A pathogenic IFNα, BLyS and IL-17 axis in Systemic Lupus Erythematosus patients

This study aims to analyze in depth the role of IFN alpha in the upregulation of BLyS in different leukocyte populations and the possible relationship of these molecules with IL-17 and other pathogenic cytokines in SLE. Thus, IFNAR1 and membrane BLyS (mBLyS) expression was upregulated on various blood cell types from patients and closely correlated in all individuals. Moreover, BLyS serum levels associated positively with IFN alpha and IL-17A amounts, as well as with mBLyS on B cells and neutrophils. Interestingly, mBLyS on neutrophils was also correlated with IL-17A levels. Additionally, intracellular IL-17A expression was increased in both CD4(+) lymphocytes and neutrophils from patients, and IL-17(+) CD4(+) T cell frequency was associated with serum IFN alpha and IFNRA1 expression on B cells. Finally, in vitro assays support an IFN alpha role in the activation of Th17 cells in SLE. In conclusion, these data suggest that IFN alpha, BLyS and IL-17 could form a pathological axis in SLE, involving T and B lymphocytes, monocytes, DCs and neutrophils, which act in a vicious circle that encourage the preexisting inflammation and propagate the disease process.