Enrolment

• All subjects with incident LN will be screened for eligibility and informed consent will be obtained.

Observational period

• Clinical observation and laboratory measurements will be reported for all subjects at each visit over time, at baseline and at month 3, 6, 12, 15, 18, 24, 30, 36, 42, 48, 54 and 60 from baseline. Data registration will be facilitated through an electronic Case Report Form (CRF) platform, centrally administered at the Karolinska Institutet.
• Serum and urine samples will be collected at baseline and at month 12 from baseline, and will be cryopreserved at -80 °C.
• Renal pathology will be assessed at the participating centres at baseline and at the time of the repeat kidney biopsy, but slides will be sent to UCLouvain for digitalisation and central review.
• Kidney tissue (two very small fragments) obtained from the kidney biopsies will be isolated, dropped into a 2.5% glutaraldehyde solution, stored at 4 °C until shipment to the coordinating centre UCLouvain.