Objective: Sickle cell disease (SCD) is a well-recognized cause of osteonecrosis of the femoral head, and total hip arthroplasty (THA) in these patients is associated with higher complication rates. Because SCD is rare in the general population, large-scale studies are limited. This study aimed to evaluate complications and mortality after THA in patients with SCD.
Materials and Methods: Data from the national e-health database of Türkiye (e-Nabız) were used to identify 138 patients with SCD who underwent primary THA between 2016 and 2022. These patients were matched by age, sex, and Charlson Comorbidity Index score with 552 non-SCD patients. The groups were compared for 90-day medical and surgical complications, hospital stay, and mortality.
Results: Venous thromboembolism and pneumonia were more frequent in SCD patients (p=0.028 and p=0.005, respectively). The need for blood transfusion was significantly higher in the SCD group (p<0.001). No significant differences were observed in mortality at 7 days or 1, 3, or 12 months (p>0.05 for all). Similarly, there were no differences in 90-day mechanical or infectious complications (p=0.68 and p=0.57). The overall 90-day medical complication rate was higher in the SCD group (13% vs. 6%; p=0.005). The mean duration of hospital stay did not differ between the groups (p=0.35).
Conclusion: Patients with SCD who underwent THA had higher rates of venous thromboembolism, pneumonia, and increased transfusion requirements. Preoperative optimization and multidisciplinary perioperative care are essential to reduce these complications.

Objective: Allogeneic hematopoietic cell transplantation (allo-HCT) remains a curative option for relapsed or refractory (R/R) Hodgkin lymphoma despite advances with novel therapeutic agents such as brentuximab vedotin (BV) and immune checkpoint inhibitors (CPIs). This study aimed to assess the benefit of prior exposure to novel therapeutic agents prior to allo-HCT in patients with R/R Hodgkin lymphoma.
Materials and Methods: This study’s retrospective multicentric analysis involved 70 patients with R/R classical Hodgkin lymphoma who underwent allo-HCT.
Results: The analyzed patients were split into two main treatment cohorts: Era 1 (2004-2010) included 16 patients, while Era 2 (2011-2021) included 54 patients. Within the total patient cohort, 63 patients had previously received autologous stem cell transplantation. Forty patients were administered only BV (n=29) or BV preceding CPI (n=11) before allo-HCT. A median follow-up duration of 64 months (range: 40.7-87.3) revealed a 100-day non-relapse mortality (NRM) rate of 26%, with 3-year overall survival (OS) and progression-free survival (PFS) rates of 39% and 28%, respectively. Allo-HCT with haplotype-matched donors was linked to better OS and PFS. Post-transplant cyclophosphamide as a prophylactic approach for graft-versus-host disease significantly improved OS and PFS. A complete response during the post-transplant period significantly improved OS and PFS. Better OS, better PFS, and reduced NRM were observed both before and after allo-HCT in patients receiving BV and CPIs, although statistical significance was not reached. The OS and PFS curves and the NRM rates were similar between Era 1 and Era 2.
Conclusion: Allo-HCT is a potentially practical therapeutic approach for the treatment of patients with R/R Hodgkin lymphoma.

Objective: Febrile neutropenia (FN) in pediatric oncology is a clinically heterogeneous syndrome in which early antibiotic escalation decisions are frequently driven by non-specific severity cues. We aimed to identify baseline clinical phenotypes of pediatric FN, to describe early glycopeptide escalation patterns across these phenotypes, and to examine their associations with short-term outcomes and acute kidney injury (AKI).
Materials and Methods: We conducted a retrospective cohort study including 106 FN episodes experienced by 82 pediatric oncology patients initially treated with piperacillin-tazobactam monotherapy. Baseline clinical and laboratory variables available within the first 6 hours of FN onset were used for unsupervised k-means clustering to derive latent clinical phenotypes. Early glycopeptide escalation was defined as the initiation of vancomycin or teicoplanin within 48 hours. Associations with clinical outcomes on day 7 and AKI were evaluated using multivariable cluster-robust regression and inverse probability of treatment weighting.
Results: Three distinct FN phenotypes were identified: a high-inflammatory/mucositis-dominant phenotype (39.6%), a hemodynamically severe phenotype (22.6%), and a lower-severity phenotype (37.7%). Early glycopeptide escalation occurred in 26.4% of episodes and was disproportionately concentrated in the high-inflammatory and hemodynamically severe phenotypes. AKI developed in 10.4% of FN episodes and clustered predominantly within escalation-prone phenotypes. After adjustment, early escalation was not associated with improved day-7 clinical success but was associated with a higher observed risk of AKI.
Conclusion: Pediatric FN comprises distinct clinical phenotypes that differentially drive antibiotic escalation behavior and renal injury risk. A phenotype-informed approach may help to optimize escalation decisions and potentially reduce preventable toxicity. However, given the observational design of this study, these associations should be interpreted with caution.

Objective: Posttransplant lymphoproliferative disorder (PTLD) is a rare yet potentially life-threatening complication following allogeneic hematopoietic stem cell transplantation (HSCT). This study aimed to determine the incidence, clinical features, management strategies, and prognostic factors influencing outcomes of PTLD after allogeneic HSCT in children.
Materials and Methods: Data were retrospectively collected from 15 pediatric centers performing allogeneic HSCT between June 2010 and May 2025. Clinical features, treatment approaches, and outcomes of the cases were analyzed.
Results: During the study period, 6129 children underwent allogeneic HSCT and 34 (0.56%) developed PTLD. The median interval between HSCT and PTLD diagnosis was 197 days, with the majority of cases occurring within the first posttransplant year. At diagnosis, gastrointestinal involvement was observed in 22 patients (64.7%), cytopenia in 17 (50%), central nervous system (CNS) involvement in 7 (20.5%), pulmonary involvement in 6 (17.6%), and macrophage activation syndrome in 4 (11.7%). Rituximab-based therapy was administered to 29 patients (85.3%) and immunosuppression was reduced in 25 (73.5%). Mortality was significantly higher among patients presenting with CNS involvement (4 of 7, 57.1%; p<0.05). Treatment response also affected the prognosis; among 27 patients who achieved remission, 25 survived (92.6%) compared to only 1 of 7 (14.3%) non-responders (p<0.05). The overall PTLD-related mortality rate was 17.6% (6 patients). Median follow-up among survivors was 43 months, with a 5-year overall survival (OS) rate of 76.5%.
Conclusion: PTLD occurred infrequently among pediatric allogeneic HSCT recipients. CNS involvement and failure to achieve remission were strongly associated with poorer OS.

Objective: Myelodysplastic syndrome (MDS) constitutes a group of clonal hematopoietic disorders in which flow cytometry plays a limited yet evolving role in diagnosis. Recent studies have identified the CD36 coefficient of variation (CV) as a potential marker of dyserythropoiesis. This study aimed to validate the diagnostic utility of the CD36 CV in a local cohort, establish control-based cut-off values, and assess the added value of the CD36 CV when integrated into the Ogata score for improved detection of lower-risk MDS.
Materials and Methods: In this retrospective study, 82 patients who underwent bone marrow aspiration for unexplained cytopenia were analyzed using multiparametric flow cytometry, cytogenetics, and morphological assessment. CD36 CV values were obtained from erythroid precursors and diagnostic thresholds were determined based on the distribution of values in the control group. Diagnostic models included CD36 CV alone, a combined binary model with the Ogata score, and an expanded five-point scoring system.
Results: CD36 CV values were numerically higher in patients with MDS (mean: 75.81) compared to the control group (mean: 65.84), although the difference was not statistically significant (p=0.099). For low-risk MDS, the 75th percentage cut-off yielded 60% sensitivity and 80% specificity. Integration of the CD36 CV into the Ogata score improved specificity from 33.3% to 80% at a ≥3-point threshold, with an area under the curve of 0.754 (p=0.003). Models with higher cut-off values demonstrated lower sensitivity.
Conclusion: Incorporating the CD36 CV into flow cytometric evaluation enhances diagnostic specificity for lower-risk MDS without requiring additional antibody panels. This locally validated marker may improve diagnostic accuracy when combined with myelomonocytic immunophenotyping. Standardization across institutions remains necessary for broader applicability.

Objective: Hydroxyurea (HU) reduces complications of sickle cell anemia (SCA), but the response is variable. L-glutamine, an antioxidant that improves redox balance, is implicated in a distinct pathophysiological pathway and may provide additional clinical benefit when added to HU. We evaluated HU plus L-glutamine versus HU alone in pediatric/ adolescent SCA.
Materials and Methods: In a 6-month, double-blind, placebocontrolled trial, 53 patients with HbSS or HbS/β0-thalassemia were randomized to the HU + L-glutamine (n=27) or the HU + placebo (n=26) group while continuing HU at ~20 mg/kg/day. The primary endpoint was vaso-occlusive crisis (VOC) frequency; secondary endpoints included acute chest syndrome (ACS), hospitalizations, and hematological parameters. Analyses were performed for intention-totreat with baseline-adjusted models for key outcomes.
Results: Over 6 months, the HU + L-glutamine group experienced significantly fewer VOCs (1.00±0.73 vs. 1.65±0.80; p=0.003) and ACS episodes (0.19 vs. 0.77; p=0.006). Hospitalizations declined by 40% (p=0.04). Hemoglobin (Hb) rose more in the combination arm (+0.78 vs. +0.32 g/dL; p=0.028), with larger reductions in reticulocytes (p=0.04) and greater fetal Hb increases (+6.2% vs. +1.6%; p<0.001). Adherence exceeded 80% in both arms and no serious adverse events occurred.
Conclusion: Adding L-glutamine to HU significantly reduced VOCs, ACS, and hospitalizations while improving Hb and hemolysis markers, without added toxicity. The combination’s efficacy likely reflects synergistic effects on oxidative stress and sickle cell pathophysiology. This well-tolerated combination may improve SCA control, but larger confirmatory trials are needed.