Determination of specific autoantibodies in patients with systemic lupus erythematosus by Line immunoassay, ELISA and CLIF
Kanphai Wongjarit,1 Niramol Thammacharoenrach,2 Kanthaporn Dityen,2 Yadah Kaewopas,2 Naravadee Kositpesat,3 Sittichai Ukritchon,4 Manathip Osiri,4 Jongkonnee Wongpiyabovorn5
Affiliations:
1 Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
2 Division of Immunology, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
3 Internal Medicine and Rheumatology, Bangkok Hospital Hua Hin, Prachuap Khirikhan, Thailand
4 Division of Rheumatology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
5 Center of Excellence in Immunology and Immune-mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
Abstract
Background: Detection of specific antinuclear antibodies (ANA) is very importance in term of diagnosis, prognosis and management of patients with systemic lupus erythematosus (SLE). To date, Line immunoassay (LIA), enzyme-linked immunosorbent assay (ELISA) and Crithidia luciliae indirect immunofluorescence assay (CLIF) are commonly used for detection of specific ANA.
Objective: To determine the performance of LIA, ELISA and CLIF for the detection of anti-double-stranded DNA (dsDNA), anti-nucleosome, and anti-extractable nuclear antigens (ENA) antibodies in patients with SLE.
Methods: A total 100 sera from 50 patients with SLE, 25 patients with disease control and 25 healthy control subjects were tested for anti-dsDNA, anti-nucleosome, and anti-ENA antibodies by LIA, ELISA, and CLIF. Agreement and diagnostic performance of each assay were analyzed using Cohen’s kappa coefficient and receiver operating characteristic curve analysis.
Results: For the detection of anti-dsDNA antibody, ELISA had a substantial agreement with CLIF (κ = 0.74) but LIA had a fair agreement with ELISA and CLIF (κ = 0.37, and 0.35 respectively). For the detection of anti-nucleosome, anti-nRNP/Sm, anti-Sm, anti-SSA, and anti-SSB antibodies, LIA had a substantial to perfect agreement with ELISA (κ = 0.64, 0.78, 0.68, 0.91, and 0.74, respectively). Anti-dsDNA-NcX ELISA and anti-dsDNA CLIF had equally diagnostic performance (sensitivity, 66% vs. 68%, and specificity, 96% vs. 94%, respectively) whereas, anti-dsDNA LIA has low sensitivity (22%) but high specificity (100%).
Conclusion: LIA, ELISA, and CLIF demonstrated comparable performance for the detection of specific antinuclear-antibodies. However, there were some discrepancy between assays particularly in the detection of anti-dsDNA antibody.
Key words: Systemic lupus erythematosus (SLE), Specific antinuclear antibodies, Line immunoassay (LIA), Enzyme-linked immunosorbent assay (ELISA), Crithidia luciliae indirect immunofluorescence assay (CLIF)