Association Between Vitamin D Status, Regulatory T Cells, and Disease Severity in Pediatric Systemic Lupus Erythematosus

Abstract

Objective: Systemic lupus erythematosus (SLE) is characterized by loss of immune tolerance that is often associated with regulatory T (Treg) cell dysfunction. Vitamin D is known to enhance Treg differentiation and expansion. This study aimed to investigate the associations between serum vitamin D and zinc levels, Th17 and Treg cell percentages, and disease activity in pediatric patients with SLE. Materials and Methods: A cross-sectional study was conducted among children aged 7.5–18.9 years who were diagnosed with SLE at Dr. Saiful Anwar Hospital, Malang, Indonesia. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured using an enzyme-linked immunosorbent assay (ELISA). Treg cell percentages were determined via flow cytometry. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score. Results: The study included 32 pediatric patients with SLE. Among the study participants, 25.0% had sufficient vitamin D levels, whereas 75.0% had suboptimal vitamin D status, including 28.1% with vitamin D insufficiency and 46.9% with vitamin D deficiency. Moderate-to-severe disease activity (SLEDAI ≥7) was observed in 84.4% of the participants. A significant positive correlation was observed between serum 25(OH)D levels and Treg cell percentages (r=0.402, p=0.0225), indicating that higher vitamin D levels were associated with increased Treg cell percentages. Conclusion: Pediatric patients with SLE show a high prevalence of vitamin D deficiency and insufficiency. Adequate vitamin D status is associated with increased Treg cell percentages, suggesting a potential role for vitamin D in enhancing immune regulation and managing disease severity in pediatric SLE.