Angela Mastronuzzi

Allogeneic hematopoietic stem cell transplantation in thalassemia major: results of a reduced-toxicity conditioning regimen based on the use of treosulfan

Sixty thalassemia patients (median age, 7 years; range, 1-37) underwent allogeneic hematopoietic stem cell transplantation (HSCT) after a preparation combining thiotepa, treosulfan, and fludarabine. Before HSCT, 27 children were assigned to risk class 1 of the Pesaro classification, 17 to class 2, and 4 to class 3; 12 patients were adults. Twenty patients were transplanted from an HLA-identical sibling and 40 from an unrelated donor. The cumulative incidence of graft failure and transplantation-related mortality was 9% and 7%, respectively. Eight patients experienced grade II-IV acute GVHD, the cumulative incidence being 14%. Among 56 patients at risk, 1 developed limited chronic GVHD. With a median follow-up of 36 months (range, 4-72), the 5-year probability of survival and thalassemia-free survival are 93% and 84%, respectively. Neither the class of risk nor the donor used influenced outcome. This treosulfan-based preparation proved to be safe and effective for thalassemia patients given allogeneic HSCT.

Donor/recipient mixed chimerism does not predict graft failure in children with β-thalassemia given an allogeneic cord blood transplant from an HLA-identical sibling

This study indicates that mixed chimerism is a frequent event and does not predict the occurrence of graft failure in children with thalassemia major given a cord blood transplant from an HLA-identical sibling. See related perspective article on page 1780. Background Donor/recipient mixed chimerism has been reported to be associated with an increased risk of graft failure in patients with β-thalassemia given a bone marrow transplant. We investigated the relationship between the degree of mixed chimerism over time and clinical outcome of children undergoing cord blood transplantation for β-thalassemia. Design and Methods Twenty-seven consecutive children given a cord blood transplant from a related donor were analyzed by short tandem repeat polymerase chain reaction and their chimerism results were compared with those of 79 consecutive patients who received a bone marrow transplant from either a relative (RD-BMT, n=42) or an unrelated donor (UD-BMT, n=37). Cord blood and bone marrow recipients received comparable preparative regimens. Results All cord blood recipients engrafted and displayed mixed chimerism early after transplantation; 13/27 converted to full donor chimerism over time, while 14 maintained stable mixed chimerism; all patients are alive and transfusion-independent. Twenty-four of the 79 bone marrow-recipients (12 UD- and 12 RD-BMT) exhibited full donor chimerism at all time points examined, 4/79 (2 UD- and 2 RD-BMT) did not engraft and 51/79 (23 UD- and 28 RD-BMT) displayed mixed chimerism at the time of hematologic reconstitution. Forty of 51 bone marrow recipients with mixed chimerism converted to full donor chimerism (17 UD- and 23 RD-BMT), 3/51 maintained stable mixed chimerism (1 UD- and 2 RD-BMT), while 8/51 (5 UD- and 3 RD-BMT) progressively lost the graft, and became transfusion-dependent again. Conclusions Mixed chimerism is a frequent event and does not predict the occurrence of graft failure in children with β-thalassemia given a cord blood transplant from a relative.

Treosulfan‐based conditioning regimen for allogeneic haematopoietic stem cell transplantation in patients with thalassaemia major

The safety and efficacy of a preparation with treosulfan/thiotepa/fludarabine were explored in 20 thalassaemia patients given allogeneic marrow transplantation. Seventeen patients were transplanted from unrelated donors after receiving anti‐thymocyte globulin. The regimen was well tolerated. Two patients experienced secondary graft failure; one died of acute graft‐versus‐host disease. Cumulative incidence (95% confidence interval, CI) of transplantation‐related mortality and graft failure was 5% (95% CI, 0–34%) and 11% (95% CI, 3–43%), respectively. Two‐year probability of survival and thalassaemia‐free survival was 95% (95% CI, 85–100%) and 85% (95% CI, 66–100%), respectively. This regimen might find elective application in patients at high risk of developing life‐threatening complications.

The route to development of myelodysplastic syndrome/acute myeloid leukaemia in Shwachman-Diamond syndrome: the role of ageing, karyotype instability, and acquired chromosome anomalies

An investigation of 22 new patients with Shwachman‐Diamond syndrome (SDS) and the follow‐up of 14 previously reported cases showed that (i) clonal chromosome changes of chromosomes 7 and 20 were present in the bone marrow (BM) of 16 out of 36 cases, but if non‐clonal changes were taken into account, the frequency of anomalies affecting these chromosomes was 20/36: a specific SDS karyotype instability was thus confirmed; (ii) the recurrent isochromosome i(7)(q10) did not include short arm material, whereas it retained two arrays of D7Z1 alphoid sequences; (iii) the deletion del(20)(q11) involved the minimal region of deletion typical of myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML); (iv) only one patient developed MDS, during the rapid expansion of a BM clone with a chromosome 7 carrying additional material on the short arms; (v) the acquisition of BM clonal chromosome anomalies was age‐related. We conclude that karyotype instability is part of the natural history of SDS through a specific mutator effect, linked to lacking SBDS protein, with consequent clonal anomalies of chromosomes 7 and 20 in BM, which may eventually promote MDS/AML with the patients’ ageing.

Monitoring of Human Cytomegalovirus and Virus- Specific T-Cell Response in Young Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation

In allogeneic hematopoietic stem-cell transplantation (HSCT) recipients, outcome of human cytomegalovirus (HCMV) infection results from balance between viral load/replication and pathogen-specific T-cell response. Using a cut-off of 30,000 HCMV DNA copies/ml blood for pre-emptive therapy and cut-offs of 1 and 3 virus-specific CD4+ and CD8+ T cells/µl blood for T-cell protection, we conducted in 131 young patients a prospective 3-year study aimed at verifying whether achievement of such immunological cut-offs protects from HCMV disease. In the first three months after transplantation, 55/89 (62%) HCMV-seropositive patients had infection and 36/55 (65%) were treated pre-emptively, whereas only 7/42 (17%) HCMV-seronegative patients developed infection and 3/7 (43%) were treated. After 12 months, 76 HCMV-seropositive and 9 HCMV-seronegative patients (cumulative incidence: 90% and 21%, respectively) displayed protective HCMV-specific immunity. Eighty of these 85 (95%) patients showed spontaneous control of HCMV infection without additional treatment. Five patients after reaching protective T-cell levels needed pre-emptive therapy, because they developed graft-versus-host disease (GvHD). HSCT recipients reconstituting protective levels of HCMV-specific T-cells in the absence of GvHD are no longer at risk for HCMV disease, at least within 3 years after transplantation. The decision to treat HCMV infection in young HSCT recipients may be taken by combining virological and immunological findings.

Germ-line mutation of the NRAS gene may be responsible for the development of juvenile myelomonocytic leukaemia

We report the case of a child with clinical and haematological features indicative of juvenile myelomonocytic leukaemia (JMML). The patient showed dysmorphic features: high forehead, bilateral epicanthal folds, long eyebrows, low nasal bridge and slightly low‐set ears. A 38G>A (G13D) mutation in exon 1 of the NRAS gene was first demonstrated on peripheral blood cells, and then confirmed on granulocyte‐macrophage colony‐forming units. The same mutation was also found in buccal swab, hair bulbs, endothelial cells, skin fibroblasts. This case suggests for the first time that constitutional mutations of NRAS may be responsible for development of a myeloproliferative/myelodysplastic disorder in children.

Final results of the second prospective AIEOP protocol for pediatric intracranial ependymoma

BACKGROUND This prospective study stratified patients by surgical resection (complete = NED vs incomplete = ED) and centrally reviewed histology (World Health Organization [WHO] grade II vs III). METHODS WHO grade II/NED patients received focal radiotherapy (RT) up to 59.4 Gy with 1.8 Gy/day. Grade III/NED received 4 courses of VEC (vincristine, etoposide, cyclophosphamide) after RT. ED patients received 1-4 VEC courses, second-look surgery, and 59.4 Gy followed by an 8-Gy boost in 2 fractions on still measurable residue. NED children aged 1-3 years with grade II tumors could receive 6 VEC courses alone. RESULTS From January 2002 to December 2014, one hundred sixty consecutive children entered the protocol (median age, 4.9 y; males, 100). Follow-up was a median of 67 months. An infratentorial origin was identified in 110 cases. After surgery, 110 patients were NED, and 84 had grade III disease. Multiple resections were performed in 46/160 children (28.8%). A boost was given to 24/40 ED patients achieving progression-free survival (PFS) and overall survival (OS) rates of 58.1% and 68.7%, respectively, in this poor prognosis subgroup. For the whole series, 5-year PFS and OS rates were 65.4% and 81.1%, with no toxic deaths. On multivariable analysis, NED status and grade II were favorable for OS, and for PFS grade II remained favorable. CONCLUSIONS In a multicenter collaboration, this trial accrued the highest number of patients published so far, and results are comparable to the best single-institution series. The RT boost, when feasible, seemed effective in improving prognosis. Even after multiple procedures, complete resection confirmed its prognostic strength, along with tumor grade. Biological parameters emerging in this series will be the object of future correlatives and reports.

Comparison between an artificial neural network and logistic regression in predicting acute graft-vs-host disease after unrelated donor hematopoietic stem cell transplantation in thalassemia patients.

OBJECTIVE There is growing interest in the development of prognostic models for predicting the occurrence of acute graft-vs-host disease (aGVHD) after unrelated donor hematopoietic stem cell transplantation. A high number of variables have been shown to play a role in aGVHD, but the search for a predictive algorithm is still ongoing. Artificial neural networks (ANNs) represent an attractive alternative to multivariate analysis for clinical prognosis. So far, no reports have investigated the ability of ANNs in predicting HSCT outcome. MATERIALS AND METHODS We compared the prognostic performance of ANNs with that of logistic regression (LR) in 78 beta-thalassemia major patients given unrelated donor hematopoietic stem cell transplantation. Twenty-four independent variables were analyzed for their potential impact on outcomes. RESULTS Twenty-six patients (33.3%) developed grade II to IV aGVHD. In multivariate analysis, homozygosity for donor KIR haplotype A (p = 0.03), donor age (p = 0.05), and donor homozygosity for the deletion of the human leukocyte antigen-G 14-bp polymorphism (p = 0.05) were independently significantly correlated to aGVHD. The mean sensitivity of LR and ANNs (capability of predicting aGVHD in patients who developed aGVHD) in test datasets was 21.7% and 83.3%, respectively (p < 0.001); the mean specificity (capability of predicting absence of aGVHD in patients who did not develop aGVHD) was 80.5% and 90.1%, respectively (p = NS). CONCLUSION Although ANNs are unable to calculate the weight of single variables on outcomes, they were found to have a better performance than LR. A combination of these two methods could be more efficient in predicting outcomes and help tailor GVHD prophylaxis regimens according to the predicted risk of each patient. Whether ANN technology will provide better predictive performance when applied to other datasets remains to be confirmed.

Strategies to optimize the outcome of children given T-cell depleted HLA-haploidentical hematopoietic stem cell transplantation

The most advanced frontier of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is represented by the use of an HLA-partially matched relative as donor. In this type of transplantation, donor-derived natural killer (NK) cells, which are alloreactive toward recipient cells, significantly contribute to the eradication of leukemia blasts. Alloreactive NK cells may also kill host dendritic cells and T lymphocytes, thus preventing graft-versus-host disease and graft rejection, respectively. Sophisticated strategies of adoptive infusion of T-cell lines/clones specific for the most life-threatening pathogens (namely cytomegalovirus, Epstein-Barr virus, Aspergillus and Adenovirus) have been envisaged, and successfully tested in a few pilot trials, to protect the recipient in the early post-transplantation period. In these patients, also ex-vivo expanded mesenchymal stromal cells have been shown to be beneficial for preventing graft failure. Novel and effective strategies aimed at further augmenting the graft-versus-leukemia effect and at optimizing prevention/treatment of opportunistic/viral infections are warranted.

The role of killer immunoglobulin-like receptor haplotypes on the outcome of unrelated donor haematopoietic SCT for thalassaemia

Recent insight into the pathophysiology of acute GVHD after allogeneic haematopoietic SCT has led to a growing interest in the role of natural killer (NK) cells. NK cell cytotoxicity is mainly regulated by the interaction of activating and inhibitory killer immunoglobulin-like receptors (KIRs) with their respective ligands. To investigate the impact of KIRs and their ligands on haematopoietic SCT outcome, we performed a retrospective study of 78 transfusion-dependent thalassaemia patients (median age 10 years, range 1–29 years) transplanted from an unrelated donor selected using high-resolution molecular typing for both class I and II loci after a myeloablative conditioning regimen. GVHD prophylaxis consisted of CsA, short-term MTX and anti-thymocyte globulin in all patients. We found that patients transplanted from donors homozygous for KIR haplotype A had a greater risk of developing grade II–IV acute GVHD compared with those transplanted from a donor carrying at least one B haplotype (hazard ratio=4.5, 99% confidence interval=1.2–17.1, P=0.003). Our study suggests that KIR genotyping of donor and recipient pairs could contribute to the identification of patients at high risk for developing severe complications of haematopoietic SCT and thus may help with the choice of intensity of GVHD prophylaxis.