Evaluation of a novel line-blot immunoassay for the detection of antibodies to extractable nuclear antigens

Ann N Y Acad Sci. 2005 Jun;1050:340-7. doi: 10.1196/annals.1313.036.


We have evaluated the performance of a novel line-blot immunoassay (LIA; Mikrogen) and compared results with those obtained by CIE (in-house), ELISA (Pharmacia Diagnostics), and FEIA (Pharmacia Diagnostics). Sera from systemic lupus erythematosus (SLE) patients (n = 123), systemic sclerosis patients (n = 25), and healthy controls (n = 40) were analyzed for the presence of antibodies to RNP, Sm, SSA, SSB, CENP-B, Scl-70, and Jo-1. Reading of LIA results, as compared with a cutoff control, was performed by automatic analysis of the test strips. Because LIA enables recognition of separate subunits of RNP (68, A, and C), Sm (B and D), and SSA (52 and 60), at least two of the RNP antigens and either one of the Sm or SSA antigens should be detected for considering the test RNP, Sm, or SSA-positive, respectively. LIA had the highest sensitivity in patients with autoimmune connective tissue diseases: 131 specificities (not PO, PCNA, or histones), as compared with ELISA (121), FEIA (119), and CIE (80). However, LIA revealed three positive reactions in healthy controls; other assays were completely negative. LIA is better than CIE, but similar to ELISA and FEIA, in terms of detecting systemic sclerosis-associated antibodies (CENP-B and Scl-70). Furthermore, LIA had the highest sensitivity (17.9%) for the SLE-specific anti-Sm antibodies, as compared with ELISA (11.4%), CIE (8.1%), and FEIA (5.7%). Finally, anti-SSA antibodies were far more prevalent by LIA in the systemic sclerosis samples because of anti-SSA52 reactivity. The clinical relevance of the latter finding remains to be determined. In conclusion, LIA is suitable for routine evaluation of autoantibodies to extractable nuclear antigens.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Antibodies, Antinuclear / analysis*
  • Antigens, Nuclear / immunology*
  • Autoantigens / immunology
  • Case-Control Studies
  • Centromere Protein B
  • Chromosomal Proteins, Non-Histone / immunology
  • Connective Tissue Diseases / diagnosis
  • Connective Tissue Diseases / immunology
  • Counterimmunoelectrophoresis
  • DNA Topoisomerases, Type I
  • DNA-Binding Proteins / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Evaluation Studies as Topic
  • Fluorescent Antibody Technique, Indirect
  • Humans
  • Immunoassay*
  • Lupus Erythematosus, Systemic / diagnosis
  • Lupus Erythematosus, Systemic / immunology
  • Nuclear Proteins / immunology
  • Ribonucleoproteins / immunology
  • Ribonucleoproteins, Small Nuclear / immunology
  • Scleroderma, Systemic / diagnosis
  • Scleroderma, Systemic / immunology
  • Sensitivity and Specificity
  • snRNP Core Proteins


  • Antibodies, Antinuclear
  • Antigens, Nuclear
  • Autoantigens
  • CENPB protein, human
  • Centromere Protein B
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Ribonucleoproteins
  • Ribonucleoproteins, Small Nuclear
  • SS-A antigen
  • Scl 70 antigen, human
  • snRNP Core Proteins
  • DNA Topoisomerases, Type I