Frequency of dense fine speckled pattern in immunofluorescence screening test

Area of Science:

• Immunology
• Rheumatology
• Clinical Diagnostics

Background:

• Antinuclear antibodies (ANA) are key indicators of systemic autoimmune rheumatic diseases (SARDs).
• Indirect immunofluorescence (IIF) is the standard screening method for ANA.
• Anti-dense fine speckled 70 (anti-DFS70) antibodies, initially identified via ANA IIF, have been linked to various conditions.

Purpose of the Study:

• To determine the frequency of anti-DFS70 antibodies in patients undergoing routine ANA testing.
• To investigate the potential of anti-DFS70 antibodies as a biomarker for SARDs exclusion.

Main Methods:

• Screened 5800 serum samples for ANA using indirect immunofluorescence (IIF) between January 2011 and January 2012.
• Specifically searched for the dense fine speckled (DFS) pattern indicative of anti-DFS70 antibodies.
• Analyzed patient demographics and clinical departments for anti-DFS70 positive cases.

Main Results:

• ANA were detected in 22.4% of patients (1302/5800).
• Anti-DFS70 antibodies were identified in 1.2% of patients (16/5800), all with titers ≥1/320.
• Of the 16 anti-DFS70 positive patients, 11 were female and 5 were male; only one patient had a SARD diagnosis.

Conclusions:

• Anti-DFS70 antibodies, despite lacking a clear clinical association, are proposed as a potential biomarker for excluding SARDs.
• This preliminary study highlights the need for reliable assays to confirm anti-DFS70 reactivity.
• Further research involving large population screening is recommended to validate the diagnostic utility of anti-DFS70 antibodies.