SC5b-9 is the most sensitive marker in assessing disease activity in Brazilian SLE patients

J Investig Allergol Clin Immunol. Jul-Aug 1998;8(4):239-44.


This study investigated whether increased plasma levels of terminal complement complex (SC5b-9) or split products correlate with disease activity and clinical manifestations in Brazilian systemic lupus erythematosus (SLE) patients. Comparisons with conventional measurements of complement and other inflammatory markers were also performed. Plasma levels of SC5b-9, C3a desArg, C1rs-C1Inhibitor, C3b(Bb)P, C3, C4, erythrocyte sedimentation rate (ESR) and mucoproteins (MP) were measured in 41 patients with SLE of different disease activity: 10 patients with none, 15 patients with mild, and 16 patients with moderate or severe activity. All parameters, with the exception of C3 and C3b(Bb)P, showed a statistically significant correlation with disease activity. Plasma levels of SC5b-9, C3a desArg, C4, CH50, ESR and MP revealed significant differences between the groups of patients without activity and those with moderate or severe disease. Although none of the variables were able to discriminate between patients without and those with mild activity, SC5b-9, C3a desArg, C4, ESR and mucoproteins showed significant differences between the patients with mild and those with moderate or severe disease. Among all the variables, SC5b-9 levels showed the most significant results and correlated well with the severity of the disease (p < 0.0005). Our data suggest that elevated levels of complement activation products, particularly of SC5b-9 are more sensitive markers in assessing disease activity than conventional laboratory diagnosis. Modern complement diagnosis is therefore recommended for monitoring disease progress in SLE patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antibodies, Antinuclear / analysis
  • Biomarkers
  • Blood Sedimentation
  • Complement C1 Inactivator Proteins / analysis
  • Complement C1r / analysis
  • Complement C3 / analysis
  • Complement C3a / analogs & derivatives
  • Complement C3a / analysis
  • Complement C3b / analysis
  • Complement C4 / analysis
  • Complement Membrane Attack Complex
  • Complement System Proteins / analysis*
  • Female
  • Glycoproteins / analysis*
  • Humans
  • Lupus Erythematosus, Systemic / blood*
  • Male
  • Middle Aged


  • Antibodies, Antinuclear
  • Biomarkers
  • Complement C1 Inactivator Proteins
  • Complement C3
  • Complement C4
  • Complement Membrane Attack Complex
  • Glycoproteins
  • SC5b-9 protein complex
  • complement C3a, des-Arg-(77)-
  • Complement C3a
  • Complement C3b
  • Complement System Proteins
  • Complement C1r