title: Soluble macrophage-derived CD163 is a marker of disease activity and progression in early rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate the expression of the soluble form of the resident macrophage marker CD163 (sCD163) and its association with core parameters for disease activity, including radiographic progression in early rheumatoid arthritis (RA).
  
  
  METHODS
  In a longitudinal sample set from early RA patients (n=34) we measured plasma levels of sCD163 at initiation of treatment and after 9 months of treatment and correlated levels with disease activity in 28 joints (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and total Sharp score (TSS). We also measured plasma levels of sCD163 in 55 healthy volunteers (HV) and in a transverse sample set of chronic (>8 years of disease) RA patients (n=24) and OA patients (n=24) with paired plasma and joint fluid.
  
  
  RESULTS
  Early RA patients had significantly higher plasma levels of sCD163 (1.69mg/l (1.42-2.10)) (median (IQR)) at baseline than after 9 months of treatment (1.28mg/l (0.963-1.66), p=0.001), but not significantly changed compared with HV (1.66mg/l (1.22-2.02)). In early RA patients, baseline levels of sCD163, correlated with DAS28, CRP and ESR. Interestingly, sCD163 at 9 months was associated with radiographic progression (TSS) between year 0 and 5 (r=0.468, p=0.02). Levels of sCD163 were higher in RA patients, than in OA patients and higher in SF than in plasma.
  
  
  CONCLUSIONS
  Plasma levels of macrophage derived sCD163 are associated with disease activity and predict radiographic progression in early RA patients, supporting that sCD163 may have a role as a biomarker of disease activity and that resident macrophages are important for joint destruction.
authors.affiliation: Institute of Medical Microbiology and Immunology, Aarhus University Hospital, Denmark.
authors.forename: S R
authors.initials: SR
authors.lastname: Greisen
authors.forename: H J
authors.initials: HJ
authors.lastname: Moller
authors.forename: K
authors.initials: K
authors.lastname: Stengaard-Pedersen
authors.forename: M L
authors.initials: ML
authors.lastname: Hetland
authors.forename: K
authors.initials: K
authors.lastname: Hørslev-Petersen
authors.forename: A
authors.initials: A
authors.lastname: Jørgensen
authors.forename: M
authors.initials: M
authors.lastname: Hvid
authors.forename: B
authors.initials: B
authors.lastname: Deleuran
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000097:blood*; D015214:Antigens, Differentiation, Myelomonocytic / Q000097:blood*; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D003718:Denmark; D018450:Disease Progression; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008264:Macrophages / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000175:diagnosis / Q000276:immunology; D011237:Predictive Value of Tests; D011859:Radiography; D011956:Receptors, Cell Surface / Q000097:blood*; D013582:Synovial Fluid / Q000276:immunology; D013997:Time Factors; D016896:Treatment Outcome; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D018501:Antirheumatic Agents; D015415:Biomarkers; D000098902:CD163 Antigen; D011956:Receptors, Cell Surface; D002097:C-Reactive Protein