Serum Interleukin-18 in Children with Henoch-Schönlein Purpura: A Promising Marker of Disease Activity?

Abstract

Henoch-Schönlein purpura (HSp) is the most common systemic vasculitis of childhood with typical skin involvement and concurrent signs involving joints, gastrointestinal tract, and kidney. HSp pathogenesis is still far from being completely understood, though a knotty cytokine complex is believed to contribute to its intimate processes. The aim of our evaluation is to establish the relationship between serum levels of interleukin (IL)-18 and disease outcome and establish its feasibility to provide a marker of disease activity or even a prognostic tool in clinical practice. We examined clinical/laboratory variables and serum IL-18 in 17 children hospitalized during a year for HSp, diagnosed by EULAR/PRINTO/PRES criteria; the same patients were re-evaluated after 6 months. All results were compared with 25 age-matched healthy controls. IL-12 and IL-6 were also evaluated in a cohort of the same patients and compared with controls. General and clinical variables (sex, edema of the extremities, gastrointestinal or renal complications, relapses and renal involvement at 6 months) had no relationship with cytokine levels. Serum IL-18 and IL-6 levels were found significantly increased at diagnosis in HSp patients when compared with healthy controls. After 6 months, serum IL-18 and IL-12 levels were significantly decreased in patients, while IL-12 and IL-6 levels were significantly increased compared to healthy controls. Though preliminary and expecting further confirmation on a larger sample, our data support the conclusion that serum IL-18 levels reflect HSp activity.