Associations between Specific Antinuclear Antibodies, detected by Line Immunoassay, and Clinical Features of Patients with Systemic Lupus Erythematosus

Background: Autoantibodies are an integral part of the process of classifying, detecting, and, at
least in some cases, mediating autoimmune diseases. The antinuclear antibody is not just one
antibody but, actually, many different antibodies associated with a variety of diseases and disease
manifestations. Antinuclear antibodies (ANA), anti-Sm, or anti-dsDNA antibodies are part of the
American College of Rheumatology criteria (ACR) for SLE. Specific reactivities are associated with
distinct clinical features of SLE.
Objectives: To study associations between antinuclear antibodies (ANA) detected by Line
Immunoassay and signs/symptoms in patients with systemic lupus erythematosus (SLE).
Methods: A total of 38 unselected consecutive patients, diagnosed as having SLE and attending the
rheumatology and nephrology units, Suez Canal University Hospital, were included in this study.
The patients met the American College of Rheumatology (ACR) revised criteria for classification of
SLE. ANA profiles were determined by line immunoassay and by indirect immunofluorescence on
Crithidia luciliae. An extensive list of signs/symptoms was evaluated.
Results: ANA were found by indirect immunofluorescence (IIF) in 36/38 (95%) patients. The
frequencies of the specific reactivities were: anti-dsDNA 60%, anti-SmB 35%, anti-SmD 25%, antiRNP-C 25%, anti-Ro60 15%, anti-SSB 15%, anti-RNP-A 10%, antiRibosomal P 10%, anti-Ro52
5%, anti Cenp-B 5%, anti Scl-70 2.6%, and anti-Histones 60%. Cutaneous manifestations were
associated with anti-SSB, Ro52, Ribosomal P, anti-dsDNA and histones. Raynaud's phenomenon
was associated with Ro52 and 60, histones and RNP-C. Xerostomia was associated with Ro52 and
60 as well as Cenp-B. Renal manifestations were associated with RNP-A, Ro52, Ro60 and dsDNA.
Conclusion: By using a sensitive and specific multiparameter assay like LIA for identifying
antinuclear reactivities, we could confirm some of the previously reported associations of antibodies
with clinical symptoms of SLE. We also found several new associations meriting further study.