Abstract
            Introduction: Chronic kidney disease (CKD) is described by structural or functional defects staying  for three months. End-stage kidney disease (ESKD) patients undergoing renal replacement therapy  (RRT) face complications and increased susceptibility to infections due to their compromised  immune system. In addition, malnutrition and chronic inflammatory conditions are prevalent in  CKD patients. Selenium, an essential trace element, plays a crucial role as a cofactor in antioxidant  enzymes like glutathione peroxidase (GPX), contributing to vascular endothelial function.  Selenium deficiency in patients with ESKD may intensify oxidative stress, increase susceptibility to  cardiovascular complications, and impact mortality rates. Despite the significance of selenium in  this context, studies on its levels in children undergoing hemodialysis (HD) are limited.  
  Objectives: This study assessed serum selenium levels in children undergoing HD, compared with  healthy children. Furthermore, we sought to establish correlations between selenium levels and  inflammatory profiles in the HD group.  
  Patients and Methods: An observational cross-sectional study was conducted with 30 pediatric  patients with ESKD undergoing HD (HD group) and 50 healthy children (control group) in  Tehran, Iran. Blood samples were collected from both groups, and serum selenium levels along with  inflammatory markers were analyzed. The inclusion criteria encompassed pediatric ESKD patients  undergoing HD for at least six months without recent inflammation or infections. The exclusion  criteria comprised active infections, immunodeficiency syndromes, and corticosteroid therapy.  Statistical analyses were performed using SPSS statistics.  
  Results: Significant differences were observed in serum selenium levels between the HD and control  groups (P=0.039). Correlation analysis disclosed a direct relationship among selenium levels and  participant age (r = 0.235, P=0.036), with no significant difference between genders. Notably,  significant correlations were found between selenium levels and erythrocyte sedimentation rate  (ESR) and platelet-to-lymphocyte ratio (PLR). In contrast, no significant correlation between  selenium levels and other inflammatory profiles was established.  
  Conclusion: This study underscores the importance of assessing serum selenium levels in pediatric  ESKD patients undergoing HD. Understanding the interplay between selenium deficiency and  inflammatory profiles can inform interventions aimed at improving outcomes and reducing  complications in this vulnerable population. Further researches are necessary to explain these  associations and to explore possible therapeutic interventions.