Th113 - Serum C-type Lectin Domain Family 7 Member a Reflects Disease Activity in Patients with Systemic Lupus Erythematosus

Abstract Text: [Aim]
To investigate new biomarkers to monitor disease activity in systemic lupus erythematosus (SLE).
[Methods]
Inflammatory proteins were analyzed by proteome analysis in sera from 34 patients with SLE and 10 healthy controls (HC). Peripheral blood mononuclear cells were isolated, and proportions of 45 peripheral immune cell types were assessed by flow cytometry. Clinical data, including SLE disease activity index (SLEDAI), were collected, and correlations were evaluated. The selected protein level was measured in 21 patients with systemic sclerosis (SSc), as a disease control.
[Results]
From proteome analysis, 82 proteins were significantly different between SLE and HC. Among them, 14 had positive and 4 had negative correlations (|r|>0.4) with SLEDAI. We focused on C-type lectin domain family 7 member A (CLEC7A), which showed one of the strongest correlations with SLEDAI (r=0.48). CLEC7A levels were higher in patients with SLE compared to HC (p < 0.001) or to SSc (p < 0.05). CLEC7A levels were significantly higher in SLE patients with normal complement and negative anti ds-DNA antibodies compared to HC (p < 0.001). From the immune cell subset analysis, 19 subsets showed significant differences between patients with SLE and HC. Fourteen subsets, including activated follicular helper T (Tfh, p< 0.001) and type 17 peripheral helper T (Tph17, p< 0.0001), were significantly different between SLE patients with low disease activity (SLEDAI≤4) and HC. Furthermore, 6 out of 19 subsets, including activated Tfh (r=0.46) and Tph17 (r=0.50), correlated with CLEC7A levels (|r|>0.4).
[Conclusion]
CLEC7A could be a novel biomarker to monitor disease activity beyond the established immunological markers in SLE.