Objective: Therapeutic plasma exchange has been used as a primary or supportive treatment in many diseases in recent years and has achieved satisfactory results in lots of diseases in children. Therapeutic plasma exchange procedure is changing plasma component of a patient's blood with the new plasma as a replacement solution. The aim of this study is to share our experience of therapeutic plasma exchange on varying indications in critically ill children who were accepted to our pediatric intensive care unit. Materials and Methods: We conducted this study between December 2010 and February 2020, retrospectively. Patients’ data such as age, sex, indication, number of sessions, vascular access route, and type of replacement fluid used were obtained from medical records. Indications for therapeutic plasma exchange were classified according to the 2019 American Society for Apheresis categorization. The patient’s follow-up, clinical courses, therapeutic plasma exchange season count, complications, and outcome were evaluated according to each indications and their overall condition. Results: This study included a total of the 84 patients who underwent therapeutic plasma exchange, and their median (minimum-maximum) ages were 7.07 years (0.2-18), 57.1% were male (n = 48) and 42.9% were female (n = 36). A total of 463 sessions of therapeutic plasma exchange were performed in 84 patients. The most common indication was thrombocytopenia-associated multi-organ failure with sepsis (40.4%, n = 34) followed by liver failure/hepatic encephalopathy (28.5%, n = 24) and autoimmune encephalitis (9.5%, n = 8), and according to The American Society for Apheresis 2019 category, patients distributions were as follows: 15.4% of the patients were placed in category 1 (n = 13), 5.9% in category 2 (n = 5), 77.3% in category 3 (n = 65), and 1.1% in category 4 (n = 1). Therapeutic plasma exchange was combined to extracorporeal membrane oxygenation in 10 patients (11.9%) and continuous renal replacement therapies in 39 (46.4%) patients. Finally, the survival rate was 50% in all patients, and the lowest survival rate was 41.5% (n = 27) in category 3 group. Conclusion: Therapeutic plasma exchange is enlarging to varying indications and showing to be more effective on a lot of disorders in children. Also, it is available in pediatric age groups and in different states like combined with other extracorporeal therapies. Cite this article as: Gökcan Öztürk A, Erva Küçük Z, Özcan S, et al. Use of therapeutic plasma exchange in the pediatric intensive care unit. Turk Arch Pediatr. 2022;57(2):186-192.

There are several complications of hematopoietic stem cell transplantation. Without any doubt, most important of these is aGvHD that increases transplant-related mortality. The aim of this study is to investigate whether ST-2 and Reg3α levels measured at an early stage in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation can be individual biomarkers identifying future GvHD and predicting treatment response. From January 2019 to January 2021, 27 patients undergoing hematopoietic stem cell transplantation for primary immunodeficiency or hematopoietic diseases formed the study group. During their follow-up, the patients were classified into two groups as those developing and those not developing aGvHD. Nineteen healthy volunteers from a similar age group who needed their blood samples drawn for other reasons and who did not have any history of chronic disease, infection or medication use formed the control group. Blood samples of patients scheduled to have allogeneic HSCT were obtained before the administration of the preparative regimen, on Day +7 post-transplant and on the day of diagnosis if they developed aGvHD. Serum samples were stored at -20ºC until the day of processing. ST2 and Reg3α levels were measured using the ELISA method. For patients who developed aGvHD (n = 13), ST2 levels obtained before the transplantation, on Day +7 post-transplant and on the day of aGvHD diagnosis (in patients developing GvHD) were significantly higher compared to the healthy Control Group (p-value 0.05). ST2 levels of samples obtained on the days that acute skin and gastrointestinal tract GvHD developed did not differ significantly between these two groups (p-value >0.05). Reg3α levels of the pre-transplant samples, on Day +7 after the transplantation and on the day of aGvHD diagnosis did not show any difference between any of the groups (p-value >0.05). As only two patients died after transplantation, thus correlation of ST2 and Reg3α levels with transplant-related mortality could not be proven. The results of this study suggest that ST2 and Reg3α levels are neither diagnostic nor prognostic or predictive biomarkers of aGvHD, steroid resistance or transplant-related mortality in pediatric patients. This study can be regarded as a pilot study because of the small patient population; more research involving a larger patient population is required.

Cite this article as: Öztürk G, Balaban B, Kendirli T. Is humerus a good choice for intraosseous access during fluid resuscitation in a child with severe septic shock? Turk Arch Pediatr. 2022;57(2):237-238.

Inborn errors of immunity (IEI) are caused by deficiencies or functional abnormalities in the immune system, leading to increased susceptibility to infections, autoimmunity, autoinflammatory diseases, allergies, and/or malignancies. Primary hemophagocytic lymphohistiocytosis (HLH) arises from genetic mutations affecting the function of cytotoxic T lymphocytes and natural killer (NK) cells, while secondary HLH is triggered by infections, malignancies, rheumatologic disorders, or immune deficiencies. Treatment consists of remission induction, control of triggers, maintenance of remission, rescue treatment and HSCT as approach curative steps. The aim of this study is to evaluate the clinical and laboratory features, as well as the outcomes, of primary HLH patients who were diagnosed and treated in a multidisciplinary manner over the past 25 years. From 2000 to 2025, 30 HLH cases with primary HLH/IEI who were diagnosed and treated at the departments of pediatric hematology, immunology and oncology of Ankara University School of Medicine Children Hospital and Bone Marrow Transplantation Unit were included in this study. Of the 30 patients, 18 were boys and 12 were girls. The mean age at the onset of the first symptom was 10 months (range: 0.5-204 months), while the mean age at the time of admission to our center was 12.5 months (range: 1-204 months). Pedigree analysis showed that 21 patients were born to consanguineous parents. All patients had a fever lasting longer than five days, with a mean duration of 13.30±14.05 days (range: 5-60 days). Splenomegaly was detected in 29 patients (96.6%), and hepatomegaly in 25 patients (83%). Anemia was observed in 27 patients (90%), neutropenia in 23 patients (76.6%), and thrombocytopenia in 30 patients (100%). Genetic evaluation was performed in all patients, and a causative gene was identified in 19 out of 30 cases (63%). The most common genetic diagnosis was perforin deficiency (FHLH2), detected in 8 patients (26,6%), followed by UNC13D gene defect (FHLH3) in 4 patients (13,3%). HSCT was performed in 17 patients (56,6%), with 6 receiving transplants from matched related donors (MRD), 4 from matched sibling donors (MSD), 5 from matched unrelated donors (MURD), and 2 from mismatched related donors (MMRD). 13 patients remain alive, with a mean survival of 119.89 months. 17 patients (56.6%) died, primarily from mortality included multi-organ dysfunction syndrome (MODS), acute respiratory distress syndrome (ARDS), HLH reactivation, septic shock, and heart failure. HSCT patients had a significantly longer survival (mean 165.6 months) compared to non-HSCT patients (45.36 months, p <0.01). PICU admission, organ failure, and neurological involvement were identified as adverse prognostic factors, all significantly associated with higher mortality (p < 0.05). Given the increasing recognition of HLH as a possible manifestation of IEIs, comprehensive immunological and genetic evaluations should be pursued without delay in suspected cases. Our findings, in line with national and international cohorts, confirm that HSCT remains the only curative option for familial HLH, and should be performed as early as possible after achieving disease remission. Improving access to early diagnostics and HSCT could significantly enhance outcomes, particularly in genetically predisposed populations.