Procalcitonin as a marker of bacterial sepsis in patients infected with HIV-1

Procalcitonin (ProCT) is a recently described marker of severe sepsis. It was decided to assess the value of proCT as a marker of secondary infection in patients infected with HIV-1. ProCT plasma levels were measured by immunoluminometric assay in a prospective study in 155 HIV-infected individuals: 102 asymptomatic and 53 with fever or suspected secondary infections. The baseline plasma level of ProCT was low (0.5 ng/ml+/-0.37), even in the latest stages of the disease, and did not differ from the values of healthy subjects (0.54 ng/ml+/-0.08). EDTA-treated whole blood was collected from patients before starting specific antimicrobial therapy. No elevation of ProCT lever was detected in HIV-infected patients with evolving secondary infections including PCP (n=4), cerebral toxoplasmosis (n=4), viral infections (n=9), mycobacterial infections (n=5), localized bacterial (n=12) and fungal infections (n=4), malignancies (n=3), and in various associated infectious and non-infectious febrile events (n=13). All these plasma values were lower than 2.1 ng/ml. In contrast, high ProCT plasma levels were detected in one HIV-infected patient with a septicaemic Haemophilus influenzae infection (16.5 ng/ml) and another one with a septicaemic Pseudomonas aeruginosa infection (44.1 ng/ml). ProCT values decreased rapidly under appropriate therapy. ProCT seems to be aspecific marker of bacterial sepsis in HIV-infected patients, as no increase in other secondary infections could be detected in those patients. A rapid determination of ProCT level could be useful to confirm or refute bacterial sepsis for a better management of febrile HIV-infected patients.