Antinuclear antibody profile in Italian patients with connective tissue diseases.

In the present work we report data on the specificity of antinuclear antibodies (ANA) in a large series of Italian patients suffering from a broad spectrum of connective tissue diseases (CTD), by using a series of homogeneous and validated techniques. The present study confirms, on the one hand, generally accepted concepts, i.e. that certain autoantibodies are strictly associated to certain disease states (such as anti-PCNA and anti-Sm in systemic lupus erythematosus, Jo 1 in polymyositis, and ACA and Scl-70 in scleroderma); the presence of 'marker' antibodies is, however, restricted to a relative minority of CTD patients. The application of a new methodological approach that considers the entire profile of ANA can greatly augment their diagnostic relevance and may provide useful indications for their interpretation, allowing us to establish for the first time the diagnostic usefulness not only of marker autoantibodies but also of certain associations between non-marker autoantibodies. Finally, the application of a more appropriate and powerful statistical tool (multiple correspondence analysis) has further emphasized the clear relationship existing between antibody specificities and certain disease states.