Serum level of soluble triggering receptor expressed on myeloid cells-1 as a biomarker of disease activity in relapsing polychondritis.

OBJECTIVES

We aimed to identify a serum biomarker for evaluating the disease activity of relapsing polychondritis (RP).

METHODS

We measured and compared serum levels of 28 biomarkers potentially associated with this disease, including soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), high-sensitivity C-reactive protein (hs-CRP), and cartilage oligomeric matrix protein (COMP), in 15 RP patients and 16 healthy donors (HDs). We divided the 15 RP patients into active RP (n = 8) and inactive RP (n = 7) groups, depending on the extent of the disease, and compared candidate markers between groups. The localization of membrane-bound TREM-1 in the affected tissue was examined by immunohistochemistry.

RESULTS

Serum levels of sTREM-1, interferon-γ, chemokine (C-C motif) ligand 4, vascular endothelial growth factor, and matrix metalloproteinases-3 were significantly higher in RP patients than HDs. Among these markers, sTREM-1 had the highest sensitivity and specificity (86.7 and 86.7 %, respectively). Furthermore, the serum level of sTREM-1 was significantly higher in active RP patients than inactive RP patients (p = 0.0403), but this was not true for hs-CRP or COMP. TREM-1 was expressed on endothelial cells in RP lesions.

CONCLUSIONS

The serum level of sTREM-1 may be a useful marker of disease activity in RP.