Serum vitamin D and peripheral T-regulatory cells in systemic lupus erythematosus and their relation with disease activity

Abstract

Background Systemic lupus erythematosus (SLE) patients have a decreased number of T-regulatory cells (Tregs) in peripheral blood. Vitamin D deficiency is prevalent in SLE. Immunomodulatory effects of vitamin D include the expansion of Tregs. Objectives The aim of this study was to assess the percentage of Tregs and vitamin D level in SLE and their relation with disease activity. Patients and methods A total of 40 SLE patients underwent evaluation for disease activity using the SLE disease activity index and were tested for the percentage of peripheral Tregs using anti-CD4, anti-CD25, and anti-FOXP3 monoclonal antibodies. Vitamin D was assessed using a commercially available 25-OH VitD-EIA kit. The study also included 40 healthy individuals who served as controls. Results SLE patients had lower levels of vitamin D (22.3 ± 7.53) and Treg% (1.95 ± 0.18) in comparison with controls. Patients with active disease had significantly lower levels of vitamin D. However, there was no significant difference between patients with and those without disease activity as regards Tregs. Correlation between vitamin D and various disease parameters showed negative correlation between vitamin D and each of disease activity, creatinine, and urinary protein (P < 0.05) and a positive correlation with C 4 (P < 0.05). Correlation between Tregs% and various disease parameters showed a significant negative correlation as regards anti-dsDNA (P < 0.05). No correlation was detected between Tregs% and vitamin D. Conclusion There are decreased levels of vitamin D and Treg% in SLE. Lower levels of vitamin D correlate with disease activity; yet, no correlation between serum vitamin D and Treg% was detected.

Keywords

• systemic lupus erythematosus, T-regulatory cells, vitamin D