Procalcitonin level in systemic lupus erythematosus patients and its relation to disease activity and infection

Aim of the work: To evaluate the role of serum procalcitonin (PCT) and compare it with other available biomarkers in differentiating flare from infection in systemic lupus erythematosus (SLE) patients. Patients and methods: Ninety SLE patients were enrolled and classified into 2 groups; group 1 included 60 active SLE patients with/without fever, and group 2 included 30 afebrile inactive SLE patients. Group 1 patients were further classified according to presence or absence of infection. Patients were subjected to detailed medical history, clinical examination, disease activity assessment, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), serum PCT, appropriate body fluid cultures, and radiological assessment. Results: The study included 80 (88 %) females. The mean age was 30.17 ± 9.7 years and the median disease duration 5 years. The commonest clinical manifestations of SLE were arthritis (58.9 %), skin rash (51.1 %), mucosal ulcers (37.8 %) and nephritis (36.7 %). Serum PCT, ESR, CRP, NLR and PLR were significantly higher in active SLE patients (group 1) than those in remission (group 2). Serum PCT, CRP and NLR were significantly higher in SLE patients with infection than those without infection whereas ESR and PLR showed no significant difference between both groups. PCT level significantly correlated with CRP, NLR, and PLR. Conclusion: Although serum PCT, CRP levels, and NLR rise with SLE disease activity, their levels are significantly higher when associated with infection, indicating that high levels of these inflammatory markers could differentiate between infection and disease activity in SLE patients.