Blood Marrow Transplant Research Articles

Ex Vivo Expanded Hematopoietic Stem Cells Overcome the MHC Barrier in Allogeneic Transplantation

The lack of understanding of the interplay between hematopoietic stem cells (HSCs) and the immune system has severely hampered the stem cell research and practice of transplantation. Major problems for allogeneic transplantation include low levels of donor engraftment and high risks of graft-versus-host disease (GVHD). Transplantation of purified allogeneic HSCs diminishes the risk of GVHD but results in decreased engraftment. Here we show that exvivo expanded mouse HSCs efficiently overcame the major histocompatibility complex barrier and repopulated allogeneic-recipient mice. An 8-day expansion culture led to a 40-fold increase of the allograft ability of HSCs. Both increased numbers of HSCs and culture-induced elevation of expression of the immune inhibitor CD274 (B7-H1 or PD-L1) on the surface of HSCs contributed to the enhancement. Our study indicates the great potential of utilizing exvivo expanded HSCs for allogeneic transplantation and suggests that the immune privilege of HSCs can be modulated.

Development and Validation of a Test Dose Strategy for Once-Daily i.v. Busulfan: Importance of Fixed Infusion Rate Dosing

Intravenous (i.v.) busulfan (Bu) administered once daily in myeloablative transplant regimens is convenient, effective, and relatively well tolerated. Therapeutic drug monitoring is recommended as nonrelapse mortality increases when daily exposure, as determined by the area under the plasma concentration versus time curve (AUC), exceeds 6000 μM·min. We describe sequential studies to achieve accurate prediction of treatment doses of Bu based on the kinetics of a smaller test dose. A total of 335 patients with hematologic malignancies were given daily i.v. Bu 3.2 mg/kg × 4 and fludarabine 50 mg/m(2) × 5. Pharmacokinetic monitoring was conducted for both the test dose and first treatment dose of Bu (day -5). Three different test dose schedules were evaluated: 12 mg Bu administered over 20 minutes, 0.8 mg/kg over 3 hours, and 0.8 mg/kg infused at 80 mg/h. The 3.2 mg/kg treatment doses were infused over a fixed time of 3 hours for the first 2 test dose trials and at a fixed rate of 80 mg/h for the final protocol. All test dose infusions were on day -7. In the first 2schedules, Bu administered over a fixed time had significantly higher clearance for the test dose compared with the treatment dose. However, when both the test and the treatment doses were administered at the same infusion rate, clearance of the drug between the 2 dosing days was equivalent. Predicted day -5 AUC (AUC(-5)) showed a high linear correlation (r(2) = 0.74) to the actual AUC(-5). The error of these predictions was <20% in 98% of patients and <10% in 80%. In 24 individuals, the test dose predicted an AUC >5500μM·min; therefore, the first Bu treatment dose was reduced to a desired target AUC. All adjusted doses fell within 20% of the targeted exposure. We conclude that a test dose strategy for therapeutic drug monitoring of daily i.v. Bu is accurate if the test and treatment doses are infused at the same rate. This approach allows targeting of therapeutic doses of Bu to desired levels and the potential for improved safety and efficacy.

Genome-wide Profiling in AML Patients Relapsing after Allogeneic Hematopoietic Cell Transplantation

Molecular pathogenesis of relapse after allogeneic hematopoietic cell transplantation is poorly understood. Data regarding relapse mechanisms after transplantation is scarcely available. We investigated genomic aberrations (GAs) in 21 patients undergoing related and unrelated HLA-matched transplantation in leukemic blasts before transplant and at relapse after transplantation. We found a higher number of GAs after transplantation, suggesting increased genomic instability during relapse. Two of 21 patients showed a large homozygous region spanning the whole HLA-locus on chromosome 6p in the relapse sample. In both patients sequence-based HLA typing of the blasts revealed a loss of the patient-specific allele at the mismatched locus leading to homozygosity for the HLA haplotype shared by the patient and the donor. In addition, GAs were found in critical regions such as 12p13, 13q12.2, and 17p13. Our results suggest that escape from immunologic surveillance may be a relevant mechanism of relapse after transplantation in patients with GAs on chromosome 6p. A combination of continuous immunologic pressure mediated by donor T cells and clonal evolution of myeloid leukemia may result in acquired GAs after transplantation.

EBMT Risk Score Predicts Outcome of Allogeneic Hematopoietic Stem Cell Transplantation in Patients Who Have Failed a Previous Transplantation Procedure

Increasing numbers of allogeneic hematopoietic stem cell transplantation (allo-SCT) are being performed for patients who have failed a previous allogeneic or autologous SCT. We investigated whether the EBMT risk score could predict outcome after a subsequent allo-SCT. We analyzed prognostic factors in 124 consecutive patients who underwent a second transplantation using an allogeneic donor at our institution. Patients with either a first autologous (N = 64) or first allogeneic (N = 60) SCT were included. Age, disease stage, time interval from diagnosis to transplantation, donor type, and donor-recipient sex combination were used to establish a score from 0 to 7 points, from which 3 groups were identified. The 5-year survival probability decreased from 51.7% for risk scores 0-3 (low, n = 25), to 29.3% for risk score 4 (intermediate, n = 42), and only 10.4% for risk scores 5-7 (high, n = 57), P = .001. We propose that the EBMT risk score can identify patients most likely to benefit from a second transplantation.

The Incidence of Veno-Occlusive Disease Following Allogeneic Hematopoietic Stem Cell Transplantation Has Diminished and the Outcome Improved over the Last Decade

The evolution of the incidence, morbidity, and mortality of veno-occlusive disease (VOD) was analyzed in 845 allogeneic hematopoietic stem cell transplantations (allo-HSCTs) performed over 24 years. A total of 117 patients and 73 patients developed VOD following the Seattle and the Baltimore diagnostic criteria, respectively (cumulative incidence 13.8% and 8.8%). The cumulative incidence was significantly higher in the period 1985 to 1996 than in 1997 to 2008 (11.5% vs 6.5%; P= .01). This decline was because of the low incidence of VOD among reduced-intensity conditioning-HSCT (RIC-HSCT) (2.1%) and the reduction among those receiving myeloablative-HSCT from unrelated donors (32.7% vs 10.5%, P = .001). A total of 35 patients had severe VOD (26 with multiorgan failure [MOF]), and 20 died by VOD (cumulative mortality rate 17.3%, Seattle, or 22.5%, Baltimore). The mortality declined since 1997 (from 22% to 9%; P = .06, Seattle, and from 36% to 14%; P= .04, Baltimore), with the introduction of defibrotide being the only relevant change in the management of patients. This occurred even though the severity of VOD was similar in both periods. Among those with MOF, only 2 of 8 (25%) receiving defibrotide died versus 14 of 18 (78%) receiving other treatments (P = .007). Myeloablative conditioning, previous liver disease, poor performance status, and alternative donors were the variables with higher impact on VOD development. In summary, although VOD remains a dreaded early complication of HSCT, technical and therapeutic progress in recent decades have notably reduced its incidence and improved the outcome.

CMV Infection after Transplant from Cord Blood Compared to Other Alternative Donors: The Importance of Donor-Negative CMV Serostatus

Cytomegalovirus (CMV) infection and disease are important complications after hematopoietic stem cell transplant, particularly after transplant from alternative donors. Allogeneic cord blood transplantation (CBT) is being increasingly used, but immune recovery may be delayed. The aim of this study was to compare CMV infection in CBT with transplants from unrelated or mismatched related donors, from now on defined as alternative donors. A total of 165 consecutive transplants were divided in 2 groups: (1) alternative donors transplants (n = 85) and (2) CBT recipients (n = 80). Donor and recipient (D/R) CMV serostatus were recorded. The incidence of CMV infection, its severity, timing, and outcome were compared. Median follow-up was 257 days (1-1328). CMV infection was monitored by CMV antigenemia and expressed as CMV Ag positive cell/2 × 10(5) polymorphonuclear blood cells. There was a trend toward a higher cumulative incidence of CMV infection among CBT than alternative donor transplant recipients (64% vs 51%, P = .12). The median time to CMV reactivation was 35 days, and was comparable in the 2 groups (P = .8). The maximum number of CMV-positive cells was similar in the 2 groups (11 versus 16, P = .2). The time interval between the first and the last positive CMV antigenemia was almost 4 times longer in CBT compared with alternative donor transplants (109 vs 29 days, respectively, P = .008). The incidence of late CMV infection was also higher in CBT (62% vs 24%, P < .001). The incidence of early and late CMV infection in CBT was similar to D-/R+ alternative transplants, and higher than in D+/R+ alternative transplants: early infection, 72% in CBT versus 69% in D-/R+ alternative versus 55% in D+/R+ alternative (P = .21); and late infection, 67% in CBT versus 60% in D-/R+ alternative versus 7% in D+/R+ alternative (P < .001). Transplant-related mortality and overall survival were similar between the groups: 34% versus 36% (P = .6) and 54% versus 46% (P = .3) for alternative transplant and CBT, respectively. Longer duration and higher incidence of late CMV infection was seen in CBT patients, when compared with alternative donor transplants, whereas no difference in mortality was observed. The duration and incidence of late CMV infection were similar when D-/R+ CBT were compared with D-/R+ alternative donor transplants.

Pretransplantation Liver Function Impacts on the Outcome of Allogeneic Hematopoietic Stem Cell Transplantation: A Study of 455 Patients

Liver dysfunction is frequent before allogeneic stem cell transplantation (allo-SCT). However, its characteristics and impact on transplantation outcomes are uncertain, especially in the reduced-intensity conditioning (RIC) setting. We analyzed 455 patients receiving an allo-SCT in 3 Spanish centers. Pretransplantation aspartate aminotransferase (AST), alanine aminotransaminase (ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (AP), total bilirubin, and international normalized ratio were analyzed. Pretransplantation liver function test abnormalities were found in 94 (22%) patients. The most frequent cause of pretransplantation liver dysfunction was isolated elevation of GGT/AP (n = 49, 53%). Patients with high bilirubin levels before allo-SCT showed higher 4-year nonrelapse mortality (4y-NRM) (hazard ratio [HR] 2 [95% confidence interval [CI] 1.1-3.8] P = .02) and patients with high GGT levels showed higher 100-day NRM and lower 4-year overall survival (OS) (HR 3.4 [95% CI 1.8-6.7] P < .001, and HR 2 [95% CI 1.4-3], P = .001), respectively. High levels of transaminases did not influence on survival or mortality. In conclusion, hepatic dysfunction before allo-SCT is frequent and has an impact on transplantation outcomes. The best indicator of liver dysfunction still has to be determined.

Translational Research Efforts in Biomarkers and Biology of Early Transplant-Related Complications

In the time since the first allogeneic hematopoietic stem cell transplantation (HSCT) was performed over 40 years ago, this life-saving procedure has been used increasingly for patients with hematologic, metabolic, and malignant diseases. Despite major advances in our understanding of the immunologic processes (both beneficial and injurious) that are associated with HSCT and improvements in supportive and critical care medicine, successful outcomes are still limited by several serious complications. As such, the establishment of effective therapeutic strategies for these complications will be crucial as increasing numbers of high-risk transplants are performed each year. The development of such approaches is fundamentally dependent upon a basic understanding of pathophysiologic mechanisms of disease and also on our ability to successfully translate these insights back to the bedside. This brief review will highlight breakthroughs in translational research endeavors that have paved the way for the development of novel strategies intended to change the standard of care and optimize outcomes for patients in whom allogeneic HSCT offers the only hope for a cure.

Minimal Residual Disease following Allogeneic Hematopoietic Stem Cell Transplantation

Minimal residual disease (MRD), both before and after transplantation, is a clinically important yet relatively poorly defined aspect of allogeneic hematopoietic stem cell transplantation (alloHSCT). The clinical relevance of MRD in the context of alloHSCT has been demonstrated by its association with the development of clinical relapse. However, with the possible exception of chronic myeloid leukemia (CML), the specific techniques, timing, frequency, and clinical utility, relative to improvement in patient outcomes, for monitoring MRD in the setting of alloHSCT has yet to be clearly defined. A concise overview of monitoring techniques for detecting MRD, as well as treatment strategies and biological and clinical research initiatives for MRD suggested by the National Cancer Institute First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation, is covered in this article.

Comparison of Outcomes after Transplantation of G-CSF–Stimulated Bone Marrow Grafts versus Bone Marrow or Peripheral Blood Grafts from HLA-Matched Sibling Donors for Patients with Severe Aplastic Anemia

We compared outcomes of patients with severe aplastic anemia (SAA) who received granulocyte-colony stimulating factor (G-CSF)-stimulated bone marrow (G-BM) (n = 78), unstimulated bone marrow (BM) (n= 547), or peripheral blood progenitor cells (PBPC) (n = 134) from an HLA-matched sibling. Transplantations occurred in 1997 to 2003. Rates of neutrophil and platelet recovery were not different among the 3 treatment groups. Grade 2-4 acute graft-versus-host disease (aGVHD) (relative risk [RR] = 0.82, P = .539), grade 3-4 aGVHD (RR = 0.74, P = .535), and chronic GVHD (cGVHD) (RR = 1.56, P = .229) were similar after G-BM and BM transplants. Grade 2-4 aGVHD (RR = 2.37, P = .012) but not grade 3-4 aGVHD (RR = 1.66, P = .323) and cGVHD (RR = 5.09, P < .001) were higher after PBPC transplants compared to G-BM. Grade 2-4 (RR = 2.90, P < .001), grade 3-4 (RR = 2.24, P = .009) aGVHD and cGVHD (RR = 3.26, P < .001) were higher after PBPC transplants compared to BM. Mortality risks were lower after transplantation of BM compared to G-BM (RR = 0.63, P = .05). These data suggest no advantage to using G-BM and the observed higher rates of aGVHD and cGVHD in PBPC recipients warrants cautious use of this graft source for SAA. Taken together, BM is the preferred graft for HLA-matched sibling transplants for SAA.

5-Azacytidine as Salvage Treatment in Relapsed Myeloid Tumors after Allogeneic Bone Marrow Transplantation

Relapse after allogeneic blood or marrow transplantation carries a very poor prognosis. Current strategies for management that include donor lymphocyte infusions (DLIs) and salvage chemotherapies are usually toxic and ineffective. Here we report the outcome of 10 patients with myeloid malignancies that received 5-azacytidine after a failed allogeneic bone marrow transplant. Of the 10 patients, 6 achieved a complete remission, 1 had stable disease, and 3 progressed after a median of 6 cycles administered. Only 1 patient has died (of disease progression), and no flares of graft-versus-host disease (GVHD) were observed with 5-azacytidine. As of latest follow-up, the median overall survival (OS) for the group was 422.5 days (127-1411). These results further suggest that 5-azacytidine is an active agent after failing an allogeneic bone marrow transplant, and prospective studies are warranted.

Expansion of Human Cord Blood Hematopoietic Stem Cells for Transplantation

A recent Science paper reported a purine derivative that expands human cord blood hematopoietic stem cells in culture (Boitano et al., 2010) by antagonizing the aryl hydrocarbon receptor. Major problems need to be overcome before ex vivo HSC expansion can be used clinically.

HLA-C Antigen Mismatch Is Associated with Worse Outcome in Unrelated Donor Peripheral Blood Stem Cell Transplantation

The association between HLA matching and outcome in unrelated-donor peripheral blood stem cell (PBSC) transplantation has not yet been established. In the present study, a total of 1933 unrelated donor-recipient pairs who underwent PBSC transplantation between 1999 and 2006 for acute myelogenous leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, or chronic myelogenous leukemia and received high-resolution HLA typing for HLA-A, -B, -C, -DRB1, -DQA1, and -DQB1 were included in the analysis. Outcomes were compared between HLA-matched and HLA-mismatched pairs, adjusting for patient and transplant characteristics. Matching for HLA-A, -B, -C, and -DRB1 alleles (8/8 match) was associated with better survival at 1 year compared with 7/8 HLA-matched pairs (56% vs 47%). Using 8/8 HLA-matched patients as the baseline (n = 1243), HLA-C antigen mismatches (n = 189) were statistically significantly associated with lower leukemia-free survival (relative risk [RR], 1.36; 95% confidence interval [CI], 1.13-1.64; P = .0010), and increased risk for mortality (RR, 1.41; 95% CI, 1.16-1.70; P = .0005), treatment-related mortality (RR, 1.61; 95% CI, 1.25-2.08; P = .0002), and grade III-IV graft-versus-host disease (RR, 1.98; 95% CI, 1.50-2.62; P < .0001). HLA-B antigen or allele mismatching was associated with an increased risk for acute GVHD grade III-IV. No statistically significant differences in outcome were observed for HLA-C allele (n = 61), HLA-A antigen/allele (n = 136), HLA-DRB1 allele (n = 39), or HLA-DQ antigen/allele (n = 114) mismatches compared with 8/8 HLA-matched pairs. HLA mismatch was not associated with relapse or chronic GVHD. HLA-C antigen-mismatched unrelated PBSC donors were associated with worse outcomes compared with 8/8 HLA-matched donors. The study's limited power due to small sample size precludesconclusions about other mismatches.

Diarrhea during the Conditioning Regimen Is Correlated with the Occurrence of Severe Acute Graft-versus-Host Disease through Systemic Release of Inflammatory Cytokines

Graft-versus-host disease (GVHD) is a major obstacle to the success of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although many indicators have been used to predict GVHD, the prediction of GVHD remains very difficult. Determining how to predict the occurrence of acute GVHD (aGVHD) as exactly as possible has been a huge challenge so far. Systemic release of inflammatory cytokines during the conditioning regimen and early-phase post-HSCT plays a crucial role in the generation of aGVHD; additionally, the conditioning regimen causes the damage to the intestinal tract. Diarrhea is a common symptom of intestinal tract damage during the conditioning regimen. We therefore performed a prospective study to investigate the relationship between diarrhea related to the conditioning regimen, systemic release of inflammatory cytokines during the conditioning regimen and the early-phase post-HSCT, and the development of aGVHD. This study demonstrated that duration of diarrhea was >5.5 days, with a maximal volume >8.72 mL/kg and a mean volume of diarrhea for days -3 to 0 >7.94 mL/kg were risk factors of grade II to IV aGVHD. Diarrhea with any 1 risk factor was defined as severe diarrhea. Furthermore, this study first confirmed that the correlation between diarrhea and aGVHD was related to the serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 during the conditioning regimen and during the early phase after transplantation. Our study demonstrated that diarrhea related to the conditioning regimen could be used as a marker for the prediction of aGVHD and further explain the possible mechanism underlying the linkage described here. Therefore, for the patients with severe diarrhea related to the conditioning regimen, low-dose glucocorticoid may be used to reduce the levels of inflammatory cytokine release by a damaged intestinal tract, and possibly further reduce the occurrence of aGVHD. For these patients, prophylaxis of aGVHD may be need to be adjusted individually.

Robust In Vivo Transduction of Nervous System and Neural Stem Cells by Early Gestational Intra Amniotic Gene Transfer Using Lentiviral Vector

Presently, in vivo methods to efficiently and broadly transduce all major cell types throughout both the central (CNS) and peripheral adult nervous system (PNS) are lacking. In this study, we hypothesized that during early fetal development neural cell populations, including neural stem cells (NSCs), may be accessible for gene transfer via the open neural groove. To test this hypothesis, we injected lentiviral vectors encoding a green fluorescent protein (GFP) marker gene into the murine amniotic cavity at embryonic day 8. This method (i) efficiently and stably transduced the entire nervous system for at least 80% of the lifespan of the mice, (ii) transduced all major neural cell types, and (iii) transduced adult NSCs of the subventricular zone (SVZ) and subgranular zones (SGZs). This simple approach has broad applications for the study of gene function in nervous system development and adult NSCs and may have future clinical applications for treatment of genetic disorders of the nervous system.

Regulatory T Cell Content in the Bone Marrow Graft Does Not Predict the Occurrence of Acute GVHD

The subpopulation of regulatory T cells (Treg) was shown to play a key role in alloreactive responses. In allogeneic hematopoietic stem cell transplantation, several groups tested whether Treg content in transplants correlates with graft-versus-host disease (GVHD) with controversial results. In a retrospective study of 49 consecutive HLA-matched sibling transplantations, we studied the relationship between Treg content in bone marrow transplants and acute GVHD (aGVHD) occurrence. We observed a large variability in Treg in bone marrow grafts. However, contrary to previous observations in peripheral blood stem cells transplantation, we report that the Treg content of allogeneic bone marrow transplantation did not predict the occurrence of aGVHD.

Pretransplant Predictors and Posttransplant Sequels of Acute Kidney Injury after Allogeneic Stem Cell Transplantation

Acute kidney injury (AKI) is a common complication after allogeneic stem cell transplantation (SCT). Although various risk factors for AKI have been reported, the influence of pretransplant comorbidity on the incidence of AKI has not been well investigated. We performed a retrospective analysis of 207 consecutive patients undergoing myeloablative or nonmyeloablative SCT between 2001 and 2009, using the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) as a representative of pretransplant comorbidities. According to Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) criteria, 158 patients (76.3%) developed AKI, and 92 patients (44.4%) developed severe AKI (RIFLE class I or class F) within 100 days after SCT. The cumulative incidence of severe AKI within 100 days in patients with an HCT-CI score 0, 1-2, and ≥3 was 21.3%, 48.8%, and 73.9%, respectively. In multivariate analysis, the HCT-CI was independently associated with severe AKI (HCT-CI 1-2: adjusted hazard ratio [HR] 2.42, P < .01; HCT-CI ≥3: adjusted HR 4.69, P < .01). In a landmark analysis, patients with severe AKI had a lower 3-year overall survival (OS) (39.3% versus 61.4%, P < .01), and a higher 3-year nonrelapse mortality (NRM) (40.8% versus 5.6%, P < .01) than those without AKI. Multivariate analysis showed that severe AKI was a significant risk factor for worse OS (HR: 2.10, P = .01) and NRM (HR: 6.15, P < .01). Thus, it is important to assess the HCT-CI to predict the incidence of AKI, which is a strong indicator of worse prognosis after SCT.

Autologous Peripheral Blood Stem Cell Transplantation in Children with Refractory or Relapsed Lymphoma: Results of Children’s Oncology Group Study A5962

This prospective study was designed to determine the safety and efficacy of cyclophosphamide, BCNU, and etoposide (CBV) conditioning and autologous peripheral blood stem cell transplant (PBSCT) in children with relapsed or refractory Hodgkin and non-Hodgkin lymphoma (HL and NHL). Patients achieving complete remission (CR) or partial remission (PR) after 2 to 4 courses of reinduction underwent a granulocyte-colony stimulating factor (G-CSF) mobilized PBSC apheresis with a target collection dose of 5 × 10⁶ CD34(+)/kg. Those eligible to proceed received autologous PBSCT after CBV (7200 mg/m², 450-300 mg/m², 2400 mg/m²). Forty-three of 69 patients (30/39 HL, 13/30 NHL) achieved a CR/PR after reinduction. Thirty-eight patients (28 HL, 10 NHL) underwent PBSCT. All initial 6 patients who received BCNU at 450 mg/m² experienced grade III or IV pulmonary toxicity compared to none of the subsequent 32 receiving 300 mg/m² (P < .0001). The probability of overall survival (OS) at 3 years for all patients is 51% and for transplanted patients is 64%. The 3-year event-free survival (EFS) is 38% (45% for HL; 30% NHL). The 3-year EFS in transplanted patients is 66% (65% HL; 70% NHL). Initial duration of remission of ≥12 versus <12 months was associated with a significant increase in OS (3 years OS 70% versus 34%) (P = .003). BCNU at 300 mg/m(2) in a CBV regimen prior to PBSCT is well tolerated in relapsed or refractory pediatric lymphoma patients. A short duration (<12 months) of initial remission is associated with a poorer prognosis. Last, a high percentage of patients achieving a CR/PR after reinduction therapy can be salvaged with CBV and autologlous PBSCT.

Leukemia Lineage-Specific Chimerism Analysis and Molecular Monitoring Improve Outcome of Donor Lymphocyte Infusions

A retrospective analysis was performed of 118 patients with hematologic malignancies who received donor lymphocyte infusions (DLIs) after allogeneic stem cell transplantation (ASCT). Treatment was either given because of hematologic relapse (n = 44), molecular/cytogenetic relapse (n = 52), or other causes (n = 22). Molecular relapse was in most cases based on leukemia lineage-specific chimerism analysis. Patients with acute leukemia and myelodysplastic syndrome showed a 3-year survival of 42% if DLI treatment was given because ofmolecular relapse, compared to 16% in hematologic relapse (P < .006). In multivariate analysis, there was a correlation between response to DLI and nonhematologic relapse (risk ratio [RR] 3.36, P = .001), chronic graft-versus-host disease (cGVHD) (RR = 1.51, P = .005), and late relapse (RR = 2.06, P = .017). The overall incidences of acute GVHD (aGVHD) grades I-II and grades III-IV aGVHD were 33% and 8.5%, respectively. Probability of cGVHD was 33%. The development of aGVHD or cGVHD did not significantly influence the response of DLI in patients with molecular/cytogenetic relapse. However, the development of cGVHD was significantly associated with a better response in patients with hematologic relapse because only 4 of 29 patients without cGVHD responded compared to 7 of 12 with cGVHD (P = .007). The development of cGVHD increased significantly if DLI was given >12 months after ASCT (46% versus 27%, P = .04). In contrast, time between ASCT and start of DLI treatment had no significant influence on the risk of developing aGVHD. To conclude, monitoring of leukemia lineage-specific chimerism is of utmost importance for DLI response after ASCT.

Feasibility and Safety of Adoptive Immunotherapy with CIK Cells after Cord Blood Transplantation

Five patients with aggressive acute leukemias who had relapsed after cord blood transplantation were treated with cord blood derived cytokine-induced killer (CIK) cells. These were obtained by ex vivo expansion, using as starting material the washouts of the cord blood units, left over at the end of the transplant. We did not observe any acute or delayed adverse event, and observed 1 partial response in 1 patient concomitantly with the development of acute grade III graft-versus-host disease (GVHD). These observations show the relatively low toxicity of cord blood-derived CIK cells and, more importantly, the feasibility of this immunotherapy program for patients who could not otherwise benefit from donor lymphocyte infusions.