BAFF-R and TACI expression on CD3+ T cells: Interplay among BAFF, APRIL and T helper cytokines profile in systemic lupus erythematosus

•The TACI receptor is increased on CD3+ T cells of active SLE patients and correlates with IL-10 and IL-6.•BAFF serum levels correlate with disease activity in SLE.•APRIL serum levels are increased in SLE patients with renal activity and correlate with SLICC.•APRIL mainly associates with Th1 cytokines, whereas BAFF correlates with Th2 cytokine profile.•BAFF and APRIL could promote imbalance in Th1 and Th2 cytokines. Systemic lupus erythematosus (SLE) is the prototype of systemic autoimmune disease, characterized by loss of immune tolerance against self-antigens where autoantibody production is the hallmark of disease. B-cell-activating factor (BAFF) and A proliferation-inducing ligand (APRIL) are cytokines that promote autoreactive cell survival, immunoglobulin-class switching and autoantibody responses in human and mouse SLE models. BAFF and APRIL exert their functions through interactions with their receptors BAFF-R and TACI that are differentially expressed in B lymphocyte subsets, monocytes, dendritic cells and T lymphocytes. BAFF stimulation favors T lymphocyte activation and cytokine production through BAFF-R, which could contribute to the Th1, Th17 and/or Th2 response dysregulation observed in SLE patients. To evaluate the expression of the cytokines BAFF and APRIL and their association with the receptors BAFF-R and TACI on CD3+ T cells and to evaluate Th1/Th2/Th17 cytokine profile in patients with SLE. Fifteen healthy controls (HC) and 36 SLE patients were included, and their demographic and clinical data were assessed. The disease activity index (Mex-SLEDAI) and damage index (SLICC) were applied to the SLE patients. BAFF-R and TACI expression on CD3+ T cells were evaluated by flow cytometry. Serum BAFF and APRIL concentrations were measured by enzyme-linked immunosorbent assays (ELISA). Cytokine levels of Th1 (IL-12, IL-2, IFN-γ, TNF-α), Th2 (IL-4, IL-6, IL-10, IL-13) and Th17 (IL-1β e IL-17) were quantified with a multiplex assay (MAGPIX). Statistical analysis was performed using PASW Statistics v.20 and GraphPad Prism v.6 software. No differences in BAFF-R or TACI expression on the CD3+ T cells of SLE and HC were observed. BAFF-R expression correlates inversely with disease activity (r = −0.538, p