Serum-soluble CXCL16 in juvenile systemic lupus erythematosus: a promising predictor of disease severity and lupus nephritis

Juvenile systemic lupus erythematosus (jSLE) is a multisystem autoimmune disease of unpredicted course and prognosis. Rates of organ involvement in SLE are higher in children, and overt lupus nephropathy is more often a presenting manifestation of SLE in children than adults. Inflammatory soluble chemokine CXC motif-ligand 16 (sCXCL16) is an important pathogenic mediator in inflammatory diseases as SLE. Herein, we aimed to evaluate serum level of sCXCL16 in jSLE patients in comparison to healthy controls and to correlate it with disease activity and extent of cutaneous and renal affection, to detect its possible role in disease pathogenesis. Serum level of sCXCL16 was determined by ELISA in 27 patients with jSLE (mean age 12.35 years ± 2.26 SD) in addition to 30 age- and sex-matched healthy controls and correlated with clinical and laboratory parameters in lupus group. Serum sCXCL16 was significantly higher in jSLE patients than controls (P ≤ 0.001), and it correlated positively with SLE disease activity, severity of lupus nephritis, 24-h urinary protein, anti-dsDNA titre, blood pressure, and ESR, while it correlated negatively with serum C3 levels. Serum sCXCL16 was higher in jSLE patients with alopecia and malar erythema. Serum sCXCL16 might play a role in inflammatory pathogenesis of jSLE particularly in periods of disease activity. It might serve as a future useful laboratory test for detection of jSLE activity, renal insult, and its severity which might limit the need for invasive renal biopsies in such a delicate patient population.