Outcomes of HLA-mismatched HSCT with TCRαß/CD19 depletion or post-HSCT cyclophosphamide for inborn errors of immunity.

ABSTRACT: HLA-mismatched transplants with either in vitro depletion of CD3+ T-cell receptor (TCR)αß/CD19 (TCRαß) cells or in vivo T-cell depletion using posttransplant cyclophosphamide (PTCY) have been increasingly used for patients with inborn errors of immunity (IEIs). We performed a retrospective multicenter study via the EBMT registry on 306 children with IEIs undergoing their first transplant between 2010 and 2019 from an HLA-mismatched donor using TCRαß (n = 167) or PTCY (n = 139). The median age for hematopoietic stem cell transplantation (HSCT) was 1.2 years (range, 0.03-19.6 years). The 3-year overall survival (OS) was 78% (95% confidence interval (CI), 71-84) after TCRαß and 66% (57-74) after PTCY (P = .013). Pre-HSCT morbidity score (hazard ratio [HR], 2.27; 1.07-4.80, P = .032) and non-busulfan/treosulfan conditioning (HR, 3.12; 1.98-4.92, P < .001) were the only independent predictors of unfavorable OS. The 3-year event-free survival (EFS) was 58% (50%-66%) after TCRαß and 57% (48%-66%) after PTCY (P = .804). The cumulative incidence of severe acute graft-versus-host disease (GvHD) was higher after PTCY (15%, 9%-21%) than TCRαß (6%, 2%-9%, P = .007), with no difference in chronic GvHD (PTCY, 11%, 6%-17%; TCRαß, 7%, 3%-11%, P = .173). The 3-year GvHD-free EFS was 53% (44%-61%) after TCRαß and 41% (32%-50%) after PTCY (P = .080). PTCY had significantly higher rates of veno-occlusive disease (14.4% vs TCRαß 4.9%, P = .009), acute kidney injury (12.7% vs 4.6%, P = .032), and pulmonary complications (38.2% vs 24.1%, P = .017). Adenoviremia (18.3% vs PTCY 8.0%, P = .015), primary graft failure (10% vs 5%, P = .048), and second HSCT (17.4% vs 7.9%, P = .023) were significantly higher in TCRαß. In conclusion, this study demonstrates that both approaches are suitable options in patients with IEIs, although they are characterized by different advantages and outcomes.

Epidemiologic and microbiologic evaluation of catheter-line bloodstream infection in a pediatric hematopoietic stem cell transplant center.

BACKGROUND: Children who underwent hematopoietic stem cell transplant (HSCT) transplants are at high risk of developing central-line-associated bloodstream infections (CLABSIs). The present study aimed to identify possible risk factors for mortality by analyzing the clinical and laboratory characteristics of patients diagnosed with CLABSI in our pediatric hematopoietic stem cell transplant unit. METHODS: The initial CLABSI episodes of 102 children were analyzed. Medical records of the patients were evaluated by preformed standardized surveys. Univariate analysis and multivariate logistic regression analysis were performed to identify risk factors for mortality. RESULTS: Thirty-five patients (34.3%) were female. The median age was 48 months (3-204). The median time to onset of CLABSI was 19 days (4-150). The gram-negative and gram-positive bacteria ratio among the causative agents was 57.8% to 34.3%. The mortality rate was 12.6%. The presence of severe neutropenia, initiation of inappropriate empirical antibiotic therapy, the presence of hypotension, persistent bacteremia, pediatric intensive care unit admission, growth of carbapenemase-positive gram-negative microorganism and multidrug-resistant bacteria were significantly high in the mortality group when compared to survivors. The presence of hypotension, inappropriate empirical antibiotic therapy, and persistent bacteremia were found to be independent risk factors for mortality. CONCLUSIONS: Rational use of antibiotics, active surveillance and screening of patients together with improved infection control practices may reduce the incidence and the consequences of CLABSIs.

Neurologic Status of Patients with Purine Nucleoside Phosphorylase Deficiency Before and After Hematopoetic Stem Cell Transplantation.

BACKGROUND: Purine nucleoside phosphorylase (PNP) deficiency is a rare autosomal recessive combined immunodeficiency. The phenotype is profound T cell deficiency with variable B and NK cell functions and results in recurrent and persistent infections that typically begin in the first year of life. Neurologic findings occur in approximately two-thirds of patients. The mechanism of neurologic abnormalities is unclear. Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for PNP deficiency. METHODS: We report here six patients from five unrelated families with PNP deficiency treated in two centers in Turkey. We evaluated the neurological status of patients and compared to post-transplantation period if available. Then, we performed PubMed, Google Scholar, and Researchgate searches using the terms "PNP" and "hematopoietic stem cell transplantation" to find all reported cases of PNP transplantation and compared to our cohort. RESULTS: Six patients were treated in two centers in Turkey. One patient died from post-transplant complications. The other four patients underwent successful HSCT with good immune reconstitution after transplantation (follow-up 21-48 months) and good neurological outcomes. The other patient with a new mutation is still waiting for a matching HLA donor. DISCUSSION: In PNP deficiency, clinical manifestations are variable, and this disease should be considered in the presence of many different clinical findings. Despite the comorbidities that occurred before transplantation, HSCT currently appears to be the only treatment option for this disease. HSCT not only cures immunologic disorders, but probably also improves or at least stabilizes the neurologic status of patients.

The impact of Treosulfan-based conditioning for inborn errors of immunity: Is dose monitoring crucial?

INTRODUCTION: In children with inborn errors of immunity (IEI) who will receive a hematopoietic stem cell transplant (HSCT) treosulfan-based conditioning is currently preferred. The aim of this study was to investigate early and late outcomes in pediatric IEI patients receiving pre-HSCT treosulfan and to examine the effect of treosulfan dose monitoring on outcomes. METHODS: Seventy-three pediatric patients receiving this management between 2015 and 2022 were included. RESULTS: Overall survival rate was 80%, and event-free survival was 67.8%. A larger treosulfan dose AUC after first application increased the rate of early toxicity (p = .034) and slowed lymphocyte engraftment (r = .290; p = .030). Underlying disease, treosulfan AUC, donor type, stem cell type, number of immunosuppressive agents, the dose of anti-thymocyte globulin, and post-transplantation cyclophosphamide did not to increase risk of acute graft-versus-host disease. The risk of mixed chimerism (MC) in patients with autoimmune lymphoproliferative syndrome and leukocyte adhesion deficiency were higher than those with severe combined immunodeficiency (p = .021 and p = .014, respectively). The risk of MC was lower in those receiving peripheral blood stem cells (SC) compared with bone marrow derived SC (OR = .204, p = .022). CONCLUSION: The AUC of the treosulfan dose was not associated with poorer late outcomes. Treosulfan is an agent that can be used safely in the IEI patient group,  level measurement appears essential to identify early toxicities. Prospective studies with more extended follow-up periods are needed.

Hepatocellular Carcinoma in ADA-SCID Patient After Hematopoietic Stem Cell Transplantation.

Adenosine deaminase (ADA) deficiency is one of the most prevalent forms of severe combined immunodeficiency and results in the accumulation of toxic substrates which creates a systemic metabolic disease. It predisposes patients to the development of malignancies, most commonly lymphoma. We report an 8-month-old infant with ADA deficient severe combined immunodeficiency who developed progressive liver dysfunction and hepatocellular carcinoma after successful hematopoietic stem cell transplantation. This is the first case report of an ADA-deficient patient who presented with hepatocellular carcinoma and gives an insight into the complex etiology that can lie behind liver dysfunction in these patients.

Tandem high-dose chemotherapy followed by autologous stem cell transplantation: An infant with trilateral retinoblastoma.

BACKGROUND: Retinoblastoma (RB) is the most common intraocular malignancy in childhood. Advanced RB, associated with exceedingly poor prognosis, requires more intensive multiagent chemotherapy than conventional regimens. Rescue of the bone marrow after intensive chemotherapy is achieved with stem cell transplantation. The sequential courses (tandem transplantation) of high-dose chemotherapy followed by autologous stem cell transplantation allow for even greater dose intensity in consolidation with the potential to use different active chemotherapeutics at each transplant and have proven feasible and successful in treating children with recurrent/refractory solid tumors. CASE DESCRIPTION: We report an infant with trilateral high-risk RB who received tandem high-dose chemotherapy (HDC) followed by autologous stem cell transplantation after the conventional chemotherapy. A 5-month-old female patient presented with strabismus, and the ophthalmoscopic examination showed intraocular tumoral lesions in both eyes. Magnetic resonance imaging (MRI) concluded the trilateral retinoblastoma diagnosis due to a tumoral mass in the optic chiasm. The follow-up ophthalmologic examinations and the MRI detected stable disease after six cycles of multiagent chemotherapy. CONCLUSIONS: Rescue with autologous stem cell transplantation after HDC allows for an increase in chemotherapy intensity. Tandem transplantation provides the chance to perform different chemotherapeutics at each transplant and enables an increase in the chemotherapy intensity, thus providing a positive effect on disease-free survival.

A comparison of hypersensitivity reactions between intravenous and intramuscular applications of native E. coli asparaginase in children with acute lymphoblastic leukemia.

INTRODUCTION: Asparaginase is an indispensable drug in treating childhood acute lymphoblastic leukemia (ALL). Hypersensitivity reactions (HSR) are the most common side effects and interfere with the antineoplastic activity of the drug. This study aims to compare the intramuscular (IM) and intravenous (IV) administration routes of Native Escherichia coli Lasparaginase (L-ASNase) in terms of hypersensitive reactions. METHODS: L-ASNase was randomly administered IV or IM to newly diagnosed ALL patients and HSR was monitored in all patients for 1 h following the end of the IV infusion and for 2 h following the end of the IM administration of L-ASNase. Based on a retrospective review of clinical charts, reactions were identified. In order to determine the severity of each allergic reaction, we used the Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 for allergic reactions. RESULTS: A total of 1032 doses of L-ASNase were administered to 85 patients (42 males and 43 females) during the study period. Among 85 patients, 30 reactions were recorded, which means that 35% of the patients reacted. According to the CTCAE, twenty-nine out of 30 reactions (97%) were grade 2, while one (3%) was grade 4. In terms of individual doses, there was a non-significant trend toward increased incidence of reactions with IV administration (3.8% versus 0.9%, p = 0.064). The rate of reactions was higher in patients who received all IV doses (n: 60) as compared to those who received all IM doses (n: 25) (31.7% vs. 3.5%; chi-square= 8.415, p value=0.04). Based on the risk groups and HSR incidence, it was found that high risk group (HRG) patients were significantly more likely to develop HSR compared to the standart risk group (SRG) and intermediate risk group (MRG) patients (chi-square p = 0.003, CI: 95%; odds ratio: 3.12 and 5.91, respectively). CONCLUSIONS: In conclusion, IM administration of L-ASNase causes significantly less HSR to L-ASNase than the IV route. Patients with HRGALL have a higher risk of HSR. Since L-ASNase is still used in many developing countries and there are problems in the supply of Erwinia chrysanthemi ASNase (Erwinia), LASNase can be administered IM to reduce the frequency of HSR.

Evaluation of the risk factors for BK virus-associated hemorrhagic cystitis in pediatric bone marrow transplantation patients: Does post-transplantation cyclophosphamide increase the frequency?

BACKGROUND: BKV-HC is one of the most significant complications of HSCT. This retrospective study aimed to determine the frequency of BKV-HC in pediatric patients undergoing HSCT, detect the associated risk factors for the development of BKV-HC, and explore the effects of post-transplantation Cy use. METHODS: Three hundred twenty-seven patients (girls: 121, boys: 206) were analyzed according to sex, conditioning regimen, transplantation type, donor relatedness, stem cell source, the presence and grade of aGVHD, CMV co-existence, and Cy use. RESULTS: Multivariate analysis confirmed the prognostic importance of age (OR: 4.865), TBI use, the presence of aGVHD (OR: 2.794), CMV coinfection (OR: 2.261), and Cy use (OR: 27.353). A statistically significant difference was found between the mean BKV-HC follow-up times compared with post-transplantation Cy intake (p < .001). The BKV-HC rate increased as the number of risk factors of the patient increased. CONCLUSION: BKV-HC is an essential complication of HSCT primarily associated with Cy use, the presence of aGVHD, and donor relatedness. The present study shows that the use of Cy in the post-transplantation period further increases BKV-HC risk in pediatric patients, regardless of dose.

The effect of biofilm inhibitor N-acetylcysteine on the minimum inhibitory concentration of antibiotics used in Gram-negative bacteria in the biofilm developed on catheters.

The study determined the effect of N-acetylcysteine (NAC) on the susceptibility of various antibiotics used to treat Gram-negative catheter-related infection in isolates obtained from pediatric patients admitted to the hematology and oncology department of Medical Park Bahçelievler hospital in Istanbul, Turkey. Biofilms were created in vitro utilizing clinical isolates of Escherichia coli, Pseudomonas aeruginosa, Pseudomonas putida, and Proteus mirabilis. 24 h old biofilms were developed on 96-well plate with strains and the minimum biofilm inhibitory concentration (MBIC) of six antibiotics were measured before and after the addition of 75 mg/ml N-acetylcysteine with microplate reader at 450 nm after crystal violet assay. The addition of NAC reduce the MBIC of cefepime, ceftazidime, colistin, meropenem from (16, 16, 8, 4 µg/ml) to (8, 4, 4, 2 µg/ml) respectively in E. coli (isolate 1). In P. aeruginosa (isolate 4), the MBIC of amikacin, ceftazidime, meropenem (64, 32, and 32 µg/ml) reduced to (8, 1, and 0.5 µg/ml) respectively. MBIC of cefepime, colistin, meropenem (32, 16,and 16 µg/ml) reduced to (2, 2,and 0.5 µg/ml) respectively in P. putida (isolate 5). In P. mirabilis (isolate 6), MBIC of amikacin, cefepime, ceftazidime, colisitin and meropenem (64, 128, 32, 4, and 32 µg/ml) reduced to (8, 8, 1, 1, 4 µg/ml). NAC in combination therapy can practically reduce the MBIC of antibiotics used to treat Gram negative bacteria that develop biofilm in medical catheters. As a result, these combinations can be considered as an essential alternative for increasing the antibiotic susceptibility of pathogenic microorganisms and thus increasing treatment success rates.

Safety and efficacy of deferasirox in patients with transfusion-dependent thalassemia: A 4-year single-center experience.

This study was organized to determine the efficacy and safety of deferasirox (DFX) in reducing the SF of patients with transfusion-dependent thalassemia (TDT). This is a retrospective, descriptive study of 101 transfusion- dependent patients with thalassemia major who were followed for 48 months. Twenty-nine patients who used an alternative chelator either alone or combined, who were not compliant to the treatment, changed the drug due to adverse reactions, and had multiple transfusions and did not complete 4 years of DFX use were excluded. A total 72 out of 101 patients completed the study. SF decreases were noted for the 6-12 and >18-year age groups, from a median of 1532 ng/mL to 1190 ng/mL, and from 1386 ng/mL to 1165 ng/mL, respectively (p > 0.05). The proportion of patients with SF concentrations >2000 ng/mL is decreased (29% at baseline decreased to 15% at the end of the study) during the 48 months. The median SF of those who used <30 mg/kg/day (n = 38) increased from 767 ng/mL to 1006 ng/mL, whereas the >30 mg/kg/day (n = 34) group's SF concentrations decreased from a median of 1575 ng/mL to 1209 ng/mL (p = 0.029). The decrease of median SF values for Syrian patients was statistically significant (p = 0.043). Most common adverse events were gastric irritation symptoms (19.4%). The total DFX discontinuation ratio was calculated as 9.7%. Although dosages between 25-30 mg/kg/day are adequate to stabilize SF concentrations higher dosages are needed to achieve a statistically significant decrease.

Burkitt Leukemia With Precursor B-Cell Immunophenotype and Dual Translocation of t(14;18) and t(8;14) in a Child: Case Report and Review of the Literature.

BACKGROUND: Burkitt leukemia (BL) with the precursor B-cell immunophenotype is a rarely reported condition. The prognosis of such patients is similar to that of classic BL. However, the combination of chromosomal translocations associated with bcl-2 and c-myc rearrangement has a poor prognosis. OBSERVATIONS: An 11-year-old child presented with fever and weakness. Bone marrow aspiration showed morphologically L1 type blasts and flow cytometry analysis was compatible with precursor B-cell immunophenotype. Cytogenetic analysis revealed a combination of t(8;14) and t(14;l8). CONCLUSIONS: The combination of t(8;14) and t(14;l8) can exhibit different immunophenotypical and morphologic features in leukemias.

Thiol Disulfide Homeostasis and Ischemia-modified Albumin Level in Children With Beta-Thalassemia.

OBJECTIVE: It is well known that increased oxidative stress leads to tissue damage in beta-thalassemia (ß-thal) patients. Thiols are one of the most important antioxidant agents, and thiol/disulfide (SH/SS) homeostasis is a novel oxidative stress marker. This study aimed to investigate the relationship of thiol levels, SH/SS homeostasis, and ischemia-modified albumin (IMA) in patients with ß-thal. MATERIALS AND METHODS: A hundred transfusion-dependent ß-thal patients and 41 healthy controls were included in the study. RESULTS: Native thiol, total thiol, disulfide, catalase, and IMA levels were significantly higher in the ß-thal group compared with the control group (P<0.02). There were no correlation between serum ferritin level and SH/SS homeostasis, and weak positive correlations were found between serum ferritin and IMA (r=0.242, P=0.022). CONCLUSIONS: Our study results suggest that antioxidant systems try to compensate for peroxidative damage in the patients' group and serum IMA level was found increased because of increased oxidative status. To the best of our knowledge, there has been no report evaluating plasma dynamic SH/SS homeostasis in ß-thal patients.

Causes of Hypochromic Microcytic Anemia in Children and Evaluation of Laboratory Parameters in the Differentiation.

Most common causes of microcytic anemia in children are iron deficiency anemia (IDA) and thalassemia. Differentiation of these and detection of coexistence is essential for genetic counseling and to set a treatment plan. Aim is to characterize the frequency of IDA and thalassemia trait (TT) in children presenting with hypochromic, microcytic anemia and to define the significance of blood count parameters in differential diagnosis. Of the 200 enrolled, 107 were male (53.5%). In total 154 had IDA (77%), 27 had ß-TT (13.5%), and in 11 (5.5%) both conditions coexisted. Eight patients had α-thalassemia gene mutations, 3 of these also had IDA. RBC, MCV, Mentzer index, serum iron, TIBC, ferritin were significantly different between IDA and ß-TT patients (P<0.001); however, RDW was not different between the 2 groups (P>0.05). Sensitivity and specificity of Mentzer index for the detection of ß-TT were 100% and 69.4%, respectively. The positive and negative predictive values of Mentzer index in diagnosing ß-TT were 36.6% and 100%, respectively. Differential diagnosis of microcytic anemia is important in children, especially in regions where IDA and thalassemia are both prevalent. We found that 7% of children referred to our clinic for hypochromic, microcytic anemia had both TT and IDA. Our data showed that serum iron, ferritin, TIBC, MCV, and Mentzer index were all valuable markers in diagnosing IDA and were significantly different compared with ß-TT patients; RDW was not different between the 2 groups.

Congenital Factor Deficiencies in Children: A Report of a Single-Center Experience.

Congenital factor deficiencies (CFDs) refer to inherited deficiency of coagulation factors in the blood. A total of 481 patients with CFDs, who were diagnosed and followed at our Pediatric Hematology and Oncology Clinic between 1990 and 2015, were retrospectively evaluated. Of the 481 cases, 134 (27.8%) were hemophilia A, 38 (7.9%) were hemophilia B, 57 (11.8%) were von Willebrand disease (vWD), and 252 (52.3%) were rare bleeding disorders (RBDs). The median age of the patients at the time of diagnosis and at the time of the study was 4.1 years (range: 2 months to 20.4 years) and 13.4 years (range: 7 months to 31.3 years), respectively. The median duration of the follow-up time was 6.8 years (range: 2.5 months to 24.8 years). One hundred nineteen (47.2%) of 252 patients with RBDs were asymptomatic, 49 (41.1%) of whom diagnosed by family histories, 65 (54.6%) through preoperative laboratory studies, and 5 (4.2%) after prolonged bleeding during surgeries. Consanguinity rate for the RBDs was 47.2%. Prophylactic treatment was initiated in 80 patients, 58 of whom were hemophilia A, 7 were hemophilia B, 13 were RBDs, and 2 were vWD. Significant advances have been achieved during the past 2 decades in the treatment of patients with CFDs, particularly in patients with hemophilias. The rarity and clinical heterogeneity of RBDs lead to significant diagnostic challenges and improper management. In this regard, multinational collaborative efforts are needed with the hope that can improve the management of patients with RBDs.