The LUNET Registry is intended to serve as a comprehensive primary data source, capturing real-world longitudinal clinical information, and the heterogeneity of patient presentations that are often underrepresented in traditional clinical trials. Ultimately, the LUNET Registry will help to optimize SLE management in routine clinical practice by enabling the compilation of real-world evidence to inform clinical decision-making and health policy. Patients will be enrolled by secondary and tertiary care centres for SLE across Italy in a real-world clinical set-up.