Soluble urine activated leukocyte cell adhesion molecule is a strong predictor of lupus nephritis.

Objectives: To evaluate urinary activated leucocyte cell adhesion molecule (ALCAM) and CD6 as predictors of lupus nephritis (LN) progression or disease resolution across a 1-year study.

Methods: Serum and urine samples from biopsy proven LN subjects (n = 122) were prospectively collected over the course of a year at 3- or 6-month intervals (weeks 0, 12, 26, and 52) across multiple study sites and assessed for soluble ALCAM and CD6 levels. Urine creatinine from the same urine sample was used to normalize the levels of urinary ALCAM and urinary CD6. Measured levels of serum and urine ALCAM and CD6 were then analyzed against disease metrics cross-sectionally and longitudinally.

Results: Cross-sectional analysis at baseline revealed that urinary ALCAM significantly correlated with urine protein creatinine ratio (UPCR), renal SLEDAI, and the Physician Global Assessment (PGA), and negatively correlated with serum C3 and C4. Receiver operating characteristic (ROC) curve analysis demonstrated that urinary ALCAM is a predictor of LN with an area under the curve (AUC) of 0.97, compared with urinary CD6 with an AUC of 0.71. Importantly, the change in urinary ALCAM over a 3-month period distinguished between non-responders and responders at week 52.

Conclusion: Urinary ALCAM is reflective of changes in LN and may be predictive of response status.