Anti-ficolin-3 Antibodies in Lupus Nephritis

PRIMARY OUTCOME MEASURE Exploration of the inhibition of anti-ficolin-3 antibodies purified from the serum of 14 patients with active lupus nephritis in ficolin-3-dependent necrotic cells recognition. The criterion used is the shift of MFI (Mean Fluorescence Intensity) measured after addition of these antibodies to necrotic Jurkat cells incubated with ficolin-3. The study has a single visit approach with serum collection, so every outcome is measured at T0, which is the only visit for the patient. SECONDARY OUTCOME MEASURES 1. Investigation of ficolin-3 deposition in renal biopsy of the same 14 patients with active LN. Analysis: deposition of ficolin-3 will be evaluated by immunostaining on renal biopsy. 2. Quantification of anti-ficolin-3 antibodies. Analysis: Anti-ficolin-3 antibodies are quantified by ELISA. 3. Quantification of serum levels of ficolin-3. Analysis: Ficolin-3 is quantified by ELISA. 4. Correlation between anti-ficolin-3 antibodies and serum levels of ficolin-3. Analysis: Anti-ficolin-3 antibodies and ficolin-3 are quantified by ELISA. 5. Correlation between serum levels of anti-ficolin-3 antibodies and ficolin-3 deposition in the kidney. 6. Correlation between serum levels of ficolin-3 and ficolin-3 deposition in the kidney. 7. Exploration of the inhibition of anti-ficolin-2 antibodies purified from the serum of 14 patients with active lupus nephritis in ficolin-2-dependent necrotic cells recognition. The criterion used is the shift of MFI (Mean Fluorescence Intensity) measured after addition of these antibodies to necrotic Jurkat cells incubated with ficolin-2. 8. Investigation of ficolin-2 deposition in renal biopsy of the same 14 patients with active LN. Analysis: deposition of ficolin-2 will be evaluated by immunostaining on renal biopsy. 9. Quantification of anti-ficolin-2 antibodies. Analysis: Anti-ficolin-2 antibodies are quantified by ELISA. 10. Quantification of serum levels of ficolin-2. Analysis: Ficolin-2 is quantified by ELISA. 11. Correlation between anti-ficolin-2 antibodies and serum levels of ficolin-2. Analysis: Anti-ficolin-2 antibodies and ficolin-2 are quantified by ELISA. 12. Correlation between serum levels of anti-ficolin-2 antibodies and ficolin-2 deposition in the kidney. 13. Correlation between serum levels of ficolin-2 and ficolin-2 deposition in the kidney.