Donor lymphocytes expressing the herpes simplex virus thymidine kinase suicide gene: detailed immunological function following add-back after haplo-identical transplantation.

BACKGROUND AIMS: Haplo-identical hematopoietic stem cell transplantation (HSCT) with add-back of donor lymphocytes expressing the herpes simplex virus thymidine kinase suicide gene (TK cells) is one of the most widely applied promising new gene therapy approaches. However, the immunological status of added-back TK cells after HSCT has yet to be well characterized. METHODS: We investigated TK cells through the use of flow cytometry, T-cell receptor (TCR) Vß repertoire spectratyping and linear amplification-mediated polymerase chain reaction followed by insertion site analysis in a patient enrolled in our clinical trial. RESULTS: A comparison of onset with remission of acute graft-versus-host disease confirmed that TK cells were predominantly eliminated and that proliferative CD8(+) non-TK cells were also depleted in response to ganciclovir administration. The TCR Vß-chain repertoire of both TK cells and non-TK cells markedly changed after administration of ganciclovir, and, whereas the TCR repertoire of non-TK cells returned to a normal spectratype long after transplantation, that of TK cells remained skewed. With the long-term prophylactic administration of acyclovir, TK cells oligoclonally expanded and the frequency of spliced variants of TK cells increased. Known cancer-associated genes were not evident near the oligoclonally expanded herpes simplex virus (HSV)-TK insertion sites. CONCLUSIONS: We demonstrate obvious differences in immunological status between TK cells and non-TK cells. In addition, we speculate that long-term prophylactic administration of acyclovir increases the risk of oligoclonal expansion of spliced forms of TK cells.

A Markov decision analysis of allogeneic hematopoietic cell transplantation versus chemotherapy in patients with acute myeloid leukemia in first remission.

Various prospective trials have been performed to assess the roles of allogeneic hematopoietic cell transplantation (allo-HCT) and chemotherapy in patients with acute myeloid leukemia (AML) in first complete remission (CR1). However, the results have not always been consistent, and there has been a limited evaluation of quality of life (QOL) in these postremission strategies. We performed a Markov decision analysis that enabled us to compare survival outcomes with a QOL evaluation using a database of 2029 adult AML patients who achieved CR1. The Markov decision model compared 2 strategies: allo-HCT or chemotherapy in CR1. Patients who had intermediate- or unfavorable-risk AML had a longer life expectancy when they received allo-HCT in CR1 than patients treated with chemotherapy alone. Likewise, patients who had a suitable related donor who received allo-HCT in CR1 had a longer life expectancy. The life expectancy was shortened to a greater degree by adjustment for QOL in the allo-HCT group. Nevertheless, QOL-adjusted life expectancies in most of the subgroups remained longer in the allo-HCT group than in the chemotherapy group. Our results showed that older patients with a related donor and younger patients with unfavorable cytogenetics benefited the most from allo-HCT in CR1.

In vivo T-cell depletion with alemtuzumab in allogeneic hematopoietic stem cell transplantation: Combined results of two studies on aplastic anemia and HLA-mismatched haploidentical transplantation.

We evaluated the efficacy of in vivo T-cell depletion with alemtuzumab in two prospective studies according to the International Conference on Harmonisation (ICH)-Good Clinical Practice (ICH-GCP) guidelines; one was for patients with aplastic anemia (AA study) and the other was for patients who were undergoing hematopoietic stem cell transplantation (HSCT) from a 2- or 3-antigen-mismatched haploidentical donor (MM study). The final dose of alemtuzumab in these studies was 0.16 mg/kg/day for 6 days. At this dose, all of the 12 and 11 patients in the AA and MM studies, respectively, achieved initial engraftment and the incidences of Grade II-IV acute graft-versus-host disease (GVHD) were 0% and 18%. While cytomegalovirus (CMV) frequently reactivated, none of the patients developed fatal CMV disease. Transplantation-related mortality within 1 year after HSCT was observed in only two and one patients, respectively. The numbers of CD4+ and CD8+ T-cells and T-cell receptor rearrangement excision circles remained low within 1 year after HSCT. These findings suggest that the use of alemtuzumab at this dose in a conditioning regimen enables safe allogeneic HSCT even from a 2- or 3-antigen-mismatched donor. However, the use of a lower dose of alemtuzumab should be explored in future studies to accelerate immune recovery after HSCT.

Comparison of outcomes after allogeneic hematopoietic stem cell transplantation in patients with follicular lymphoma, diffuse large B-cell lymphoma associated with follicular lymphoma, or de novo diffuse large B-cell lymphoma.

The outcome after allogeneic hematopoietic stem cell transplantation (allo-HCT) for diffuse large B-cell lymphoma (DLBCL) associated with follicular lymphoma (FL), which includes DLBCL with pre- or co-existing FL, remains controversial, and few previous reports have compared the outcomes after allo-HCT for FL, DLBCL associated with FL, and de novo DLBCL. We retrospectively analyzed 97 consecutive patients with FL (n = 46), DLBCL associated with FL (n = 22), or de novo DLBCL (n = 29) who received allo-HCT at our institute between 2000 and 2010. With a median follow-up of 53 months, the 5-year overall survival (OS) and progression-free survival (PFS) were, respectively, 77% and 70% for FL, 62% and 57% for DLBCL associated with FL, and 26% and 23% for de novo DLBCL. The 5-year cumulative incidences of non-relapse mortality and disease progression/relapse were, respectively, 16% and 15% for FL, 19% and 24% for DLBCL associated with FL, and 36% and 41% for de novo DLBCL. By a multivariate analysis, the OS and PFS for DLBCL associated with FL were significantly better than those for de novo DLBCL, whereas they were not significantly different from those for FL. These results suggest that allo-HCT may be a promising option for patients with not only advanced FL but also DLBCL associated with FL.

Comparison of allogeneic hematopoietic cell transplantation and chemotherapy in elderly patients with non-M3 acute myelogenous leukemia in first complete remission.

The benefits of allogeneic hematopoietic cell transplantation (allo-HCT) for patients with acute myelogenous leukemia (AML) in first complete remission (CR1) have mostly been evaluated in younger patients. Although favorable outcomes of allo-HCT over chemotherapy have been reported with the use of reduced-intensity conditioning (RIC) regimens in elderly patients with AML in CR1, information is still limited, especially on the effects of cytogenetic risks and donor sources. We collected data from AML patients aged 50 to 70 years who achieved CR1, and compared the outcome in 152 patients who underwent allo-HCT in CR1 (HCT group) to that in 884 patients who were treated with chemotherapy (CTx group). The cumulative incidence of relapse in the HCT group was significantly lower than that in the CTx group (22% versus 62%). Both overall survival (OS) and relapse-free survival (RFS) were significantly improved in the HCT group (OS: 62% versus 51%, P = .012), not only in the whole population, but also in the intermediate-risk group. Among patients who had a suitable related donor, the outcomes in the HCT group were significantly better than those in the CTx group. The introduction of appropriate treatment strategies that include allo-HCT may improve the outcome in elderly patients with AML in CR1.

Feasibility of reduced-intensity cord blood transplantation as salvage therapy for graft failure: results of a nationwide survey of adult patients.

To evaluate whether rescue with cord blood transplantation (CBT) could improve the poor survival after graft failure (GF), we surveyed the data of 80 adult patients (median age, 51 years) who received CBT within 3 months of GF (primary 64, secondary 16), with fludarabine-based reduced-intensity regimens with or without melphalan, busulfan, cyclophosphamide, and/or 2-4 Gy total-body irradiation (TBI). A median number of 2.4 × 10(7)/kg total nucleated cells (TNC) were infused, and among the 61 evaluable patients who survived for more than 28 days, 45 (74%) engrafted. The median follow-up of surviving patients was 325 days, and the 1-year overall survival rate was 33% despite poor performance status (2-4, 60%), carryover organ toxicities (grade 3/4, 14%), and infections (82%) prior to CBT. Day 100 transplantation-related mortality was 45%, with 60% related to infectious complications. Multivariate analysis showed that the infusion of TNC ≥2.5 × 10(7)/kg and an alkylating agent-containing regimen were associated with a higher probability of engraftment, and that high risk-status at the preceding transplantation and grade 3/4 organ toxicities before CBT were associated with an increased risk of mortality. In conclusion, in an older population of patients, our data support the feasibility of CBT with a reduced-intensity conditioning regimen for GF.

Prognostic factors and outcomes of adult patients with acute myeloid leukemia after first relapse.

BACKGROUND: Patients with acute myeloid leukemia who are treated with conventional chemotherapy still have a substantial risk of relapse; the prognostic factors and optimal treatments after relapse have not been fully established. We, therefore, retrospectively analyzed data from patients with acute myeloid leukemia who had achieved first complete remission to assess their prognosis after first relapse. DESIGN AND METHODS: Clinical data were collected from 70 institutions across the country on adult patients who were diagnosed with acute myeloid leukemia and who had achieved a first complete remission after one or two courses of induction chemotherapy. RESULTS: Among the 1,535 patients who were treated with chemotherapy alone, 1,015 relapsed. Half of them subsequently achieved a second complete remission. The overall survival was 30% at 3 years after relapse. Multivariate analysis showed that achievement of second complete remission, salvage allogeneic hematopoietic cell transplantation, and a relapse-free interval of 1 year or longer were independent prognostic factors. The outcome after allogeneic transplantation in second complete remission was comparable to that after transplantation in first complete remission. Patients with acute myeloid leukemia and cytogenetic risk factors other than inv(16) or t(8;21) had a significantly worse outcome when they did not undergo salvage transplantation even when they achieved second complete remission. CONCLUSIONS: We found that both the achievement of second complete remission and the application of salvage transplantation were crucial for improving the prognosis of patients with acute myeloid leukemia in first relapse. Our results indicate that the optimal treatment strategy after first relapse may differ according to the cytogenetic risk.

Cost and effectiveness of reduced-intensity and conventional allogeneic hematopoietic stem cell transplantation for acute myelogenous leukemia and myelodysplastic syndrome.

GOALS OF WORK: Allogeneic stem cell transplantation with a reduced-intensity regimen (RIST) has been evaluated mostly in terms of its clinical benefit, and the pharmacoeconomic aspects of this procedure remain unclear. We compared the cost and effectiveness of RIST with those of stem cell transplantation using a conventional myeloablative regimen (CST). PATIENTS AND METHODS: Fifty consecutive patients who underwent transplantation for myeloid malignancy were included. Life years and medical costs during the entire treatment course for up to 2 years after transplantation were evaluated, and cost-effectiveness was assessed from the payer's perspective. MAIN RESULTS: Of these 50 cases, 35 were treated with CST and 15 were treated with RIST. The mean survival time was 1.5 years in CST and 1.2 years in RIST, while the mean total cost per patient within the first 2 years was $29,630 for CST and $29,466 for RIST, with no significant difference. The duration of total hospitalization was shorter in RIST than in CST; then, the cost for hospitalization represented a lower proportion of the total cost in RIST (49% of total cost) than in CST (63%). In contrast, the cost related to the conditioning regimen was significantly higher in RIST than in CST. CONCLUSIONS: This result suggests that the increased cost of the conditioning regimen offsets the reduced cost of hospitalization in RIST. Although some differences were observed in the details of the cost, the total cost and mean survival were comparable between CST and RIST, and this result was confirmed by a probabilistic sensitivity analysis.

Outcome of 93 patients with relapse or progression following allogeneic hematopoietic cell transplantation.

Relapse/progression after allogeneic hematopoietic cell transplantation (allo-HCT) remains the major cause of treatment failure. In this study, the subsequent clinical outcome was overviewed in 292 patients with leukemia/myelodysplastic syndrome who received allo-HCT. Among them, 93 (32%) showed relapse/progression. Cohort 1 was chosen to receive no interventions with curative intent (n = 25). Cohort 2 received reinduction chemotherapy and/or donor lymphocyte infusion (n = 48), and Cohort 3 underwent a second allo-HCT (n = 20). Sixty-three patients received reinduction chemotherapy, and 27 (43%) achieved subsequent complete remission (CR). The incidence of nonrelapse mortality (NRM) was similar among the three cohorts (4, 15, and 5%). The 1-year overall survival (OS) after relapse was significantly better in patients with a second HCT (58%) than in others (14%, Cohorts 1 and 2; P <.001). However, the 2-year OS did not differ between the two groups, which suggests that it is difficult to maintain CR after the second HCT. Multivariate analysis showed that reinduction chemotherapy, CR after intervention, second HCT, and longer time to post-transplant relapse were associated with improved survival. In conclusion, for patients with relapse after allo-HCT, successful reinduction chemotherapy and a second HCT may be effective for prolonging survival without excessive NRM. However, effective measures to prevent disease progression after a second HCT clearly need to be developed.

Regular dose of gemcitabine induces an increase in CD14+ monocytes and CD11c+ dendritic cells in patients with advanced pancreatic cancer.

OBJECTIVE: Chemotherapy and immunotherapy often seem to contradict each other. However, recent reports suggested that the anticancer effects in some chemotherapeutic agents were concerned with immune response. This study was designed to evaluate the immunological reaction by gemcitabine for future clinical trial of combination therapy with gemcitabine and cancer vaccines. METHODS: We evaluated several immunological parameters in patients with advanced pancreatic cancer who received a conventional dose of gemcitabine for 2 months. Twenty-eight patients with metastasis or locally advanced tumor, including 18 gemcitabine-naïve and 10 with a history of preceding gemcitabine treatment, were enrolled in this study. The patients received gemcitabine 1000 mg/m(2) for 3 weeks, followed by 1 week of rest. We monitored the kinetics of lymphocytes, natural killer cells, monocytes, dendritic cells (DC), human leukocyte antigen (HLA)-multimer conjugated with CMV or WT1 peptide, and intracellular cytokine production of interferon-gamma and interleukin-4 by flow cytometry. The T cell receptor (TCR) repertoire was also analyzed. RESULTS: The absolute number and percentage of CD14(+) monocytes and CD11c(+) (myeloid) DC increased with gemcitabine treatment (P = 0.033 and P = 0.021). The percentage of CD123(+) (plasmacytoid) DC also increased (P = 0.034), whereas no significant change was observed in other immune parameters, including multimer, intracellular cytokine production and TCR repertoire. CONCLUSIONS: Our finding that gemcitabine treatment induced the proliferation of CD14(+) monocytes and CD11c(+) DC could support combination therapy with gemcitabine and specific immunotherapy such as peptide vaccination against pancreatic cancers.

Interleukin (IL)-4 promotes T helper type 2-biased natural killer T (NKT) cell expansion, which is regulated by NKT cell-derived interferon-gamma and IL-4.

CD1d-restricted natural killer T (NKT) cells can rapidly produce T helper type 1 (Th1) and Th2 cytokines and also play regulatory or pathological roles in immune responses. NKT cells are able to expand when cultured with alpha-galactosylceramide (alpha-GalCer) and interleukin (IL)-2 in a CD1d-restricted manner. However, the expansion ratio of human NKT cells is variable from sample to sample. In this study, we sought to determine what factor or factors are responsible for efficient in vitro expansion of NKT cells from various inbred mouse strains. Although the proportion of NKT cells in the spleen was nearly identical in each mouse strain, the growth rates of NKT cells cultured in vitro with alpha-GalCer and IL-2 were highly variable. NKT cells from the B6C3F1 and BDF1 mouse strains expanded more than 20-fold after 4 days in culture. In contrast, NKT cells from the strain C3H/HeN did not proliferate at all. We found that cell expansion efficiency correlated with the level of IL-4 detectable in the supernatant after culture. Furthermore, we found that exogenous IL-4 augmented NKT cell proliferation early in the culture period, whereas interferon (IFN)-gamma tended to inhibit NKT cell proliferation. Thus, the ratio of production of IL-4 and IFN-gamma was important for NKT cell expansion but the absolute levels of these cytokines did not affect expansion. This finding suggests that effective expansion of NKT cells requires Th2-biased culture conditions.

Impact of T cell chimerism on clinical outcome in 117 patients who underwent allogeneic stem cell transplantation with a busulfan-containing reduced-intensity conditioning regimen.

Within the concept of reduced-intensity stem cell transplantation (RIST) there is a wide range of different regimens used, and little information is available on the clinical impact of chimerism status in patients conditioned with a busulfan-containing regimen. Therefore, we retrospectively reviewed lineage-specific chimerism and the subsequent clinical outcome in 117 patients (median age, 55 years; range: 29-68) who underwent busulfan-containing RIST. The conditioning regimen consisted of busulfan (oral 8 mg/kg or i.v. 6.4 mg/kg) and fludarabine (180 mg/m(2), n = 64) or cladribine (0.66 mg/kg, n = 53), with or without 2-4 Gy total-body irridiation (TBI) (n = 26) or antihuman T-lymphocyte immunoglobulin (ATG; 5-10 mg/kg; n = 31). Chimerism was evaluated with peripheral blood samples taken on days 30, 60, and 90 after transplantation by polymerase chain reaction (PCR)-based amplification of polymorphic short tandem repeat regions. The median follow-up of surviving patients was 1039 days (153-2535). The percent donor-chimerism was significantly higher in granulocyte than T cell fraction throughout the entire course, and the median (mean) values were, respectively, 100% (96%) versus 95% (83%), 100% (98%) versus 100% (89%), and 100% (98%) versus 100% (91%) at days 30, 60, and 90 after RIST. In a multivariate analysis, having received <2 types of chemotherapy regimens before RIST was the only factor that was significantly associated with low donor T cell chimerism (<60%) at day 30 (hazard ratio [HR]: 6.1; 95% confidence interval [CI], 2.1-18.4; P < .01). The median percentage of donor T cell chimerism at day 30 was 9% (0%-63%) in 5 patients who experienced graft failure, which was significantly lower than that (97%; 15%-100%) in the rest of the patients (P < .01). No correlation was found between the kinetics of T cell chimerism and the occurrence of acute or chronic GVHD (aGVHD, cGVHD). The stem cell source and the addition of TBI or ATG were not associated with the degree of T cell chimerism, overall survival (OS) or event-free survival (EFS). In a Cox proportional hazard model, low donor T cell chimerism of <60% at day 30 was associated with both poor OS (HR: 2.2; 95% CI, 1.1-4.5; P = .02) and EFS (HR: 2.0; 95% CI, 1.1-3.8; P = .02). In conclusion, we found that 43% of the patients retained mixed donor T cell chimerism (<90% donor) at day 30, whereas 92% achieved complete chimerism in granulocyte fraction. Low donor T cell chimerism of <60% at day 30 may predict a poor outcome, and a prospective study to examine the value of early intervention based on chimerism data is warranted.

Preengraftment serum C-reactive protein (CRP) value may predict acute graft-versus-host disease and nonrelapse mortality after allogeneic hematopoietic stem cell transplantation.

In a mouse model, inflammatory cytokines play a primary role in the development of acute graft-versus-host disease (aGVHD). Here, we retrospectively evaluated whether the preengraftment C-reactive protein (CRP) value, which is used as a surrogate marker of inflammation, could predict posttransplant complications including GVHD. Two hundred twenty-four adult patients (median age, 47 years; range: 18-68 years) underwent conventional stem cell transplantation (CST, n = 105) or reduced-intensity stem cell transplantation (RIST, n = 119). Patients were categorized according to the maximum CRP value during neutropenia: the "low-CRP" group (CRP < 15 mg/dL, n = 157) and the "high-CRP" group (CRP >or= 15 mg/dL, n = 67). The incidence of documented infections during neutropenia was higher in the high-CRP group (34% versus 17%, P = .004). When patients with proven infections were excluded, the CRP value was significantly lower after RIST than after CST (P = .017) or after related than after unrelated transplantation (P < .001). A multivariate analysis showed that male sex, unrelated donor, and HLA-mismatched donor were associated with high CRP values. The high-CRP group developed significantly more grade II-IV aGVHD (P = .01) and nonrelapse mortality (NRM) (P < .001), but less relapse (P = .02). The present findings suggest that the CRP value may reflect the net degree of tissue damage because of the conditioning regimen, infection, and allogeneic immune reactions, all of which lead to subsequent aGVHD and NRM.

Characterization of acute graft-versus-host disease following reduced-intensity stem-cell transplantation from an HLA-identical related donor.

To investigate clinical features of acute graft-versus-host disease (GVHD) following reduced intensity stem-cell transplantation (RIST), we retrospectively investigated medical records of 65 patients with hematologic malignancies who underwent RIST from a matched related donor. Preparative regimen comprised fludarabine 30 mg/m(2) (n = 53) or cladribine 0.11 mg/kg (n = 12) for 6 days plus busulfan 4 mg/kg for 2 days. Twelve patients received rabbit antithymocyte globulin 2.5 mg/kg/day for 2-4 consecutive days. Grade II to IV acute GVHD was diagnosed in 36 patients (55%). Its median onset was day 58 (range, 17-109), while it was bimodal, peaking day 15-29 (early-onset GVHD, n = 18) and day 75-89 days (late-onset GVHD, n = 18). Variables that were more common in early-onset GVHD than late-onset GVHD included skin rash (89% vs. 61%) and noninfectious fevers (33% vs. 11%). Desaturation, pulmonary infiltrates and hyperbilirubinemia (>2.0 mg/dL) were more common in late-onset GVHD (6% vs. 22%, 0% vs. 17%, and 6% vs. 33%, respectively). All of the patients with early-onset GVHD given corticosteroid responded to it, while 5 of the 18 patients with late-onset GVHD failed to respond it. Patients with either early-onset or late-onset GVHD tended to have better progression-free survival (PFS) than those without it; however, there was no significant difference in PFS between patients with early-onset GVHD and those with late-onset GVHD. This study suggests that several etiologies might have contributed to the development of acute GVHD following RIST.

Hyperglycemia during the neutropenic period is associated with a poor outcome in patients undergoing myeloablative allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Recipients of allogeneic hematopoietic stem cell transplantation (HSCT) frequently require support with parenteral nutrition and immunosuppressive drugs, which introduce the risk of hyperglycemia. Van den Berghe et al. showed that the strict glucose control improved the outcome of patients treated in the intensive care unit, and this point was evaluated in this study in a HSCT setting. METHODS: A cohort of 112 consecutive adult patients treated by myeloablative allogeneic HSCT between January 2002 and June 2006 was reviewed retrospectively. Twenty-one patients were excluded due to graft failure, preexisting infectious diseases, preexisting neutropenia or previous allogeneic HSCT. The remaining 91 patients were categorized according to mean fasting blood glucose (BG) level in the neutropenic period after conditioning: normoglycemia (BG <110 mg/dL, n=28), mild hyperglycemia (110 to 150 mg/dL, n=49), and moderate/severe (>150 mg/dL, n=14). The primary endpoint was the occurrence of febrile neutropenia (FN) and documented infection during neutropenia, and the secondary endpoints included organ dysfunction according to the definition used by van den Berghe, acute graft-versus-host disease (GVHD), overall survival, and nonrelapse mortality (NRM). RESULTS: Although the incidence of FN or documented infections was similar between the three groups, hyperglycemia was significantly associated with an increased risk of organ dysfunction, grade II-IV acute GVHD, and NRM. CONCLUSIONS: While the results suggested an association between the degree of hyperglycemia during neutropenia and an increased risk of posttransplant complications and NRM, the possibility that intensive glucose control improves the outcome after HSCT can only be confirmed in a prospective randomized trial.

Unrelated-donor bone marrow transplantation with a conditioning regimen including fludarabine, busulfan, and 4 Gy total body irradiation.

We investigated the feasibility of reduced-intensity conditioning with 4 Gy total body irradiation, fludarabine (30 mg/m2 for 6 days), and busulfan (4 mg/kg for 2 days) for bone marrow transplantation from a serologically HLA-matched unrelated donor. Seventeen adult patients (median age, 55 years; range, 27-67 years) with various hematologic malignancies (6 in remission, 11 not in remission) were treated. Successful engraftment was achieved in all patients at a median of day 18 (range, day 14-35) after transplantation, although subsequent secondary graft failure was observed in 2 patients. The cumulative incidence of acute graft-versus-host disease (GVHD) of grades II to IV at day 100 was 48%. With a median follow-up of 286 days (range, 56-687 days), the rates of 1-year overall survival, 100-day nonrelapse mortality, and 1-year nonrelapse mortality were 41%, 14%, and 46%, respectively. Eleven patients died, and the causes of death were relapse (n = 4), pulmonary complications (n = 4), acute GVHD (n = 2), and sepsis (n = 1). The remaining 6 patients (at transplantation, 2 were in remission, and 4 were not in remission) are currently still in remission. These results suggest that this regimen reduces the risk of graft failure, but further studies are needed to ameliorate transplantation-related toxicities, primarily GVHD and/or pulmonary complications.

T-cell large granular lymphocyte leukemia of donor origin after cord blood transplantation.

We report the first case of T-cell large granular lymphocyte leukemia of donor origin after a second cord blood transplantation for acute myeloid leukemia, and review the literature regarding rare cases of T-cell-origin posttransplantation lymphoproliferative disorders.

Modulation of acute graft-versus-host disease and chimerism after adoptive transfer of in vitro-expanded invariant Valpha14 natural killer T cells.

Mouse natural killer T cells with an invariant Valpha14-Jalpha18 TCR rearrangement (Valpha14i NKT cells) are able to regulate immune responses through rapid and large amounts of Th1 and Th2 cytokine production. It has been reported that in vivo administration of the Valpha14i NKT cell ligand, alpha-galactosylceramide (alpha-GalCer) significantly reduced morbidity and mortality of acute graft-versus-host disease (GVHD) in mice. In this study, we examined whether adoptive transfer of in vitro-expanded Valpha14i NKT cells using alpha-GalCer and IL-2 could modulate acute GVHD in the transplantation of spleen cells of C57BL/6 mice into (B6xDBA/2) F(1) mice. We found that the adoptive transfer of cultured spleen cells with a combination of alpha-GalCer and IL-2, which contained many Valpha14i NKT cells, modulated acute GVHD by exhibiting long-term mixed chimerism and reducing liver damage. Subsequently, the transfer of Valpha14i NKT cells purified from spleen cells cultured with alpha-GalCer and IL-2 also inhibited acute GVHD. This inhibition of acute GVHD by Valpha14i NKT cells was blocked by anti-IL-4 but not by anti-IFN-gamma monoclonal antibody. Therefore, the inhibition was dependent on IL-4 production by Valpha14i NKT cells. Our findings highlight the therapeutic potential of in vitro-expanded Valpha14i NKT cells for the prevention of acute GVHD after allogeneic hematopoietic stem cell transplantation.

Graft-versus-Tax response in adult T-cell leukemia patients after hematopoietic stem cell transplantation.

Adult T-cell leukemia (ATL) caused by human T-cell leukemia virus type I (HTLV-I) is characterized by poor prognosis after chemotherapy. Recent clinical trials have indicated, however, that allogeneic but not autologous hematopoietic stem cell transplantation (HSCT) for ATL can yield better clinical outcomes. In the present study, we investigated cellular immune responses of ATL patients who obtained complete remission after nonmyeloablative allogeneic peripheral blood HSCT from HLA-identical sibling donors. In the culture of peripheral blood mononuclear cells (PBMCs) from a post-HSCT but not pre-HSCT ATL patient, CD8(+) CTLs proliferated vigorously in response to stimulation with autologous HTLV-I-infected T cells that had been established before HSCT in vitro. These CTLs contained a large number of monospecific CTL population directed to a HLA-A2-restricted HTLV-I Tax 11-19 epitope. The frequency of Tax 11-19-specific CD8+ CTLs in this patient markedly increased also in vivo after HSCT, as determined by staining with HLA-A2/Tax 11-19 tetramers. Similar clonal expansion of HTLV-I Tax-specific CTLs exclusively directed to a HLA-A24-restricted Tax 301-309 epitope was observed in the PBMCs from another ATL patient after HSCT from a HTLV-I-negative donor. Among four post-HSCT ATL patients tested, HTLV-I-specific CTLs were induced in the PBMC culture from three patients but not from the remaining one who had later recurrence of ATL. These observations suggested that reconstituted immunity against antigen presentation in ATL patients after HSCT resulted in strong and selective graft-versus-HTLV-I response, which might contribute to graft-versus-leukemia effects.

A prospective trial to evaluate the safety and efficacy of pravastatin for the treatment of refractory chronic graft-versus-host disease.

This prospective study evaluates the safety and efficacy of pravastatin for the treatment of chronic graft-versus-host disease (GVHD). We included 18 patients with refractory chronic GVHD. Oral pravastatin was started at 10 mg/day, and the dose was increased up to 40 mg/day in 4 weeks. This maximum dose was administered over 8 weeks. There were no severe adverse events caused by pravastatin. A clinical response was observed in the skin score in two patients, mouth score in five patients, eye score in two patients, liver score in three patients, platelet count score in one patient, and weight loss in two patients. The overall response rate was 28%. Immunophenotypic analyses showed that T-helper (Th)1 cells were dominant in all but one patient before treatment and that the Th1/Th2 ratio tended to be lower in the responders than in the nonresponders. A randomized controlled trial is warranted to evaluate the efficacy of pravastatin against chronic GVHD.