RESUMO
OBJECTIVE: Rhupus is a rare disease that shares characteristics of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). While several studies have explored the clinical and immunological profiles of patients with rhupus, the underlying cause of the disease remains unknown due to its complex pathogenesis. The objective of this study was to investigate the role of tumour necrosis factor (TNF) in the production of inflammatory molecules by peripheral blood mononuclear cells (PBMCs) from patients with rhupus. METHODS: The study involved five healthy controls, seven patients with rhupus and seven patients with SLE. PBMCs were obtained from each participant and stimulated with recombinant human TNF for 24 hours. The levels of various molecules secreted by the cells, such as cytokines and chemokines, were measured using immunobead-based assays on xMAP technology. RESULTS: The production levels of some molecules were higher in TNF-stimulated PBMCs from patients with rhupus and SLE than in unstimulated cells. In addition, the levels of certain molecules, including gp130/sIL-6Rb, a proliferation-inducing ligand (APRIL), interferon-ß, matrix metalloproteinase-3 and interleukin (IL)-12, were higher in PBMCs from patients with rhupus even without TNF stimulation. Similarly, the levels of gp130/sIL-6Rb and APRIL were higher in TNF-stimulated PBMCs from patients with rhupus than in healthy controls. These results were further validated against patients with RA using enzyme-linked immunosorbent assay. CONCLUSIONS: These findings suggest that the spontaneous production of molecules by cells from patients with rhupus may contribute to the development of the disease, and that TNF may play a role in this process by regulating the secretion of gp130/sIL-6Rb and APRIL.