Diagnostic value of trait antinuclear antibodies and multiple immunoglobulin production in autoimmune diseases.

BACKGROUND: Our article aims to evaluate the proportion of monospecific antinuclear antibodies (ANA) and polyclonal ANAs in patients with autoimmune diseases based on the results of an ANA panel and to evaluate the efficiency of trait ANAs as a novel diagnostic tool. This study also aims to investigate immunoglobulin production in autoimmune diseases by detecting different antibodies.

METHODS: The serum ANA profile of 634 patients with autoimmune diseases was analyzed using the immunoblot method. A specific formula was developed in an effort to calculate the theoretical proportion of monospecific ANA (TPM) in different disease groups. Different IgM, IgG, and IgE variants for several pathologies were detected.

RESULTS: The observed proportions of monospecific ANAs (OPM) were all lower than the predicted TPM in autoimmune diseases. Polyclonal ANAs were predominant in patients with systemic lupus erythematosus (SLE). There were statistical differences in OPM and TPM in all disease groups (P < .001). Receiver operating characteristic curve (ROC curve) analysis of trait ANAs between the SLE group and the control groups indicated an area under the curve of 0.916. Differences were found in IgM of Toxoplasma gondii (TOXO) and IgG of hepatitis C virus (HCV) and Treponema pallidum (TP) when comparing the various disease groups to the control group.

CONCLUSION: The higher TPM suggests that polyclonal differentiation is the major mechanism of ANA in autoimmune diseases. Trait ANA is potentially a valuable new index for diagnosis in SLE. Further investigation is needed to understand the link between B-cell differentiation and autoimmune diseases.