Altered cytokine expression by macrophages from HLA-B27-positive spondyloarthritis patients without evidence of endoplasmic reticulum stress.

Objectives: We investigated endoplasmic reticulum (ER) stress and cytokine expression in peripheral blood-derived macrophages and synovial tissue from HLA-B27 SpA patients.

Methods: Macrophages from healthy donors, SpA and RA patients were polarized with IFN-γ or IL-10 and activated with lipopolysaccharide. Expression of ER stress markers (BiP, CHOP, ERdj4) and cytokines (IL-23, IL-12, TNF, IL-10) was measured by qRT-PCR. Expression of ER stress markers and cytokines in synovial tissue from SpA patients was evaluated by microarray analysis.

Results: Macrophages from HLA-B27 SpA patients did not show elevated ER stress markers. However, the expression of IL-23 and IL-12 by peripheral blood-derived macrophages was higher in HLA-B27 SpA in comparison with healthy donors. Synovial tissue from HLA-B27 SpA patients showed higher expression of TNF compared with HLA-B27 SpA patients.

Conclusion: HLA-B27 SpA patients showed increased expression of IL-23, IL-12 and TNF without evidence of ER stress.