Blood gene expression profiling in pediatric systemic lupus erythematosus and systemic juvenile idiopathic arthritis: from bench to bedside.

Blood gene expression profiling has led to major advances in the field of rheumatology over the last few decades. Specifically, DNA microarray technology has been integral in increasing our knowledge of key players in the pathogenesis of some rare pediatric rheumatic diseases. Our group, using microarray analysis, identified the interferon (IFN) gene signature in pediatric systemic lupus erythematosus (SLE) and has published data that suggest high doses of intravenous corticosteroid treatment may have benefit over strictly oral regimens. Additionally, DNA microarray technology led to our discovery that the interleukin (IL)-1 gene signature is associated with systemic juvenile idiopathic arthritis (sJIA) and to the use of IL-1 blockade with anakinra in this disease. We also reported the biologic rationale for use of anakinra early in the disease course. Anakinra is now being used as first-line treatment in sJIA in multiple centers. Herein, we review how information obtained from blood gene expression profiling has changed our clinical practice.