Article Text

Download PDFPDF

Reduction in erythrocyte-bound complement activation products and titres of anti-C1q antibodies associate with clinical improvement in systemic lupus erythematosus
  1. Jill Buyon1,
  2. Richard Furie2,
  3. Chaim Putterman3,
  4. Rosalind Ramsey-Goldman4,
  5. Kenneth Kalunian5,
  6. Derren Barken6,
  7. John Conklin6 and
  8. Thierry Dervieux6
  1. 1NYU School of Medicine, New York, New York, USA
  2. 2Hofstra Northwell School of Medicine, New York, New York, USA
  3. 3Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, USA
  4. 4Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
  5. 5UCSD School of Medicine, La Jolla, California, USA
  6. 6Exagen Diagnostics, Vista, California, USA
  1. Correspondence to Dr Thierry Dervieux; tdervieux{at}exagen.com

Abstract

Background The relationship between cell-bound complement activation products (CB-CAPs: EC4d, EC3d), anti-C1q, soluble complement C3/C4 and disease activity in systemic lupus erythematosus (SLE) was evaluated.

Methods Per protocol, at baseline all SLE subjects enrolled in this longitudinal study presented with active disease and elevated CB-CAPs. At each monthly visit, the non-serological (ns) Safety of Estrogens in Lupus Erythematosus: National Assessment (SELENA-SLEDAI) and the British Isles Lupus Assessment Group (BILAG)-2004 index scores were determined as was a random urinary protein to creatinine ratio (uPCR). Short-form 36 (SF-36) questionnaires were also collected. All soluble markers were determined using immunoassays, while EC4d and EC3d were determined using flow cytometry. Statistical analysis consisted of linear mixed models with random intercept and fixed slopes.

Results A total of 36 SLE subjects (mean age 34 years; 94% female) were enrolled and evaluated monthly for an average 11 visits per subject. Clinical improvements were observed during the study, with significant decreases in ns-SELENA-SLEDAI scores, BILAG-2004 index scores and uPCR, and increases in all domains of SF-36 (p<0.01). The longitudinal decrease in ns-SELENA-SLEDAI and BILAG-2004 index scores was significantly associated with reduced EC4d and EC3d levels, reduced anti-C1q titres and increased serum complement C3/C4 (p<0.05). The changes in uPCR significantly correlated with C3, C4, anti-C1q and EC4d, with EC4d outperforming C3/C4 by a multivariate analysis. The reduced EC4d or EC3d was associated with improvements in at least six out of the eight domains of SF-36 and outperformed C3/C4. Anti-dsDNA titres did not correlate with changes in disease activity.

Conclusions These data indicate that CB-CAPs and anti-C1q are helpful in monitoring patients with SLE.

  • Systemic Lupus Erythematosus
  • Disease Activity
  • Treatment

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/

View Full Text

Statistics from Altmetric.com

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.