OBJECTIVE: To identify individuals with antinuclear antibodies (ANA) not 
fulfilling criteria for systemic lupus erythematosus (SLE) or other connective 
tissue diseases (CTD); to describe their clinical and serological features, to 
identify factors indicating evolution to SLE.
METHODS: A case-control study, based on retrospective evaluation of clinical 
files. The cases were ANA positive individuals (n = 50) examined in a medical 
outpatient setting, for symptoms compatible with SLE, but not fulfilling SLE 
classification criteria. Two patients with SLE were matched to each case in 
terms of age at initial symptom onset and sex. Thyroid autoimmunity was assessed 
by detecting antithyroid antibodies. Fisher's exact test and conditional 
logistic regression were used to evaluate the predictive ability of initial 
findings for SLE development.
RESULTS: ANA positive individuals suspected of having a CTD present a wide 
variety of symptoms and findings, usually at the 4th to 5th decade of life. 
Antibodies to Sm and U1RNP were absent; anti-Ro(SSA) and anti-La(SSB) occurred 
in 6%, while anti-dsDNA occurred in less than 10% of the cases. Arthritis, 
butterfly and discoid rash, Raynaud's phenomenon, and anti-Ro/SSA antibodies are 
the initial findings indicating evolution to SLE. Hematological abnormalities 
such as leukopenia and thrombocytopenia as well as constitutional symptoms such 
as easy fatigue and arthralgias are not associated with evolution to SLE. 
Antithyroid antibodies were detected in 16% of the cases and 2.3% of controls.
CONCLUSION: ANA may connote a form of systemic autoimmunity that is expressed as 
a wide variety of complaints, even in the absence of a definite diagnosis of 
CTD. Arthritis, rash, Raynaud's phenomenon, and anti-Ro/SSA antibodies indicate 
evolution to SLE. Autoimmune thyroid disease occurs in ANA positive individuals 
not fulfilling SLE classification criteria rather than in patients with SLE.