Background/Purpose:

Serum 14-3-3 eta has been described to have diagnostic utility and in established RA an association has been established between the levels of this marker and the degree of joint damage. The η isoform of 14-3-3 is expressed extracellularly in much higher concentration than the ϒ isoform or MMP 1 and 3 levels in the synovial fluid and serum of patients with rheumatoid arthritis compared to the normal population. Rheumatoid factor (RF) is known to be sensitive and anti-CCP highly specific for RA, but a high number of patients remain seronegative .There is a need for a biomarker to prevent underdiagnosis in this subset.

The purpose of the study was to investigate if serum 14-3-3 η enhanced the detection of RA over RF or anti-CCP in RA patients. We also studied the utility of 14-3-3 eta as a diagnostic test by comparing presence of this protein in RA v/s non-RA patients.

Methods:

A retrospective chart review study was conducted in RA patients at an outpatient rheumatology clinic in an inner city population at a community teaching hospital serving a large immigrant population. 90 RA patients were identified who satisfied the 2010 ACR diagnostic criteria and 37 non RA patients seen in the clinic for other rheumatologic conditions were chosen as the control group. Serum 14-3-3η protein was measured by ELISA. The positive threshold range using Quest Diagnostic for RF was 15 International Unit/ml, Anti CCP was 20 Units and for 14-3-3 eta was 0.2 ng/mL. The chi-square goodness-of-fit test was used to analyze the frequency of eta positivity in the RA population while kappa was calculated to compare the RA and non RA patients.

Results:

Of the 90 RA patients, 75.8 % were females and mean age was 58 (range 28- 90) years. The population was predominantly Hispanic (75%). In the non-RA group, 9% had psoriatic arthritis and 14% lupus, 73% were females, 76% Hispanic and the mean age was 54 (range 19-93) years. In the non-RA population, 22 patients were ETA positive, of these 11 patients were also RF positive and 9 were ACPA positive. In the RA population, 1 RF negative patient was ETA positive, while 47 patients were both ETA and RF positive. Further 1 patient was found to be ETA positive with a negative ACPA, while 47 patient’s were both ETA and ACPA positive.

Table I: Non-Rheumatoid Arthritis Patients

Table II: Rheumatoid Arthritis Patients

Conclusion:

 In our population, measurement of 14-3-3η ETA offered limited additional diagnostic value when compared to RF and ACPA. Furthermore, it was found to offer no additional value in differentiating RA from other inflammatory arthropathies where RF can also be found positive.

« Back to 2015 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/does-14-3-3-eta-protein-offer-any-additional-diagnostic-value-in-rheumatoid-arthritis/