Increased release of soluble CD163 by the peripheral blood mononuclear cells is associated with worse prognosis in patients with systemic sclerosis.

Purpose: CD163 is a scavenger receptor which is exclusively expressed on monocytes/macrophages and participates in modulation of inflammatory response. We aimed to evaluate ex vivo production of soluble CD163 (sCD163) by peripheral blood mononuclear cells (PBMC) from patients with systemic sclerosis (scleroderma, SSc).

Material/methods: Concentration of sCD163 was measured by commercially available ELISA kit in the PBMC suparnates from 23 SSc patients and 16 age- and sex-matched healthy controls (HC). Eighteen SSc patients were subsequently followed for at least three years or until death whichever happened earlier. Disease progression was defined as death due to SSc-related organ complication, development of a new or progression of pre-existing SSc-related organ involvement.

Results: PBMC from SSc patients released significantly greater amounts of sCD163 as compared with HC (p<0.05). No significant associations between release of sCD163 by PBMC and baseline clinical or laboratory parameters of the disease could be found. However, concentration of sCD163 in cell culture supernates was significantly higher in 6 SSc patients who experienced subsequent progression of the disease as compared with 12 SSc patients with stable disease course over a 3-year follow-up period (p<0.05).

Conclusions: We show, for the first time, that PBMC from SSc release significantly greater amounts of sCD163 than do PBMC from healthy subjects. Evaluation of sCD163 production by PBMC ex vivo may serve as a new biomarker of disease progression. Further studies are required to evaluate the role of sCD163 in the development of SSc.