Association between antinuclear antibodies (ANA) patterns and extractable nuclear antigens (ENA) in HEp-2 cells in patients with autoimmune diseases in Riyadh, Saudi Arabia

Antinuclear antibodies (ANA) and extractable nuclear antigens (ENA) are instrumental biomarkers crucial in the detection of autoimmune disorders (AID) such as systemic lupus erythematosus (SLE), Sjogren syndrome, etc.. In the present study, an assessment of the most frequent ANA patterns associated with most detectable ENA that could be used as efficient prognostic markers in the diagnosis of autoimmune diseases was conducted. Data was retrospectively analyzed from AID patients, retrieved from the medical records of King Fahad Medical City, Riyadh, KSA, from January 2016 to October 2018 who underwent ANA immunofluorescence of HEp-2 cells and their ENA detection was studied. Of the 453 total patients, 39/55 AID males (71%) and 332/398 AID females (83.4%) exhibited ANA positivity. The most common pattern was speckled S-ANA (32.4%) in females and homogenous H-ANA pattern (25.4%) in males. The histones were found at higher frequency in different ANA patterns. anti-Sjogren syndrome related antigen A (SSA), anti-ribonucleoprotein antibody (RNP-Sm), and histones were observed to be associated with homogenous and speckled nuclear patterns. Frequencies of ENA in all ANA patterns were found significant at p < 0.05 in males and p < 0.001 in females. Spearman's rank correlation of ENA within and among the ANA patterns was non-significant. SSA was significantly correlated with RNP-Sm and Sm at p < 0.05 and p < 0.01, respectively. The extractable nuclear antigens SSA, RNP-Sm, and histones were found associated with the S-ANA and H-ANA patterns. These correlations are of relevance for the accurate diagnosis of autoimmune diseases.