Macaque liver substrate for evaluating dense fine speckled-like patterns on HEp2010 cells.

Area of Science:

• Immunology
• Autoimmunity
• Clinical Diagnostics

Background:

• Antinuclear antibody (ANA) detection via indirect immunofluorescence (IIF) is crucial for diagnosing systemic autoimmune diseases (SADs).
• Dense fine speckled (DFS) ANA patterns typically indicate anti-DFS70 antibodies, which are generally associated with the absence of SAD.
• However, DFS patterns can obscure other potentially significant ANA patterns.

Purpose of the Study:

• To investigate if negative liver nucleus immunofluorescence can exclude extractable nuclear antigen (ENA) antibodies in sera exhibiting DFS-like ANA patterns.
• To evaluate the utility of a liver substrate in conjunction with HEp2010 for comprehensive ANA screening.

Main Methods:

• One hundred consecutive sera with DFS-like ANA patterns and 15 control sera were analyzed.
• Samples were examined on HEp2010 and liver substrates by two independent readers using IIF.
• Anti-DFS70 antibodies were quantified using line and chemiluminescent immunoassays.

Main Results:

• DFS-like sera were more frequently liver nucleus-negative than control sera.
• Among liver-negative sera, 95.3% were negative for anti-ENA antibodies.
• The liver substrate demonstrated a sensitivity of 90.0% and a negative predictive value of 95.4% for anti-ENA detection.

Conclusions:

• Concurrent evaluation using a liver substrate aids in ruling out other anti-ENA antibodies in cases with DFS-like ANA patterns.
• This approach serves as a safeguard against masking of clinically relevant anti-ENA by DFS-like patterns on IIF.
• The liver substrate enhances the diagnostic accuracy of ANA testing in complex cases.