairs were HLA-A, -B or -C KIR-ligand incompatible and 149 compatible. KIR-ligand-incompatible UCBT showed improved LFS (hazards ratio=2.05, P=0.0016) and overall survival (OS) (hazards ratio=2.0, P=0.004) and decreased RI (hazards ratio=0.53, P=0.05). These results were more evident for AML transplant recipients (2-year LFS and RI with or without KIR-ligand incompatibility 73 versus 38% (P=0.012), and 5 versus 36% (P=0.005), respectively). UCBT for acute leukemia in CR from KIR-ligand-incompatible donors is associated with decreased RI and improved LFS and OS.

Richter's syndrome after allogeneic stem cell transplantation for chronic lymphocytic leukaemia successfully treated by withdrawal of immunosuppression, and donor lymphocyte infusion.

Development of high-grade non-Hodgkin's lymphoma is a possible complication of chronic lymphocytic leukaemia/small lymphocytic lymphoma, known as Richter's syndrome (RS). Treatment for RS includes systemic chemotherapy and, recently, allogeneic stem cell transplantation (SCT). We describe a patient with B-chronic lymphocytic leukaemia who developed RS 4 months after allogeneic SCT from an HLA-identical sibling. The RS presented with systemic symptoms, lymphadenopathy, pancytopenia and serum lactate dehydrogenase elevation. The patient was treated with immunosuppressive drug withdrawal and a donor lymphocyte infusion (DLI) of 1 x 10(7) CD3/kg, leading to the disappearance of all symptoms and the attainment of complete donor chimerism. After 18 months of the therapeutic DLI, the patient continues in complete remission.

Combined isolation of CD34+ progenitor cells and reduction of B cells from peripheral blood by use of immunomagnetic methods.

BACKGROUND: Malignant cells may contribute to relapse after autologous hematopoietic cell transplantation The effectiveness of a double immunomagnetic purging strategy combining CD34-positive with B-negative cell selection to purge peripheral blood progenitor cells (PBPCs) from patients with chronic lymphoproliferative disorders has been analyzed. STUDY DESIGN AND METHODS: Twenty-two CD34+ cell selections from patients with follicular lymphoma (n = 14), chronic lymphocytic leukemia (n = 6), mantle cell lymphoma (n = 1), and splenic marginal zone lymphoma (n = 1) were performed by use of a magnetic cell selector followed by a negative cell selection step with anti-CD19 monoclonal antibody bound to immunomagnetic beads. RESULTS: The PBPC components contained median CD34+ cells of 1.24 percent (range, 0.38-3.92%) and CD19+ cells of 1.83 percent (range, 0.06-69.7%). After positive selection (n = 22), 49 percent (range, 16-72%) of CD34+ cells were recovered with a purity of 93 percent (range, 24-99%). The double-positive and -negative selections (n = 20) yielded 57.5 percent of CD34+ cells (range, 33.4-79.4%) with a purity of 95 percent (range, 63-99%). Logarithms of B-cell reduction in the CD34+-cell-enriched B-cell-depleted component had a median value of 3.63 (range, 2.74-4.84 log) and CD19+ and CD5+ cells for chronic lymphocytic leukemia patients with more than 4.56 log (>3.6-5.6 log). Of 13 PBPC components that had a tumor-specific clonal signal, 10 became PCR negative after the double-selection procedure. CONCLUSION: Combined positive and negative magnetic cell selection achieves a high grade of tumor cell reduction with up to 77 percent of the grafts being negative for tumor-specific clonal signal by PCR analysis. This technique preserves an adequate recovery of progenitor cells able to engraft.

Individually adjusted prophylactic donor lymphocyte infusions after CD34-selected allogeneic peripheral blood stem cell transplantation.

T cell depletion of the graft increases graft failure and relapse rate in allogeneic PBSC transplantation. Delayed lymphocyte add-back after T cell-depleted transplants might prevent these complications. We present 22 consecutive allogeneic PBSC transplants from related histocompatible donors with positive selection of CD34+ cells. Recipients received prophylactic donor lymphocyte infusions (DLI) depending on their risk of relapse and of developing GVHD. Patients were considered at high risk of relapse with AML > first CR, ALL > second CR, and CML in accelerated or blastic phase. Patients were considered at high risk of developing GVHD if older than 35 years, or with a donor sensitized through previous pregnancy or blood transfusion. Patients at high risk of relapse and low risk of GVHD were scheduled to receive three DLI. Patients at low risk of relapse and high risk of GVHD did not receive DLI. The remaining patients were scheduled to receive two DLI. The DLI were administered on days +28 (2 x 10(5)/kg), +60 (2 x 10(5)/kg) and +90 (2 x 10(6)/kg) after transplant. G-CSF mobilized peripheral stem cells from healthy donors were positively selected by an immunomagnetic method. The mean CD34+ cells and CD3+ cells infused were 4.4 x 10(6)(range 1.9-10.6) and 0.085 x 10(5) (range 0.01-0.67). Cyclosporin A was given to prevent GVHD. All the patients engrafted. Twenty-two prophylactic DLI were performed in 12 patients: seven developed acute GVHD (one case grade III-IV) and none presented pancytopenia. At a mean follow-up of 585 days (range 89-1103), 14 patients were alive in CR, one patient was alive in relapse, four patients had died of relapse and three had died of transplant-related complication. Individually adjusted prophylactic DLI at the doses we used with an escalating schedule allowed an acceptable GVHD rate and a good engraftment of donor hematopoiesis.

Severe infections after allogeneic peripheral blood stem cell transplantation: a matched-pair comparison of unmanipulated and CD34+ cell-selected transplantation.

BACKGROUND AND OBJECTIVES: T-cell depletion of the graft delays immune recovery following allogeneic peripheral blood stem cell transplantation (PBSCT), but it is not clear whether it actually increases the risk of severe infections after the transplant. DESIGN AND METHODS: We have compared the occurrence of severe infections following 162 CD34+ cell-selected allogeneic PBSCT and 162 unmanipulated PBSCT (CD34+ and UM groups, respectively) from HLA-identical siblings. RESULTS: The probability of infection-related mortality (IRM) was 22% in the UM group and 31% in the CD34+ group (log-rank, p=0.2). In multivariate analyses only the use of fluconazole prophylaxis showed a protective effect on IRM in the whole set of patients, while in both transplant groups the most significant factor was the development of moderate-to-severe graft-versus-host disease (GVHD). The probability of developing cytomegalovirus (CMV) infection was 42% in the UM group and 59% in the CD34+ group (p=0.002), with no differences in CMV disease (10% and 9%, respectively). Multivariate analysis of CMV infection identified three variables associated with a higher risk in the whole set of patients: CMV positive serostatus, CD34+ transplant group and recipient age above 40 years. The development of moderate-to-severe GVHD was a significant factor only in the UM group. Disseminated varicella-zoster virus infection was more common in the CD34+ group (19% and 12%, p=0.05), as were early (< 30 days post-transplant) severe bacterial infections (28% vs 14%, p=0.002). Invasive fungal infections and pneumonias of unknown origin did not differ between groups. INTERPRETATION AND CONCLUSIONS: Our results do not show a significant increase in the risk of dying from an opportunistic infection with CD34+-PBSCT, but the risk of CMV infection is increased, with no differences in CMV disease or mortality attributable to CMV. There is an additive effect on IRM of developing moderate-to-severe GVHD (acute or chronic) following CD34+-PBSCT, and in this subset of patients maximum efforts for the prevention and early treatment of opportunistic infections should be pursued.

Allogeneic transplantation of CD34+-selected cells from peripheral blood in patients with myeloid malignancies in early phase: a case control comparison with unmodified peripheral blood transplantation.

An allogeneic transplantation of CD34(+)-selected cells from peripheral blood (allo-PBT/CD34(+)) from HLA-identical sibling donors was performed in 50 adult patients with acute myeloid leukemia in first complete remission (AML CR1) (n = 29), myelodysplastic syndrome (MDS) (n = 4), or chronic myeloid leukemia in first chronic phase (CML CP1) (n = 17). Clinical results were compared to a concurrent group of 50 patients transplanted with unmodified peripheral blood progenitor cells (allo-PBT), matched for age, diagnosis, and disease stage. The median follow-up period was 29 months (range 1-69). The actuarial probability of developing acute GVHD clinical grade II to IV was 16% (95%CI: 6-26) for the allo-PBT/CD34(+) group and 41% (95%CI: 29-57) for the allo-PBT group (P = 0.002). The actuarial probability of developing extensive chronic GVHD was 22% (95%CI: 8-36) for the allo-PBT/CD34(+) group and 47% (95%CI: 31-63) for the allo-PBT group (P = 0.02). Recipients of allo-PBT/CD34(+) had less toxicity associated with the transplant and better Karnofsky index at the last follow-up. For AML/MDS patients, the actuarial probability of disease-free survival (DFS) for recipients of allo-PBT/CD34(+) and allo-PBT was 65% (95%CI: 45-85) vs43% (95%CI: 28-58) (P = 0.05), respectively. These data provide a rationale for a randomised trial of allo-PBT/CD34(+) vs allo-PBT in AML/MDS patients in early stage of the disease.

Do corticosteroids add any benefit to standard GVHD prophylaxis in allogeneic BMT?

In a retrospective study, we compared 15 patients who received cyclosporine (CsA), methotrexate (MTX) and prednisone (PDN) and 15 patients who received CsA-MTX for GVHD prophylaxis after allogeneic BMT (HLA-identical sibling (n = 22), related one HLA mismatch (n = 1), unrelated matched donors (n = 6), unrelated one HLA mismatch (n = 1)). The primary objectives of this study were to compare the incidence of GVHD and post-transplantation complications. Secondary objectives were to compare relapse rate, transplant-related mortality and overall survival. The incidence of acute GVHD grade III-IV was similar between the two groups (P = 0.66), as was the incidence of chronic GVHD (P = 0.67). Incidence of arterial hypertension was significantly higher in patients who received prophylactic PDN, (P = 0.03) and more insulin treatment was required in this group (P = 0.003). We observed no differences in the incidence of infections or upper digestive tract bleeding. Musculoskeletal complications appeared earlier in the group which received PDN. With a median follow-up of 4.4 years, patients in the CsA-MTX group had better overall survival, 46.7% vs 13.3% (P = 0.026). Relapse was a more frequent cause of death in the CsA-MTX group, whereas procedure-related mortality was more frequent in the CsA-MTX-PDN group (P = 0.013). These results suggest that prophylactic prednisone when combined with cyclosporine and methotrexate adds no benefit in acute or chronic GVHD prevention and may increase the morbidity of allogeneic transplantation. Corticosteroids may be reserved for GVHD treatment.

Combined positive and negative cell selection from allogeneic peripheral blood progenitor cells (PBPC) by use of immunomagnetic methods.

Twenty-four mobilized peripheral blood products from healthy donors for allogeneic transplantation were positively selected for CD34(+) cells and depleted of CD4(+) and CD8(+) cells (+/- selection) by combining clinical grade immunomagnetic methods. A sequential, "two-step" strategy combining positive selection of CD34(+) cells by use of the Isolex 300i (versions 1 and 2) device and T cell depletion (TCD) using the MaxSep device and a simultaneous, "one-step" method of CD34(+)cell selection and TCD using the Isolex 300i (software versions 1 and 2) have been investigated. Using these magnetic bead separation systems, two groups of sequential +/- selection (Isolex 300i version 1/MaxSep and Isolex 300i version 2/MaxSep) and two groups of simultaneous +/- selection (Isolex 300i versions 1 and 2) were analysed. In the sequential +/- selection, logarithms of TCD (CD3(+) cell depletion) obtained by the positive selection step had median values of 3.7 with the version 1 (n = 5) and 4.5 with version 2 software of the Isolex 300i (n = 5) (P = 0.07). Version 2 also gave a higher CD34(+) cell purity and yield than did version 1 (92% vs77%, P < 0.05 and 55% vs 34%, P = 0.3, respectively). Additional TCD obtained in the second step with the MaxSep device for the two groups had a median value of 0.9 log and 7% CD34(+)cell losses. In the simultaneous +/- selection, the Isolex 300i version 2 (n = 10) gave a median TCD of 5.1 log and version 1 (n = 4) of 4 log (P < 0.005). Higher CD34(+)cell purity and yield were also obtained with version 2 than with version 1 (97% and 76%, P < 0.005 and 57% and 39%, P = 0.07, respectively). These data indicate that simultaneous, "one-step" +/- selection in the Isolex 300i version 2 achieves a high TCD with a high CD34(+) cell purity and an acceptable CD34(+) cell yield.

Autologous stem-cell transplantation for Hodgkin's disease: results and prognostic factors in 494 patients from the Grupo Español de Linfomas/Transplante Autólogo de Médula Osea Spanish Cooperative Group.

PURPOSE: To analyze clinical outcome and significant prognostic factors for overall (OS) and time to treatment failure (TTF) in a group of 494 patients with Hodgkin's disease (HD) undergoing autologous stem-cell transplantation (ASCT). PATIENTS AND METHODS: Detailed records from the Grupo Español de Linfomas/Transplante Autólogo de Médula Osea Spanish Cooperative Group Database on 494 HD patients who received an ASCT between January 1984 and May 1998 were reviewed. Two hundred ninety-eight males and 196 females with a median age of 27 years (range, 1 to 63 years) received autografts while in complete remission (n = 203) or when they had sensitive disease (n = 206) or resistant disease (n = 75) at a median time of 26 months (range, 4 to 259 months) after diagnosis. Most patients received high-dose chemotherapy without radiation for conditioning (n = 443). The graft consisted of bone marrow (n = 244) or peripheral blood (n = 250). RESULTS: The 100-day mortality rate was 9%. The 5-year actuarial TTF and OS rates were 45.0% (95% confidence interval [CI], 39.5% to 50.5%) and 54.5% (95% CI, 48.4% to 60.6%), respectively. In multivariate analysis, the presence of active disease at transplantation, transplantation before 1992, and two or more lines of therapy before transplantation were adverse prognostic factors for outcome. Sixteen patients developed a secondary malignancy (5-year cumulative incidence of 4.3%) after transplantation. Adjuvant radiotherapy before transplantation, the use of total-body irradiation (TBI) in the conditioning regimen, and age > or = 40 years were found to be predictive factors for the development of second cancers after ASCT. CONCLUSION: ASCT achieves long-term disease-free survival in HD patients. Disease status before ASCT is the most important prognostic factor for final outcome; thus, transplantation should be considered in early stages of the disease. TBI must be avoided in the conditioning regimen because of a significantly higher rate of late complications, including secondary malignancies.

The number of donor CD3(+) cells is the most important factor for graft failure after allogeneic transplantation of CD34(+) selected cells from peripheral blood from HLA-identical siblings.

This study analyzed the characteristics of 257 HLA-identical sibling transplants of granulocyte colony-stimulating factor-mobilized peripheral blood progenitor cells depleted of T cells by CD34(+) positive selection (allo-PBT/CD34(+)) for their effect on the incidence of graft failure. Twenty-four patients developed graft failure (actuarial probability, 11%; 95% confidence interval, 7.1-14. 9). Prognostic factors considered were sex and age of donor and recipient, donor-recipient blood group compatibility, diagnosis, disease status at transplant, conditioning regimen, cytomegalovirus serology, number of CD34(+) and CD3(+) cells infused, and cryopreservation. The major factor associated with graft failure was the number of CD3(+) cells in the inoculum. Twenty-three of 155 patients receiving a T-cell dose in the graft less than or equal to 0.2 x 10(6)/kg experienced graft failure, compared with only one of 102 patients receiving more than 0.2 x 10(6)/kg (actuarial probability 18% vs 1%, respectively; P =.0001). The actuarial probability of graft failure progressively increased as the number of CD3(+) cells in the graft decreased, which was determined by grouping the number of CD3(+) cells in quartiles (log-rank P =.03; log-rank for trend P =.003). In the multivariate analysis by the proportional hazard method, 2 covariates entered into regression at a significant level: CD3(+) cells less than or equal to 0.2 x 10(6)/kg (risk ratio = 17; P <.0001), and patients with chronic myelogenous leukemia (CML) conditioned with busulphan-based regimens (risk ratio = 4.8; P =.001). From these results it appears that the number of CD3(+) cells in the inoculum-with a threshold of 0.2 x 10(6)/kg or less-is the most critical factor in maintaining a sustained engraftment in allo-PBT/CD34(+) from HLA-identical siblings. In addition, for patients with CML receiving 0.2 x 10(6)/kg or less CD3(+) cells, total body irradiation might be better than busulphan-based regimens.

Follow-up of chimerism status after allogeneic HLA-mismatched stem cell transplantation by detection of non-shared HLA alleles.

BACKGROUND AND OBJECTIVES: Chimerism studies after allogeneic transplantation are usually performed using cytogenetic analysis, PCR-VNTR or PCR-STR. Here, we report an alternative method for following the chimerism status after an HLA-mismatched stem cell transplantation (SCT), detecting the presence of non-shared HLA alleles by reference-strand mediated conformation analysis (RSCA). DESIGN AND METHODS: We tested this new approach on allogeneic related haploidentical SCT, unrelated cord blood transplantation, and HLA-mismatched unrelated donor SCT. The quantification of the chimerism was performed by laser detection of fluorescent-labeled primers on an automated DNA sequencer. RESULTS: In all cases this technique was able to detect mixed chimeras. The technique detected above 5% of residual cells when the analysis was based on HLA-class I and above 3% for HLA-class II. This sensitivity is similar to that of the PCR-VNTR analysis. INTERPRETATION AND CONCLUSIONS: This method avoids the need to search for an informative locus (which is essential for PCR-VNTR or -STR). Moreover, we did not find the phenomenon of preferential amplification that is observed with most VNTR, thus avoiding the need for construction of standard curves to quantify mixed chimeras. We conclude that the detection of the non-shared HLA alleles by RSCA is a useful approach for chimerism follow-up after HLA-mismatched SCT.

Isolation of CD34+ progenitor cells from peripheral blood by use of an automated immunomagnetic selection system: factors affecting the results.

BACKGROUND: The isolation of CD34+ cells from mobilized peripheral blood is being increasingly used in the setting of allogeneic or autologous hematopoietic cell transplantation. Investigation of variables that may influence the effectiveness of CD34+ cell selection is of interest. STUDY DESIGN AND METHODS: Fifty-one CD34+ cell selections from peripheral blood progenitor cells (PBPCs) (39 allogeneic and 12 autologous) were performed using a magnetic cell separator (Isolex 300i, Baxter), including version 2.0 software. The results obtained were analyzed for different processing variables. The feasibility of transplanting these isolated CD34+ cells was also analyzed. RESULTS: The isolated CD34+ cell fraction had a median purity of 88.9 percent (range, 47.8-98.3). The median recovery of CD34+ cells was 45.1 percent (13.8-76.2), and the median colony-forming unit- granulocyte-macrophage (CFU-GM) content was 17. 2 percent (0.8-58.6). Logarithms of T- and B-cell depletion had median values of 3.7 and 2.8, respectively. The version 2.0 software of the Isolex 300i gave a higher CD34+ cell recovery in the enriched cell fraction (median 57.8%) than did version 1.11 (39.4%) or 1.12 (44.4%) (p = 0.01). The use of recombinant human deoxyribonuclease I during cell processing yielded more CD34+ cells (53% vs. 41%, p = 0. 01) and higher purity (92.8% vs. 87%, p = 0.03). There was a correlation between the percentage of CD34+ cells labeled with the monoclonal antibody 8G12 clone and the percentage of CD34+ cells labeled with the monoclonal antibody used during the processing technique (9C5 clone) in the initial, enriched, and depleted CD34+ cell fractions (R(2) = 0.95; 0.92; 0.78, p< 0.005, respectively). Median times for recovering >0.5 x 10(9) per L of granulocytes and >20 x 10(9) per L of platelets were 13 and 16 days in the allograft patients and 13 and 14 days in the autograft patients. CONCLUSION: CD34+ cells can be highly and effectively isolated from allogeneic and autologous grafts by use of this automated technique, with a high grade of T- and B-cell depletion. These purified CD34+ cell components can engraft normally.