Procalcitonin as an indicator of systemic response to infection in active pulmonary Wegener's granulomacytosis.

Differential diagnosis of infection during active immune disease, such as Wegener's granulomatosis (Wegener's granulomatosis), is a major clinical challenge. Laboratory measures, erythrocyte sedimentation rate or C-reactive protein, can be elevated in infections that supervene, or coinciding with, in active Wegener's granulomatosis, and thus are nonspecific. The aim of the study was to compare the serum levels of procalcitonin (PCT) in patients with active and inactive disease. Twenty two sera were tested from 10 patients with active, generalized, and biopsyproven Wegener's granulomatosis, with pulmonary involvement, and 12 patients with nonactive one. PCT levels were measured using an immunoluminometric assay. The PCT level was markedly elevated (1.2-3.6 ng/ml) in 9 of the 10 sera from active and 2 of the 12 sera from nonactive Wegener's granulomatosis. PCT levels were in the normal range (0.28-0.56 ng/ml) in the remaining patients with nonactive Wegener's granulomatosis. We conclude that serum procalcitonin levels may be a potentially useful marker in the diagnosis of bacterial infection supervening in active Wegener's granulomatosis.