title: Downregulation of immunoglobulin-like transcript-4 (ILT4) in patients with psoriatic arthritis.
abstract: OBJECTIVE
  The immunoglobulin-like transcript-4 (ILT4) is an inhibitory receptor that modulates the activity of innate immune agents. We determined the expression of ILT4 and analysed the relationship with the expression of costimulatory proteins and tumor necrosis factor-α (TNF-α) production in monocytes from patients with psoriatic arthritis (PsA) starting anti-TNF treatment.
  
  
  METHODS
  Peripheral blood monocytes from 15 healthy controls and from 16 patients with PsA were activated in vitro by CD40 ligand (CD40L) and analyzed for ILT4, CD40, CD80 and CD86 expression, and spontaneous lipopolysaccharide (LPS)-induced TNF-α production by flow cytometry, before and after treatment with adalimumab.
  
  
  RESULTS
  The percentage of ILT4-negative monocytes was greater in PsA patients compared to controls and negatively correlated with DAS44. Normal monocytes treated with sera of PsA patients showed a reduced expression of ILT4 compared with monocytes exposed to sera from controls. CD40, CD80 and CD86 expression was higher in patients compared to controls. Both spontaneous and LPS-induced TNF-α production was restricted to ILT4-negative monocytes and was greater in PsA patients compared to controls. Finally, twelve weeks-treatment with adalimumab resulted in a significant increase of ILT4 expression and a decrease of costimulatory molecules expression in PsA patients, compared to pre-therapy levels.
  
  
  CONCLUSIONS
  These data support the possibility that changes in the immunophenotype of monocytes play a role in the pathogenesis of PSA. Thus, modulation of the expression of ILT4 may represent an enticing new therapeutic target.
authors.affiliation: Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, Unit of Rheumatology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bergamini
authors.affiliation: Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, Unit of Rheumatology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Maria Sole
authors.initials: MS
authors.lastname: Chimenti
authors.affiliation: Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, Unit of Rheumatology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Baffari
authors.affiliation: Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, Unit of Rheumatology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Maria Domenica
authors.initials: MD
authors.lastname: Guarino
authors.affiliation: Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, Unit of Rheumatology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Gigliucci
authors.affiliation: Reumatologia, Dipartimento di Medicina Interna e Specialità Mediche, Sapienza Università di Roma, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Perricone
authors.affiliation: Rheumatology, Allergology and Clinical Immunology, Department of Internal Medicine, Unit of Rheumatology, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Perricone
mesh_terms: D000068879:Adalimumab / Q000494:pharmacology / Q000627:therapeutic use; D000328:Adult; D015535:Arthritis, Psoriatic / Q000188:drug therapy / Q000235:genetics* / Q000276:immunology; D018122:B7-1 Antigen / Q000378:metabolism; D051940:B7-2 Antigen / Q000378:metabolism; D019013:CD40 Antigens / Q000378:metabolism; D023201:CD40 Ligand / Q000378:metabolism; D016022:Case-Control Studies; D016207:Cytokines / Q000096:biosynthesis; D015536:Down-Regulation; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D011971:Receptors, Immunologic / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D018122:B7-1 Antigen; D051940:B7-2 Antigen; D019013:CD40 Antigens; D016207:Cytokines; C491341:LILRB2 protein, human; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D014409:Tumor Necrosis Factor-alpha; D023201:CD40 Ligand; D000068879:Adalimumab