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THU0326 Association between Anti-C1 Q and Other Markers of Disease Activity with Nephritis in a Population of 160 Portuguese Patients with Systemic Lupus Erythematosus
  1. G. Terroso1,
  2. M. Bernardes1,
  3. A. M. Pereira2,
  4. A. Bodas2,
  5. A. Aleixo1,
  6. P. Madureira1,
  7. R. Vieira1,
  8. R. Fonseca1,
  9. D. Gonçalves1,
  10. L. Costa1
  1. 1Rheumatology
  2. 2Clinical Immunology, Centro Hospitalar São João, Porto, Portugal


Background Anti-C1q autoantibodies have been described in patients with systemic lupus erythematosus (SLE) and their presence has been closely correlated with renal disease activity. Serum anti-C1q determination seems to be a valuable non-invasive marker for prediction of renal histopathology in lupus nephritis.

Objectives To assess if anti-C1q and other markers of disease activity are associated with nephritis according to renal BILAG score in a population of patients with SLE.

Methods A sample of portuguese SLE patients was grouped according to BILAG renal score: categories A+ B+ C (active nephritis), category D (inactive nephritis) and category E (no nephritis). Anti-C1q autoantibodies were determined by ELISA (Bühlmann®) with duplicate samples. Levels < 15 units/mL were considered the cut-off for normal sera. Serum ESR, CRP, levels of C3c, C4, CH50, anti-DNAds titres, 25(OH)vitamin D, 24 hour protein excretion and SLEDAI were measured. A multivariate analysis was performed using SPSS 18.0. Adjustments were made for patients´age, disease duration, steroid daily dose (prednisolone equivalents) and hydroxychloroquine daily dose.

Results 160 patients, 148 (92.5%) women, with mean (SD) age of 44.2± 12.59 years, were grouped according to BILAG renal score in categories A+B+C (n=23; 14.4%), category D (n=45; 28.1%) and category E (n=92; 57.5%). All the patients with a history of nephritis (active or previous) had had a biopsy at the time of its diagnosis (n=68; 42.5%). They had mean (SD) disease duration of 12.2± 8.71 years, SLEDAI 3.1± 4.50, SLICC 0.6± 1.07, daily dose of prednisolone 6.5 ± 5.91 mg and of hydroxychloroquine 213.2± 192.76 mg.

An association was found between active renal disease (BILAG score categories A+ B+ C) and higher anti-C1q titres (p<0.01), higher anti-dsDNA titres (p<0.01) and lower C3c levels (p<0.01).

Conclusions In a cohort of portuguese SLE patients, an association was found between anti-C1q titres, C3c levels and anti-dsDNA titres with active nephritis evaluated by BILAG renal scores. These data support the use of anti-C1q as a marker of nephritis presence and activity in SLE.

References Yang XW, Tan Y, Yu F, Zhao MH, Combination of anti-C1q and anti-dsDNA antibodies is associated with higher renal disease activity and predicts renal prognosis of patients with lupus nephritis. Nephrol Dial Transplant. 2012 Sep(9):3552-9. Doi:10.1093/ndt/gfs179.

Chen Z, Wang GS, Wang GH, Li XP, Anti-C1q antibody is a valuable biological marker for prediction of renal pathological characteristics in lupus nephritis. Clin Rheumatol. 2012 Sep;31(9):1323-9. doi: 10.1007/s10067-012-2017-1.

Disclosure of Interest None Declared

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