Vol 20, No 2 (2021)

Busulfan-based conditioning regimens before hematopoietic stem cell transplantation (HSCT) in patients with Diamond–Blackfan anemia (DBA) are the standard therapy for a long time. Unfortunately, the high incidence of toxic complications is the cause of transplant-related mortality (TRM) or low quality of life. Treosulfan-based conditioning is very attractive, however only limited data exists of its administration in DBA patients. In this article, we present the experience of treosulfan usage along with novel approaches to “graft versus host” disease (GVHD) prophylaxis in Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The study was approved by the Independent Ethics Committee of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. From 2012 to 2020, 9 patients with DBA underwent HSCT. Matched unrelated donors were used in 7 patients, mismatched related in 1, and HLA-identical sibling in 1 patient. All patients received treosulfan-based conditioning. The sources of HSC were bone marrow (n = 3) and peripheral blood after TCRab+/CD19+ graft depletion (n = 6). Eight patients received various regimens of post-transplant prophylaxis, included calcineurin inhibitors alone or in combinations, 1 patient – mycophenolate mofetil. All transplanted patients engrafted. Median follow-up in survivors (n = 8) was 35.6 months. One patient (Karnofsky-index before HSCT 40%) died on day +58 due to multio rgan failure, caused by toxic and infectious complications. Besides, three patients had clinically signifiant toxic complications: oral mucositis grade 3 in 1 patient, treosulfan skin toxicity in 2, and moderate veno-occlusive-disease in 1 patient. Five patients had acute GVHD grade II with complete response to the 1st line therapy. There was no evidence of acute GVHD grade III–IV as well as chronic GVHD. Our data demonstrate, that treosulfan-based conditioning, alongside new cellular engineering approaches is effctive options for HSCT outcomes in patients with DBA.

There is no doubt that autologous hematopoietic stem cell transplantation (auto-HSCT) with high-dose polychemotherapy (PCT) is a standard method for the second remission consolidation in case of relapse or for the fist remission consolidation in refractory disease in adult patients with non-Hodgkin lymphomas (NHL) (with the exception of lymphoblastic lymphoma in which allogeneic transplantation is preferable). Similar to patients older than 18 years of age, an identical algorithm is applied in pediatric patients, however in the absence of randomized clinical trials and due to a small number of patients, the evidence base in children is weaker compared to adults, which complicates the analysis. Due to a signifiant number of nonrandomized studies confiming the benefis of transplantation, it is impossible to plan and make a direct comparison of auto-HSCT and standard chemotherapy in pediatric patients within a randomized study primarily because of ethical reasons. Although transplantation is not able to fundamentally change the prognosis in all children with relapsed or refractory (R/R) NHL, a cure cannot be achieved without this method. Taking into account that most of the works devoted to auto-HSCT in children with R/R NHL were published more than 10 years ago, current data on this issue are of great interest due to the large-scale implementation of the effective methods of targeted and immunotherapy over the past decade. This study was approved by the Independent Ethics Committee and the Scientifi Council of the I.P. Pavlov First Saint-Petersburg State Medical University, Ministry of Healthcare of the Russian Federation. At the R.M. Gorbacheva Research Institute of Pediatric Oncology, Hematology and Transplantation, 31 children with R/R NHL underwent auto-HSCT from 2008 to 2020. The median age at the time of transplantation was 14 (2–18) years. At the onset of the disease, most patients were diagnosed with stage III or IV cancer (n = 30, 97%), the CNS involvement was registered in 4 patients (13%), the bone marrow involvement was registered in 2 patients (6%). The histological variants were as follows: primary mediastinal large B-cell lymphoma (n = 11, 35%), anaplastic large cell lymphoma (n = 6, 9%), Burkitt's lymphoma (n = 5, 16%), diffse large B-cell lymphoma (n = 5, 16%), peripheral T-cell lymphoma (n = 2, 7%), unspecifid B-NHL (n = 1, 3%) and lymphoblastic lymphoma (n = 1, 3%). The Karnofsky performance status prior to transplantation was ≥ 90% in all patients. The median time from diagnosis to auto-HSCT was 304 (122–3888) days. The median number of prior lines of therapy was 2 (1–4). In the majority of the patients (n = 27, 87%), a fist-line treatment was carried out according to the principles developed by the BFM group and in 4 older children (13%), we used regimens based on CHOP. As a second-line treatment, 18 (58%) patients received R-ICE (rituximab, ifosfamide, carboplatin, etoposide); the rest of the patients were treated with other regimens. NHL was relapsed (n = 14, 45%) or refractory (n = 17, 55%). A histological confimation of R/R NHL was carried out in 11 (35%) patients; in the rest of the cases, the diagnosis was made based on the imaging results and their correlation with the clinical presentation. Remission prior to auto-HSCT was achieved in 90% (n = 28) of cases: complete remission was observed in 39% (n = 8) of cases, and partial remission was observed in 51% (n = 16) of cases. In addition, transplantation was carried out in three patients (10%) who did not achieve remission. The graft sources were peripheral hematopoietic stem cells (n = 19, 61%) and bone marrow (n = 12, 39%). The median CD34+cells/kg was 3.85 (2–7.6). As conditioning regimens we used BEAM (n = 13, 42%) and BeEAM (n = 18, 58%). Both regimens consisted of etoposide 200 mg/m2/day from D5 to D2, cytarabine 400 mg/m2/day from D5 to D2, melphalan 140 mg/m2/day on D1. The regimens diffred in the following: we used carmustine 300 mg/m2/day on D6 in BEAM or bendamustine 160 mg/m2/day on D7 and D6 in BeEAM. Immunotherapy or targeted therapy prior to auto-HSCT was carried out in the majority of the patients (n = 25, 80%). The following medications were used: rituximab (n = 20, 65%), brentuximab vedotin (n = 6, 19%), nivolumab (n = 3, 10%), crizotinib (n = 2, 6%). Temporary three-lineage grade IV cytopenia was observed in all patients after auto-HSCT. Grade III–IV mucositis was registered in 10 (30%) patients, and 3 (10%) children developed grade III–IV infectious complications. Transplant-related mortality was not registered. During the follow-up period, six (19%) patients died due to the underlying disease progression. At the median follow-up of 888 (66–3375) days, the 5-year overall (OS) and event-free (EFS) survival rates were 70% (95% CI: 43–86) and 62% (95% CI: 41–80), respectively. The cumulative incidence of relapse was 38% (95% CI: 20–58). Based on the data obtained in our work, we can conclude that the use of targeted or immunotherapy provides a statistically signifiant improvement in overall survival (OS) (p = 0.013). This is associated with both factors: a more sustained remission prior to auto-HSCT and the availability of effctive treatment for some patients (mainly for the patients with anaplastic large cell lymphoma) in case of relapse after auto-HSCT. The achieved long-term survival rate is comparable or even slightly superior to the data previously obtained by other researchers. Almost one third of the patients suffred from primary mediastinal large B-cell lymphoma, and this is one of the possible reasons for higher long-term OS and EFS rates compared to the previously published results. Moreover, the presence of 6 patients with R/R anaplastic large cell lymphoma with a more favorable prognosis, and, probably, the absence of the morphological confimation of R/R NHL (“second look”) in some patients (n = 20, 65%) could have inflenced the survival rates, which does not exclude the possible inclusion of a number of cured patients in the work. The importance of our work lies in the fact that a signifiant part of the patients (n = 25, 80%) underwent targeted or immunotherapy. This allowed us to show the effctiveness of transplantation in different types of NHL in children in the so-called era of immunotherapy. Auto-HSCT is an effctive and relatively safe treatment strategy for children with R/R NHL which makes it possible to achieve a cure in a signifiant number of patients. The use of targeted and immunotherapy improves the prognosis in transplanted patients. A second biopsy is recommended to confim R/R NHL.

Evans syndrome (ES) is a rare disorder accompanied by autoimmune hemolytic anemia and immune thrombocytopenia. ES in children is often associated with the defect of immune system regulation. This article presents an analysis of the results of investigation of 54 children with ES admitted to the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology during the period 2012–2019. The male-to-female ratio was 1.07:1 and the median age of the disease onset was 4 years (0 months – 16 years). Based on the results of molecular genetic testing, the diagnosis was changed in three patients to congenital TTP. Thus, for further analysis 51 patients were available. Thirty-nine out of 51 children (76.5%) had secondary ES, the median age of the disease onset was 4 years (2 months – 12 years), the male-to-female ratio was 1.05:1. PID was genetically confimed in 25 out of 39 patients, in the remaining 14 cases the diagnosis of PID was based on clinical and laboratory fidings only. Twelve patients (22.2%) had idiopathic (primary) ES, the median age of the disease onset was 8 years (7 months – 16 years) and the male-to-female ratio was 1:1. The disease onset in ES was more often accompanied by isolated cytopenia: ITP – 22 (43.1%) patients, AIHA – 15 (29.4%) patients, immune neutropenia – 1 (2%) patient, simultaneously with AIHA and ITP – 8 (15.7%) patients, pancytopenia – 5 (9.8%) patients. The second cytopenia developed on average after 2 years (1 month – 9 years). Neutropenia was observed only in secondary ES. The mortality rate for ES was 9.8%. First-line therapy (IVIG, glucocorticoids) for ES showed low effctiveness and sustained remission was observed only in 5.9% of patients. Thirty-four (87%) patients with secondary ES and 9 (75%) patients with idiopathic ES required other lines of therapy. The next-line drugs that showed good effctiveness were rituximab (76.5%), MMF (94%), and sirolimus (83%). Combinations of rituximab and MMF, rituximab and sirolimus were also effctive and induced sustained remission without other therapy in 83.3% and 75% of patients respectively. Children with ES need thorough examination, including genetic testing, for the early diagnosis of PID and the exclusion of congenital TTP. The combination of rituximab and MMF proved to be the most effctive treatment for ES.

The detection of genetic markers associated with poor prognosis is crucial to the selection of an appropriate treatment plan for B-cell precursor acute lymphoblastic leukemia (BCP-ALL). A hypodiploid karyotype in patients with BCP-ALL has an unfavorable impact and serves as a criterion for the stratification of patients into a high-risk group. However, the survival rates of patients with a hypodiploid karyotype remain poor. Russian treatment protocols for childhood acute lymphoblastic leukemia do not include a hypodiploid karyotype in risk stratification criteria. In order to determine the prognostic value of a hypodiploid karyotype and the clinical characteristics of BCP-ALL in patients with a hypodiploid karyotype, we analyzed the survival rates of 2,700 patients included in a multicenter study. Our study was approved by the Independent Ethics Committee and the Scientific Council of the D. Rogachev NMRCPHOI of the Ministry of Healthcare of the Russian Federation. All patients underwent karyotyping and fluorescence in situhybridization (FISH) testing. A hypodiploid karyotype was detected in 27 patients. Eighteen out of 27 patients had a hypoploid clone (according to karyotyping results), 2 patients had a doubled near-haploid clone (according to karyotyping and FISH results); in 7 patients with a normal karyotype or in the absence of mitosis, hypodiploidy was determined only by FISH test. BCP-ALL with hypodiploidy is usually associated with increased WBC count at disease onset. The median WBC count in the study group was 24.2 (3.4–206.0) × 10⁹/l vs 10.3 (0.2–1290.0) × 10⁹/l in the control group. The number of patients with initial leukocytosis < 30 × 109/l in the study group was significantly lower than in the control group (p< 0.062). Remission was achieved in 26/27 patients. The event-free survival rates in patients with hypodiploidy were significantly lower than in those without hypodiploidy: 50 ± 11% vs 72 ± 8% (p< 0.0001). The overall survival was 64 ± 10% and 90 ± 1%, respectively (p< 0.0001). The cumulative incidence of relapse in patients with a hypodiploid karyotype was higher (42.6 ± 10.9%) than in the controls (22.3 ± 8.1%) (p< 0.0001). The patients who received more intense treatment for intermediate- and high-risk groups showed better survival rates than those in the standard-risk group: 62 ± 13% vs 40 ± 15% (р= 0.59); the cumulative incidence of relapse according to the risk group was 26.4 ± 12.1% and 60 ± 16.9%, respectively (р= 0.19).The highest risk of relapse was observed in a group that included patients with near-haploidy and low hypodiploidy (26–39 chromosomes; 52.9 ± 14.4%). The event-free survival in this group was 36 ± 13%. The results of treatment of patients with BCP-ALL and hypodiploidy according to the national guidelines turned out to be comparable to the international ones. Patients with BCP-ALL and hypodiploidy should be initially stratified to the most intense treatment arm. In order to identify patients with hypoploidy, standard karyotyping is required; where needed, it can be supplemented by FISH analysis

Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is an aggressive malignant tumor that is mainly found in younger children and is associated with poor prognosis. Our objectives: to present the results of treatment of children with CNS AT/RT under 3 years of age and assess the impact of various prognostic factors on patient survival. The study was approved by the Independent Ethics Committee and the Scientific Council of the N.I. Pirogov Russian National Research Medical University of Ministry of Healthcare of the Russian Federation. The study included 106 patients with CNS AT/RT aged 0–3 years who had been treated and monitored from 2008 to 2020. The median age was 16 (9; 23) months. All the patients underwent primary tumor resection with subsequent chemotherapy according to various protocols. At the time of the analysis, 47 patients (44.4%) were alive, 1 patient (0.9%) was lost to follow-up and 58 patients (54.7%) were dead, of whom 52 patients (90%) had died of disease progression and 6 (10%) – of polychemotherapy complications. One patient developed shunt-related intraabdominal metastasis within 10 months of the diagnosis. The 1-year progression-free survival (PFS) was 0.50; the 2-year PFS was 0.29; the 5-year PFS – 0.27. The median PFS was 12 months. The 1-year overall survival (OS) was 0.72; the 2-year OS was 0.53; the 5-year OS – 0.40. The median OS was 27 months. An analysis of patients with CNS AT/RT under 3 years of age showed that PFS was statistically significantly higher in: children aged > 12 months; children with totally resected tumours; children who had received polychemotherapy in accordance with the ATRT-2006 protocol that included radiotherapy and regional administration of a triplet of chemotherapeutic agents. The OS in patients with CNS AT/RT aged < 3 years was statistically significantly higher in: children aged > 12 months; children who had been treated with radiation therapy; patients who had received cytosar/etoposide intrathecally/intraventricularly; patients who had undergone high-dose chemotherapy with subsequent autologous hematopoietic stem cell transplantation. A multivariate analysis revealed that PFS was influenced by age, tumor location, extent of resection and exposure to radiation therapy, regional chemotherapy or high-dose chemotherapy with autologous hematopoietic stem cell transplantation, while OS was affected by age and exposure to radiation therapy.

Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is an aggressive malignant tumor that is mainly found in younger children and is associated with poor prognosis. Our objectives: to present the results of treatment of children with CNS AT/RT under 3 years of age and assess the impact of various prognostic factors on patient survival. The study was approved by the Independent Ethics Committee and the Scientific Council of the N.I. Pirogov Russian National Research Medical University of Ministry of Healthcare of the Russian Federation. The study included 106 patients with CNS AT/RT aged 0–3 years who had been treated and monitored from 2008 to 2020. The median age was 16 (9; 23) months. All the patients underwent primary tumor resection with subsequent chemotherapy according to various protocols. At the time of the analysis, 47 patients (44.4%) were alive, 1 patient (0.9%) was lost to follow-up and 58 patients (54.7%) were dead, of whom 52 patients (90%) had died of disease progression and 6 (10%) – of polychemotherapy complications. One patient developed shunt-related intraabdominal metastasis within 10 months of the diagnosis. The 1-year progression-free survival (PFS) was 0.50; the 2-year PFS was 0.29; the 5-year PFS – 0.27. The median PFS was 12 months. The 1-year overall survival (OS) was 0.72; the 2-year OS was 0.53; the 5-year OS – 0.40. The median OS was 27 months. An analysis of patients with CNS AT/RT under 3 years of age showed that PFS was statistically significantly higher in: children aged > 12 months; children with totally resected tumours; children who had received polychemotherapy in accordance with the ATRT-2006 protocol that included radiotherapy and regional administration of a triplet of chemotherapeutic agents. The OS in patients with CNS AT/RT aged < 3 years was statistically significantly higher in: children aged > 12 months; children who had been treated with radiation therapy; patients who had received cytosar/etoposide intrathecally/intraventricularly; patients who had undergone high-dose chemotherapy with subsequent autologous hematopoietic stem cell transplantation. A multivariate analysis revealed that PFS was influenced by age, tumor location, extent of resection and exposure to radiation therapy, regional chemotherapy or high-dose chemotherapy with autologous hematopoietic stem cell transplantation, while OS was affected by age and exposure to radiation therapy.

The article describes a clinical case of a patient with Wiskott–Aldrich syndrome, in whom long- term persistence of mixed chimerism was determined after hematopoietic stem cell transplantation (HSCT) from a haploidentical donor. Based on the analysis of the patient's clinical picture after HSCT, it was shown that the presence of> 50% of donor cells in the myeloid lineage is necessary for the correction of thrombocytopenia. In addition, the presence of mixed chimerism in B-lymphocytes possibly contributed to the development of autoimmune complications in the patient, as well as to the persistent hypogammaglobulinemia, despite the restoration of the normal numbers of lymphocytes in all main sub-populations. The role of mixed chimerism in the pathogenesis of immune post-transplant complications requires study in large groups of patients with primary immunodeficiencies. The patient's parents agreed to use the information, including the child's photo, in scientific research and publications.