
The type I interferon system in the etiopathogenesis of autoimmune diseases
Author(s) -
Lars Rönnblom
Publication year - 2011
Publication title -
upsala journal of medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 41
eISSN - 2000-1967
pISSN - 0300-9734
DOI - 10.3109/03009734.2011.624649
Subject(s) - immunology , irf5 , autoimmunity , medicine , interferon regulatory factors , autoimmune disease , interferon , autoantibody , interferon type i , tlr7 , stat protein , transcription factor , immune system , toll like receptor , signal transduction , gene , biology , stat3 , innate immune system , genetics , antibody
Many patients with systemic autoimmune diseases have signs of a continuous production of type I interferon (IFN) and display an increased expression of IFN-α-regulated genes. The reason for the on-going IFN-α synthesis in these patients seems to be an activation of plasmacytoid dendritic cells (pDCs) by immune complexes (ICs), consisting of autoantibodies in combination with DNA or RNA-containing autoantigens. Such interferogenic ICs are internalized via the FcγRIIa expressed on pDCs, reach the endosome, and stimulate Toll-like receptor (TLR)-7 or -9, which subsequently leads to IFN-α gene transcription. Variants of genes involved in both the IFN-α synthesis and response have been linked to an increased risk to develop systemic lupus erythematosus (SLE) and other autoimmune diseases. Among these autoimmunity risk genes are IFN regulatory factor 5 (IRF5), which is involved in TLR signaling, and the signal transducer and activator of transcription 4 (STAT4) that interacts with the type I IFN receptor. Several other gene variants in the IFN signaling pathway also confer an increased risk to develop an autoimmune disease. The observations that IFN-α therapy can induce autoimmunity and that many autoimmune conditions have an on-going type I IFN production suggest that the type I IFN system has a pivotal role in the etiopathogenesis of these diseases. Possible mechanisms behind the dysregulated type IFNsystem in autoimmune diseases and how the IFN-α produced can contribute to the development of an autoimmune process will be reviewed.