Serum Level Of Interleukin-23 in patients with Juvenile Idiopathic Arthritis and correlation to Disease Activity

INTRODUCTION

Juvenile Idiopathic Arthritis (JIA) is the commonest rheumatic disease that affects children. ¹

JIA is diagnosed in children younger than 16 years with arthritis which presist for more than 6 weeks with no other underlying cause. ²

JIA is accounted as a significant cause of acquired impairment and disabilities in children.³

The prevalence of JIA in Egypt is estimated to be 3.43 - 20 cases in every 100,000 occupant and worldwide is 1-3 per 1,000 children. ⁴

Interleukin-23 as one of the IL-12 cytokine family with pro-inflammatory properties. it is responsible for various autoimmune responses in JIA as it promotes the expansion of the  T helper type 17.⁵

IL-23 has a crucial role in the progression and severity of JIA. ⁶

This work aimed to evaluate serum IL 23 as a novel biomarker for JIA diseases activity.

PATIENTS AND METHODS

A case-control study included Fifty JIA patients fulfilling the ILAR classification criteria were classified into three groups: Group A:  Polyarticular Rheumatoid factor positive JIA (n = 15), Group B:   Polyarticular Rheumatoid factor Negative JIA (n = 17), Group C: Oligoarticular JIA (n = 18), and eighteen healthy children as a control group. They were selected from AL Al-Azhar university hospitals Rheumatology Departments, between March 2017 and June 2020. Other reasons of childhood arthritis were excluded, such as Infection, malignancy, rheumatic fever with obtained informed consent from all participants.

All participants were subjected to Disease activity assessment by Juvenile arthritis disease activity score (JADAS 71) ⁷, CHAQ (Childhood Health Assessment Questionnaire)⁸. As well as , laboratory assessment including  C - reactive protein (CRP), Erythrocyte sedimentation rate (ESR), complete blood count (CBC), RF, ANA and Serum IL-23 by ELISA.

Statistical analysis was done as follows; 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

The mean age of JIA patients included were (9.40±10.1) and for healthy children (8.6±3.4).

The serum IL-23 receiver operating curve (ROC) has been discovered at levels greater than ≥15.00 pg/ml for JIA subgroups with 80 % sensitivity, 91.7% specificity, 92.3% positive predictive value (PPV), and 78.6 % negative predictive value (NPV) (Table 1).

Table 1: The IL 23 cutoff value, sensitivity, and specificity.

There was a highly statistically significant difference between JIA subgroups according to serum IL-23 with p-value (p<0.001). The highest value was found in the group A and group B (29.77±13.41 & 34.31±9.14), followed by Group C (11.87±5.80), while the lowest value was found in control group (2.75±2.16) (Table 2) (Figure 1).

Table 2: Comparison between study groups according to serum IL-23 in pg/ml.