CD4+Foxp3+ T cells,interleukin-35 (IL-35) and IL-10 in systemic lupus erythematosus patients: Relation to disease activity

Aim of the workTo evaluate three subtypes of CD4⁺Foxp3⁺ T cells, interleukin-35 (IL-35) and IL-10 in systemic lupus eryhtematosus (SLE) patients and study their relation to disease activity.Patients and methodsFifty SLE patients were included and divided according to the SLE disease activity index (SLEDAI) into 2 equal groups with activity or in remission. Twenty healthy subjects were included as controls. All subjects underwent flow cytometric analysis of CD4, CD25, CXCR5 and Foxp3 expression on T cells. Serum IL-35 and IL-10 levels were measured by ELISA.ResultsPatients were 46 females and 4 males with a mean age of 38.0 ± 10.0 years, disease duration of 9.2 ± 6.0 years. The mean SLEDAI was 6.8 ± 3.7 in active ones. SLE patients especially those with activity had significantly reduced percents of CD4⁺CD25⁺Foxp3⁺ and CD4⁺CXCR5⁺Foxp3⁺ T cells, but increased percents of CD4⁺CD25⁻Foxp3⁺ T cells. This was accompanied by significant higher levels of serum IL-35 and IL-10 (p < 0.0001). The SLEDAI in active patients significantly correlated with CD4⁺CD25⁻Foxp3⁺ T cell percent, serum IL-35 and IL-10 levels (p < 0.05) and inversely with the CD4⁺CD25⁺Foxp3⁺ and CD4⁺CXCR5⁺Foxp3⁺ T cell percents (p < 0.05). At cut-off values of 3.29% for CD4⁺CD25⁺Foxp3⁺ T cell, 7.62% for CD4⁺CD25⁻Foxp3⁺ T cell, 1.77% for CD4⁺CXCR5⁺Foxp3⁺ T cell, 22.04 pg/ml for IL-35 level and 30.51 pg/ml for serum IL-10 level were found to be highly sensitive and specific for detecting lupus activity.ConclusionCD4⁺Foxp3⁺ T cells, IL-35 and IL-10 showed high sensitivity and specificity for detecting SLE activity and may be considered as potentially promising therapeutic targets.