The Expression of Interferon- Induced Protein with Tetracopeptide Repeats 1 in Monocytes, a Shortcutto the Interferon Signature in Lupus

Resumen

Virtually all immune cells show alterations in lupus. Since the activation of small cell subpopulations can be missed in gene expression studies of pooled mononuclear cells, we separately assessed the expression of six relevant type I interferonstimulated genes in monocytes, T cells and B cells from 35 lupus patients and 11 healthy donors, using quantitative PCR. We observed an enhancement of five of the selected molecules in the immune cells from lupus patients, although their up-regulation was not uniform in the different cell subsets. In monocytes, the induction of the IFN-stimulated genes was associated to plasmablast counts, and skin disease, but not to antibody titres or complement levels. The expression of some, but not all, of these molecules increased during activity. Interestingly, the appearance of the IFN-stimulated genes in lymphocytes was a distinct feature of the lupus cohort, and their induction in B cells was associated to complement decrease. We suggest that the enhancement of the IFN-stimulated genes in each cell subset appears to draw distinct information, which could be complementary to other disease biomarkers. Globally, our result point to expression levels of interferon-induced protein with tetracopeptide repeats 1 in monocytes as a biomarker of the IFN signature during active lupus.