Haemopoietic cell transplantation in children with juvenile myelomonocytic leukaemia

Morphologic and Immunophenotypic Differences in Juvenile Myelomonocytic Leukemias With CBL and Other Canonical RAS-pathway Gene Mutations: A Single Institutional Experience

The diagnostic criteria for juvenile myelomonocytic leukemia have recently been revised to include clinical findings and RAS-pathway gene mutations per the 2016 World Health Organization Classification of Tumors of Hematopoietic and Lymphoid Tissues. Differing clinical behaviors have been observed in cases with CBL versus other RAS-pathway gene (RAS-p) mutations, notably the patients with CBL mutations can be self-limiting with spontaneous resolution. Additional clinical characteristics and histopathologic findings between these subsets are less well-described. We performed a retrospective search and identified cases with either CBL or RAS-p mutations, as per targeted and/or massively parallel sequencing. Eight patients had sufficient material for review, including cytogenetic studies and peripheral blood, bone marrow aspirate, and/or biopsy with flow cytometry analyses. Three patients showed CBL mutations and lower percentages of hemoglobin F and peripheral blood absolute monocyte counts, lesser degrees of leukocytosis compared with the RAS-p cohort, and normal megakaryocyte morphology and myeloblast immunophenotypes. Two of these patients were managed with observation only and experienced resolution of their disease. The patients with RAS-p mutations had severe thrombocytopenia, moderate to severe anemia, and experienced variable clinical outcomes. Abnormal megakaryocyte morphology and decreased numbers of megakaryocytes were seen in cases with RAS-p mutations. In addition, 3 of 4 cases with flow cytometry data demonstrated aberrant CD7 expression in myeloblasts. Our study is the first to identify morphologic and immunophenotypic differences between juvenile myelomonocytic leukemia cases with CBL or RAS-p mutations, and further supports previous reports of significantly different clinical behaviors between these subsets of patients.

Outcome of hematopoietic stem cell transplantation (HCT) from HLA-matched related donor for Fanconi anemia (FA) in adolescents and adults: a retrospective study by Eastern Mediterranean Blood and Marrow Transplantation Group (EMBMT)

Hematopoietic Stem Cell Transplantation (HSCT) is the only potentially curative treatment option for the hematologic complications that occur in patients with Fanconi anemia (FA). In this study, we present a retrospective multicenter analysis from the Eastern Mediterranean Blood and Marrow Transplantation Group (EMBMT) of matched related donor HSCT for FA in adolescents and adults transplanted between 1988 and 2015. Forty-five patients received HSCT with a median age at transplant of 18 years, the interquartile range (IQR) (15-23.5); 25 (55.6%) patients were females and 20 (44.4%) were males. Conditioning regimen was fludarabine-based in 29 (64.4%) patients, irradiation-based in five (11.1%) patients, and the remaining patients received other combinations. Indication for HSCT was bone marrow failure in 39 (86.7%) and myelodysplastic syndrome in six (13.3%) patients. Stem cell source was bone marrow in 22 (48.9%), peripheral blood in 20 (44.4%), umbilical cord blood in one (2.2%), and combination of bone marrow and cord blood in two (4.4%) patients. Twenty-seven (60%) patients engrafted and five (11.1%) had primary engraftment failure. The median time to neutrophil engraftment was 14 days (range 10-21 days); median time for platelet engraftment was 17 days (10-33 days). The probability of developing grade II-IV acute GVHD for all patients was 7.0% and chronic GVHD 36.6%. No new malignancies were reported. The OS probability was 53.6% (95% CI, 38.3-68.9%) with a median follow-up of 13 months (95% CI, 1-240). Our HLA-matched related HSCT results in AYA patients with FA compare favorably with other reported international registry data.

Molecular assessment of pretransplant chemotherapy in the treatment of juvenile myelomonocytic leukemia

BACKGROUND

Despite the intensity of hematopoietic stem cell transplantation (HCT), relapse remains the most common cause of death in juvenile myelomonocytic leukemia (JMML). In contrast to other leukemias where therapy is used to reduce leukemic burden prior to transplant, many patients with JMML proceed directly to HCT with active disease. The objective of this study was to elucidate whether pre-HCT therapy has an effect on the molecular burden of disease and how this affects outcome post-HCT.

PROCEDURE

Twenty-one patients with JMML who received pre-HCT therapy and were transplanted at UCSF were analyzed in this study. The mutant allele frequency of the driver mutation was assessed before and after pre-HCT therapy, using custom amplicon next-generation sequencing.

RESULTS

Of the 21 patients, seven patients (33%) responded to therapy with a significant reduction in their mutant allele frequency and were classified as molecular responders. Six of these patients received moderate-intensity chemotherapy, one patient received only azacitidine. The 5-year progression-free survival after HCT of molecular responders was 100% versus 61% for nonresponders (P = .12). Survival of molecular nonresponders was not improved by use of high-intensity conditioning, but patients were salvaged if they experienced severe graft versus host disease. There were no baseline clinical characteristics that were associated with response to pre-HCT therapy.

CONCLUSIONS

Despite the myelodysplastic nature of JMML, patients treated with pre-HCT therapy can achieve molecular remissions. These patients experienced a trend toward improved outcomes post-HCT. Importantly, molecular testing can be helpful to distinguish between responders and nonresponders and should become an integral part of clinical care.

Stem cell transplant for juvenile myelomonocytic leukemia and chronic myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) and chronic myelomonocytic leukemia (CMML) are myelodysplastic/myeloproliferative neoplasms associated with poor prognosis. There is no definitive treatment for such patients other than stem cell transplantation, and chemotherapy is not much effective. Timely diagnosis and early referral to the transplant centre is important for the management of these diseases. We report here a case of JMML and another case of CMML who were treated successfully with peripheral blood stem cell transplantation.

Outcomes of immunological interventions for mixed chimerism following allogeneic stem cell transplantation in children with juvenile myelomonocytic leukemia

BACKGROUND

For children with juvenile myelomonocytic leukemia (JMML) who undergo stem cell transplantation (SCT), the role of immunological interventions including withdrawal of immunosuppressive therapy (IST) and donor lymphocyte infusion (DLI) for treatment of disease recurrence remains uncertain.

PROCEDURE

We analyzed serial chimerism status following SCT and evaluated the efficacy of immunological interventions for the management of mixed chimerism (MC) in children with JMML.

RESULTS

Chimerism analysis was available in 26 SCT cases following the first and second SCT. MC was observed in 16 cases and withdrawal of IST was performed in 14 cases immediately after identification of MC. Donor lymphocyte infusion (DLI) was performed in five MC cases. Eight MC cases were observed at the time of neutrophil recovery. Following withdrawal of IST, three cases achieved complete chimerism (CC) while the proportion of autologous cells increased rapidly in the remaining five cases. Six MC cases were observed after achievement of hematological remission (HR) and responses to withdrawal of IST were observed in two cases. In the remaining four cases, despite withdrawal of IST, the proportion of autologous cells increased. Five cases received DLI but only one case responded.

CONCLUSION

Although the benefits of immunological interventions for MC after SCT in JMML were limited, some patients did achieve HR as a result of these treatment modalities without a second SCT. Close monitoring of donor chimerism and early detection of MC is helpful in guiding treatment after SCT in children with JMML.

Indications and donor selections for allogeneic stem cell transplantation in children with hematologic malignancies

Allogeneic stem cell transplantation (SCT) is the only curative approach for many patients with advanced or high-risk leukemia. Advances in supportive care and management of graft-versus-host disease have resulted in improvements in outcomes of related and unrelated donor SCT, creating controversies as to which strategy might be the optimal therapy for individual patients. This article discusses the indications and donor selection strategies for SCT in patients with malignant hematologic disease.

Three consecutive related bone marrow transplants for juvenile myelomonocytic leukaemia

Allogeneic haematopoietic stem cell transplantation (allo-HSCT) is the only cure for juvenile myelomonocytic leukaemia (JMML), but relapse remains the major cause of failure. A second transplant may be considered a way to induce the graft vs. leukaemia effect in patients who relapse after their first HSCT. We describe a 7-month-old girl with JMML who relapsed after a first, related allo-HSCT, and who again relapsed 8 months after the second transplant, despite discontinuation of immusuppressive therapy. She underwent a third allogeneic transplant from another related donor. At the time of this report the patient is in complete remission 26 months after the third transplant. We suggest that a third allo-HSCT may be taken into consideration for JMML patients who experience relapse, even after two previous transplants.

Donor leukocyte infusion after hematopoietic stem cell transplantation in patients with juvenile myelomonocytic leukemia

Juvenile myelomonocytic leukemia (JMML) is a clonal myeloproliferative disorder of early childhood. In all, 21 patients with JMML who received donor leukocyte infusion (DLI) after allogeneic hematopoietic stem cell transplantation (HSCT) for either mixed chimerism (MC, n=7) or relapse (n=14) were studied. Six patients had been transplanted from an HLA-matched sibling and 15 from other donors. Six of the 21 patients (MC: 3/7 patients; relapse: 3/14 patients) responded to DLI. Response rate was significantly higher in patients receiving a higher total T-cell dose (> or =1 x 10(7)/kg) and in patients with an abnormal karyotype. None of the six patients receiving DLI from a matched sibling responded. Response was observed in five of six patients who did and in one of 15 children who did not develop acute graft-versus-host disease following DLI (P=0.01). The overall outcome was poor even for the responders. Only one of the responders is alive in remission, two relapsed, and three died of complications. In conclusion, this study shows that some cases of JMML may be sensitive to DLI, this providing evidence for a graft-versus-leukemia effect in JMML. Infusion of a high number of T cells, strategies to reduce toxicity, and cytoreduction prior to DLI may improve the results.

Chimaerism analyses and subsequent immunological intervention after stem cell transplantation in patients with juvenile myelomonocytic leukaemia

Chimaerism analysis was performed by polymerase chain reaction amplification of short-tandem repeat markers in 30 children following haematopoietic stem cell transplantation for juvenile myelomonocytic leukaemia (JMML). Fourteen patients always had complete chimaerism (CC); one of them relapsed after the discontinuation of the study and 13 continued in complete remission (CR). Mixed chimaerism (MC) was noted in 16 patients. Of those 12 patients demonstrated increasing MC (i-MC); 10 relapsed and two achieved CC following discontinuation of immunosuppressive therapy (IST). Four other patients demonstrating only transient MC are alive in CR. MC with up to 20% of autologous cells could be successfully eradicated without induction of severe graft-versus-host disease when IST was reduced or discontinued directly after the first demonstration of MC. At the same time, MC with up to 10% of autologous cells could disappear without intervention. The interval between MC and relapse ranged from 0-320 d (median 38 d). Donor leucocyte infusion was given to six patients with i-MC, but only one patient responded. Peripheral blood seems as valuable as bone marrow for chimaerism studies. In conclusion, serial quantitative chimaerism studies can identify patients with i-MC who are at high risk for relapse of JMML. Immediate withdrawal of IST is advised in these patients.

Viral Infections in Juvenile Myelomonocytic Leukemia: Prevalence and Clinical Implications

OBJECTIVES

Viral infections may complicate the diagnosis of juvenile myelomonocytic leukemia (JMML) in a substantial proportion of patients, but this possibility has not been tested in a prospective study. The authors therefore measured the cellular expression of the MxA protein, a reliable marker of viral infection, at diagnosis in children with JMML to estimate the prevalence of such infections.

METHODS

Eighteen children, aged 1 to 69 months, who met the diagnostic criteria of the International JMML Working Group were prospectively studied. MxA expression was assessed by flow cytometric analysis of peripheral blood mononuclear cells stained with an antihuman MxA antibody. All data were obtained through the MDS Committee of the Japanese Society of Pediatric Hematology.

RESULTS

Twelve patients (67%) had elevated levels of the MxA protein, with rotavirus, RS virus, or CMV infection documented in three of these patients. Although none of the patients had primary Epstein-Barr virus (EBV) infection, reactivation of the virus was strongly suspected in four children, including two with monosomy 7, each having increased levels of MxA. Southern blot analysis revealed monoclonal integration of the EBV genome into bone marrow mononuclear cells from one of these patients. There was no discernible correlation between increases in the marker protein and the presenting features or course of the disease.

CONCLUSIONS

Viral infection may be present in two thirds of children with newly diagnosed JMML, but it does not constitute a basis for revising clinical management. The possibility that EBV or other viruses contribute to JMML pathogenesis by stimulating pre-exiting malignant clones warrants further investigation.

Second allogeneic hematopoietic stem cell transplantation for juvenile myelomonocytic leukemia: case report and literature review

Juvenile myelomonocytic leukemia (JMML) is a rare clonal myeloproliferative disease in young childhood. Hematopoietic stem cell transplantation (HSCT) is the only way to cure the disease, but relapse after HSCT remains a major cause of treatment failure. A 5-year-old girl with JMML, who had experienced a relapse after the first transplant, did not respond to donor lymphocyte infusion and withdrawal of immune-suppressing agents. She was successfully treated using a second transplant. Detailed reports from the English literature since 1988 relating to a total of 13 JMML patients undergoing a second transplant were reviewed. Seven of the 13 JMML patients (54%) were alive and disease-free, with a median follow-up of 53 months after the second transplant. Within the first 6 months following the initial transplant, 10 JMML patients suffered either autologous recovery (n = 6) or early relapse (n = 4). Seven of the 10 (70%) were alive, with a median survival period of 53 months after the second transplant. Six JMML patients underwent retransplantation within 6 months of the first transplant, with three of these (50%) alive at follow-ups of 24, 57, and 90 months after the second procedure. The authors conclude that a second transplant within 6 months may be worth considering for JMML patients who experience autologous recovery or earlier relapse after the first transplant.

Successful treatment of juvenile myelomonocytic leukemia relapsing after stem cell transplantation using donor lymphocyte infusion

Juvenile myelomonocytic leukemia (JMML) is a rare pediatric malignancy. Hematopoietic stem cell transplantation (SCT) is the only curative approach. However, relapse after SCT remains the major cause of treatment failure. Unlike most other pediatric malignancies, JMML may be susceptible to a graft-versus-leukemia (GVL) effect, although, unlike chronic myeloid leukemia, reports of response to donor lymphocyte infusions (DLIs) remain scanty. This is the first report that describes the successful treatment of relapsed JMML with DLI in the absence of further chemotherapy and provides definite proof of a GVL effect in JMML.

Allogeneic hematopoietic stem cell transplantation for 27 children with juvenile myelomonocytic leukemia diagnosed based on the criteria of the International JMML Working Group

Prognostic factors of juvenile myelomonocytic leukemia (JMML) have not been clarified because of its very low incidence and inaccuracy in the diagnosis. The purpose of this study was to evaluate children with JMML given an allogeneic hematopoietic stem cell transplantation (SCT) and the role of different variables potentially influencing outcome in a nationwide survey in Japan based on the newly proposed criteria by the International JMML Working Group. The study patients were 27 children who underwent SCT among 55 JMML patients retrospectively collected in the survey. The source of grafts was HLA-identical siblings in 12 cases, HLA-matched unrelated individuals in 10 and others in five. Total body irradiation was used in 18 cases. Event-free and overall survival (OS) at 4 years after SCT were 54.2 +/- 11.2% (s.e.) and 57.9 +/- 11.0% (s.e.), respectively. Six patients died of relapse and three of complications. Patients with abnormal karyotypes showed a significantly lower OS than those with normal karyotypes (P < 0.001). Patients below 1 year of age showed a significantly higher OS than those of 1 year of age or more (P = 0.02). Patients with grade 0-1 acute graft-versus-host disease (GVHD) or chronic GVHD had a more favorable OS than those without them, although they were not statistically significant (P > 0.05). Other variables studied were not associated with OS. A multivariate analysis of these factors yielded the abnormal karyotype as the only significant risk factor for lower OS (risk ratio: 11.0; 95% CI: 2.7-45.1).

Juvenile myelomonocytic leukemia relapsing after allogeneic bone marrow transplantation successfully treated with interferon-alpha

We report a 5-year-old boy with juvenile myelomonocytic leukemia (JMML) which relapsed after an allogeneic bone marrow transplant who was successfully treated with interferon-alpha (IFN-alpha). One year after starting the therapy, he remains clinically well and in complete remission while continuing treatment with IFN-alpha and bestatin. Although the precise mechanism by which remission was induced is uncertain, a GVL effect combined with a direct antileukemia effect of IFN-alpha may be responsible. Further assessment of the role of IFN-alpha in relapsed JMLL patients is warranted.

Allogeneic bone marrow transplantation for juvenile myelomonocytic leukaemia: a single centre experience and review of the literature

Juvenile myelomonocytic leukaemia (JMML) is a rare paediatric disease and allogeneic stem cell transplantation is the only curative approach. The roles of pretransplant treatment, conditioning regimen and graft-versus-host disease (GVHD) are still unclear. Eleven children with JMML underwent allogeneic BMT in our institution. Donors were matched unrelated (n = 6) matched siblings (n = 4) and one mismatch family donor. Transplant-related mortality (TRM) was 36%. Three patients relapsed after transplantation. Two of three patients with relapse are in continuous remission after donor lymphocyte infusion or second BMT, respectively. To evaluate the role of pretransplant treatment, conditioning regimen and GVHD, we have summarised our series with other published single centre reports and give an overview on a total of 65 patients with JMML who underwent allogeneic BMT. No significant correlation between pretransplant treatment, conditioning regimen and TRM could be observed. Overall relapse rate is high (47%). TBI is associated with a significantly higher relapse rate (P = 0.012). Other conditioning modalities, intensive chemotherapy and splenectomy prior to stem cell transplantation do not seem to have a significant impact on relapse rate. Patients with or without GVHD showed no significant difference in relapse rate (58% vs 45%). In the event of relapse after transplantation withdrawal of immunosuppression, donor lymphocyte infusion or second transplant was successful in 6/11 patients. Graft-versus-leukaemia effect seems to play an essential role in bone marrow transplantation for JMML.