Elevation of serum CXCL13 in SLE as well as in sepsis

Abstract

Recent studies have demonstrated that CXCL13 serum levels correlate significantly with systemic lupus erythematosus (SLE) disease activity. However, experimental studies show that CXCL13 production can also be induced by bacterial exposure as well as in response to inflammatory cytokines. This report asks whether CXCL13 serum levels are elevated in patients with evidence of bacterial infections and whether there is a correlation with the C-reactive protein (CRP) levels or the severity of illness in critically ill patients. CXCL13 levels were compared in 39 patients with active SLE (without concomitant infection), 40 non-SLE patients with sepsis, and 40 healthy controls by enzyme-linked immunosorbent assay (ELISA) methodology. We also tested storage conditions and freeze-thaw cycles for stability of CXCL13 in serum samples. Our studies demonstrated that the median CXCL13 serum levels were significantly elevated in patients with SLE [median 83 pg/ml (interquartile range 38-366)] or sepsis [359 pg/ml (151-459)] compared with healthy controls [32 pg/ml (27-41), p < 0.001]. The CXCL13 serum levels correlated with disease activity in SLE (CXCL13 vs. SLEDAI r = 0.65, p < 0.001), but were not associated with severity of illness score in critically ill patients (CXCL13 vs. SOFA r = -0.15, p = 0.35). However, CXCL13 serum levels were clearly associated with CRP levels in both sepsis (r = 0.45, p = 0.003) and SLE (r = 0.39, p = 0.02). In conclusion, CXCL13 is a stable serum marker for disease activity in SLE patients, but concomitant infections can also lead to increased CXCL13 levels.

CXCL13 as a new biomarker of systemic lupus erythematosus and lupus nephritis – from bench to bedside?

“…In this context, serum samples of septic patients were analysed. It was found that serum CXCL13 levels in septic patients were comparably high, as in patients with active SLE [39]. Therefore, CXCL13 serum levels cannot be used to distinguish between an active autoimmune response and severe infectious diseases.…”

“…In one study on 91 Caucasian patients, CXCL13 serum levels were correlated with disease activity using the SLE Disease Activity Index (SLEDAI) and to lupus nephritis. It was found that serum CXCL13 levels correlated well with SLEDAI and median CXCL13 concentrations were higher in patients with renal involvement [39]. In a further study on 35 Asian patients with SLE, plasma concentrations of CXCL13 were assessed.…”

CXCL13 as a Novel Marker for Diagnosis and Disease Monitoring in Pediatric PTLD

“…In the search for a clinical marker facilitating early diagnosis of PTLD we examined CXCL13 serum‐levels in pediatric patients with PTLD and EBV reactivation, as well as in healthy controls. In a previous study we demonstrated, that serum CXCL13 levels can be considered stable in serum and therefore is easily applicable for clinical use (15).…”

Systemic lupus erythematosus and infections: Clinical importance of conventional and upcoming biomarkers

“…Soluble biomarkers include the triggering receptor expressed on myeloid cells-1 (sTREM-1) and pentraxin 3 (PTX3) [38], phagocyte-specific S100A8/A9 protein levels [12] and CXC ligand 13 protein (CXCL13) serum levels [39]. These tests have the advantage of being tested by enzymelinked immunosorbent assay (ELISA), which makes them cheaper and faster to detect than analyses performed by flow cytometry or real-time PCR.…”

“…However, experimental studies show that CXCL13 production can also be induced by bacterial exposure as well as in response to inflammatory cytokines [52]. Nevertheless, Shiffer at al [39] showed that CXCL13 levels were increased in SLE patients with evidence of a bacterial infection as well as in patients with active SLE.…”