Background and aims Non-erosive arthritis is common in systemic lupus erythematosus (SLE). 14-3-3 eta, a chaperone protein that activates pro-inflammatory pathways is emerging as a novel biomarker for erosive Rheumatoid Arthritis. We investigated clinical associations of serum 14-3-3 eta in SLE focusing on arthritis.

Methods Sociodemographics, ACR criteria, and SLEDAI were recorded. Arthritis, assessed by the SLEDAI, was categorised as active (n=78), inactive (n=138) and never present (n=49). Serum 14-3-3 eta was measured by ELISA; titres above 0.19 ng/ml were considered positive. We report descriptive statistics and logistic regression models testing the association of 14-3-3eta with arthritis state.

Results SLE patients (n=265) were mainly female (92%), Caucasian (67%) with a mean (SD) age of 51.7 (14) years, and median (25%,75%) disease duration of 8 (4,10) years, number ACR criteria of 6 (5,7), and SLEDAI of 4 (2,7). 241 (81%) had active or inactive arthritis. 14-3-3 eta positivity was similar across the three arthritis groups (active 22/78 (28%), inactive 27/138 (20%), never present 10/49 (20%) with a median (25%75%) titre of 0.6 ng/ml (0.34, 1.82). The highest quartile of 14-3-3eta associated with active arthritis (OR 3.6 (95% CI 1.33, 9.98) p-0.012) after adjusting for ethnicity and SLEDAI. There were no differences in 14-3-3 eta positivity for other lupus criteria nor correlation of 14-3-3 eta titer with number of ACR criteria or SLEDAI.

Conclusions 14-3-3 eta titers are highest in lupus patients with active arthritis suggesting a higher risk for more severe arthritis. Further work will explore the associations of 14-3-3 eta in lupus with erosive arthritis.