Anti-DNA antibody determination in systemic lupus erythematosus (SLE). Predictive value as compared with the LE-cell...

All pathological LE-cell tests and anti-DNA antibody determinations were registered in a prospective study over a period of 9 months at a department of internal medicine with rheumatology as a subspecialty. The results were compared with the clinical diagnosis of the patients, and correlated to SLE disease activity, as evaluated clinically and by blood analysis of five acute-phase reactants. Of 159 positive LE-cell tests, 43 were from patients with SLE, giving a diagnostic value of 27%. Of 37 positive anti-DNA antibody values, 30 were from patients having SLE, giving a diagnostic value of 81%. All of the 7 false-positive anti-DNA antibody determinations were only slightly above the normal range (22--26%: normal range less than or equal to 21%). No correlation was found between the activity of the SLE and the degree of the positive LE-cell test. Pathological levels of anti-DNA antibodies were always found when the patient had active SLE--clinically and by elevation of acute phase reactants. On the other hand, it was impossible to evaluate the disease activity from the level of the anti-DNA antibody test. It is concluded that the anti-DNA antibody determination should be preferred to the LE-cell test in the evaluation of patients with connective tissue diseases.