Innate immunity and interferons in the pathogenesis of Sjögren’s syndrome

Objective To assess the efficacy and safety of anifrolumab, a type I interferon (IFN) receptor antagonist, in a phase IIb, randomized, double‐blind, placebo‐controlled study of adults with moderate‐to‐severe systemic lupus erythematosus (SLE). Methods Patients (n = 305) were randomized to receive intravenous anifrolumab (300 mg or 1,000 mg) or placebo, in addition to standard therapy, every 4 weeks for 48 weeks. Randomization was stratified by SLE Disease Activity Index 2000 score (<10 or ≥10), oral corticosteroid dosage (<10 or ≥10 mg/day), and type I IFN gene signature test status (high or low) based on a 4‐gene expression assay. The primary end point was the percentage of patients achieving an SLE Responder Index (SRI[4]) response at week 24 with sustained reduction of oral corticosteroids (<10 mg/day and less than or equal to the dose at week 1 from week 12 through 24). Other end points (including SRI[4], British Isles Lupus Assessment Group [BILAG]–based Composite Lupus Assessment [BICLA], modified SRI[6], and major clinical response) were assessed at week 52. The primary end point was analyzed in the modified intent‐to‐treat (ITT) population and type I IFN–high subpopulation. The study result was considered positive if the primary end point was met in either of the 2 study populations. The Type I error rate was controlled at 0.10 (2‐sided), within each of the 2 study populations for the primary end point analysis. Results The primary end point was met by more patients treated with anifrolumab (34.3% of 99 for 300 mg and 28.8% of 104 for 1,000 mg) than placebo (17.6% of 102) (P = 0.014 for 300 mg and P = 0.063 for 1,000 mg, versus placebo), with greater effect size in patients with a high IFN signature at baseline (13.2% in placebo‐treated patients versus 36.0% [P = 0.004] and 28.2% [P = 0.029]) in patients treated with anifrolumab 300 mg and 1,000 mg, respectively. At week 52, patients treated with anifrolumab achieved greater responses in SRI(4) (40.2% versus 62.6% [P < 0.001] and 53.8% [P = 0.043] with placebo, anifrolumab 300 mg, and anifrolumab 1,000 mg, respectively), BICLA (25.7% versus 53.5% [P < 0.001] and 41.2% [P = 0.018], respectively), modified SRI(6) (28.4% versus 49.5% [P = 0.002] and 44.7% [P = 0.015], respectively), major clinical response (BILAG 2004 C or better in all organ domains from week 24 through week 52) (6.9% versus 19.2% [P = 0.012] and 17.3% [P = 0.025], respectively), and several other global and organ‐specific end points. Herpes zoster was more frequent in the anifrolumab‐treated patients (2.0% with placebo treatment versus 5.1% and 9.5% with anifrolumab 300 mg and 1,000 mg, respectively), as were cases reported as influenza (2.0% versus 6.1% and 7.6%, respectively), in the anifrolumab treatment groups. Incidence of serious adverse events was similar between groups (18.8% versus 16.2% and 17.1%, respectively). Conclusion Anifrolumab substantially reduced disease activity compared with placebo across multiple clinical end points in the patients with moderate‐to‐severe SLE.

We have identified two cell subsets in human blood based on the lack of lineage markers (lin-) and the differential expression of immunoglobulin-like transcript receptor 1 (ILT1) and ILT3. One subset (lin-/ILT3+/ILT1+) is related to myeloid dendritic cells. The other subset (lin-/ILT3+/ILT1+) corresponds to 'plasmacytoid monocytes'. These cells are found in inflamed lymph nodes in and around the high endothelial venules. They express CD62L and CXCR3, and produce extremely large amounts of type I interferon after stimulation with influenza virus or CD40L. These results, with the distinct cell phenotype, indicate that plasmacytoid monocytes represent a specialized cell lineage that enters inflamed lymph nodes at high endothelial venules, where it produces type I interferon. Plasmacytoid monocytes may protect other cells from viral infections and promote survival of antigen-activated T cells.

Dendritic cells (DCs) are critical regulators of immune responses. Under noninflammatory conditions, several human DC subsets have been identified. Little is known, however, about the human DC compartment under inflammatory conditions. Here, we characterize a DC population found in human inflammatory fluids that displayed a phenotype distinct from macrophages from the same fluids and from steady-state lymphoid organ and blood DCs. Transcriptome analysis showed that they correspond to a distinct DC subset and share gene signatures with in vitro monocyte-derived DCs. Moreover, human inflammatory DCs, but not inflammatory macrophages, stimulated autologous memory CD4(+) T cells to produce interleukin-17 and induce T helper 17 (Th17) cell differentiation from naive CD4(+) T cells through the selective secretion of Th17 cell-polarizing cytokines. We conclude that inflammatory DCs represent a distinct human DC subset and propose that they are derived from monocytes and are involved in the induction and maintenance of Th17 cell responses. Copyright © 2013 Elsevier Inc. All rights reserved.