Diagnostic Value of ANA Titer, Anti-ds-DNA, Anti-nRNPSm, and Sm Antibodies in Early Atypical Systemic Lupus Erythematosus

Abstract

Objective: To explore the diagnostic value of antinuclear antibody(ANA) titer, anti-double-stranded DNA(anti-ds-DNA) antibody, anti-nuclear ribonucleoprotein/Smith(anti-nRNPSm) antibody, and Smith (Sm) antibody for early atypical systemic lupus erythematosus(SLE).

Methodology: This was a retrospective study. Forty-nine patients diagnosed with early atypical SLE admitted to Affiliated Hospital of Hebei University between January 2023 to June 2025 were assigned to Group-A, and 66 patients with other autoimmune diseases admitted during the same period were enrolled in Group-B. Compared the results of ANA, anti-ds-DNA, anti-nRNPSm and Sm antibody tests between the two groups, and analyzed the diagnostic value of the individual indicators and their combined detection for early atypical SLE.

Results: There were statistically significant differences in the results of ANA, anti-ds-DNA, anti-nRNPSm and Sm antibodies between the two groups(P<0.05). Multivariate Logistic regression analysis confirmed that ANA, anti-ds-DNA, anti-nRNPSm and Sm were independent influencing factors for early atypical SLE (P<0.05). ROC curve analysis showed that the AUC of combined diagnosis was 0.856, with a predictive sensitivity of 87.8%, a specificity of 71.2%, and a predictive probability of 0.79. Significant differences in AUC were observed between ANA and anti-ds-DNA antibody, Sm antibody, or the four-antibody combination(P<0.05); between anti-ds-DNA antibody and the four-antibody combination(P<0.05); and between anti-nRNPSm antibody, Sm antibody and the four-antibody combination(P<0.05).

Conclusion: ANA, anti-ds-DNA, anti-nRNPSm and Sm antibodies are major independent influencing factors for early atypical SLE. Combined detection of these indicators can effectively improve the diagnostic value for this disease.