摘要
Background: Detection of autoantibodies has played a consolidate role in diagnosis of systemic autoimmune disorders. A cascade autoantibody testing is usually performed by employing antinuclear antibodies (ANA) test as a first screening test and the other tests as second level determinations. Here, we present that supplementing extractable nuclear antigens (ENA) tests to the ANA test may capture more autoimmunity and provide critical medical information at an early stage. In this study, we?evaluated the clinical significance of a multiplex ANA + ENA panel. Methods: A cohort of 110 subjects, identified as ANA negative but ENA positive, were followed up for two years. The detection of their ANA and anti-ENA autoantibodies was assessed with a multiplex ANA + ENA panel at Vibrant America Clinical Laboratory. Results: During two years of multi-visit follow-up, 23 out of 110 subjects (20.9%) were found to become ANA positive within an average of 385 (±144) days. Histone (50/110, 45.5%) and Chromatin (25/110, 22.7%) antibodies were the most frequently found antibodies at their first visits. The subjects who were positive for RNP (5/8, 62.5%) and SSA (Ro) (10/22, 45.5%) have the highest ratio of conversion to positive ANA. No significant correlation was observed between the conversion frequency and the number of anti-ENA antibodies being carried. Conclusion: This study, which followed up on the subjects who had disparate ANA and ENA test results, showed that anti-ENA antibodies may exist years earlier than ANA. Combining ENA tests with ANA screening may reduce false negatives and improve sensitivity.
Background: Detection of autoantibodies has played a consolidate role in diagnosis of systemic autoimmune disorders. A cascade autoantibody testing is usually performed by employing antinuclear antibodies (ANA) test as a first screening test and the other tests as second level determinations. Here, we present that supplementing extractable nuclear antigens (ENA) tests to the ANA test may capture more autoimmunity and provide critical medical information at an early stage. In this study, we?evaluated the clinical significance of a multiplex ANA + ENA panel. Methods: A cohort of 110 subjects, identified as ANA negative but ENA positive, were followed up for two years. The detection of their ANA and anti-ENA autoantibodies was assessed with a multiplex ANA + ENA panel at Vibrant America Clinical Laboratory. Results: During two years of multi-visit follow-up, 23 out of 110 subjects (20.9%) were found to become ANA positive within an average of 385 (±144) days. Histone (50/110, 45.5%) and Chromatin (25/110, 22.7%) antibodies were the most frequently found antibodies at their first visits. The subjects who were positive for RNP (5/8, 62.5%) and SSA (Ro) (10/22, 45.5%) have the highest ratio of conversion to positive ANA. No significant correlation was observed between the conversion frequency and the number of anti-ENA antibodies being carried. Conclusion: This study, which followed up on the subjects who had disparate ANA and ENA test results, showed that anti-ENA antibodies may exist years earlier than ANA. Combining ENA tests with ANA screening may reduce false negatives and improve sensitivity.
