Diagnostic value of combined evaluation of neopterin and anti-DNA antibodylevels for assessment of disease activity in systemic lupus erythematosus

Objective The present study was designed to investigate whether the combined evaluati on of laboratory tests could improve their diagnostic value. Laboratory par ameters of systemic lupus erythematosus (SLE), such as anti-dsDNA, neopteri n, soluble IL-2 receptor (sIL-2R), C3, C4, and complement haemolytic activi ty (CH50), and a logistic model that provides the probable clinical activit y (PCA) of a given patient, calculated by stepwise multiple logistic regres sion analysis from the parameters mentioned above - were evaluated as SLE a ctivation markers. Methods Serum samples from 101 patients were assayed by ELISA (neopterin, sIL-2R, a nti-dsDNA), radial immunodiffusion (C3, C4) and haemolytic complement assay (CH50). Results Among the parameters investigated, PCA showed the greatest difference betwe en the values representing active and inactive stages of the disease (p < 0 .001), the highest correlation with SLEDAI (p < 0.001) and the highest sens itivity and specificity values (0.91, 0.88 respectively). Moreover, this va lue of PCA was the most useful in discriminating between active and inactiv e sample pairs. Conclusion We conclude that PCA is more useful in evaluating SLE activity than the sin gle parameters studied.