Adenosine deaminase 2 (ADA2) deficiency is an autosomal recessively inherited autoinflammatory disorder caused by loss-of-function mutations in the ADA2 gene. Although the pathogenesis involves the triggering of a proinflammatory cascade due to increased production of inflammatory cytokines such as tumor necrosis factor (TNF)-α and dysregulation of neutrophil extracellular trap formation resulting from an excess accumulation of extracellular adenosine, the pathogenetic mechanism still needs further clarification due to the broad clinical spectrum. In addition to the initially described vasculitis-related symptoms, hematological, immunological, and autoinflammatory symptoms are now well recognized. The diagnosis is made by demonstration of pathogenic variants of ADA2 with biallelic loss of function and identification of low plasma ADA2 catalytic activity. Currently, TNF-α inhibitors are the treatment of choice for controlling vasculitis manifestations and preventing strokes. However, in patients presenting with severe hematologic findings, TNF-α inhibitors are not the treatment of choice and hematopoietic stem cell transplantation has been shown to be successful in selected cases. Recombinant ADA2 protein and gene therapy are promising treatment modalities for the future. In conclusion, ADA2 deficiency has a broad phenotype and should be considered in the differential diagnosis of different clinical situations. In this review, we summarize the disease manifestations of ADA2 deficiency and available treatment options.

Objective: Primary immune thrombocytopenia (ITP) is an acquired disorder of platelets with a complex and unclear mechanism of increased immune destruction or impaired production of platelets. While the management of ITP is evolving, there is still a need for guidance, particularly in certain circumstances such as pregnancy, emergencies, or patients requiring co-medications. We aimed to determine the tendencies of hematologists in Türkiye in the event of such special considerations.
Materials and Methods: Applying a modified Delphi method, the Turkish National ITP Working Group, founded under the auspices of the Turkish Society of Hematology, developed a questionnaire consisting of statements regarding pregnancy, emergencies, and circumstances requiring co-treatment with antiaggregants or anticoagulants. A total of 107 hematologists working in university or state hospitals voted for their agreement or disagreement with the statements for two sequential rounds.
Results: The participating hematologists reached an agreement on starting treatment for pregnant patients with platelets of less than 30x109/L and delivery either vaginally or by cesarean section being safe at platelet counts above 50x109/L. For emergencies and the rescue management of ITP, the panel agreed against the use of high-dose corticosteroids alone, preferring combinations with transfusions or intravenous immunoglobulin. For patients who require interventions, platelet counts of >50x109/L were regarded as safe for low-risk procedures as well as co-treatment with antiplatelets or anticoagulants.
Conclusion: As the National ITP Study Group, we have observed the need to increase the practice guidance regarding patients with primary ITP requiring additional treatments including invasive interventions and co-treatments for coagulation. Decisions on the management of ITP during pregnancy should be individualized. There is a lack of consensus on the thresholds of platelet counts as well as co-morbidities and co-medications. This lack of consensus may be due to variations in practices.

Objective: The prognostic factors and outcomes of Turkish children with newly diagnosed acute lymphoblastic leukemia (ALL), treated with the Modified St. Jude Total XV Protocol, which was adjusted by adding high-dose methylprednisolone (HDMP) before induction in the original protocol, were assessed in this study.
Materials and Methods: The Modified St. Jude Total XV Protocol was administered to 183 newly diagnosed ALL patients, aged 1-18 years, between 1 January 2008 and 30 January 2016. HDMP was applied at doses of either 10 mg/kg/day (Group A) or 20 mg/kg/day (Group B) for 7 days before induction and then tapered over the next 7 days to 5 or 10 mg/kg/day, and continued at 2 mg/kg/day for 2 weeks during the induction phase. Absolute blast count (ABC) in peripheral blood and minimal residual disease (MRD) in bone marrow were assessed at the end of the initial 7-day HDMP treatment. MRD in the bone marrow was evaluated on day 15 and at the end of the induction period. The follow-up for these patients ended on 15 July 2019.
Results: The 5-year event-free (EFS) and overall survival (OS) rates for all patients were 85.6±2.6% and 89.2±2.3%, respectively. The rate of good response to steroids (defined as ABC in peripheral blood of less than 1000/mm3 on day 7) was 88% and 97% of children achieved complete remission after induction. The survival rate and infection frequency did not show statistically significant differences between Group A and B. EFS and OS correlated with initial leukocyte count, age of 10-18 years at diagnosis, CD20 positivity at diagnosis, and gramnegative bacterial infection during remission induction.
Conclusion: The remarkable response rates on days 7 and 15, along with the promising EFS and OS results in childhood ALL patients treated with the Modified St. Jude Total XV Protocol, highlight the early and substantial response effect of HDMP. At the onset of induction, shortterm HDMP can be initiated, preferably at 10 mg/kg/day for the first 7 days, to minimize potential side effects.

Objective: The survival rates of children with acute lymphoblastic leukemia (ALL) have improved over the years, but infections remain a significant cause of morbidity and mortality. Chemotherapy has a range of harmful side effects including the loss of protective antibodies against vaccine-preventable diseases. The objective of this study was to evaluate the serological status of pediatric ALL cases before and after intensive chemotherapy.
Materials and Methods: Children treated and followed for ALL at Dokuz Eylül University were included in this retrospective crosssectional study. Antibody levels against hepatitis A, hepatitis B, and rubella were routinely assessed at both the time of diagnosis and 6 months after completion of chemotherapy. Measles, mumps, and varicella antibody levels were evaluated at only 6 months after treatment.
Results: Seventy-eight children who completed chemotherapy for ALL were enrolled in the study. All participants had non-protective antibody levels for at least one of the diseases. The highest seropositivity rate was found for hepatitis A (55.1%) and the lowest for measles (17.9%) after chemotherapy. Overall, 50.7%, 30.6%, and 45.7% of the patients significantly lost their humoral immunity against hepatitis B, hepatitis A, and rubella, respectively. Patients in the higher-risk group for ALL had lower seropositivity rates than patients of the other risk groups. There were statistically significant relationships between the protective antibody rates for hepatitis A and varicella and the ages of the patients. Except for hepatitis A vaccination, pre-chemotherapy vaccination did not affect post-chemotherapy serology. On the other hand, all children with a history of varicella before diagnosis showed immunity after chemotherapy.
Conclusion: Patients with ALL, including those previously fully vaccinated, are at great risk of infection due to the decrease in protective antibody levels after chemotherapy. There is a need for routine post-chemotherapy serological testing and re-vaccination based on the results obtained.

Objective: It has been shown that clonal mutations occur in hematopoietic stem cells with advancing age and increase the risk of death due to atherosclerotic vascular diseases, similarly to myeloproliferative neoplasms. Endothelial cells (ECs) and hematopoietic stem cells develop from common stem cells called hemangioblasts in the early embryonic period. However, the presence of hemangioblasts in the postnatal period is controversial. In this study, JAK2 gene variants were examined in patients with atherosclerotic carotid disease and without any hematological malignancies.
Materials and Methods: Ten consecutive patients (8 men and 2 women) with symptomatic atherosclerotic carotid stenosis were included in this study. ECs (CD31+CD45-) were separated from tissue samples taken by carotid endarterectomy. JAK2 variants were examined in ECs, peripheral blood mononuclear cells, and oral epithelial cells of the patients with next-generation sequencing.
Results: The median age of the patients was 74 (range: 58-80) years and the median body mass index value was 24.44 (range: 18.42- 30.85) kg/m2. Smoking history was present in 50%, hypertension in 80%, diabetes in 70%, and ischemic heart disease in 70% of the cases. The JAK2V617F mutation was detected in the peripheral blood mononuclear cells of 3 of the 10 patients, and 2 patients also had the JAK2V617F mutation in their ECs. The JAK2V617F mutation was not found in the oral epithelial cells of any of the patients.
Conclusion: In this study, for the first time in the literature, we showed that the JAK2V617F mutation was found somatically in both peripheral blood cells and ECs in patients with atherosclerosis. This finding may support that ECs and hematopoietic cells originate from a common clone or that somatic mutations can be transmitted to ECs by other mechanisms. Examining the molecular and functional changes caused by the JAK2V617F mutation in ECs may help open a new avenue for treating atherosclerosis.

The Myeloproliferative Neoplasm Symptom Assessment Total Symptom Score (MPN-SAF TSS) is a surrogate marker for symptom evaluation in chronic myeloproliferative neoplasms (MPNs). However, insufficient data are available regarding the relationship among the MPN-SAF TSS, JAK2 mutation allele burden, and thrombosis. In this retrospective analysis, we aimed to determine the genetic burdens, clinical features, and relationships with MPN-SAF TSS in MPN patients. One hundred thirty JAK2V617F-positive patients with MPNs were included in our study. We calculated the MPN-SAF TSS for all patients and compared it with their clinical characteristics. Patients with higher JAK2V617F mutation allele burden had higher MPN-SAF TSS values (p=0.008). Patients with thrombosis had higher MPN-SAF TSS than patients without thrombosis (p=0.003). The mean MPN-SAF TSS was higher in patients with primary myelofibrosis compared to those with polycythemia vera and essential thrombocythemia. Thrombosis was associated with increased symptom severity in several domains, including fatigue, abdominal discomfort, inactivity, night sweats, pruritus, weight loss, and early satiety. Additionally, an increase in JAK2 allele burden was observed with higher symptom scores. The MPNSAF TSS proved to be a reliable tool for assessing symptom burden in Turkish MPN patients. Furthermore, the significant association between thrombosis occurrence and symptom severity suggests that thrombotic events may contribute to symptom development. Notably, increasing JAK2 allele burden was correlated with more severe symptoms, highlighting its potential role in predicting disease burden. This study emphasizes the importance of symptom assessment in MPN patients and supports the incorporation of the MPN-SAF TSS in routine clinical practice to enhance patient care and management.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a widely utilized treatment for various hematological diseases. While selection criteria for unrelated donors are well established, there is a lack of consistency and standardization in the selection of related donors. This study investigated the current approach of hematologists to the selection of related donors at Turkish HSCT centers. The study employed a cross-sectional survey design, distributing a self-administered questionnaire to 95 adult and pediatric transplantation centers in Türkiye to investigate their approaches to related donor selection for allo-HSCT. The questionnaire collected data on various topics including the center’s experience in performing allo-HSCT, patient groups treated, number of allo-HSCT procedures conducted between 2015 and 2021, preferences for related donors, considerations in related donor selection (such as sex and past pregnancies), guidelines utilized for related donor selection, upper age limit for related donors, and the use of specialized advanced analyses for elderly donors. The response rate to the survey was 38.9%. Variability was observed across centers in terms of sex consideration and the impact of past pregnancies on related female donor rejection. Different guidelines were employed for related donor selection, with the European Bone Marrow Transplantation guidelines being the most commonly used. Regarding the upper age limit for related donors, 8.1% of centers accepted an upper age limit of 55 years, 48.7% preferred an upper age limit of 65 years, and 43.2% selected related donors aged 65 and above. The lack of standardized guidelines for related donor selection in HSCT centers leads to variability in criteria and potential risks. Collaboration among centers is essential to establish consensus and develop standardized protocols.