In this mini-review, the author will first briefly summarize the features of CD11c<sup>+</sup> DN B cells in human SLE, and discuss how the IL-12-STAT4 axis might contribute to the generation of autoantibodies in SLE.
Altogether, we present a plausible molecular mechanism for increased lupus risk at the STAT1-STAT4 locus in which the risk allele of rs11889341, the most probable causal variant, leads to elevated STAT1 expression in B cells due to decreased repressor activity mediated by increased binding of HMGA1.
Our findings suggest that IL-12-mediated co-activation of STAT1 and STAT4 alters histone modification, resulting in differentiation of Tfh-Th1-like cells that are characteristically expanded in patients with SLE.
The analysis of Th17 pathway revealed 14 genes (IL-17A, IL-17C, IL-17D, IL-17F, IL-18, IL-12RB2, IL-23R, CCL2, CCL20, CXCL5, MMP3, RORC, STAT4 and TRAF6) that are differentially expressed in SLE and HC (fold change [FC] < 2, P < 0.0006).
In a combined analysis of 1596 SLE patients and 2540 controls for selected 22 candidate SNP, STAT4 and BLK as positive controls showed a strong association with SLE (FDR p=9.85×10(-13) and 2.28×10(-8), respectively).
We aimed at analyzing previously identified loci associated with SLE or with other autoimmune and/or inflammatory disorders (STAT4, IL10, IL23R, IRAK1, PSORS1C1, HCP5, MIR146a, PTPN2, ERAP1, ATG16L1, IRGM) in a sample of Italian SLE patients in order to verify or confirm their possible involvement and relative contribution in the disease.
Recent studies demonstrated an association of STAT4 polymorphisms with autoimmune diseases including systemic lupus erythematosus and rheumatoid arthritis, indicating multiple autoimmune diseases share common susceptibility genes.