The 14-3-3η (eta) protein is an emerging biomarker for RA and erosive
psoriatic arthritis diagnosis. It is produced by joints and it may play a
biologic role in the joint erosive process. Blood levels appear to be elevated
in patients with RA, but not in other diseases including psoriasis,
osteoporosis, gout, ulcerative colitis, type 1 diabetes, systemic lupus
erythematosus, Crohn disease, primary Sjögren syndrome, scleroderma, and
A positive test indicates that the patient should be considered for referral
to a rheumatologist, prior to the onset of significant joint damage. [7,8] A
positive JOINTstat test early in disease also marks high joint damage risk, and
therefore, along with other clinical indicators, would signal to a
rheumatologist how aggressively to treat and monitor the patient.
Studies to date have shown that 14-3-3η:
- Is positive in patients with joint pain who develop RA within 5 years of
- At high levels (>0.80 ug/L) is an indicator of RA that will lead to more
joint damage over 3 years.
- At lower levels (<0.40 ug/L or negative in RA diagnosed patients) is an
indicator of a higher likelihood of response to RA therapy.
- Decreasing levels with treatment or over time indicate a better disease
- Overall, RA patients who are negative or who have low levels (<0.40 ug/L)
have a more favourable outcome.