Correlation between 25(OH)D Levels with Systemic Lupus Erythematosus Activity

Background: Systemic Lupus Erythematosus (SLE) manifests immune system dysregulation leading to tissue damage, and hypovitaminosis D is reported to be a contributing factor. Vitamin D acts as an immunomodulator, actively contributing to the pathogenesis of SLE by maintaining antigen-presenting cell (APC) tolerance, inhibiting dendritic cell maturation, and exhibiting antimicrobial and antiapoptotic properties. Objective: This study aims to investigate the association between 25(OH)D serum levels and the activity of SLE in individuals diagnosed with SLE, assessed through the Systemic Lupus Activity Measure (SLAM) score. Materials and methods: A cross-sectional observational analytic study was conducted on 40 SLE subjects at Dr. Soetomo Regional Public Hospital's Outpatient and Inpatient Installation in Surabaya. The disease activity was assessed using SLAM scores, and theArchitect brand instrument, employing chemiluminescent microparticle immunoassay (CMIA), was utilized to measure 25(OH)D serum levels. Statistical analysis of the data involved the use of the Spearman correlation test, with significance set at p < 0.05. Result: The average age of the participants was 27.43 years with a standard deviation of 8.65 and a median SLAM score of 17.5 (range: 1-39). The mean 25(OH)D serum level was 21.69±2.72ng/mL, demonstrating a significant negative correlation with SLE activity (p<0.01; r = -0.671). Additionally, there was a negative correlation with C-reactive protein (CRP) (p<0.05; r = -0.414) and positive correlations with complement components C3 (p<0.01; r = 0.538) and C4 (p < 0.05; r = 0.356). Conclusion: The study establishes a substantial negative correlation between 25(OH)D serum levels and SLE activity, as assessed by the SLAM score.