The objective of this observational study is to compare the efficacy and safety of telitacicept and belimumab in the treatment of lupus nephritis in patients aged 18-65 years with lupus nephritis. The main question it aims to answer is: What are the response rates of the two drugs for the main renal therapy in the lupus nephritis population? Which drug has better efficacy and safety? This study is a retrospective study. The participants will not receive any treatment.

Inclusion Criteria:

• Age range: 18 - 65 years old;
• Meets the revised SLE classification criteria of the American College of Rheumatology in 1997 or the SLE diagnostic classification criteria issued by EULAR/ACR in 2019;
• Urine protein quantification ≥ 1g/d, or urine PCR ≥ 1g/g, or qualitative urine protein test in urine routine ≥ 1+;
• Patients who have been using telitacicept or belimumab for at least 12 weeks.

Exclusion Criteria:

• Having active central nervous system diseases;
• eGFR < 30 mL/min/1.73m², or undergoing hemodialysis or kidney transplantation;
• Pregnant women, or those who are about to become pregnant in the near future, or lactating women;
• Participants who are simultaneously participating in other clinical studies;
• Patients who have received telitacicept or belimumab treatment for less than 12 weeks.

The inclusion period is from March 1, 2021 to March 1, 2024. Patients who visited the First Affiliated Hospital of Shandong University Medical University, the Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Wuhan University People's Hospital, and the Department of Nephrology of Capital Medical University Affiliated Beijing Friendship Hospital for clinical diagnosis of lupus nephritis were included.