ABSTRACT
LL37 exerts a dual pathogenic role in psoriasis. Bound to self-DNA/RNA, LL37 licenses autoreactivity by stimulating plasmacytoid dendritic cells-(pDCs)-Type I interferon (IFN-I) and acts as autoantigen for pathogenic Th17-cells. In systemic lupus erythematosus (SLE), LL37 also triggers IFN-I in pDCs and is target of pathogenic autoantibodies. However, whether LL37 activates T-cells in SLE and how the latter differ from psoriasis LL37-specific T-cells is unknown. Here we found that 45% SLE patients had circulating T-cells strongly responding to LL37, which correlate with anti-LL37 antibodies/disease activity. In contrast to psoriatic Th17-cells, these LL37-specific SLE T-cells displayed a T-follicular helper-(TFH)-like phenotype, with CXCR5/Bcl-6 and IL-21 expression, implicating a role in stimulation of pathogenic autoantibodies. Accordingly, SLE LL37-specific T-cells promoted B-cell secretion of pathogenic anti-LL37 antibodies in vitro. Importantly, we identified abundant citrullinated LL37 (cit-LL37) in SLE tissues (skin and kidney) and observed very pronounced reactivity of LL37-specific SLE T-cells to cit-LL37, compared to native-LL37, which was much more occasional in psoriasis. Thus, in SLE, we identified LL37-specific T-cells with a distinct functional specialization and antigenic specificity. This suggests that autoantigenic specificity is independent from the nature of the autoantigen, but rather relies on the disease-specific milieu driving T-cell subset polarization and autoantigen modifications.
Subject(s)
Antimicrobial Cationic Peptides/immunology , Autoantibodies/immunology , Lupus Erythematosus, Systemic/immunology , T-Lymphocytes/immunology , Anti-Citrullinated Protein Antibodies/immunology , Antibodies, Antinuclear/immunology , Antibody Formation/immunology , DNA/immunology , Dendritic Cells/immunology , Female , Humans , Lupus Erythematosus, Systemic/etiology , Male , Psoriasis/etiology , Psoriasis/immunology , Th17 Cells/immunology , CathelicidinsABSTRACT
Without appropriate treatment, Group A streptococcal infections can lead to post-streptococcal syndrome, including post-streptococcal uveitis. This should be kept in mind in young patients with acute bilateral non-granulomatous anterior uveitis, in order to avoid ocular and systemic complications. We report two cases of bilateral post-streptococcal anterior uveitis, in young men, of respectively 20 and 16 years old, that presented to Jules Gonin Eye Hospital.
