title: Monocyte Siglec-14 expression is upregulated in patients with systemic lupus erythematosus and correlates with lupus disease activity.
abstract: Siglecs are sialic acid-binding immunoglobulin-like lectins expressed on the surface of immune cells, which participate in the discrimination of self and non-self. We investigated myeloid CD33-related Siglec expression in a cohort of patients with SLE.
  
  
  
  Cell surface expression of Siglec-5/14, Siglec-9 and Siglec-10 on peripheral myeloid subsets were analysed from 39 SLE patients using flow cytometry. Genotyping of the Siglec-5/14 locus was also performed. Clinical markers of SLE disease activity, including SLEDAI, serum complement concentrations and serum autoantibodies, were assessed and correlated with Siglec levels.
  
  
  
  Siglec-14 expression on SLE monocytes (median = 518, interquartile range: 411) was significantly higher when compared with healthy controls (median = 427, interquartile range: 289.3; P < 0.05) and correlated positively with SLEDAI scoring and anti-Sm and anti-SSB autoantibodies (P < 0.05). A negative correlation was determined with patient serum C3 concentrations (P < 0.005). Genotyping of the Siglec-5/14 locus revealed a high frequency of the Siglec-14 null allele across both groups, reflecting the incidence in Asian populations.
  
  
  
  Our data suggest that the Siglec immunomodulatory molecules, in particular Siglec-14 expression on monocytes, may play an important role in the inflammatory events of SLE. No bias was found with regard to SIGLEC14 genotype in our patient group compared with healthy controls. Larger comparisons of mixed ethnicity might, however, reveal an important role for Siglecs in the pathogenesis of autoimmune disease.
authors.affiliation: Singapore Immunology Network, A*STAR, Singapore, 138648.
authors.forename: Susannah I
authors.initials: SI
authors.lastname: Thornhill
authors.affiliation: Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.|Division of Rheumatology, National University Hospital, Singapore, 119074.
authors.forename: Anselm
authors.initials: A
authors.lastname: Mak
authors.affiliation: Singapore Immunology Network, A*STAR, Singapore, 138648.
authors.forename: Bernett
authors.initials: B
authors.lastname: Lee
authors.affiliation: Singapore Immunology Network, A*STAR, Singapore, 138648.
authors.forename: Hui Yin
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Singapore Immunology Network, A*STAR, Singapore, 138648.
authors.forename: Michael
authors.initials: M
authors.lastname: Poidinger
authors.affiliation: Institute of Molecular and Cell Biology, A*STAR, Singapore, 138673, Singapore.|Institute of Biomedical Studies, Baylor University, Waco.
authors.forename: John E
authors.initials: JE
authors.lastname: Connolly
authors.affiliation: Singapore Immunology Network, A*STAR, Singapore, 138648.|Department of Immunology, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Anna-Marie
authors.initials: AM
authors.lastname: Fairhurst
mesh_terms: D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D037102:Lectins / Q000235:genetics / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000188:drug therapy / Q000208:ethnology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011239:Prednisolone / Q000627:therapeutic use; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology; D055815:Young Adult
chemical_list: D000893:Anti-Inflammatory Agents; D037102:Lectins; D011956:Receptors, Cell Surface; C514213:SIGLEC14 protein, human; D011239:Prednisolone
keywords: Siglec; monocytes; systemic lupus erythematosus