CD163: a potential biomarker for lupus nephritis activity

Area of Science:

• Immunology
• Nephrology
• Biomarker Discovery

Background:

• CD163, a macrophage scavenger receptor, is shed during inflammation, leading to measurable soluble forms in serum and urine.
• Elevated soluble CD163 (sCD163 and uCD163) levels are associated with inflammatory and immune-mediated diseases, including lupus nephritis (LN).

Purpose of the Study:

• To investigate the relationship between soluble CD163 levels (serum and urine) and intrarenal CD163 expression in patients with systemic lupus erythematosus (SLE).
• To evaluate the association of soluble CD163 with disease activity and treatment response in lupus nephritis (LN).

Main Methods:

• Forty-five SLE patients (active LN, inactive LN, active extra-renal SLE) and 20 healthy controls were included.
• Serum and urine samples were analyzed for CD163 using ELISA; renal biopsies from active LN patients assessed CD163+ macrophage density.
• Follow-up samples were collected after 6 months of treatment for a subset of active LN patients.

Main Results:

• Urinary CD163 (uCD163) was significantly higher in active LN compared to inactive LN and active extra-renal SLE.
• uCD163 correlated with renal disease activity indices and intrarenal CD163+ macrophage density.
• Following treatment, uCD163 levels decreased significantly, indicating treatment response.

Conclusions:

• uCD163 serves as a non-invasive biomarker distinguishing active lupus nephritis from inactive disease and extra-renal manifestations.
• The correlation with intrarenal CD163+ macrophages validates uCD163 as a marker of renal inflammation.
• uCD163 shows promise for monitoring treatment response in SLE, particularly in lupus nephritis.