Beyond the Surface: Antinuclear Antibodies in Rheumatoid Arthritis-Experiences from a Single-Center, Cross-Sectional...

Area of Science:

• Rheumatology
• Immunology
• Clinical Diagnostics

Background:

• Antinuclear antibodies (ANA) presence in rheumatoid arthritis (RA) complicates diagnosis, particularly when differentiating from systemic connective tissue diseases (sCTDs).
• Assessing ANA fluorescence patterns, immunoblot profiles, and their relation to RA disease activity is crucial for diagnostic clarity.

Purpose of the Study:

• To investigate ANA fluorescence patterns and immunoblot profiles in RA patients.
• To explore the relationship between ANA titers, antibody expression intensity, and disease activity markers in RA.
• To differentiate ANA positivity in RA from other sCTDs.

Main Methods:

• Cross-sectional, observational study of 81 RA patients (53 ANA-positive) using 2010 ACR/EULAR criteria.
• Indirect immunofluorescence for ANA titers and patterns; immunoblot analysis for anti-extractable nuclear antigen (ENA) profiles.
• Spearman correlation and logistic regression analyses for relationships between ANA and clinical/laboratory variables.

Main Results:

• Heterogeneous ANA fluorescence patterns (nucleolar, homogeneous most common) and diverse immunoblot profiles observed.
• Ro-52, SS-A, and Sm antibodies detected infrequently; no dominant specificity identified.
• No significant correlations found between ANA titers and inflammatory markers, serological parameters, or disease activity indices.

Conclusions:

• RA patients with positive ANA exhibit significant immunological heterogeneity without concurrent sCTD symptoms.
• Positive ANA in RA might signify generalized immune dysregulation, not a distinct clinical subtype.
• Larger cohort studies are necessary to elucidate the precise clinical significance of ANA in rheumatoid arthritis.