Elevated procalcitonin levels in active Wegener's granulomatosis

Objective. To compare serum levels of procalcitonin (PCT) in patients with Wegener's granulomatosis (WG) in both active and inactive disease states to determine if PCT levels are increased in active WG without infection. Methods. Sera were tested from 26 patients with generalized histologically proven WG, one sample taken during an active and one during an inactive disease state. PCT serum levels were measured using an immunoluminometric assay. Results. PCT levels were in the normal range (0-0.5 ng/ml) in 23 of 26 sera taken during active WG and in all 26 sera taken during inactive WG. In sera from 3 patients with highly active WG, serum PCT concentrations were markedly elevated (0.8-3.3 ng/ml). There was a slight but significant difference in PCT concentrations between sera taken during active versus inactive disease. PCT values were found to correlate slightly with other disease activity variables (erythrocyte sedimentation rate, C-reactive protein, soluble interleukin 2 receptor, antineutrophil cytoplasmic antibodies) and with the Disease Extent Index score. Conclusion. PCT serum levels may be a potentially useful variable in the differential diagnosis of flares and bacterial infection in patients with WG. Interpretation of the values must be supported by laboratory and clinical findings, since PCT levels can be elevated in rare cases of highly active WG without infection.