Evaluation of Serum Protein 14-3-3 Eta as a Novel Biomarker for Juvenile Idiopathic Arthritis

INTRODUCTION

JIA represents a heterogeneous range of arthritis that started prior to the age of sixteen and lasted at least six weeks with no known etiology. ¹

JIA is considered a significant cause of acquired impairment and disabilities in children and adolescents. The majority of JIA patients proceed to have joint involvement in adult life. ²

The prevalence of JIA worldwide is 1-3 per 1,000 children. ³

JIA is often hard to diagnose since it represents a diverse group of conditions that appear as inflammatory arthritis with no actual testing to verify and validate the diagnosis. Moreover, because several disorders might mimic JIA, clinical evaluation is used to make a diagnosis instead of laboratory testing. ⁴

The ILAR classification system for JIA has limited diagnostic usefulness and does not include biomarkers other than rheumatoid factor (RF) and antinuclear antibody (ANA) in the diagnosis.⁵

All eukaryotic cells include 14-3-3η (eta) proteins, which are intracellular chaperonins. There are seven human 14-3-3 isoforms, each with its own name: β, γ, ε, ζ, η, σ, and τ (beta, gamma, epsilon, zeta, eta, sigma, and tau). They are involved in a variety of intracellular biological processes, including cell proliferation, differentiation, and apoptosis.⁶

During the early stages of JIA, the 14-3-3 eta protein is liberated into the extracellular space as a cellular adapter protein. It works as an innate immune system inducer. As a result, additionally to current biomarkers, 14-3-3 eta protein has the potential to improve laboratory efficiency in the early diagnosis as well as prognosis of JIA. Evaluation of 14-3-3 Eta protein role was estimated in many rheumatic diseases, but its role in JIA diagnosis is still uprising and under consideration.⁷

This study aimed to evaluate serum 14-3-3 Eta as a potential new biomarker for JIA diagnosis as well as its relation with other biomarkers like RF and Anti-CCP.

PATIENTS AND METHODS

The case-control study included fifty patients, subdivided into 20 PJIA patients, 20 OJIA patients, and 10 SJIA patients, and all of them fulfilled ILAR classification criteria. ⁸        They were selected from AL Hussein and Bab El Sharia University Hospitals                    'Rheumatology Departments' outpatient clinics and inpatients, with twenty healthy children serving as a control group, between March 2020 and June 2021. Other reasons of childhood arthritis were excluded, such as Infection, malignancy, rheumatic fever, and patients with endocrinal diseases like DM. obtained informed consent from all participants.

All participants were subjected to

Disease activity assessment :

Juvenile arthritis disease activity score (JADAS 27) ⁹, CHAQ (Childhood Health Assessment Questionnaire)¹⁰for all participants.

laboratory assessment:

Included C - reactive protein (CRP), Erythrocyte sedimentation rate (ESR), complete blood count (CBC), RF, Anti-CCP and Serum 14-3-3 Eta by ELISA.

Statistical analysis:

The statistical package for the social sciences, version 23.0, has been employed to collect, code, revise, and enter data (SPSS Inc., Chicago, Illinois, USA). The quantitative data has been presented as mean, standard deviations when the parametric distribution is normal. In contrast, non-normally distributed variables (non-parametric data) have been shown to have a median with an inter-quartile range (IQR). Numbers and percentages have also been employed to represent qualitative variables. Data was examined for normalcy employing the Kolmogorov-Smirnov and Shapiro-Wilk tests, as well as the relationship between qualitative variables employing the Chi-square test (X2).  ANOVA or Kruskal-Wallis, Spearman's correlation to compare differences between quantitatively independent multiple groups. The margin of error acceptable was 5%, with a confidence interval of 95%. As a result, the significance of the p-value was determined as follows: p-values > 0.05 indicate non-significant (NS), p-values < 0.05 indicate significance (S), and p-values < 0.01 indicate highly significant (HS).

RESULTS

Fifty JIA patients have been categorized into three groups: polyarticular JIA (PJIA n = 20), oligoarticular JIA (OJIA n = 20), systemic-onset JIA (SJIA n = 10), and twenty healthy children (control group n= 20).The mean age of JIA patients (11.80±2.75) and for healthy children (5.55±3.38).

The serum 14-3-3 eta protein receiver operating curve (ROC) has been discovered at levels greater than1.45 ng/ml among all JIA subgroup patients with 84 % sensitivity, 55 % specificity, 65.6% positive predictive value (PPV), and 69.2% negative predictive value (NPV). (Table 1) (figure1).

Table 1: The 14-3-3 eta protein's cutoff value, sensitivity, and specificity.

Fig. 1: ROC curve for diagnosis and prediction of JIA using Serum Protein 14-3-3 Eta.

The levels of 14-3-3η eta (ng/ml) in JIA subgroups and control group normal children showed statistically significant differences (P-value <0.05). It has been discovered that polyarticular JIA (median 27.7 ng/ml) had significantly greater levels followed by OJIA and SOJIA (median 22.03 ng/ml) (Table 2) (figure2).

Table 2: Comparison of 14-3-3η eta (ng/ml) levels in sub-group JIA patients and control group (normal children).

Fig. 2: Eta protein levels (ng/ml) in JIA subgroups and normal children according to     14-3-3η eta (ng/ml).

There was a statistically significant (p-value < 0.05) relationship between 14-3-3 eta level with RF and Anti-CCP, In which 14-3-3η eta levels being higher in positive RF and Anti-CCP JIA cases compared to negative cases (p values = 0.034 and 0.040 respectively) (Table 3).

Table 3: Relation between RF, Anti-CCP and 14-3-3η eta (ng/ml) in JIA patients.

In JIA patients, serum 14-3-3 eta (ng/ml) levels exhibited a statistically significant positive association with CHAQ (Table 4).

Table 4: Correlation between 14-3-3 eta (ng/ml) with all parameters, using Spearman's rho in JIA patients.