Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Levels of Soluble CD163 Is Associated with Disease Activity and Radiographic Progression in Early Rheumatoid Arthritis.

Greisen6,  Stinne R., Hvid4,  Malene, Stengaard-Pedersen1,  Kristian, Hetland2,  Merete L., Horslev-Petersen7,  Kim, Moller3,  Holger J., Deleuran5,  Bent

Arhus University Hospital, Aarhus, Denmark
Copenhagen Univ Hosp Hvidovre, Hvidovre, Denmark
Department of Clinical Biochemistry, Aarhus University Hospital, Denmark
Institute of Medical Microbiology and Immunology, University of Aarhus and Department of Dermato-venerology Aarhus University Hospital, Denmark
Institute of Medical Microbiology and Immunology, University of Aarhus, and Aarhus University Hospital, Denmark
Institute of Medical Microbiology and Immunology, University of Aarhus, Denmark
King Christian X Hospital for Rheumatic Disease, University of Southern Denmark

Background:

The macrophage is the predominant cell type in the cartilage-panus junction, and is strongly associated with joint destruction in rheumatoid arthritis (RA). Resident macrophages exclusively express the scavenger receptor CD163, which is also present in plasma and joint fluid in a soluble form (sCD163).

Objective:

The aim was to investigate the degree of macrophage activity by the presence of solouble and cell surface CD163. Soluble CD163 was investigated for its association with core parameters for disease activity including radiographic progression in early RA, and cell surface CD163 was examined for its co-expression with the known monocyte/macrophage marker CD14.

Methods:

In a longitudinal sample set of early RA patients (n=34) we measured plasma levels of sCD163 at baseline and after 9 months of treatment, and correlation levels with disease activity in 28 joints (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and total Sharp score (TSS). In a transverse sample set of chronic (>8 years of disease) RA patients (n=24) we measured paired plasma and joint fluid levels of sCD163 by ELISA. We also examined the cellular expression of CD163 and CD14 by flow cytometry. Statistical correlations were assessed by Spearman's rho, and data are expressed as median with IQR in parenthesis.

Results:

In early RA, patients had significantly higher plasma levels of sCD163 (1.69 mg/L (1.42–2.10)) at baseline, than after 9 months of treatment (1.28 mg/L (0.963–1.66) p=0.001). Plasma levels of sCD163 at baseline were strongly correlated with sCD163 at 9 months, (r2=0.672, p=0.00001). At baseline sCD163 correlated with DAS28, CRP and ESR. Interestingly sCD163 at 9 months, but not at baseline, was associated with radiographic progression (TSS) between year 2 and 3 (r2=0.468, p =0.02). Chronic RA patients had higher plasma levels of sCD163 than early RA patients (3.05 mg/L (1.84–6.04)), p<0.001). The levels in joint fluid were even higher (8.32 mg/L (6.04–10.65)) and correlated with sCD163 in plasma (r2=0.4, p=0.05).

Cell surface CD163 was almost exclusively detected on synovial macrophages, compared with cells in peripheral blood (p=0.02), and all CD163+ cells co-expressed CD14.

Conclusion:

Plasma levels of sCD163 are associated with core parameters for disease activity and radiographic progression, and decreases significantly after 9 months of effective treatment. The observation that sCD163 in the synovial fluid correlates with plasma levels, and that CD163 is highly expressed by synovial macrophages, supports that resident macrophages are important for the joint destruction in early RA, and that plasma sCD163 reflects the macrophages population within the inflamed joint. This supports the role of sCD163 as a biomarker of disease activity and joint destruction.

To cite this abstract, please use the following information:
Greisen, Stinne R., Hvid, Malene, Stengaard-Pedersen, Kristian, Hetland, Merete L., Horslev-Petersen, Kim, Moller, Holger J., et al; Levels of Soluble CD163 Is Associated with Disease Activity and Radiographic Progression in Early Rheumatoid Arthritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1761
DOI: 10.1002/art.29526

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