PAPER Urinary sCD25 as a biomarker of lupus nephritis disease activity

Objectives: T cells play an important role in the pathogenesis of lupus nephritis (LN). We studied the role of urinary soluble CD25 (sCD25) as a biomarker of LN disease activity in a cross-sectional and longitudinal study. Methods: Patients with systemic lupus erythematosus were classified as active LN (AN), inactive disease (ID) and active non-renal (ANR) based on disease activity and renal involvement at the time of enrolment. Urine and serum samples were collected at baseline from all patients and at 3-monthly follow-up from patients with AN. SLE disease activity index (SLEDAI) was used for disease activity assessment at all visits. sCD25 was measured by ELISA and normalized to urinary creatinine excretion and is expressed as pg/mg. Urine samples from 10 healthy individuals (HC) served as controls. Results: Ther