Can procalcitonin be used to distinguish between disease flare and infection in patients with systemic lupus erythematosus: a systematic literature review.

Distinction between infection and febrile disease flare in patients with systemic lupus erythematosus (SLE) is fundamental but often difficult to make, because clinical presentation can be similar. A systematic review of all articles indexed in PubMed through October 2013 was performed, in order to examine the potential role of procalcitonin (PCT) for the discrimination between SLE flare and infection. Among the 12 papers identified, 5 articles reported on PCT levels in SLE patients without infection, 6 compared PCT levels between SLE patients with flare versus those with infection, and 1 analyzed PCT levels in active patients with and without bacterial infection. These data suggest the absence of correlation between PCT levels and SLE disease activity. Furthermore, PCT levels detected during disease flares are lower than those observed during bacterial infections. PCT can therefore be used accurately in the early differentiation between bacterial infection and flare in febrile SLE patients. Raised PCT levels ≥0.5 µg/L should strongly suggest bacterial infection in the context of SLE, keeping in mind the limited data available in case of hemophagocytic syndrome. Elevated PCT levels in SLE patients should always prompt a thorough search for sources of potential infection.