Identification of the molecular etiology in rare congenital hemolytic anemias using next-generation sequencing with exome-based copy number variant analysis.

OBJECTIVES: In congenital hemolytic anemias (CHA), it is not always possible to determine the specific diagnosis by evaluating clinical findings and conventional laboratory tests. The aim of this study is to evaluate the utility of next-generation sequencing (NGS) and clinical-exome-based copy number variant (CNV) analysis in patients with CHA. METHODS: One hundred and forty-three CHA cases from 115 unrelated families referred for molecular analysis were enrolled in the study. Molecular analysis was performed using two different clinical exome panels in 130 patients, and whole-exome sequencing in nine patients. Exome-based CNV calling was incorporated into the traditional single-nucleotide variant and small insertion/deletion analysis pipeline for NGS data in 92 cases. In four patients from the same family, the PK Gypsy variant was investigated using long-range polymerase chain reaction. RESULTS: Molecular diagnosis was established in 86% of the study group. The most frequently mutated genes were SPTB (31.7%) and PKLR (28.5%). CNV analysis of 92 cases revealed that three patients had different sizes of large deletions in the SPTB and six patients had a deletion in the PKLR. CONCLUSIONS: In this study, NGS provided a high molecular diagnostic rate in cases with rare CHA. Analysis of the CNVs contributed to the diagnostic success.

Central nervous system thrombosis in pediatric acute lymphoblastic leukemia in Turkey: A multicenter study.

BACKGROUND: In patients with acute lymphoblastic leukemia (ALL), the risk of thromboembolism increases due to hemostatic changes secondary to the primary disease and due to treatment-related factors. In this multicenter study, we aimed to research the frequency of central nervous system (CNS) thrombosis occurring during treatment, hereditary and acquired risk factors, clinical and laboratory features of patients with thrombosis, treatment approaches, and thrombosis-related mortality and morbidity rates in pediatric ALL patients. PROCEDURE: Pediatric patients who developed CNS thrombosis during ALL treatment from 2010 to 2021 were analyzed retrospectively in 25 different Pediatric Hematology Oncology centers in Türkiye. The demographic characteristics of the patients, symptoms associated with thrombosis, the stage of the leukemia treatment during thrombosis, the anticoagulant therapy applied for thrombosis, and the final status of the patients recorded through electronic medical records were determined. RESULTS: Data from 70 patients with CNS thrombosis during treatment, out of 3968 pediatric patients with ALL, were reviewed. The incidence of CNS thrombosis was 1.8% (venous: 1.5 %; arterial: 0.03%). Among patients with CNS thrombosis, 47 had the event in the first 2 months. Low molecular weight heparin (LMWH) was the most commonly used treatment with a median of 6 months (min-max: 3-28 months). No treatment-related complications occurred. Chronic thrombosis findings occurred in four patients (6%). In five (7%) patients who developed cerebral vein thrombosis, neurological sequelae (epilepsy and neurological deficit) remained. One patient died related to thrombosis, and the mortality rate was 1.4%. CONCLUSION: Cerebral venous thrombosis and, less frequently, cerebral arterial thrombosis may develop in patients with ALL. The incidence of CNS thrombosis is higher during induction therapy than during other courses of treatment. Therefore, patients receiving induction therapy should be monitored carefully for clinical findings suggestive of CNS thrombosis.

Family Knowledge, Attitudes, and Practices Toward Severe Congenital Neutropenia.

Severe congenital neutropenia is a rare disorder. The survival and quality of life of patients radically improved through infection prevention, use of granulocyte colony-stimulating factor, and the appropriate use of antibiotics during infections. The aim of this study was to evaluate the precautions taken by families to prevent infections, the level of knowledge regarding the disease, and the impact of external factors such as education and economic status on behavior and compliance in patients and caregivers in terms of the following treatment protocols. Questionnaires were designed with the aim of determining how the social, cultural, and economic conditions of the families of children with severe congenital neutropenia affected their behavior and knowledge levels. They were completed using one-on-one video interviews with the caregivers. Thirty-one patients from 25 families were enrolled into the study. No correlations between family disease knowledge, parent education levels, working status of the mother, sibling numbers, economic status, ease of hospital access, and/or residential location were found. An increase in disease knowledge of patients and caregivers, as well as proven approaches to living with the disease, would directly correlate to increased life quality and long-term survival rates of patients.

Invasive Fungal Infections in Children With Acute Myeloid Leukemia: A Single-center Experience Over 19 Years.

OBJECTIVE: Invasive fungal infections (IFIs) remain a significant cause of morbidity and mortality in children with acute myeloid leukemia (AML). This study aimed to evaluate the incidence, risk factors, etiology, and outcome of IFIs in children with AML and the effect of mold-active antifungal prophylaxis. MATERIALS AND METHODS: We retrospectively reviewed pediatric patients treated for AML between January 2004 and December 2022. Proven, probable, or possible IFIs were defined using standardized definitions of the European Organization for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) classification published at 2008. RESULTS: A total of 298 febrile neutropenia episodes from 78 patients were evaluated. Proven, probable, and possible IFI rates were 3%, 2.6%, and 9.4%, respectively. Profound neutropenia was detected in 18 (58%) and prolonged neutropenia in 20 (64.5%) of the IFI episodes.. Invasive aspergillosis accounted for the majority of IFI episodes; however, non-albicans Candida spp. were the most isolated pathogens in the proven group. Patients with relapsed AML were particularly at risk for the development of IFI ( P =0.02). A significant decrease in IFI episodes was achieved with mold-active antifungal prophylaxis with voriconazole ( P =0.01, odds ratio: 0.288, %95 CI:0.104-0.797). The overall mortality was 35.8%, and the IFI-attributable mortality rate was 25%. In the multivariate analysis, relapsed disease was the most significant risk factor associated with mortality ( P =0.006, odds ratio:4.745; 95% CI: 1.573-14.316). CONCLUSION: Mold-active prophylaxis reduced the rate of IFIs in this cohort however IFI-related mortality was still high as 25% in pediatric AML patients. Relapsed AML was the most significant risk factor associated with mortality.

Modern management of iron overload in thalassemia major patients guided by MRI techniques: real-world data from a long-term cohort study.

Monitoring liver and cardiac iron stores by magnetic resonance imaging (MRI) enables identifying patients at risk of organ-specific morbidity and better tailoring of iron chelation therapy in thalassemia. Nevertheless, serum ferritin (SF) remains the only tool for monitoring iron status in most resource-poor regions. In this study, we assessed the impact of using MRI techniques to guide iron chelation therapy on iron overload outcomes in a cohort of 99 patients with thalassemia major (TM, mean age at baselines 20.7 ± 6.9 years) followed from 2006 to 2019. We also assessed the ability of SF trends to predict changes in consecutive liver iron concentration (LIC) and cardiac T2* (cT2*) measurements. The most commonly used chelator was deferasirox at baseline (65%) and final (72%) assessments. Overall, patients with safe LIC values (< 7 mg/g dw) increased from 57 to 77%, and safe cT2* values (> 20 ms) increased from 72 to 86%. We obtained the most significant improvement in patients with severe and moderate liver (p = 0.006 and p < 0.001) and cardiac (p < 0.0013 and p < 0.0001) iron overload at baseline. SF trends were in the same direction in 64% of changes in LIC, but only 42% of changes were proportional. Most of the changes in SF (64%) and LIC (61%) could not predict changes in cT2*. Moreover, downward trends in SF and LIC were associated with worsening cardiac iron in 29% and 23.5% of consecutive cT2* measurements. Liver and cardiac MRI-driven oral iron chelation improved the iron status of subjects with TM and demonstrated the importance of using validated MRI techniques in critical clinical decisions.

Is Monitoring of Cytomegalovirus Disease Required in Nontransplant Pediatric Acute Lymphoblastic Leukemia?

INTRODUCTION: Cytomegalovirus (CMV) infections in developing countries are experienced at an early age. This study was performed to investigate the frequency of reactivation and risk factors of infection acquired at an early age of nontransplant acute lymphoblastic leukemia (ALL) patients receiving immunosuppressive therapy with weekly monitoring of CMV levels in Turkey. MATERIALS AND METHODS: This was a retrospective, single-center study of 172 pediatric patients (102 boys and 70 girls) with ALL. All patients were monitored routinely for CMV-DNA at the initial presentation of leukemia and twice a week during chemotherapy. The CMV immunoglobulin (Ig)M/IgG titers were measured at admission. RESULTS: CMV seropositivity at baseline was 90,11%. The overall prevalence of CMV infection (viremia) was 70.34%, 116 of whom were seropositive for CMV IgG and 5 of whom were negative for CMV at the time of ALL diagnosis. Reactivation was more common than de novo CMV infections (P=0.000). CMV seropositivity at the beginning of the leukemia diagnosis was found to be an independent predictor for developing CMV infection (P=0.001). A total of 60 CMV infection episodes were treated with antivirals. Four of these included organ involvement. The duration of CMV-DNA viremia episodes was longer in patients with CMV-DNA ≥1000 copies/mL (n=45) than in those with lower CMV-DNA levels (P=0.002). Infection was shown not to be associated with chemotherapy phase. CONCLUSION: This study suggests the importance of monitoring for CMV infections in developing countries because of frequent reactivations in seropositive ALL patients. It should be kept in mind that low CMV-DNA levels may also lead to organ involvement.

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.

Insulin secretion-sensitivity index-2 could be a novel marker in the identification of the role of pancreatic iron deposition on beta-cell function in thalassemia major.

The purpose of this study is to evaluate the impact of insulin secretion-sensitivity index-2 (ISSI-2) in the identification of the role of pancreatic iron deposition on beta-cell function in thalassemia major. Tissue iron stores were measured with magnetic resonance imaging (MRI) in the liver (R2), pancreas (R2*), and heart (T2*). ISSI-2 was assessed as a novel oral glucose tolerance test-based measure of beta-cell function. Also, the Stumvoll index showing the insulin sensitivity and Stumvoll index estimating first and second phase insulin secretion were calculated. Fourteen of the 51 Thalassemia Major patients, aged 8-34 (mean 21.1 ± 7.2) years-old, had either an impaired glucose tolerance test (n = 9, 17.6%) or diabetes mellitus (n = 5, 9.8%)-referred to as the glucose dysregulation (GD) group. The median serum ferritin and the mean liver R2 and cardiac T2* values were not significantly different between the GD and normal glucose tolerance (NGT, n = 37) groups whereas pancreas R2* was significantly higher in the GD group compared to the NGT group (p = 0.004). Patients with GD showed significantly lower ISSI-2 index (p < 0.001) as well as the Stumvoll index and Stumvoll first and second phase indices compared to those with NGT (p < 0.001). All patients with GD displayed a pancreas R2* >50 Hz and ISSI-2 <2. In conclusion, Pancreas R2* MRI combined with ISSI-2 index may be valuable parameters to identify patients at the highest risk for developing glucose dysregulation.

Quality of Life and Depression in Turkish Patients with ß-Thalassemia Major: A Cross-Sectional Study.

Thalassemias are the most common monogenic disorders worldwide. Thalassemia patients experience difficulties in their schooling, finding jobs and/or marriage because of functional and physical limitations caused by this disease. It is expected that the quality of life (QoL) of patients with thalassemia will be lower than those without this disease. The aim of this study was to benefit worldwide thalassemia patients in terms of QoL and mental health. This cross-sectional study was performed in Turkey. The study population consisted of of 57 ß-thalassemia major (ß-TM) patients and the control group. The short form-36 (SF-36) questionnaire and Beck depression inventory (BDI) were used. The mean age of the patients was 21.6 ± 6.6 (age range 15-39) and the male-to-female ratio was 0.7. The mean SF-36 scores of the patient and the control groups were 59.2 ± 12.4 and 75.7 ± 11.8, and the mean BDI scores of the patients and controls were 13.5 ± 6.4 and 6.1 ± 3.7, respectively. There was a statistically significant difference between the total SF-36 and BDI scores of patients and controls. We aimed to investigate the effects of the decrease in morbidity and mortality of ß-thalassemia (ß-thal) due to regular transfusions and chelation therapy on the QoL and mental health of patients. The ß-TM patients have a comparatively worse QoL score than the normal population. Improving QoL should be the target of clinicians who are monitoring adolescent or young adult ß-TM patients.

A successful desensitization protocol for horse-derived antithymocyte globulin in severe aplastic anemia.

BACKGROUND: Horse antithymocyte globulin (h-ATG) (ATGAM(®) ) is the first choice of treatment in very severe patients with aplastic anemia who do not have any HLA matched sibling donor. h-ATG is a heterologous serum that may cause anaphylaxis. Alternative treatment strategies must be planned in case of hypersensitivity. Desensitization must be considered in patients without an alternative treatment of choice. We aimed to present the h-ATG desensitization protocol and consider its effectiveness in patients with aplastic anemia who are hypersensitized with h-ATG and do not have an alternative treatment of choice. METHODS: Skin prick tests were performed with non-diluted solution in eight very severe patients with aplastic anemia who are followed up in Ege University Children's Hospital. Although skin prick test was found negative in these eight patients, different dilution h-ATG intradermal tests were performed and found positive in all patients. h-ATG desensitization program was started to these hypersensitized patients. RESULTS: Desensitization program was started to six male and two female very severe patients with aplastic anemia whose ages were between seven and 19 yr (median: 12.9 yr). All of the patients completed the desensitization program. While local reaction was seen in two patients, systemic reaction was seen in one patient and late reaction was seen in one patient during and after desensitization program. CONCLUSION: A successful desensitization program with h-ATG in children with aplastic anemia is presented. Even though there is not an exposure before to such high allergy potential heterologous serum, skin tests should be performed and desensitization must be started to patients who are hypersensitized to h-ATG. As the expected effectiveness of the treatment is so much, the desensitization protocol can be carried out safely and effectively with trained stuff although allergic reactions can be seen.

Successful Treatment With Total Skin Electron Beam Therapy in a Child With Isolated Cutaneous Relapsed AML.

A 9-year-old girl diagnosed with acute myeloblastic leukemia M4 developed isolated cutaneous relapse. She was given chemotherapy including idarubicin, fludarabine, and cytarabine. Although she developed very severe pancytopenia, increase in the number and size of the lesions was seen. Total skin electron beam therapy was applied to the skin lesions for a total of 18 Gy. All lesions responded to total skin electron beam therapy, some of them completely disappeared. After resolution of the skin findings, she underwent bone marrow transplantation from her matched brother. Twenty-six months after hematopoietic stem cell transplantation she is alive without any event.

Brain natriuretic peptide: the reason of respiratory distress is heart disease or lung disease?

OBJECTIVES: The aim of this study was to determine whether plasma levels of amino-terminal brain natriuretic peptide (BNP) could differentiate between heart failure and lung disease among infants with acute bronchiolitis. METHODS: Sixty-eight infants (age range, 1-26 months; median age, 5.9 ± 5.0 months) who presented with respiratory distress underwent physical examination, plasma BNP measurement, and echocardiography within 24 hours after admission. Nineteen (28%) patients had congenital heart disease. The control group was consisted of 30 healthy infants. RESULTS: Although mean plasma BNP levels were 118.9 ± 219.5 pg/mL in patients with isolated bronchiolitis (n = 49), it was 841.2 ± 1475.8 pg/mL in patients with congenital heart disease (n = 19). Plasma BNP levels were significantly higher in infants with congenital heart disease (P = .001). CONCLUSION: It was shown that plasma BNP levels were affected much more in cardiac disease rather than lung disease. Among infants with respiratory distress, plasma BNP measurements can differentiate congenital heart disease and lung disease and can be used to monitor the effects of treatment for infants with heart failure. RESPONSE TO REVIEWERS: The comments were taken for consideration. The patient groups control BNP levels were attached to the results. As it was a clinical study and multiple factors (respiratory score, respiratory rate, treatment, etc) may effect on BNP levels, the tables could not be decreased to 1 table.

Proven and probable invasive fungal infections in children with acute lymphoblastic leukaemia: results from an university hospital, 2005-2013.

Despite improvements in diagnosis and treatment, invasive fungal infections (IFIs) are still a major cause of morbidity and mortality in immunocompromised patients. The data on IFI among children with acute lymphoblastic leukaemia (ALL) are still scarce, and our aim was to estimate the risk, aetiology and outcome of proven and probable IFIs in children with ALL who did not receive primary prophylaxis over an 8-year period. Between January 2005 and February 2013, 125 children who were treated for ALL at the Pediatric Hematology Department of the Medical School of Ege University were retrospectively reviewed. Proven and probable IFIs were defined according to revised definitions of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group. The proven and probable IFI incidence was 30/125 (24%). Profound neutropenia was detected in 18 (60%) patients, and prolonged neutropenia was detected in 16 (53.3%) of the patients. The most isolated agents were non-albicans Candida spp. The crude and attributable mortality was 20% and 13.3% respectively. Profound neutropenia was associated with mortality (P < 0.05). The younger patients were especially at risk for proven IFI. Prolonged neutropenia, to be in the induction phase of chemotherapy, and profound neutropenia were found to be the most common predisposing factors for IFI episodes.

Trichosporon asahii, sepsis, and secondary hemophagocytic lymphohistiocytosis in children with hematologic malignancy.

Trichosporon asahii (T. asahii) is an uncommon fungal pathogen rarely seen in patients with hematologic malignancies. Although appropriate therapy is started, infection with T. asahii usually leads to mortality. Here, we describe two patients developed severe T. asahii infection and secondary HLH. Despite rapid identification of T. asahii and negative blood cultures achieved by prompt initiation of treatment with voriconazole, fever and pancytopenia, persisted and both developed hepatosplenomegaly, and their clinical state worsened. Bone marrow aspiraton revealed hemophagocytosis. Elevated ferritin, triglyceride levels were seen. The first patient did not receive HLH directed therapy and died with multiple organ dysfunctions. Prompt diagnosis and treatment of secondary HLH led to rapid improvement in clinical and laboratory abnormalities in the second patient and kept her alive. We suggest that HLH may present as a secondary condition, accompanying a severe infection with T. asahii may, at least in part, contribute to high mortality rates in these cases.

Rabbit antithymocyte globulin treatment in childhood acquired severe aplastic anemia.

Acquired severe aplastic anemia (SAA) is a life threatening bone marrow failure characterized by pancytopenia and hypocellular bone marrow. Matched sibling donor is not available for majority of the patients and many children receive immunosuppressive therapy (IST). Although horse antithymocyte globuline (ATG) is the preferred option, our patients received rabbit ATG; since horse ATG is not available in Turkey. We reviewed the medical records of children with SAA who were treated with rabbit ATG, cyclosporine, and granulocyte colony stimulating factor (GCSF) between 2006 and 2012. Fifteen children with SAA aged between 1.5 and 17 years received rabbit ATG as first line treatment. Only two of them showed partial response and the others did not give any response at 3rd, 6th, and 12th months after the first course of IST. The second course of ATG was given to 8 of the patients; Rabbit ATG at the same dosage was used for 3 of them, and others were given horse ATG. None of the patients responded to the second course of ATG. Invasive fungal infection (IFI) which was seen in 80% of the patients was the most significant problem. Overall survival rate was 60%. The median time between the diagnosis and initiation of IST was 57 (range; 29-144) days. This delay might be significantly contributed to unresponsiveness. In our series, the use of rabbit ATG was not effective for these patients as first line treatment modality. Response rate was very low and the incidence of fungal infections was very high in the SAA patients who received rabbit ATG.

Leukapheresis in childhood acute leukemias: single-center experience.

Hyperleukocytosis in patients with leukemia is associated with early mortality, especially due to the pulmonary and neurological complications of leukostasis. The prompt use of leukapheresis may improve patients' survival in the initial treatment period. The medical records of all previously untreated acute leukemia patients were reviewed to determine whether there was hyperleukocytosis at presentation. This study summarizes a single-center experience of leukapheresis that was applied to 12 children with acute leukemia and hyperleukocytosis. The median leukocyte count at diagnosis was 589,000/mm(3) (range: 389,000-942,000/mm(3)) for ALL patients and 232,000/mm(3) (range: 200,000-282,000/mm(3)) for AML patients. A central venous catheter (CVC) was inserted, and leukapheresis procedures were repeated at 12-hour intervals. A total of 29 leukapheresis cycles were performed on 12 children. The median number of cycles of leukapheresis required by each patient was two (range: 1-4). The median absolute and percentage reductions in white blood cell (WBC) count after the first cycle of leukapheresis were 113,000/mm(3) (range: 55,000-442,000/mm(3)) and 36% (range: 16-57.4%), respectively. As a laboratory finding, mild hypocalcemia was the most frequently observed complication. No patients developed any other problem related to the procedure. Our results showed that leukapheresis is a safe and effective procedure if performed by experienced staff.

Primary Mold-Active Antifungal Prophylaxis Decreases the Need for Chest Computed Tomography Scans in Patients with Acute Lymphoblastic Leukemia.

Current guidelines recommend computed tomography (cCT) scans of the chest in children with leukemia following 96 h of the onset of idiopathic neutropenia to eliminate pulmonary invasive fungal infections (IFIs). However, cCT exposes some children who are at a very high risk of developing secondary cancers to radiation. We aimed to determine the effect of antifungal prophylaxis (AFP) with voriconazole (VCZ) on the need for cCT scans in children with acute lymphoblastic leukemia (ALL) to eliminate pulmonary IFIs during chemotherapy. We retrospectively screened all patients' data from their electronic charts. Children who were diagnosed as having ALL before February 2013 and did (AFP group) or did not (NoP group) receive AFP were divided into two groups and compared regarding cCT scans and relapse-mortality rates. Ninety-six children were diagnosed before February 2013 and did not receive primary AFP and 146 children were administered VCZ following a diagnosis of ALL. There were no significant demographic differences between the groups. A total of 128 cCTs had been required in 62 children in the NoP group, compared with 64 cCTs in 52 children in the AFP group. The percentage of the patients who had required at least one chest CT scan and the mean number of cCT scans in the NoP group were significantly higher compared with the AFP group. Proven-probable IFIs and relapse-mortality rates were higher in the NoP group compared with the AFP group. Mold-active AFP revealed a significant decrease in the need for cCT scans in children with ALL.

Therapeutic plasma exchange in critically ill children: A single center experience.

INTRODUCTION: Therapeutic plasma exchange (TPE) is used in a wide spectrum of diseases in critically ill pediatric patients. We aim to review the indications, complications, safety, and outcomes of critically ill children who received TPE. METHODS: All of the TPE procedures performed in a pediatric intensive care unit providing tertiary care during 19 years (January 2013-January 2023) were evaluated retrospectively. A total of 154 patients underwent 486 TPE sessions. RESULTS: Median age was 6 years (2-12.5) and 35 children had a body weight of <10 kg (22.7%). Number of organ failure was 4 (2-6). Liver diseases were the most common indication for TPE (31.2%) followed by sepsis with multiorgan dysfunction syndrome (27.3%). Overall survival rate was 72.7%. The highest mortality was observed in hemophagocytic lymphohistiocytosis group. Non-survivors had significantly higher number of organ failure (p < 0.001), higher PRISM score (p < 0.001), and higher PELOD score on admission (p < 0.001). Adverse events were observed in 68 (13.9%) sessions. Hypotension (7.8%) and hypocalcemia (5.1%) were the most frequent adverse events. CONCLUSION: TPE is safe for critically ill pediatric patients with experienced staff. Survival rate may vary depending on the underlying disease. Survival decreases with the increase in the number of failed organs.