INTRODUCTION: The finding of antinuclear antibody (ANA) positivity in a healthy 
individual is usually of unknown significance and in most cases is benign. 
However, a subset of such individuals is at risk for development of autoimmune 
disease. We examined demographic and immunological features that are associated 
with ANA positivity in clinically healthy persons to develop insights into when 
this marker carries risk of progression to lupus.
METHODS: Biological samples from healthy individuals and patients with systemic 
lupus erythematosus (SLE) were obtained from the Dallas Regional Autoimmune 
Disease Registry (DRADR). Measurements carried out on serum samples included 
ANA, extractable nuclear antibodies (ENA) and autoantibody profiling using an 
array with more than 100 specificities. Whole blood RNA samples from a subset of 
individuals were used to analyze gene expression on the Illumina platform. Data 
were analyzed for associations of high ANA levels with demographic features, the 
presence of other autoantibodies and with gene expression profiles.
RESULTS: Overall, ANA levels are significantly higher in females than in males 
and this association holds in patients with the autoimmune diseases lupus and 
rheumatoid arthritis (RA) as well as in healthy controls (HC). Age was not 
significantly associated with ANA levels and the elevated ANA values could not 
be explained by higher IgG levels. Another autoantibody, anti- cyclic 
citrullinated peptide (CCP), did not show gender dimorphism in rheumatoid 
arthritis (RA) or healthy individuals. The autoantigen array showed significant 
elevations of other autoantibodies in high ANA HCs. Some of these autoantibodies 
were directed to antigens in skin and others were related to autoimmune 
conditions of kidney, thyroid or joints. Gene expression analyses showed a 
greater prevalence of significantly upregulated genes in HCs with negative ANA 
values than in those with significant ANA positivity. Genes upregulated in high 
ANA HCs included a celiac disease autoantigen and some components of the Type I 
interferon (IFN) gene signature.
CONCLUSIONS: Risks for ANA positivity include female gender and organ-specific 
autoimmunity. Upregulation of skin-specific autoantibodies may indicate that 
early events in the break of tolerance take place in cutaneous structures. Some 
of these changes may be mediated by Type I IFN. Blood profiling for expressed 
autoantibodies and genes has the potential to identify individuals at risk for 
development of autoimmune diseases including lupus.