Preclinical studies targeting normal and leukemic hematopoietic cells with Yttrium-90-labeled anti-CD45 antibody in vitro and in vivo in nude mice.

A study was undertaken to investigate the suitability of using a high affinity (Kd = 1.1 nM) anti-CD45 monoclonal antibody for delivering the high energy beta-particle emitting isotope (90)Y to lymphohematopoietic target cells in vivo. The antibody, AHN-12, recognized the tyrosine phosphatase CD45 expressed on the surface of normal and malignant hematopoietic cells and studies showed that it reacted with both CD45-expressing normal peripheral blood cells and leukemia cells from patients. The antibody was readily labeled with (90)Y using the highly stable chelate 1B4M-DTPA and the radioimmunoconjugate was designated (90)Y-anti-CD45. The agent selectively bound to CD45(+) B cell line Daudi, but not CD45(-) control cells and significantly (p = 0.007) more bound to Daudi tumors growing in athymic nude mice than did a control non-reactive antibody. Moreover, biodistribution data correlated well to an anti-Daudi effect observed against established tumors in nude mice. The effect was dose dependent and irreversible with the best results in mice receiving a single dose of 137 microCi (90)Y-anti-CD45. These mice displayed a significantly (p < 0.0095) better anti-tumor effect than a control (90)Y-labeled antibody and survived over 135 days with no evidence of tumor. Histology studies showed no significant injury to kidney, liver, or small intestine even at 254 microCi, the highest dose tested. Because radiolabeled anti-CD45 antibody can be used to deliver radiation selectively to lymphohematopoietic tissue, these data indicate that this agent may be used to improve treatment of hematopoietic malignancies, particularly leukemia and lymphoma, when combined with hematopoietic stem cell transplantation in a future clinical trial.

Successful bone marrow transplantation for severe aplastic anemia following orthotopic liver transplantation: long-term follow-up and outcome.

Severe aplastic anemia (SAA) is well described in children following liver transplantation for fulminant hepatic failure (FHF) secondary to non-A, non-B, non-C hepatitis, and is associated with a high mortality rate. Successful immunosuppressive treatment of SAA following liver transplantation has been reported, but death from infectious complications is not uncommon. We report the 8-year follow-up of a 3.5-year-old boy who underwent successful HLA-identical sibling donor bone marrow transplant for SAA 7 months following orthotopic liver transplant for non-A, non-B, non-C hepatitis. His post-bone marrow transplantation course was uneventful with no evidence of liver toxicity. Eight months following BMT he developed renal cell carcinoma metastatic to lymph nodes which was treated surgically. Six years following BMT he developed a mucoepidermoid carcinoma of the parotid gland also treated surgically. Despite these malignancies, he is currently well 8 years following liver and bone marrow transplantation, without signs of GVHD, growth failure or liver graft rejection. This is the first report of long-term follow-up of bone marrow transplantation for SAA following liver transplantation. The occurrence of two subsequent malignancies in this child underscores the need for close follow-up of future similar cases.

Survival after transplantation of unrelated donor umbilical cord blood is comparable to that of human leukocyte antigen-matched unrelated donor bone marrow: results of a matched-pair analysis.

Umbilical cord blood (UCB) is being increasingly used for hematopoietic stem cell transplantation and has been associated with a reduced incidence of severe graft-versus-host disease (GVHD). To further investigate the relative merits of unrelated donor UCB versus bone marrow (BM), a matched-pair analysis comparing the outcomes of recipients of 0 to 3 human leukocyte antigen (HLA)-mismatched UCB and HLA-A, B, DRB1-matched BM was performed. UCB patients, who received cyclosporine (CSA) and methylprednisolone (MP), were matched for age, diagnosis, and disease stage with BM patients, who received either methotrexate (MTX) and CSA (26 pairs) or T-cell depletion (TCD) and CSA/MP (31 pairs). Patients were predominantly children (median age, 5 years) undergoing transplantation for malignancy, storage diseases, BM failure, and immunodeficiency syndromes between 1991 and 1999. Although neutrophil recovery was significantly slower after UCB transplantation, the probability of donor-derived engraftment at day 45 was 88% in UCB versus 96% in BM-MTX recipients (P =.41) and 85% in UCB versus 90% in BM-TCD recipients (P =.32), respectively. Platelet recovery was similar in UCB versus BM pairs. Furthermore, incidences of acute and chronic GVHD were similar in UCB and BM recipients, with 53% of UCB versus 41% of BM-MTX recipients alive (P =.40) and 52% of UCB versus 56% of BM-TCD recipients alive at 2 years (P >.80), respectively. These data suggest that despite increased HLA disparity, probabilities of engraftment, GVHD, and survival after UCB transplantation are comparable to those observed after HLA-matched BM transplantation. Therefore, UCB should be considered an acceptable alternative to HLA-matched BM for pediatric patients.

Late outcomes after bone marrow transplant for aplastic anaemia.

Allogeneic transplantation is effective in reconstituting haemopoiesis in severe aplastic anaemia (SAA). We report long-term health-related outcomes in 37 children and young adults with SAA transplanted between 1975 and 1996. The median length of follow-up was 17 years (range, 4-25 years). Using a case-control design, late social and medical outcomes in transplant recipients were compared with 146 control subjects matched for gender and age. The majority of patients received an irradiation-containing preparative regimen. There were no significant differences in the self-rating of health status between transplant recipients and controls (P = 0.8), with 71% reporting their health status as excellent and 29% as good compared with 74% and 26% of controls. They demonstrate the same normal psychosexual function as their peers and have similar educational achievements and employment history. Transplant recipients and controls are equally likely to have held a job or be currently employed and there are no significant differences in their personal income (OR = 0.60, 95% CI = 0.11-3.37). Although transplant recipients have had problems related to health insurance policies, the majority have adequate health insurance coverage. There were no differences in chronic health problems between transplant recipients and control subjects, except for expected increases in cataracts, short stature in men, hypothyroidism and gonadal dysfunction. Using self-assessment, these transplant recipients indicated an excellent level of satisfaction and social integration, showing transplantation to be an effective long-term therapy for SAA.

Response to thalidomide therapy in refractory chronic graft-versus-host disease.

Chronic graft-versus-host disease (GVHD) refractory to standard immunosuppressive therapy remains a major cause of morbidity and mortality after allogeneic bone marrow transplantation (BMT). Thalidomide may be effective in some patients with high-risk or refractory chronic GVHD. We report a single-institution study of thalidomide in 37 BMT patients with extensive chronic GVHD refractory to standard immunosuppressive therapy. Acute GVHD occurred in 34 (91%) of patients and evolved progressively into chronic GVHD in 23 (62%) patients. Thalidomide was added to standard immunosuppressive therapy a median of 11 months (range 0-105 months) after the diagnosis of chronic GVHD. Fourteen of 37 (38%) patients responded after introduction of thalidomide (one complete, 13 partial). Ten of 21 (46%) children and four of 16 (25%) adults responded. Responses were seen in eight of 17 (47%) recipients of related donor marrow and six of 20 (30%) recipients of unrelated donor marrow. Eight of 23 (34%) patients with progressive onset of chronic GVHD showed a response. There were no deaths among the responders. The remaining 23 patients (62%) did not respond and of these only two survive, one with progressive scleroderma, and the other with bronchiolitis obliterans. Chronic GVHD with associated infection (most commonly disseminated fungal infection) was a major contributor to mortality in all cases. Overall, after initiation of thalidomide, the 2-year Kaplan-Meier survival was 41% (95% C.I. 24%-59%). We conclude that thalidomide is a useful and well-tolerated therapy for patients with previously treated refractory chronic GVHD, including those with progressive onset of chronic GVHD, recipients of unrelated donor marrow, and children. Earlier introduction of thalidomide as an adjunct to standard immunosuppressive therapy may lead to more frequent responses and possible better survival.

Wolman disease successfully treated by bone marrow transplantation.

Wolman disease is characterized by severe diarrhea and malnutrition leading to death during infancy. Lysosomal acid lipase deficiency is the cause of the symptoms and signs. It is inherited in an autosomal recessive manner. All Wolman disease patients have adrenal gland calcification. Previous therapeutic attempts have failed to provide remission. We report successful long-term bone marrow engraftment in a patient with Wolman disease resulting in continued normalization of peripheral leukocyte lysosomal acid lipase enzyme activity. Diarrhea is no longer present. Now, at 4 years of age, this patient is gaining developmental milestones. Cholesterol and triglyceride levels are normal. Liver function is normal. This is the first long-term continued remission reported for Wolman disease.

Matched-pair analysis of peripheral blood stem cells compared to marrow for allogeneic transplantation.

We performed a case-control analysis of 42 patients with advanced leukemia or MDS comparing peripheral blood stem cell (PBSC) with marrow grafts (BMT) from HLA-matched sibling donors. PBSC were mobilized with G-CSF (7.5 microg/kg/day) and yielded a median of 6.7 x 10(6) CD34+ cells/kg (range, 1.6-15.0) and 2.7 x 10(8) CD3+ cells/kg (range, 1.1-7.1) vs marrow grafts with a median of 2.0 x 10(8) nucleated cells/kg (range, 1.8-2.2). Recovery was significantly faster after PBSCT compared to BMT, with a median of 17 (range, 12-26) vs 26 (range, 16-36) days, respectively, to neutrophils >0.5 x 10(9)/l (P < 0.01), and 22 (range, 12->60) vs 42 (range, 18->60) days, for platelet recovery (P < 0.01). Transplantation of >/=7 x 10(6) CD34+ cells/kg accelerated recovery to >20 x 10(9) l platelets; median 17 days (range, 12-19) vs 23 days (range, 17-36) for those receiving <7 x 10(6)/kg (P = 0.01). PBSC and marrow recipients had similar risks of grades II-IV or III-IV acute GVHD or extensive chronic GVHD (all P > 0.3). At 1 year after PBSCT and BMT, the risk of relapse was 41% and 32%, respectively (P = 0.47), and the probability of survival was 46% and 48%, respectively (P = 0.70). HLA-matched sibling PBSCT resulted in faster neutrophil and platelet engraftment compared to BMT, with no subsequent differences in acute or chronic GVHD, relapse or survival. A minimum of 7 x 10(6) CD34+ cells/kg in PBSC grafts may be required for very rapid platelet engraftment. Bone Marrow Transplantation (2000) 26, 723-728.

Busulfan pharmacokinetics do not predict relapse in acute myeloid leukemia.

The purpose of this study was to evaluate the influence of busulfan (BU) pharmacokinetics on survival, grades II-IV acute graft-versus-host disease (GVHD), non-relapse mortality (NRM) and relapse in a group composed of 45 children (<18 years) and seven adults with acute myeloid leukemia (AML) in first complete remission and undergoing hematopoietic stem cell transplantation (SCT). Fifty-two patients underwent autologous (n = 25) or allogeneic (n = 27) SCT. The median age was 8.9 years (range 0.6-53 years). Conditioning therapy consisted of BU and cyclophosphamide. Improved disease-free survival was found in those patients with a steady-state concentration of BU (CssBU) below the median (<578 mg/ml, P = 0.05), and the same trend was noted for overall survival (P = 0.07). This was secondary to a higher incidence of NRM in the group of patients with CssBU above the median (P = 0.06). There was no significant correlation with CssBU and relapse (P = 0.31). No association between CssBU and GVHD was found in allogeneic patients (P = 0.30). Relapse was evaluated among the subgroups of age (< or >10 years) and transplant type (allogeneic or autologous) with no statistically significant association observed among these factors. Multiple regression analysis for relapse revealed no significant correlation with CssBU above or below the median, age, or transplant type. In this study, CssBU below the median did not correlate with an inferior outcome for patients with AML. Pharmacokinetic dosing of BU may be important for prevention of NRM but does not appear to influence the risk of relapse in this largely pediatric population with AML.

Haematopoietic cell transplantation in patients with Fanconi anaemia using alternate donors: results of a total body irradiation dose escalation trial.

Allogeneic haematopoietic cell transplantation (HCT) is the only therapeutic modality capable of correcting the haematologic manifestations of Fanconi anaemia (FA). However, HCT from alternative donors has been associated with poor survival. Between June 1993 and July 1998, 29 FA patients (median age 12.1 years; range 3.7-48.5 years) were enrolled in a prospective phase I-II dose escalation study. All patients were treated with cyclophosphamide 40 mg/kg, total body irradiation (TBI) 450 cGy or 600 cGy and antithymocyte globulin (ATG), followed by HCT from an alternative donor. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporin A for 6 months, short course methylprednisolone (2 mg/kg/day) between days +5 and +19 and marrow T-cell depletion by counterflow elutriation. The probability of developing grade III-IV toxicity was 17% (95% CI 3-31%). For the 25 marrow recipients, the probability of neutrophil engraftment (ANC 0.5 x 109/l by day 45) was 63% (95% CI 42-82%). Probabilities of grade II-IV acute GVHD and chronic GVHD were 32% (95%CI 10-54%) and 0% respectively. With a median follow-up of 18 months, the probability of survival for the entire cohort at 1 year was 34% (95% CI 17-51%). The presence of lymphocyte somatic mosaicism [i.e. the presence of diepoxybutane (DEB)-insensitive cells] was associated with a significantly increased risk of graft failure. Disappointingly, the use of higher dose TBI and post-transplant ATG did not improve engraftment. More effective peritransplant immunosuppression, especially in FA patients with somatic mosaicism, was required to overcome the barrier of graft rejection. New conditioning regimens adapted to each individual's alkylator sensitivity are needed to improve the outcome of alternative donor HCT for FA.

Pulmonary cytolytic thrombi: a newly recognized complication of stem cell transplantation.

Over the past 5 years we have recognized a new pulmonary complication of hematopoietic stem cell transplantation (HSCT) associated with fever and pulmonary nodules termed 'pulmonary cytolytic thrombi' (PCT). Retrospective analysis of medical and radiographic records and pathologic material from 13 HSCT recipients with PCT and a review of the Blood and Marrow Transplant Database for all patients with radiographic evidence of pulmonary nodules or who underwent open-lung biopsy from 1 January 1993 to 31 December 1998 (n = 1228) were performed. The median age of patients with PCT was 11.9 years (range, 1.3-29.7 years). All patients developed fever at a median of 72 days (range, 8-343 days) post transplant, followed by pulmonary nodules on chest CT. Eleven patients were receiving therapy for active GVHD (acute, grades I-IV (n = 10); extensive chronic (n = 1)). Biopsy of the pulmonary nodules revealed a unique pattern of necrotic, basophilic thromboemboli with amorphous material suggestive of cellular breakdown products. This was descriptively labeled 'pulmonary cytolytic thrombi'. Immunohistochemical staining revealed entrapped leukocytes and disrupted endothelium, but was negative for histiocytes. Cultures and immunohistochemical stains were negative for infectious agents. Empiric therapy included systemic corticosteroids (n = 9) and amphotericin (n = 7). Nine patients survive with resolution of PCT at a median follow-up of 1.5 years. Bone Marrow Transplantation (2000) 25, 293-300.

Comparison of preparative regimens in transplants for children with acute lymphoblastic leukemia.

PURPOSE: Preparative regimens involving total-body irradiation (TBI) produce significant late toxicities in some children who receive bone marrow transplants, including impaired growth and intellectual development. Busulfan is often used as an alternative to TBI, but there are few data regarding its relative efficacy. PATIENTS AND METHODS: We compared outcomes of HLA-identical sibling transplants for acute lymphoblastic leukemia (ALL) in children (< 20 years of age) who received cyclophosphamide plus TBI (CY/TBI) (n = 451) versus those who received busulfan plus cyclophosphamide (Bu/CY) (n = 176) for pretransplant conditioning. Patients received transplants between 1988 and 1995 and their results were reported to the International Bone Marrow Transplant Registry by 144 participating institutions. The CY/TBI and Bu/CY groups did not differ in gender, immune phenotype, leukocyte count at the time of diagnosis, chromosome abnormalities, remission status, or length of initial remission. T-cell depletion was used more frequently in the CY/TBI group; the Bu/CY group included a higher proportion of children who were less than 5 years of age. The median follow-up period was 37 months. RESULTS: The 3-year probabilities of survival were 55% (95% confidence interval [CI], 50% to 60%) with TBI/CY and 40% (95% CI, 32% to 48%) with Bu/CY (univariate P =.003). The 3-year probabilities of leukemia-free survival were 50% (95% CI, 45% to 55%) and 35% (95% CI, 28% to 43%), respectively (univariate P =.005). In a multivariate analysis, the risks of relapse were similar in the two groups (relative risk [RR], 1.30 for Bu/CY v CY/TBI; P =.1). Treatment-related mortality was higher in the Bu/CY group (RR, 1.68; P =.012). Death and treatment failure (relapse or death, inverse of leukemia-free survival) were more frequent in the Bu/CY group (RR, 1. 39; P =.017 for death; RR, 1.42; P =.006 for treatment failure). CONCLUSION: These data indicate superior survival with CY/TBI conditioning, compared with Bu/CY conditioning, for HLA-identical sibling bone marrow transplants in children with ALL.

A prospective randomized trial of the anti-emetic efficacy of ondansetron and granisetron during bone marrow transplantation.

To determine the comparative anti-emetic efficacy of ondansetron and granisetron in patients undergoing bone marrow transplantation, we performed a double-blind, randomized trial in pediatric and adult patients receiving transplants at the University of Minnesota. The results in 187 patients stratified by age (<18 years, n = 51; > or =18 years, n = 136) were analyzed. The average number of emetic episodes in the entire group from day -7 to 2 was 0.86/day for patients receiving ondansetron and 0.73/day for those receiving granisetron (p = 0.32). No differences were noted between the two drugs in total days of complete or major control of emesis or in the number of requests for additional drugs to alleviate symptoms of nausea. The use of total-body irradiation-containing conditioning regimens was associated with a decreased number of emetic episodes compared with regimens of chemotherapy alone. Perceived nausea was evaluated using a nausea scoring system, and no differences were apparent between the granisetron and ondansetron groups; however, reported nausea was significantly higher in females (p<0.01) and in the adult population (p = 0.05). We conclude that both ondansetron and granisetron provide good control of nausea and vomiting experienced with conditioning regimens for bone marrow transplantation. The relative cost of the drugs within an institution must be considered in developing standard anti-emetic regimens for bone marrow transplantation.

Treatment of high-risk neuroblastoma with intensive chemotherapy, radiotherapy, autologous bone marrow transplantation, and 13-cis-retinoic acid. Children's Cancer Group.

BACKGROUND: Children with high-risk neuroblastoma have a poor outcome. In this study, we assessed whether myeloablative therapy in conjunction with transplantation of autologous bone marrow improved event-free survival as compared with chemotherapy alone, and whether subsequent treatment with 13-cis-retinoic acid (isotretinoin) further improves event-free survival. METHODS: All patients were treated with the same initial regimen of chemotherapy, and those without disease progression were then randomly assigned to receive continued treatment with myeloablative chemotherapy, total-body irradiation, and transplantation of autologous bone marrow purged of neuroblastoma cells or to receive three cycles of intensive chemotherapy alone. All patients who completed cytotoxic therapy without disease progression were then randomly assigned to receive no further therapy or treatment with 13-cis-retinoic acid for six months. RESULTS: The mean (+/-SE) event-free survival rate three years after the first randomization was significantly better among the 189 patients who were assigned to undergo transplantation than among the 190 patients assigned to receive continuation chemotherapy (34+/-4 percent vs. 22+/-4 percent, P=0.034). The event-free survival rate three years after the second randomization was significantly better among the 130 patients who were assigned to receive 13-cis-retinoic acid than among the 128 patients assigned to receive no further therapy (46+/-6 percent vs. 29+/-5 percent, P=0.027). CONCLUSIONS: Treatment with myeloablative therapy and autologous bone marrow transplantation improved event-free survival among children with high-risk neuroblastoma. In addition, treatment with 13-cis-retinoic acid was beneficial for patients without progressive disease when it was administered after chemotherapy or transplantation.

B cell lymphoproliferative disorders following hematopoietic stem cell transplantation: risk factors, treatment and outcome.

Twenty-six cases of B cell lymphoproliferative disorder (BLPD) were identified among 2395 patients following hematopoietic stem cell transplants (HSCT) for which an overall incidence of BLPD was 1.2%. The true incidence was probably higher, since 9/26 of the diagnoses were made at autopsy. No BLPD was observed following autologous HSCT, so risk factor analyses were confined to the 1542 allogeneic HSCT. Factors assessed were HLA-mismatching (> or = 1 antigen), T cell depletion (TCD), presence of acute GvHD (grades II-IV), donor type (related vs unrelated), age of recipient and donor, and underlying disease. Factors found to be statistically significant included patients transplanted for immune deficiency and CML, donor age > or = 18 years, TCD, and HLA-mismatching, with recipients of combined TCD and HLA-mismatched grafts having the highest incidence. Factors found to be statistically significant in a multiple regression analysis were TCD, donor age and immune deficiency, although 7/8 of the patients with immunodeficiencies and BLPD received a TCD graft from a haploidentical parent. The overall mortality was 92% (24/26). One patient had a spontaneous remission, but subsequently died >1 year later of chronic GVHD. Thirteen patients received therapy for BLPD. Three patients received lymphocyte infusions without response. The only patients with responses and longterm survival received alpha interferon (alphaIFN). Of seven patients treated with alphaIFN there were four responses (one partial and three complete). These data demonstrate that alphaIFN can be an effective agent against BLPD following HSCT, if a timely diagnosis is made.

Late graft rejection and second infusion of bone marrow in children with aplastic anaemia.

Late graft rejection following allogeneic bone marrow transplantation (BMT) for aplastic anaemia is a significant clinical problem and is associated with a high risk of mortality. We report two children with severe aplastic anaemia (SAA) who developed very late graft rejection 2 years and 4 months and 10 years respectively after allogeneic BMT from HLA-identical siblings. Following a second BMT from their initial donors, engraftment has been sustained in both cases. The patients are alive with full donor chimaerism, 18 and 19 years from initial transplant. These cases illustrate that graft failure can be an extremely late event after allogeneic BMT for SAA, and that long-term sustained engraftment can be achieved in these patients with second BMT from the original donors.

Hematopoietic stem cell transplantation for infantile osteopetrosis.

Infantile osteopetrosis is a lethal disorder resulting from a severe defect in the ability of osteoclasts to resorb bone. The only therapy shown to be capable of providing lasting benefit is allogeneic hematopoietic stem cell transplantation (HCT). We report the outcome of 10 patients with infantile malignant osteopetrosis treated with HCT from an HLA A, B, DRB1 matched (n=6) or A or B locus mismatched (n=4) family member or unrelated donor at the University of Minnesota between 1978 and 1997. Eight of 10 patients achieved primary engraftment; secondary graft failure was seen in two patients. Five of 10 patients survive; three with full or partial donor chimerism and two with autologous hematological recovery. Transient or partial donor chimerism can be sufficient to correct the hematological manifestations of osteopetrosis. We recommend early referral for consideration of HCT with a related or unrelated donor as neurosensory manifestations of osteopetrosis are generally not reversible. Donor engraftment may be easier to achieve early in the course of the disease.

Haemopoietic cell transplantation in children with juvenile myelomonocytic leukaemia.

Seven children, 11 months to 5.9 years of age, with juvenile myelomonocytic leukaemia (JMML) underwent allogeneic haemopoietic cell transplantation (HCT) using related or unrelated donor bone marrow or umbilical cord blood. All patients had active disease at time of transplant despite chemotherapy in five patients and chemotherapy and splenectomy in one patient prior to HCT conditioning. All patients received cyclophosphamide and TBI, with the addition of busulphan in two cases. Engraftment was documented in all cases. Notably, six of seven patients relapsed after allogeneic HCT with one achieving a return to full donor chimaerism after cyclosporin A (CSA) withdrawal. Two patients are alive in remission, 23+ and 30+ months after transplant. The role of allogeneic HCT in patients with JMML is discussed. A cooperative multicentre trial is needed to establish the optimal therapy for these patients.

Outcomes following mechanical ventilation in children undergoing bone marrow transplantation.

Between 1976 and 1992, 869 patients <19 years of age underwent BMT at the University of Minnesota for a variety of malignant and non-malignant disorders. One hundred and ninety-six required mechanical ventilation (MV) at some time from the start of pre-BMT cyto reduction through the first year following BMT. Reasons for MV included respiratory compromise, upper airway management and non-pulmonary indications for respiratory support. In multivariate models, underlying diagnosis, receipt of HLA-mismatched marrow and the presence of acute graft-versus-host disease (aGVHD) were independent predictors of the need for MV. Indication for MV, underlying diagnosis, and presence of aGVHD were independent predictors of successful extubation. Overall survival at 2 years was 14% among MV patients and 52% among non-MV patients. While the need for MV during BMT reduces the overall likelihood of survival, 40% of children who required MV were successfully extubated; 35% of these extubated patients were long-term survivors. This outcome is better than that reported for adult BMT patients requiring respiratory support, who show survival of <5% at 6 months following BMT. Our data suggest extrapolation of outcome data from adult to pediatric patients is not appropriate and aggressive care of pediatric patients requiring respiratory support is not futile.

Graft-versus-leukemia is sufficient to induce remission in juvenile myelomonocytic leukemia.

It has been unclear whether a graft-versus-leukemia (GVL) effect assists in the control of juvenile myelomonocytic leukemia (JMML) following allogeneic bone marrow transplant. We describe a patient with JMML who relapsed early after an unrelated donor transplant, and following withdrawal of immunosuppression developed graft-versus-host disease (GVHD). Associated with GVHD the proportion of donor cells measured by variable nucleotide tandem repeat (VNTR) analysis increased, and peripheral blasts and cutaneous disease were eliminated. These findings strongly suggest that GVL has a role in the control of JMML.