Inflammatory and T Helper 17/ Regulatory T Cells Related Cytokines Balance in Cutaneous Lupus Erythematosus (CLE)

Abstract

The cutaneous lupus erythematosus (CLE) is a common manifestation among systemic lupus erythematosus (SLE) patients. Malar rash and discoid lupus (DLE) are in the category of acute and chronic CLE, respectively. The pathogenesis of CLE is multifactorial, and cytokine imbalances contribute to immune dysfunction and the induction of organ damage. Many aspects of cytokine dysregulation are still unclear in SLE and in particular CLE. Therefore, we concurrently measured the inflammatory [Tumor necrosis factor-alpha (TNF-α) and Interleukin (IL)-6)], T helper (Th)-17 (IL-17 and IL-23) and regulatory T cells [Transforming growth factor-beta (TGFβ) and IL-10)]-related cytokines in patients with CLE (patients with malar rash and/or DLE) and compared them with SLE patients and healthy individuals (n=25 in each group, a total of 75 patients). The serum levels of cytokines were assessed by Enzyme-Linked Immunosorbent Assay (ELISA) method. IL-6 cytokine was significantly higher in SLE, DLE, and malar rash patients compared to those in healthy controls (p=0.025) and in patients with arthralgia (p=0.038), and gastrointestinal involvement (p=0.048). IL-17 was significantly higher in malar rash patients compared to normal individuals (p=0.023), SLE (p=0.008) and DLE patients (p=0.019) and in patients with oropharyngeal ulcer (p=0.05) but, IL-23 was significantly higher only in DLE patients than healthy controls (p=0.019). In conclusion, inflammatory cytokines such as IL-6 involved in inflammation and differentiation of Th17 cells are probably responsible in part for Th17 activity in CLE. IL-17, IL-23, and IL-6/IL-6R (IL-6 receptor) inhibitors may be good treatments for CLE patients. So targeting these cytokines activity pathways can improve the CLE treatment strategy and may open a novel guideline for SLE and CLE treatment.

Keywords: Cutaneous lupus erythematosus; Inflammatory cytokines; Regulatory T cells; T helper 17.