Procalcitonin for discrimination between activity of systemic autoimmune disease and systemic bacterial infection

Intensive Care Med. 2000 Mar;26 Suppl 2:S199-201. doi: 10.1007/BF02900738.


Objective: To investigate whether serum procalcitonin (PCT) levels could be useful to differentiate between systemic infection and the activity of the underlying disease in autoimmune disease.

Methods: In 18 patients with systemic lupus erythematodes (SLE) and 35 patients with systemic antineutrophil cytoplasmic antibody-associated vasculitis (AAV) clinical disease activity was assessed by score systems. Infection was defined by clinical and microbiological means. PCT was determined in parallel with concentrations of neopterin, interleukin-6 (IL-6), and C-reactive protein (CRP) in 397 serum samples.

Results: Only in 3 of the 324 samples taken from patients with autoimmune disease but without concomitant infection, serum PCT levels were above the normal range (>0.5 ng/ml), whereas neopterin, CRP and IL-6 were elevated in patients with active underlying disease. All systemic infections (N=16 in AAV-patients) were associated with markedly elevated PCT-levels (mean+/-SD:1.93+/-1.19 ng/ml).

Conclusion: PCT may serve as a useful marker for the detection of systemic bacterial infection in patients with autoimmune disease.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Antibodies, Antineutrophil Cytoplasmic / blood*
  • Bacterial Infections / blood
  • Bacterial Infections / diagnosis*
  • Biomarkers / blood
  • Calcitonin / blood*
  • Calcitonin Gene-Related Peptide
  • Diagnosis, Differential
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Lupus Erythematosus, Systemic / blood
  • Lupus Erythematosus, Systemic / diagnosis*
  • Male
  • Middle Aged
  • Protein Precursors / blood*
  • Sensitivity and Specificity
  • Vasculitis / blood
  • Vasculitis / diagnosis*


  • Antibodies, Antineutrophil Cytoplasmic
  • Biomarkers
  • CALCA protein, human
  • Protein Precursors
  • Calcitonin
  • Calcitonin Gene-Related Peptide