Anti-ENA Antibodies, ANA Patterns, Anti-ds DNA results, and Clinical Diagnosis: A Laboratory and Clinical Audit.

Abstract

Background:The diagnosis of autoimmune diseases (AID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA) /anti-cellular antibodies are the sensitive screening tests but anti-double-stranded-deoxyribonucleic-acid-antibody (anti-ds-DNA), and anti-extractable nuclear antigens (anti-ENA) are specific for AIDs. We aimed to look at anti-ENA in our patients and correlated them with ANA patterns, anti-ds-DNA and clinical diagnosis for proper interpretation and better patient management cost-effectively. Methods:A retrospective data analysis of 654 patients was done (1st-February-2019 to 31st –July-2021) who were tested for anti-ENA at the Immunology Department of Indus Hospital and Health Network. ANA and anti-ds-DNA results and clinical diagnosis were also analyzed for anti-ENA-positive patients. The statistical analysis was performed using IBM SPSS 24.0, P < 0.05.was considered statistically significant.Results:Anti-ENA was positive for at least one autoantibody in 245 (38.2%). ANA was positive in 97% of these patients (P=0.000) with speckled and homogenous as most predominant ANA patterns (63% and 33% respectively). Anti-SSA was the most common anti-ENA (n=50%) followed by anti-histones (23%), anti-Sm/RNP (26%), anti-nucleosome (22%). Among ANA-negative patients, anti-SSA was most common (n=5). Anti-ds-DNA was found in 66% of SLE patients. 14% of patients did not have a confirmed diagnosis before anti-ENA testing.Conclusions: Anti-ENA, ANA, and anti-ds-DNA antibodies are essential for AID diagnosis. However, their testing repertoire should follow an algorithm comprising of clinical features, followed by ANA results with nuclear, mitotic, and cytoplasmic patterns, anti-ENA, and anti-ds-DNA for a more meaningful, and cost-effective diagnostic approach.

Association between antinuclear antibodies (ANA) patterns and extractable nuclear antigens (ENA) in patients with autoimmune diseases

“…Among ENA, the most prevalent Ag was SSA, which was associated with coarse speckled and peripheral patterns of ANA (19). Another study also reported that coarse speckled ANA patterns are associated with SSA antibodies (22). The second most prevalent ENA antigen was SSB, which was associated with a coarse speckled pattern.…”