Patients and controls
This was a cross-sectional study conducted at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, a tertiary care center in Mexico City. We included 15 patients with SLE in long-term remission without treatment (PR-SLE). Prolonged remission was defined as a clinical SLEDAI of 0 (regardless of serological activity, i.e., anti-dsDNA antibodies and/or hypocomplementemia) and being free of immunosuppressive or antimalarial treatment for at least 10 years [8]. As controls, we included 15 patients with clinically active SLE (Act-SLE) with a clinical SLEDAI 2K ≥3 (excluding hypocomplementemia and high titers of anti-dsDNA) and 29 healthy subjects (HS). All the healthy controls were confirmed negative for antinuclear antibodies and with no personal or familial history of autoimmune diseases. All patients with SLE met the SLICC 2012 classification criteria [9].