CRP LEVELS IN AUTOIMMUNE-DISEASE CAN BE SPECIFIED BY MEASUREMENT OF PROCALCITONIN

Autoimmune diseases (AID) are prone to infection particularly under im munosuppression. The differentiation of infection from active AID is o ften difficult. In order to specify; the diagnostic value of measureme nt of procalcitonin (PCT) in AID 81 patients with anti-neutrophil cyto plasmic antibody (ANCA)-positive vasculitis were analyzed, 27 with rhe umatoid arthritis and 25 patients with systemic lupus erythematosus at various stages of the disease. Although PCT levels (95th percentile) were below 0.5 ng/ml in patients with active systemic lupus erythemato sus and rheumatoid arthritis, the cutoff for normal values (95th perce ntile) in patients with active ANCA-positive vasculitis was 0.89, Ther efore PCT levels of < 1 ng/ml are recommended as cutoff for invasive i nfections in patients with ANCA-positive vasculitis. In view of the in creased mortality under immunosuppression in patients with AID and add itional bacterial infection the measurement of PCT is helpful when an infectious origin is suspected.