Is it useful to repeat and monitor autoantibody levels in the follow-up of patients with systemic rheumatic disease?
In general, the screening IIF-ANA titer does not correlate with clinical characteristics such as disease activity or flares, and therefore is not a particularly useful parameter for following the course of the disease or estimating the efficacy of therapy (4;5) . It should be emphasized that this conclusion is not based on careful prospective laboratory studies using standardized tests on advanced diagnostic platforms or in defined indices of clinical disease (e.g. SLEDAI, SLAM). Likewise, the quantification of anti-ENA autoantibodies also has limited diagnostic and prognostic value as compared to the mere presence or absence of the specificity. One exception may be the presence of high levels of anti-U1-RNP antibodies that are characteristic of mixed connective tissue disease (6) . In general, levels of anti-ENA fluctuate over time, and the antibodies tend to be detectable in phases both of disease activity and remission (7-9) , although clearly there are some exceptions. The anti- ds
