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Low-Dose Total Body Irradiation and Fludarabine Conditioning for HLA Class I-Mismatched Donor Stem Cell Transplantation and Immunologic Recovery in Patients with Hematologic Malignancies: A Multicenter Trial

2009; Elsevier BV; Volume: 16; Issue: 3 Linguagem: Inglês

10.1016/j.bbmt.2009.11.004

1523-6536

Hirohisa Nakamae, Barry E. Storer, Rainer Storb, Jan Storek, Thomas R. Chauncey, Michael A. Pulsipher, Finn Bo Petersen, James C. Wade, Michael B. Maris, Benedetto Bruno, Jens Panse, Effie W. Petersdorf, Ann E. Woolfrey, David G. Maloney, Brenda M. Sandmaier,

Immune Cell Function and Interaction

HLA-mismatched grafts are a viable alternative source for patients without HLA-matched donors receiving ablative hematopoietic cell transplantation (HCT), although their use in reduced intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT has been not well established. Here, we extended HCT to recipients of HLA class I-mismatched grafts to investigate whether NMA conditioning can establish stable donor engraftment. Fifty-nine patients were conditioned with fludarabine (Flu) 90 mg/m2 and 2 Gy total body irradiation (TBI), followed by immunosuppression with cyclosporine (CsA) 5.0 mg/kg twice a day and mycophenolate mofetil (MMF) 15 mg/kg 3 times a day for transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSCs) from related (n = 5) or unrelated donors (n = 54) with 1 antigen ± 1 allele HLA class I mismatch or 2 HLA class I allele mismatches. Sustained donor engraftment was observed in 95% of the evaluable patients. The incidence of grade II-IV acute and extensive chronic graft-versus-host disease (aGVHD, cGVHD) was 69% and 41%, respectively. The cumulative probability of nonrelapse mortality (NRM) was 47% at 2 years. Two-year overall and progression-free survival (OS, PFS) was 29% and 28%, respectively. NMA conditioning with Flu and low-dose TBI, followed by HCT using HLA class I-mismatched donors leads to successful engraftment and long-term survival; however, the high incidence of aGVHD and NRM needs to be addressed by alternate GVHD prophylaxis regimens. HLA-mismatched grafts are a viable alternative source for patients without HLA-matched donors receiving ablative hematopoietic cell transplantation (HCT), although their use in reduced intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT has been not well established. Here, we extended HCT to recipients of HLA class I-mismatched grafts to investigate whether NMA conditioning can establish stable donor engraftment. Fifty-nine patients were conditioned with fludarabine (Flu) 90 mg/m2 and 2 Gy total body irradiation (TBI), followed by immunosuppression with cyclosporine (CsA) 5.0 mg/kg twice a day and mycophenolate mofetil (MMF) 15 mg/kg 3 times a day for transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSCs) from related (n = 5) or unrelated donors (n = 54) with 1 antigen ± 1 allele HLA class I mismatch or 2 HLA class I allele mismatches. Sustained donor engraftment was observed in 95% of the evaluable patients. The incidence of grade II-IV acute and extensive chronic graft-versus-host disease (aGVHD, cGVHD) was 69% and 41%, respectively. The cumulative probability of nonrelapse mortality (NRM) was 47% at 2 years. Two-year overall and progression-free survival (OS, PFS) was 29% and 28%, respectively. NMA conditioning with Flu and low-dose TBI, followed by HCT using HLA class I-mismatched donors leads to successful engraftment and long-term survival; however, the high incidence of aGVHD and NRM needs to be addressed by alternate GVHD prophylaxis regimens. IntroductionAllogeneic hematopoietic stem cell transplantation (HSCT) from HLA-matched donors is a well- established curative strategy for patients with hematopoietic malignancies; however, only 20% to 30% of patients needing HSCT have a genotypically matched sibling donor. Although unrelated donor registries have grown enormously, currently potential donors cannot be identified for 20% of Caucasian recipients and more than 60% of African-American recipients. Moreover, patients with rare haplotypes are unlikely to find HLA-matched unrelated donors (MUDs) in a timely fashion. There is a need for a suitable transplantation procedure that can extend the application of HSCT with reduced-intensity conditioning (RIC) or nonmyeloablative (NMA conditioning to patients who have no readily available HLA-matched donor. Alternative sources, including HLA-mismatched unrelated donors, have been explored to extend the donor pool [1Finke J. Schmoor C. Lang H. et al.Matched and mismatched allogeneic stem-cell transplantation from unrelated donors using combined graft-versus-host disease prophylaxis including rabbit anti-T lymphocyte globulin.J Clin Oncol. 2003; 21: 506-513Crossref PubMed Scopus (69) Google Scholar, 2Sedlacek P. Formankova R. Keslova P. et al.Low mortality of children undergoing hematopoietic stem cell transplantation from 7 to 8/10 human leukocyte antigen allele-matched unrelated donors with the use of antithymocyte globulin.Bone Marrow Transplant. 2006; 38: 745-750Crossref PubMed Scopus (14) Google Scholar].The use of HLA class I-mismatched unrelated donors is associated with an increased risk of graft rejection in the myeloablative (MA) setting [3Morishima Y. Sasazuki T. Inoko H. et al.The clinical significance of human leukocyte antigen (HLA) allele compatibility in patients receiving a marrow transplant from serologically HLA-A-, HLA-B-, and HLA-DR-matched unrelated donors.Blood. 2002; 99: 4200-4206Crossref PubMed Scopus (372) Google Scholar, 4Petersdorf E.W. Gooley T.A. Anasetti C. et al.Optimizing outcome after unrelated marrow transplantation by comprehensive matching of HLA class I and II alleles in the donor and recipient.Blood. 1998; 92: 3515-3520PubMed Google Scholar, 5Petersdorf E.W. Hansen J.A. Martin P.J. et al.Major histocompatibility complex class I alleles and antigens in hematopoietic cell transplantation.N Engl J Med. 2001; 345: 1794-1800Crossref PubMed Scopus (270) Google Scholar]. The intensity of conditioning for HSCT is also associated with successful engraftment. Thus, the increased risk of graft rejection in the HLA-mismatched NMA setting compared with the MA setting may result from less-intensive conditioning. The degree of mismatch that would lead to unacceptable levels of rejection in recipients of NMA HSCT is not known.Based on preclinical studies [6Storb R. Yu C. Wagner J.L. et al.Stable mixed hematopoietic chimerism in DLA-identical littermate dogs given sublethal total body irradiation before and pharmacological immunosuppression after marrow transplantation.Blood. 1997; 89: 3048-3054PubMed Google Scholar], we have successfully applied a NMA conditioning regimen involving fludarabine (Flu) 90 mg/m2, 2 Gy of total body irradiation (TBI), and postgrafting immunosuppression with mycophenolate mofetil (MMF) and cyclosporine (CsA) as conditioning for grafts from either HLA-matched related or MUD in more than 1200 patients ineligible for high-dose HSCT because of advanced age or comorbidities [7Maris M.B. Niederwieser D. Sandmaier B.M. et al.HLA-matched unrelated donor hematopoietic cell transplantation after nonmyeloablative conditioning for patients with hematologic malignancies.Blood. 2003; 102: 2021-2030Crossref PubMed Scopus (309) Google Scholar, 8Niederwieser D. Maris M. Shizuru J.A. et al.Low-dose total body irradiation (TBI) and fludarabine followed by hematopoietic cell transplantation (HCT) from HLA-matched or mismatched unrelated donors and postgrafting immunosuppression with cyclosporine and mycophenolate mofetil (MMF) can induce durable complete chimerism and sustained remissions in patients with hematological diseases.Blood. 2003; 101: 1620-1629Crossref PubMed Scopus (399) Google Scholar, 9McSweeney P.A. Niederwieser D. Shizuru J.A. et al.Hematopoietic cell transplantation in older patients with hematologic malignancies: replacing high-dose cytotoxic therapy with graft-versus-tumor effects.Blood. 2001; 97: 3390-3400Crossref PubMed Scopus (1228) Google Scholar, 10Feinstein L. Sandmaier B. Maloney D. et al.Nonmyeloablative hematopoietic cell transplantation: replacing high-dose cytotoxic therapy by the graft-versus-tumor effect.Ann NY Acad Sci. 2001; 938: 328-339Crossref PubMed Scopus (70) Google Scholar, 11Maris M.B. Sandmaier B.M. Storer B.E. et al.Allogeneic hematopoietic cell transplantation after fludarabine and 2 Gy total body irradiation for relapsed and refractory mantle cell lymphoma.Blood. 2004; 104: 3535-3542Crossref PubMed Scopus (233) Google Scholar, 12Sorror M.L. Maris M.B. Sandmaier B.M. et al.Hematopoietic cell transplantation after nonmyeloablative conditioning for advanced chronic lymphocytic leukemia.J Clin Oncol. 2005; 23: 3819-3829Crossref PubMed Scopus (199) Google Scholar]. In this multicenter phase I/II trial, we extended NMA HSCT to include recipients of related or unrelated granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood stem cell (PBSC) grafts from donors who were mismatched for 1 HLA-class I antigen with or without 1 allele-level HLA-class I mismatches, or donors who were mismatched for 2 HLA-class I alleles. In addition, we evaluated immune reconstitution after HSCT in a subset of the unrelated recipients.Patients, Materials, and MethodsThis phase I/II multicenter trial included 7 transplant centers: Fred Hutchinson Cancer Research Center (FHCRC), University of Utah, University of Torino, Medical College of Wisconsin, LDS Hospital, Rocky Mountain Cancer Center, and Veterans Affairs Puget Sound Health Care System, with FHCRC acting as the coordinating center. The study protocol was approved by the institutional review boards of FHCRC and the collaborating performance sites. Written informed consent was obtained from all patients.Study EndpointsThe primary objective of this trial was to determine whether stable allogeneic engraftment from related and unrelated HLA-mismatched PBSC donors could be safely established using the NMA Flu/2Gy TBI conditioning regimen with or without escalating doses of the anti-CD52 monoclonal antibody (mAb) alemtuzumab in patients with hematologic malignancies. Secondary objectives included evaluation of acute and chronic graft-versus-host disease (aGVHD, cGVHD), infections, disease progression and relapse, and immunologic reconstitution.Eligibility CriteriaAll of the 59 patients enrolled in this study were ineligible for conventional HSCT and had disease expected to be stable for at least 100 days without further chemotherapy. Forty-one patients were aged > 50 years; the 18 patients aged ≤ 50 years met the eligibility criteria either because of previous HSCT (autologous, n = 14; allogeneic, n = 1), neurologic toxicity (n = 1), fungal infection and a history of major toxicity to chemotherapy (n = 1), or pancytopenia for 3 months (n = 1).Histocompatibility testing for donor selection was performed for all patients and donors, using methods described previously [13Hansen J.A. Mickelson E.M. Choo S.Y. et al.Clinical bone marrow transplantation: donor selection and recipient monitoring.in: Rose N.R. De Macario E.C. Fahey J.L. Manual of Clinical Laboratory Immunology. American Society for Microbiology, Washington, DC1992: 850-866Google Scholar, 14Dupont B. Yang S.Y. Histocompatibility.in: Forman S.J. Blume K.G. Thomas E.D. Bone Marrow Transplantation. Blackwell Scientific, Boston1994: 22-40Google Scholar, 15Petersdorf E.W. Smith A.G. Mickelson E.M. et al.Ten HLA-DR4 alleles defined by sequence polymorphisms within the DRB1 first domain.Immunogenetics. 1991; 33: 267-275Crossref PubMed Scopus (95) Google Scholar]. HLA-A, -B, -C, -DRB1, and -DQB1 alleles were typed prospectively by oligonucleotide hybridization or DNA sequencing methods [16Petersdorf E.W. Anasetti C. Martin P.J. et al.Limits of HLA mismatching in unrelated hematopoietic cell transplantation.Blood. 2004; 104: 2976-2980Crossref PubMed Scopus (232) Google Scholar]. Donor-recipient compatibility was further tested by lymphocyte cross-match (recipient serum vs donor T and B cells) before HSCT [17Anasetti C. Amos D. Beatty P.G. et al.Effect of HLA compatibility on engraftment of bone marrow transplants in patients with leukemia or lymphoma.N Engl J Med. 1989; 320: 197-204Crossref PubMed Scopus (576) Google Scholar]. Related or unrelated donors were allowed if matched for HLA-DRB1 and -DQB1 alleles, and mismatched for a single antigen at HLA-A, -B, or -C, with or without an additional single allele mismatch at HLA-A, -B, or -C. Donors were excluded if the recipient was homozygous at the mismatched locus, or if both mismatches were at the same locus (HLA-A, -B, or -C).Patients were ineligible for the present study if they were pregnant or breast-feeding, or had rapidly progressive intermediate- or high-grade non-Hodgkin lymphoma (NHL), circulating leukemic blasts in the PB detected by standard pathology, central nervous system involvement refractory to intrathecal chemotherapy, infection with the human immunodeficiency virus (HIV), active bacterial or fungal infection unresponsive to therapy, decompensated liver disease, corrected pulmonary diffusion capacity < 35%, cardiac ejection fraction < 35%, poorly controlled hypertension, or a Karnofsky performance score < 50%.Patient CharacteristicsA total of 59 patients were enrolled between February 2002, and October 2008 (Table 1). Classification for risk of relapse, as described previously [18Kahl C. Storer B.E. Sandmaier B.M. et al.Relapse risk among patients with malignant diseases given allogeneic hematopoietic cell transplantation after nonmyeloablative conditioning.Blood. 2007; 110: 2744-2748Crossref PubMed Scopus (150) Google Scholar], found 16 patients with high-risk disease, 27 with standard-risk disease, and 16 with low-risk disease. Disease status at the time of HSCT included complete remission (CR) in 29 patients, partial remission (PR) in 14, stable disease (SD) in 4, and refractory or relapsed disease in 12. All patients with acute myelogenous leukemia (AML), secondary AML from myelodysplastic syndrome (MDS/AML), or acute lymphoblastic leukemia (ALL) were in CR at the time of HSCT. Four patients received a planned tandem autologous transplant followed by NMA HSCT (auto-allo). The HSCT-specific comorbidity index (HSCT-CI) [19Sorror M.L. Maris M.B. Storb R. et al.Hematopoietic cell transplantation (HCT)-specific comorbidity index: a new tool for risk assessment before allogeneic HCT.Blood. 2005; 106: 2912-2919Crossref PubMed Scopus (1925) Google Scholar] score was available in 57 of the 59 patients; 12 patients had an HSCT-CI score of 0, 21 patients had a score of 1 or 2, and 24 patients had a score of 3 or higher.Table 1Patient and Disease CharacteristicsNumber of patients59Median age, years, n (range)56 (13-72)Males/females, n44/15Unrelated/related donor, n54/5Previous courses of chemotherapy, n (range)6 (2-19)Previous transplantations (autologous/allogeneic), n26/1Time to HCT, months, median (range)36 (5-205)Dose of CD34+ G-CSF-mobilized PBSCs, median (range)7.0 × 106 cells /kg (2.1-37.7 × 106 cells/kg)Dose of CD3+ G-CSF-mobilized PBSCs, median (range)2.6 × 106 cells /kg (0.3-6.6 × 108 cells/kg)Diagnosis, n (disease status pretransplantation) Non-Hodgkin lymphoma18 (CR2, 2; CR3, 2; PR, 9; stable, 1; refractory, 4) Hodgkin lymphoma5 (CR1, 1; PR, 2; refractory, 2) Adult T cell leukemia/lymphoma1 (CR1, 1) AML16 (CR1, 6; CR2, 5; CR3, 4; CR4, 1) Acute lymphoblastic leukemia5 (CR1, 1; CR2, 1; CR3, 3) Chronic lymphocytic leukemia6 (stable, 1; refractory, 5) Multiple myeloma7 (CR2, 1; PR, 3; stable, 2; refractory, 1) MDS/AML1 (CR1, 1)HLA mismatch, n, total (related donor) Both HVG and GVHD vectors51 (4) GVHD vector8 (1) One HLA antigen alone48 (5) HLA-A/-B/-C20 (5)/5/23 One HLA antigen + 1 allele10 (0) HLA-A/-B/-C (additional allele mismatch)2/4/4 Two allele-level1HCT indicates hematopoietic stem transplantation; G-CSF, granulocyte colony-stimulating factor; MDS, myelodysplastic syndrome; AML, acute myelogenous leukemia; HVG, host-versus-graft; GVHD, graft-versus-host disease. Open table in a new tab HLA Typing and MatchingFinal selection of unrelated donors was based on the results of high-resolution HLA typing for HLA-A, -B, -C, -DRB1, and -DQB1 alleles (Table 1). Seven unrelated pairs and 1 related pair were mismatched only in the GVHD vector and were not considered evaluable for the rejection endpoint. Fifty-four unrelated pairs were mismatched for at least 1 antigen (19 at HLA-A, 8 at HLA-B, and 26 at HLA-C), except 1 patient, who had 2 allele mismatches (HLA-A and HLA-B). All 5 related pairs were mismatched for 1 HLA-A antigen. Ten patients had, in addition to the class I antigen mismatch, 1 allelic mismatch (2 at HLA-A, 4 at HLA-B, and 4 at HLA-C).Conditioning Regimen and GVHD ProphylaxisPatients received Flu (30 mg/m2/day) on days −4, −3, and −2 before HCT and 2 Gy TBI at a rate of 0.07 Gy/minute from a linear accelerator on day 0. Postgrafting immunosuppression with oral CsA was started at 5 mg/kg twice a day on day −3 and continued to day +180, then tapered to day +365. MMF was given orally at a dose of 15 mg/kg, based on adjusted body weight (rounded to the nearest 250-mg increment), every 8 hours from the evening of day 0 (4-6 hours after HSCT infusion) up to day +100, and then tapered at a rate of approximately 11% per week for the next 8 weeks. The taper was completed by day +156 unless GVHD occurred. When significant nausea or vomiting occurred during MMF treatment, MMF was administrated i.v. at the same dose. CsA levels were measured by immunoassay, and doses were targeted to achieve trough levels of 500 ng/mL for the first 28 days and 150-450 ng/mL thereafter. CsA was given i.v. in patients not able to take it orally.Escalation of Alemtuzumab DoseThe initial study design incorporated a provision for the addition of low-dose alemtuzumab if more than 1 rejection was seen in either of the first 2 cohorts of 7 evaluable patients treated without alemtuzumab. Eleven patients were enrolled in the first cohort, of whom 7 were evaluable for the chimerism endpoint and engrafted. In the second cohort, only 1 of 7 patients rejected the graft. Therefore, the protocol was amended to allow continued accrual without alemtuzumab. A total of 59 patients underwent transplantation without alemtuzumab.Collection of Hematopoietic CellsAll patients received G-CSF-mobilized PBSC grafts. All related donors received 16 μg/kg/day of G-CSF by s.c. injection for 5 consecutive days before PBSC collection on days −1 and 0. Collection of unrelated donor PBSCs was arranged through the National Marrow Donor Program (NMDP) or international donor centers. G-CSF 10 μg/kg was administered by s.c. injection starting 5 days before day 0 according to the NMDP protocol.Supportive CareAll patients received standard prophylactic antibiotics with a third-generation cephalosporin or quinolone when absolute neutrophil counts (ANCs) declined to < 500 μL. All patients received fluconazole (400 mg/day) from the start of conditioning to at least day +75 as prophylaxis for yeast infection. Trimethoprim-sulfamethoxazole (TMP-SMZ) was used as first-line prophylaxis against Pneumocystis jiroveci, with dapsone (50 mg twice a day) as second-line prophylaxis until day +180 or until discontinuation of immunosuppressive therapy. The varicella zoster virus (VZV) prophylaxis (acyclovir 250 mg/m2 i.v., followed by 800 mg orally or valacyclovir 500 mg orally twice a day) was given until 1 year after HSCT or 6 months after discontinuation of all immunosuppressive therapy. Preemptive treatment with ganciclovir was started during the first 100 days after HSCT when cytomgalovirus (CMV) polymerase chain reaction or pp65 antigenemia for weekly CMV surveillance was positive. After day +100, surveillance and preemptive therapy, on a weekly or biweekly basis, were recommended for patients at intermediate or high risk for CMVGVHD Grading and TreatmentDiagnosis and clinical grading of aGVHD and cGVHD were done by local investigators according to established criteria [20Przepiorka D. Weisdorf D. Martin P. et al.1994 Consensus conference on acute GVHD grading.Bone Marrow Transplant. 1995; 15: 825-828PubMed Google Scholar, 21Sullivan K.M. Agura E. Anasetti C. et al.Chronic graft-versus-host disease and other late complications of bone marrow transplantation.Semin Hematol. 1991; 28: 250-259PubMed Google Scholar]. In most cases, biopsy analysis confirmed the clinical diagnosis. Treatment of aGVHD typically involved prednisone 1-2 mg/kg/day and reinitiation of CsA at full dose if it had been previously tapered or discontinued. Primary treatment of extensive cGVHD comprised of prednisone 1 mg/kg/day and CsA 5.0 mg/kg orally twice a day.Treatment of Persistent/Progressive or Relapsed MalignanciesSubstantial persistent disease at day +84 or disease progression at any time was considered an indication for therapeutic intervention. In the absence of GVHD, MMF was stopped and CsA was tapered over 2 weeks orso, at the attending physician's discretion. If stopping immunosuppression provoked no response, then chemotherapy or radiation therapy was considered. Donor lymphocyte infusion (DLI) was not offered on this trial.Chimerism AnalysesChimerism analysis of peripheral blood T cell (CD3+), granulocyte (CD33+), and whole marrow were performed on days +28, +56 +84, + 180, and +365, and then yearly as described previously [7Maris M.B. Niederwieser D. Sandmaier B.M. et al.HLA-matched unrelated donor hematopoietic cell transplantation after nonmyeloablative conditioning for patients with hematologic malignancies.Blood. 2003; 102: 2021-2030Crossref PubMed Scopus (309) Google Scholar]. For the purposes of this study, full donor T cell chimerism was defined as > 95% donor CD3+ T cells, and graft rejection was defined as the inability to detect at least 5% donor CD3+ T cells (as a proportion of the total T cell population in the PB) after HSCT. Mixed or full donor chimerism was considered evidence of donor engraftment. Sustained engraftment was defined as continued evidence of donor engraftment up to evaluation on day +84 without subsequent loss at later evaluations.Immune ReconstitutionImmune reconstitution was studied in 9 recipients of HLA-class I mismatched unrelated grafts at FHCRC. PB samples were obtained before conditioning, immediately before HSCT on day 0, and at 1, 3, 6, and 12 months after HSCT. Mononuclear cells (MNCs) were separated from blood specimens, stained with fluorochrome-conjugated mAbs, and analyzed by 3-color flow cytometry as described previously [22Storek J. Dawson M.A. Storer B. et al.Immune reconstitution after allogeneic marrow transplantation compared with blood stem cell transplantation.Blood. 2001; 97: 3380-3389Crossref PubMed Scopus (323) Google Scholar, 23Storek J. Zhao Z. Lin E. et al.Recovery from and consequences of severe iatrogenic lymphopenia (induced to treat autoimmune diseases).Clin Immunol. 2004; 113: 285-298Crossref PubMed Scopus (51) Google Scholar].Naive B cells were represented by IgD+ B cells, because most of these cells lack somatic mutations [24Klein U. Kuppers R. Rajewsky K. Human IgM+IgD+ B cells, the major B cell subset in the peripheral blood, express V kappa genes with no or little somatic mutation throughout life.Eur J Immunol. 1993; 23: 3272-3277Crossref PubMed Scopus (133) Google Scholar, 25Suzuki I. Milner E.C.B. Glas A.M. et al.Immunoglobulin heavy-chain variable region gene usage in bone marrow transplant recipients: lack of somatic mutation indicates a maturational arrest.Blood. 1996; 87: 1873-1880PubMed Google Scholar, 26Klein U. Rajewsky K. Kuppers R. Human immunoglobulin (Ig)M+IgD+ peripheral blood B cells expressing the CD27 cell surface antigen carry somatically mutated variable region genes: CD27 as a general marker for somatically mutated (memory) B cells.J Exp Med. 1998; 188: 1679-1689Crossref PubMed Scopus (913) Google Scholar]. Naive CD4+ T cells were defined as CD45RAhigh CD4+ T cells, because this subset contains thymic emigrants [27Douek D.C. McFarland R.D. Keiser P.H. et al.Changes in thymic function with age and during the treatment of HIV infection.Nature. 1998; 396: 690-695Crossref PubMed Scopus (1572) Google Scholar, 28Dumont-Girard F. Roux E. van Lier R.A. et al.Reconstitution of the T-cell compartment after bone marrow transplantation: restoration of the repertoire by thymic emigrants.Blood. 1998; 92: 4464-4471PubMed Google Scholar, 29Storek J. Witherspoon R.P. Storb R. T cell reconstitution after bone marrow transplantation into adult patients does not resemble T cell development in early life.Bone Marrow Transplant. 1995; 16: 413-425PubMed Google Scholar]. Naive CD8+ T cells were defined as CD11alow CD8+ T cells, because virtually all cord blood (CB) CD8+ T cells are CD11alow and become CD11ahigh after activation [30Okumura M. Fujii Y. Inada K. et al.Both CD45RA+ and CD45RA- subpopulations of CD8+ T cells contain cells with high levels of lymphocyte function-associated antigen-1 expression, a phenotype of primed T cells.J Immunol. 1993; 150: 429-437PubMed Google Scholar, 31Okumura M. Fujii Y. Takeuchi Y. et al.Age-related accumulation of LFA-1high cells in a CD8+CD45RAhigh T cell population.Eur J Immunol. 1993; 23: 1057-1063Crossref PubMed Scopus (103) Google Scholar]. CD28+ T cells represent cells that can receive both the T cell receptor-mediated signal and the CD28-mediated costimulatory signal. Monocytes were defined as CD14+ MNCs. Natural killer (NK) cells were defined as MNCs expressing CD16 or CD56 and not expressing CD3 or CD14. Dendritic cells (DCs) were defined as HLA-DRhigh MNCs not expressing CD3, CD14, CD16, CD20, CD34, or CD56.Statistical AnalysisSurvival curves were estimated by the Kaplan-Meier method. Cumulative incidence curves for aGVHD and cGVHD and relapse treated death as a competing risk. Cumulative incidence curves for nonrelapse mortality (NRM) treated relapse as a competing risk. Comparative analyses of mortality and competing risk endpoints were performed via Cox regression; all P values reflect likelihood ratio statistics from these models and are 2-sided.ResultsEngraftment, Chimerism, and Graft RejectionThe median numbers of CD34+ and CD3+ cells in the grafts were 7.0 ×106 (range, 2.1-37.7 × 106) and 2.6 ×108 (range, 0.3-6.6 × 108) cells/kg recipient body weight, respectively. The median neutrophil nadir was 100 cells/μL (range, 0-860 cells/μL). The median duration of neutropenia (ANC <0.5 ×103/μL) was 9 days (range, 0-33 days), and 9% of patients did not experience neutropenia. The median platelet nadir was 23 ×103/μL (range, 4-110 ×103/μL). The median duration of thrombocytopenia (platelet count < 20 ×103/μL) was 0 days (range, 0-23 days), and 62% of patients did not develop thrombocytopenia.The rates of full donor T cell chimerism in the evaluable patients were 76% at day +28, 84% at day +56, and 81% at day +84. Sixteen patients were excluded for evaluation of the graft rejection outcome: 4 died early (less than 30 days after HSCT), 8 received transplants from donors mismatched only in the GVHD vector, and 4 received planned tandem auto-allo transplants. Four patients died, at days +8, +16, +23, and +29, because of NRM in 2 patients and disease progression in 2 patients. The patient who died at day 8 after HSCT did not exhibit hematopoietic recovery.Among the 43 patients eligible for evaluation of engraftment outcome, 77% achieved full donor T cell chimerism at day +28, and 92% did so at day +56. Sustained engraftment was observed in 95% of the evaluable patients.Two patients (one with follicular lymphoma and the other with AML) experienced early graft rejection (on day +56 and day +84, respectively), and no late graft rejections occurred. Both patients with early graft rejection underwent successful retransplantation, one from the same donor with conditioning consisting of Flu and 4 Gy TBI, and the other from an alternative HLA class I-mismatched donor with Flu, 4 Gy TBI, and alemtuzumab (total dose, 10 mg).GVHDForty-four of 57 patients (70%; excluding the 2 patients who experienced rejection) developed aGVHD (grade I, n = 3; grade II, n = 25; grade III, n = 8; grade IV, n = 8). The cumulative incidences of grade II-IV and grade III-IV aGVHD were 69% and 26%, respectively (Figure 1A). Twenty-one patients developed cGVHD; the 3-year cumulative incidence of extensive cGVHD was 41% (Figure 1B).Toxicity and NRMThirty-five patients (59%) experienced at least one nonhematopoietic grade III toxicity, and 20 (34%) had at least one nonhematopoietic grade IV toxicity. The most common grade III and IV nonhematopoietic toxicities were cardiovascular and pulmonary complications (Table 2). Grade IV cardiac toxicities included atrial fibrillation/flutter (n = 3), elevated cardiac enzymes suggestive of ischemic events (n = 3), pulmonary embolism (n = 1), septic shock with kidney failure requiring dialysis (n = 1), acute myocardial infarction (n = 1), severe congestive heart failure (n = 1), and acute vascular leak syndrome (n = 1). Grade IV pulmonary toxicities included hypoxia/apnea requiring intubation or pressure support (n = 7) and acute respiratory distress syndrome (ARDS) (n = 2). Grade IV gastrointestinal toxicity consisted of diarrhea or colitis associated with GVHD (n = 6) and small bowel perforation of unknown etiology (n = 1).Table 2Incidence of Grade III and IV Toxicities (n = 59)Number of Episodes/Number of Patients (% of Patients)Grade IIIGrade IVCardiovascular16/16 (27)11/7 (12)Pulmonary12/10 (17)9/8 (14)Hepatic10/10 (17)5/5 (8)Renal/genitourinary6/6 (10)3/2 (3)Gastrointestinal2/2 (3)7/7 (12)Neurologic2/2 (3)2/2 (3)Hemorrhage3/3 (5)0/0 (0) Open table in a new tab Infection rates were calculated based on infections within the first 100 days posttransplantation or until death before day +100. The rates of documented viral (including CMV reactivation), fungal, and bacterial infection were 1.5, 0.3, and 2.1 per 100 patient-days, respectively, with an overall infection rate of 3.9 per 100 patient-days.Overall, 26 of 59 patients died from nonrelapse causes. The cumulative probabilities of NRM were 22% at day 100, 36% at 1 year, and 47% at 2 years (Figure 2A). The cumulative incidence of NRM at 2 years wa