Autoantibodies Against Albumin in Patients With Systemic Lupus Erythematosus

Front Immunol. 2018 Oct 2:9:2090. doi: 10.3389/fimmu.2018.02090. eCollection 2018.

Abstract

Objectives: Autoantibodies and aberrant immune complexes are pathological hallmarks of systemic lupus erythematosus (SLE). This study aimed to determine the occurrence of IgG autoantibodies against human serum albumin (anti-HSA IgG) and their potential association with antibodies against bovine serum albumin (anti-BSA IgG) in patients with SLE. Methods: Sera of 180 SLE patients included to the Swiss SLE Cohort Study and 188 age- and sex-matched healthy controls were evaluated. Levels of anti-HSA IgG and anti-BSA IgG were quantified by ELISA. Selected samples were further characterized using serum fractions obtained by fast liquid chromatography (FPLC). Results: SLE patients had increased levels of anti-HSA IgG (p = 0.002) but similar levels of anti-BSA IgG compared to matched healthy controls. Anti-HSA IgG levels correlated with the SLE Disease Activity Index (SLEDAI), which was more pronounced in patients with an physician's global assessment (PGA) of ≥ 1 (r = 0.309, p = 0.0066). Anti-HSA IgG was partially complexed with serum albumin but also occurred as monomeric autoantibodies in highly positive SLE patients. A positive correlation between anti-HSA IgG and anti-BSA IgG was found that was stronger in SLE patients than in healthy controls (r = 0.3172, p < 0.001 vs. r = 0.2122, p < 0.0035). Binding of anti-BSA IgG was inhibited partially in the presence of HSA in samples with double positivity for anti-HSA and anti-BSA (median inhibition 47.9%, range 0.9-100%) and vice versa. Conclusion: In SLE patients there is an increased prevalence of anti-HSA IgG antibodies that are associated with SLE disease activity.

Keywords: antibodies; human serum albumin; multicenter study; patients; systemic lupus erythematosus.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Autoantibodies* / blood
  • Autoantibodies* / immunology
  • Cohort Studies
  • Female
  • Humans
  • Immunoglobulin G* / blood
  • Immunoglobulin G* / immunology
  • Lupus Erythematosus, Systemic* / blood
  • Lupus Erythematosus, Systemic* / immunology
  • Male
  • Middle Aged
  • Serum Albumin, Human / immunology*
  • Serum Albumin, Human / metabolism

Substances

  • Autoantibodies
  • Immunoglobulin G
  • Serum Albumin, Human