Artemis deficiency: A large cohort including a novel variant with increased radiosensitivity.

BACKGROUND: Artemis deficiency is an autosomal recessive disorder characterized by a combined immunodeficiency with increased cellular radiosensitivity. In this review, the clinical and genetic characteristics of 15 patients with DCLRE1C variants are presented. METHODS: The demographic, clinical, immunologic, and genetic characteristics of patients with confirmed DCLRE1C variants diagnosed between 2013 and 2023 were collected retrospectively. Three patients were evaluated for radiosensitivity by the Comet assay, compared with age- and sex-matched healthy control. RESULTS: Seven patients who had severe infections in the first 6 months of life were diagnosed with T-B-NK+ SCID (severe combined immunodeficiency). Among them, four individuals underwent transplantation, and one of those died due to post-transplant complications in early life. Eight patients had hypomorphic variants. Half of them were awaiting a suitable donor, while the other half had already undergone transplantation. The majority of patients were born into a consanguineous family (93.3%). Most patients had recurrent sinopulmonary infections (73.3%), and one patient had no other infection than an acute respiratory infection before diagnosis. Two patients (13.3%) had autoimmunity in the form of autoimmune hemolytic anemia. Growth retardation was observed in only one patient (6.6%), and no malignancy was detected in the surviving 11 patients during the median (IQR) of 21.5 (12-45) months of follow-up. Three patients who had novel variants exhibited increased radiosensitivity and compromised DNA repair, providing a potential vulnerability to malignant transformation. CONCLUSION: Early diagnosis, radiation avoidance, and careful preparation for transplantation contribute to minimizing complications, enhancing life expectancy, and improving the patient's quality of life.

Adverse COVID-19 outcomes in immune deficiencies: Inequality exists between subclasses.

BACKGROUND: Genetic deficiencies of immune system, referred to as inborn errors of immunity (IEI), serve as a valuable model to study human immune responses. In a multicenter prospective cohort, we evaluated the outcome of SARS-CoV-2 infection among IEI subjects and analyzed genetic and immune characteristics that determine adverse COVID-19 outcomes. METHODS: We studied 34 IEI patients (19M/15F, 12 [min: 0.6-max: 43] years) from six centers. We diagnosed COVID-19 infection by finding a positive SARS-CoV-2 PCR test (n = 25) and/or a lung tomography scoring (CORADS) ≥4 (n = 9). We recorded clinical and laboratory findings prospectively, fitted survival curves, and calculated fatality rates for the entire group and each IEI subclass. RESULTS: Nineteen patients had combined immune deficiency (CID), six with predominantly antibody deficiency (PAD), six immune dysregulation (ID), two innate immune defects, and one in the autoinflammatory class. Overall, 23.5% of cases died, with disproportionate fatality rates among different IEI categories. PAD group had a relatively favorable outcome at any age, but CIDs and IDs were particularly vulnerable. At admission, presence of dyspnea was an independent risk for COVID-related death (OR: 2.630, 95% CI; 1.198-5.776, p < .001). Concerning predictive roles of laboratory markers at admission, deceased subjects compared to survived had significantly higher CRP, procalcitonin, Troponin-T, ferritin, and total-lung-score (p = .020, p = .003, p = .014, p = .013, p = .020; respectively), and lower absolute lymphocyte count, albumin, and trough IgG (p = .012, p = .022, p = .011; respectively). CONCLUSION: Our data disclose a highly vulnerable IEI subgroup particularly disadvantaged for COVID-19 despite their youth. Future studies should address this vulnerability and consider giving priority to these subjects in SARS-Cov-2 therapy trials.

Deferasirox in children with transfusion-dependent thalassemia or sickle cell anemia: A large cohort real-life experience from Turkey (REACH-THEM).

OBJECTIVES: To evaluate the long-term efficacy and safety of deferasirox therapy in a large observational cohort of children with transfusion-dependent thalassemia (TDT) and sickle cell anemia (SCA) in Turkey. METHODS: This was a multicenter, prospective cohort study including TDT and SCA patients aged 2-18 years with iron overload (≥100 mL/kg of pRBC or a serum ferritin [SF] level >1000 µg/L) receiving deferasirox. Patients were followed for up to 3 years according to standard practice. RESULTS: A total of 439 patients were evaluated (415 [94.5%] TDT, 143 [32.6%] between 2 and 6 years). Serum ferritin levels consistently and significantly decreased across 3 years of deferasirox therapy from a median of 1775.5 to 1250.5 µg/L (P < 0.001). Serum ferritin decreases were noted in TDT (1804.9 to 1241 µg/L), SCA (1655.5 to 1260 µg/L), and across age groups of 2-6 years (1971.5 to 1499 µg/L), 7-12 years (1688.5 to 1159.8 µg/L), and 13-18 years (1496.5 to 1107 µg/L). Serum ferritin decreases were also noted for all deferasirox dose groups but only significant in patients with doses ≥30 mg/kg/d (n = 120, -579.6 median reduction, P < 0.001). Only 9 (2%) patients had adverse events suspected to be related to deferasirox. Serum creatinine slightly increased but remained within the normal range. CONCLUSIONS: Deferasirox has long-term efficacy and safety in children with TDT and SCA, although higher doses (≥30 mg/kg/d) may be required to achieve iron balance.

Homozygous c.130-131 ins A (pW44X) mutation in the HAX1 gene as the most common cause of congenital neutropenia in Turkey: Report from the Turkish Severe Congenital Neutropenia Registry.

BACKGROUND: Severe congenital neutropenia is a rare disease, and autosomal dominantly inherited ELANE mutation is the most frequently observed genetic defect in the registries from North America and Western Europe. However, in eastern countries where consanguineous marriages are common, autosomal recessive forms might be more frequent. METHOD: Two hundred and sixteen patients with severe congenital neutropenia from 28 different pediatric centers in Turkey were registered. RESULTS: The most frequently observed mutation was HAX1 mutation (n = 78, 36.1%). A heterozygous ELANE mutation was detected in 29 patients (13.4%) in our cohort. Biallelic mutations of G6PC3 (n = 9, 4.3%), CSF3R (n = 6, 2.9%), and JAGN1 (n = 2, 1%) were also observed. Granulocyte colony-stimulating factor treatment was given to 174 patients (80.6%). Two patients died with infectious complications, and five patients developed myelodysplastic syndrome/acute myeloblastic leukemia. The mean (± mean standard error) follow-up period was 129.7 ± 76.3 months, and overall survival was 96.8% (CI, 94.4-99.1%) at the age of 15 years. In Turkey, severe congenital neutropenia mostly resulted from the p W44X mutation in the HAX1 gene. CONCLUSION: In Turkey, mutation analysis should be started with HAX1, and if this is negative, ELANE and G6PC3 should be checked. Because of the very high percentage of consanguineous marriage, rare mutations should be tested in patients with a negative mutation screen.

A Phase II, Multicenter, Single-Arm Study to Evaluate the Safety and Efficacy of Deferasirox after Hematopoietic Stem Cell Transplantation in Children with ß-Thalassemia Major.

We conducted a prospective, phase II, multicenter, single-arm study to evaluate the efficacy and safety of deferasirox in patients age >2 to <18 years with ß-thalassemia major (TM) who underwent hematopoietic stem cell transplantation (HSCT) and had evidence of iron overload (serum ferritin >1000 µg/L; cardiac MRI T2* <20 ms, or liver iron concentration [LIC; by MRI R2] ≥5 mg/g). Patients received deferasirox at an initial dose of 10 mg/kg/day, with up-titration to a maximum of 20 mg/kg/day. The study continued for 52 weeks and included a total of 27 patients (mean age, 9.1 ± 3.8 years; 70.4% male). One patient (3.7%) was lost to follow-up. The majority of patients (n = 20; 74.1%) were able to achieve the intended dose of 20 mg/kg/day. No deaths occurred. A total of 134 adverse events (AEs) were reported in 25 patients (92.6%) during the study. The majority of patients had grade 1 or 2 AEs, with only 8 patients (29.6%) experiencing grade 3 AEs. Only 10 AEs occurring in 4 patients (14.8%) were suspected to be related to deferasirox (ALT/AST increase, n = 4; urinary tract infection, n = 1). The deferasirox dose had to be adjusted or interrupted for 6 AEs occurring in 4 patients (14.8%). A total of 6 serious AEs occurred in 3 patients (11.1%), none of which were suspected to be related to deferasirox. From baseline to week 52, there were decreases in median concentrations of alanine aminotransferase (ALT), from 30.0 to 17.0 IU/L, and aspartate aminotransferase (AST), from 35.5 to 26.0 IU/L. Median serum creatinine and cystatin C concentrations were similar at baseline and week 52. There was a continuous and significant decrease in median serum ferritin level from 1718.0 µg/L at baseline to 845.3 µg/L following 52 weeks of therapy (P < .001); 9 patients (33.3%) achieved a level of <500 µg/L. There was also a significant decrease in median LIC (from 8.6 to 4.1 mg/g; P < .001) and an increase in median cardiac T2* (from 26.0 to 28.0 ms; P = .520) from baseline to week 52. Our findings indicate that deferasirox treatment at doses up to 20 mg/kg/day reduces the iron burden in children with TM post-HSCT, with a manageable safety profile.

Hematopoietic Stem Cell Transplantation Using Preimplantation Genetic Diagnosis and Human Leukocyte Antigen Typing for Human Leukocyte Antigen-Matched Sibling Donor: A Turkish Multicenter Study.

Preimplantation genetic diagnosis involves the diagnosis of a genetic disorder in embryos obtained through in vitro fertilization, selection of healthy embryos, and transfer of the embryos to the mother's uterus. Preimplantation genetic diagnosis has been used not only to avoid the risk of having an affected child, but it also offers, using HLA matching, preselection of potential HLA-genoidentical healthy donor progeny for an affected sibling who requires bone marrow transplantation. Here, we share the hematopoietic stem cell transplantation results of 52 patients with different benign and malign hematological or metabolic diseases or immunodeficiencies whose donors were siblings born with this technique in Turkey since 2008. The median age of the patients' at the time of the transplantation was 8 years (range, 3 to 16 years) and the median age of the donors was 2 years (range, .5 to 6 years). The most common indication for HSCT was thalassemia major (42 of all patients, 80%). The stem cell source in all of the transplantations was bone marrow. In 37 of the transplantations, umbilical cord blood of the same donor was also used. In 50 of the 52 patients, full engraftment was achieved with a mean of 4.6 × 106 CD 34+ cells per kg of recipient weight. Ninety-six percent of the patients have been cured through hematopoietic stem cell transplantation without any complication. Primary engraftment failure was seen in only 2 patients with thalassemia major. All of the donors and the patients are alive with good health status. Preimplantation genetic diagnosis with HLA matching offers a life-saving chance for patients who need transplantation but lack an HLA genoidentical donor.

Successful haematopoietic stem cell transplantation in 44 children from healthy siblings conceived after preimplantation HLA matching.

Haematopoietic stem cell transplantation (HSCT) remains the best therapeutic option for many acquired and inherited paediatric haematological disorders. Unfortunately, the probability of finding an HLA matched donor is limited. An alternative technique is PGD combined with HLA matching, which offers the possibility of selecting unaffected embryos that are HLA compatible with the sick child, with the aim of possible use of stem cells from the resulting baby in future. Since the first successful report for Fanconi anaemia a decade ago, the therapeutic success of this technique was reported in a few cases and for a limited number of disorders. Here, we report full recovery of 44 sick children who received HSCT from healthy infants conceived after pre-implantation HLA matching for the following 10 indications; beta-thalassaemia, Wiskott-Aldrich syndrome, Fanconi anaemia, sickle cell anaemia, acute myeloid leukaemia, acute lymphoblastic leukaemia, Glanzmann's thrombasthaenia, Diamond-Blackfan anaemia, X-linked adrenoleukodystrophy and mucopolysaccharidosis type I. No serious complications were observed among recipients and donors. Graft failure occurred in four children with beta-thalassaemia where a second HSCT was planned. Preimplantation HLA matching is a reliable technique and provides a realistic option for couples seeking treatment for an affected child when no HLA-matched donor is available.

Evaluating the patients with thalassemia major for long-term endocrinological complications after bone marrow transplantation.

The aim of this study was to evaluate the endocrinological complications of the patients with thalassemia major (TM) who underwent bone marrow transplantation (BMT) and followed-up more than two years in our center, prospectively. "BMT group" consisted of 41 patients with TM. The mean age was 12.4 ± 5.4 years and transplantation age was mean 7.5 ± 4.9 years. Post-BMT follow-up lasted from 24 to 122 months (mean 65.07 months). Also, 32 TM patients with similar age group and same history of transfusion and chelation therapy were recruited for the study as "control (C) group". The weight SDS score after transplantation was found better than before transplantation (p = 0.010). There was a negative correlation between height SDS and BMT age (p = 0.008). The height SDS scores were better in patients whose BMT age was under seven years old compared to those older than seven years old (p = 0.02). Z-scores of femur neck and L2-4 vertebrae DEXA were decreased (p = 0.032, p = 0.0001) and incidence of insulin resistance increased (p = 0.01) in patients with increased BMT age. The risk of gonadal insufficiency was significantly lower in the patients who underwent BMT <7 years of age (p = 0.009). There was no statistically significant relationship between BMT age and complications such as hypothyroidism, hypoparathyroidism, and adrenal insufficiency. The patients with TM should be evaluated for transplantation in early stage of the disease, especially before the age of seven years. Because the BMT cannot correct the endocrinological complications of TM completely, the patients should be followed up regularly after the transplantation.

Better posttransplant outcome with fludarabine based conditioning in multitransfused fanconi anemia patients who underwent peripheral blood stem cell transplantation.

Several investigators have been looking for less toxic conditioning regimen for stem cell transplantation in Fanconi anemia (FA) patients because of sensitivity to DNA cross-linking agents and tendency to malignancy. We report 16 multitransfused FA patients who underwent peripheral stem cell transplantation from 13 related and 3 unrelated donors. Although the first 6 patients received thoraco-abdominal irradiation + cyclophosphamide + antithymocyte globulin (regimen A) for conditioning, fludarabine (FLU) + cyclophosphamide + antithymocyte globulin (regimen B) were used in the last 10 patients in which 3 of them received unrelated graft. Cyclosporin A was given alone for the related allografts but also included mycophenolate mofetil for the unrelated allograft as graft versus host disease prophylaxis. We observed a lower risk of peritransplant morbidity and mortality with fewer and milder graft versus host disease in FLU based group. We lost 3 patients in regimen A group and 1 of them from secondary acute myeloid leukemia. Three patients are alive with transfusion independent. In regimen B group, 9 of 10 patients are alive with normal hematologic parameters and full donor chimerism. The longest follow-up durations are 90 and 60 months in regimen A and B, respectively. In conclusion, FLU based conditioning is more effective and successful with lower toxicity in multitransfused FA patients. However, it needs more experience and longer follow up duration.

Juvenile Myelomonocytic Leukemia in Turkey: A Retrospective Analysis of Sixty-five Patients.

OBJECTIVE: This study aimed to define the status of juvenile myelomonocytic leukemia (JMML) patients in Turkey in terms of time of diagnosis, clinical characteristics, mutational studies, clinical course, and treatment strategies. MATERIALS AND METHODS: Data including clinical and laboratory characteristics and treatment strategies of JMML patients were collected retrospectively from pediatric hematology-oncology centers in Turkey. RESULTS: Sixty-five children with JMML diagnosed between 2002 and 2016 in 18 institutions throughout Turkey were enrolled in the study. The median age at diagnosis was 17 months (min-max: 2-117 months). Splenomegaly was present in 92% of patients at the time of diagnosis. The median white blood cell, monocyte, and platelet counts were 32.9x109/L, 5.4x109/L, and 58.3x109/L, respectively. Monosomy 7 was present in 18% of patients. JMML mutational analysis was performed in 32 of 65 patients (49%) and PTPN11 was the most common mutation. Hematopoietic stem cell transplantation (HSCT) could only be performed in 28 patients (44%), the majority being after the year 2012. The most frequent reason for not performing HSCT was the inability to find a suitable donor. The median time from diagnosis to HSCT was 9 months (min-max: 2-63 months). The 5-year cumulative survival rate was 33% and median estimated survival time was 30±17.4 months (95% CI: 0-64.1) for all patients. Survival time was significantly better in the HSCT group (log-rank p=0.019). Older age at diagnosis (>2 years), platelet count of less than 40x109/L, and PTPN11 mutation were the factors significantly associated with shorter survival time. CONCLUSION: Although there has recently been improvement in terms of definitive diagnosis and HSCT in JMML patients, the overall results are not satisfactory and it is necessary to put more effort into this issue in Turkey.

Hematopoetic stem cell transplantation in children.

Bone marrow transplantation is called hematopoetic stem cell transplantation (HSCT), since peripheral blood and umbilical cord blood can also be used as sources of stem cell currently. In children, bone marrow transplantation is used as a definite treatment method in many diseases including hemoglobinopaties, immune deficiencies, bone marrow failure and congenital metabolic diseases in addition to hematological malignancies. In addition to the underlying disease, the most important factors which have an impact on prognosis include infections which develop during the process of transplantation and graft-versus-host disease. In this article, it was aimed to give brief information on stem cell sources, preparation therapies, HSCT indications and post-transplantation complications in children.

Aberrations of chromosomes 9 and 22 in acute lymphoblastic leukemia cases detected by ES-fluorescence in situ hybridization.

A reciprocal translocation between chromosomes 9 and 22 creates oncogenic BCR/ABL fusion in the breakpoint region of the derivative chromosome 22. The aim of this study was to evaluate the importance of atypical fluorescence in situ hybridization (FISH) signal patterns in pediatric and adult acute lymphoblastic leukemia (ALL) cases. We evaluated t(9;22) translocation in 208 cases with ALL (294 tests), including 139 childhood and 69 adult cases by FISH technique using BCR/ABL extra signal (ES) probe. FISH signal patterns observed in pediatric ALL cases were as follows; Major-BCR/ABL (M-BCR/ABL) (1.4%), minor-BCR/ABL (m-BCR/ABL) (3.6%), trisomy 9 (4.3%), trisomy 22 (4.3%), trisomy or tetrasomy of both chromosomes 9 and 22 (2.9%), monosomy 9 (1.4%), monosomy 22 (0.7%), ABL gene amplification (1.4%), derivative chromosome 9 deletion (1.4%), and extra copies of the Philadelphia chromosome (1.4%). FISH signal patterns observed in adult ALL cases were as follows; M-BCR/ABL (5.8%), m-BCR/ABL (11.6%), two different cell clones with major and minor BCR/ABL signal pattern (2.9%), extra copies of Philadelphia chromosome (4.3%), derivative chromosome 9 deletion (1.4%), trisomy 9 (2.9%), tetraploidy (1.4%), monosomy 9 (1.4%), trisomy 22 (1.4%), and coexistence of both trisomy 22 and monosomy 9 (1.4%). Trisomy 9, trisomy 22, and polyploidy of chromosomes 9 and 22 were specific atypical FISH signal patterns for childhood B cell acute lymphoblastic leukemia (B-ALL) patients. However, monosomy 9 and ABL gene amplification were highly specific for childhood T cell acute lymphoblastic leukemia (T-ALL) patients. Our report presents the correlation between atypical FISH signal patterns and clinical findings of a large group of ALL cases.