Abstract:

Objective To investigate the relationship between serum 25-hydroxyvitamin D3 [25（OH）D3] level and lymphocyte subsets in children with systemic lupus erythematosus （SLE）. Methods A total of 52 children with SLE （SLE group） and 50 healthy children （healthy control group） were enrolled from Hainan Women and Children's Medical Center from June 2022 to June 2023. Serum 25（OH）D3 level and lymphocyte subsets [CD3+T cells，CD4⁺T cells，CD8⁺T cells，total B cells，natural killer（NK）cell percentage and CD4⁺/CD8⁺ratio] were determined. According to the vitamin D deficiency standard，SLE children were classified into vitamin D deficiency group [20 cases，25（OH）D3<50 nmol·L^-1] and vitamin D normal group [32 cases， 25（OH）D3≥50 nmol·L^-1]. The correlation between serum 25（OH）D3 level and lymphocyte subsets was evaluated by Pearson correlation analysis. Results The serum 25（OH）D3 level，CD4⁺T cell percentage，CD4⁺/CD8⁺ ratio，NK cell percentage and total B cell percentage in SLE group were lower than those in healthy control group（P<0.05），and the percentages of CD3+T cells and CD8⁺T cells were higher（P<0.05）. The percentages of CD4⁺T cells，NK cells，total B cells and CD4⁺/CD8⁺ ratio in vitamin D deficiency group were lower than those in vitamin D normal group（P<0.01），and the percentages of CD3+T cells and CD8⁺T cells were higher（P<0.05）. Serum 25（OH）D3 was positively correlated with CD4⁺T cells，CD4⁺/CD8⁺ ratio，NK cells and total B cells in SLE children（r values were 0.455，0.579，0.574 and 0.448，P<0.001）. It was negatively correlated with CD3+T cells and CD8⁺T cells （r values were -0.574 and -0.466，P<0.001）. Conclusions Serum 25（OH）D3 level is associated to lymphocyte subsets in children with SLE，suggesting that vitamin D levels may have diagnostic and therapeutic value in the diagnosis and treatment of SLE.

Key words: 25-Hydroxyvitamin D3, Lymphocyte subset, Systemic lupus erythematosus, Children