Aberrant T cell subsets and cytokines expression profile in systemic lupus erythematosus

To assess T cell subsets and levels of chemokines and cytokines in patients with SLE and determine their relationships between disease activity and organ involvement. Blood samples from SLE patients (n = 24) and healthy controls (n = 36) were analyzed. Frequency of circulating follicular help T cells (Tfh), central memory T cells (Tcm), effector memory T cells (Tem), and naïve T cell subsets was enumerated and their surface markers expression of inducible T cell co-stimulator (ICOS) and programmed death 1(PD-1) protein was examined by flow cytometry. The disease state in SLE patients was evaluated using the SLE Disease Activity Index (SLEDAI). Concentrations of autoantibodies, serum C-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), lgG, complement 3, complement 4, cytokines, and chemokines, such as IL-21, IL-17A, and IL-1β, were measured. The frequencies of circulating Tfh and Tcm cell subsets were significantly lower than those in healthy controls. However, the percentages of circulating PD1⁺ICOS⁺Tfh, PD1⁺ICOS⁺Tcm, and PD1⁺ICOS⁺Tem of PBMCs from SLE patients were higher than those in healthy controls. Furthermore, increased levels of serum IL-1β, IL-4, IL-6, MCP-1, IL-21, and IL-17A were detected in the patients with SLE compared to healthy controls. In addition, patients with immune thrombocytopenia displayed elevated proportions of serum IL-10, IL-17A, and IL-1β. Aberrant T cell subsets and cytokines expression profile were observed in SLE patients. PD1⁺ICOS⁺Tem cell subset was clearly influenced by disease activity and serum IL-10, IL-17A, and IL-1β were significantly increased in patients with immune thrombocytopenia. Therefore, PD1⁺ICOS⁺Tem cells might serve as an important tool for recognition and serum IL-10, IL-17A, and IL-1β might be an effective monitor for SLE patients with immune thrombocytopenia.