Serum Interleukin 5 as an Indicator of Eosinophilic Esophagitis in Patients with Chronic Upper GIT Symptoms

Interleukin-5 (IL-5) in serum by ELISA was measured in all subjects. Results: By histopathological examination, six patients (7.5%) were diagnosed to have EoE. Endoscopic esophageal furrows, fissures/wrinkles; white exudate/granularity and concentric rings (trachealization) were significantly more frequent in patients with EoE than non EoE. Median concentration of serum IL-5 in EoE patients was 222.2pg/ml with range 187.5-307pg/ml while, it was 32.1pg/ml with range 15.6-113.6pg/ml in non EoE patients and 11.8pg/ml with range 13.4-38.2pg/ml in controls with P value < 0.001. ROC curve analysis showed that serum IL-5 can significantly predict EoE at a cut-off value of ≥103.2pg/ml with sensitivity 100%, specificity 93.2%, PPV 54.5%, NPV 100%, Accuracy 93.8%, AUC = 0.989 and (95%CI) = 0.96-1.0. Conclusion: Serum interleukin 5 could be used as an indicator for eosinophilic esophagitis diagnosis in patients with chronic upper GIT symptoms. However, histopathological diagnosis still necessary .


INTRODUCTION
Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus that had become widely recognized as a major cause of upper gastrointestinal morbidity [1].EoE  Endoscopic examination is required for diagnosis of EoE in which typical endoscopic findings include esophageal rings, narrowing or strictures, linear furrows, white plaques/exudates and mucosal fragility also termed crêpe-paper mucosa.However, in a small proportion of cases, esophageal mucosa may appear normal and the diagnosis would be missed if biopsies are not taken [6].At least two to four biopsies should be taken from the proximal, mid and distal esophagus to maximize the sensitivity of EoE diagnosis [7].The presence of more than 15 eosinophils/HPF with history of non-intake of PPI for 30 days before were used as prerequisite diagnostic criteria for eosinophilic esophagitis [8].Central role for interleukin 5 (IL-5) in inducing eosinophil trafficking to the esophagus which, is necessary for the induction of eosinophilic esophagitis [9].Usage of humanized monoclonal blocking anti-IL-5 antibody, that brought about significant decrease in symptoms of esophageal eosinophilia [10].Serum indicators for diagnosis of EoE are required to be complement with histopathological assessment.This study aimed to determine the value of serum IL-5 as an indicator for EoE diagnosis.

PATIENTS AND METHODS
This case-control study was performed from January 2019 to November 2020 after ethical committee approval of the scientific research in Benha Faculty of Medicine and written medical consent included 80 consecutive adult patients attended to the endoscopy unit of Hepatology, Gastroenterology and Infectious disease Department-Benha University Hospitals for upper GIT endoscopy.Ten cross-matched age and sex apparently healthy subjects were enrolled as a control group.

Inclusion criteria:
-At least one or more of chronic symptoms suggestive of esophageal dysfunction as heartburn, dysphagia, odynophagia, chronic epigastric pain, recurrent vomiting, noncardiac chest pain, regurgitation, belching, globus sensation, water brash and/or history of food impaction.
-Non response to standard daily PPI therapy for at least 8 weeks.

Exclusion criteria:
-History of upper GIT bleeding.
-Recent PPI intake for at least one month before endoscopic examination.
-Patients with organic lesions (mass or ulcer …etc.)detected during endoscopic examination.
Most of these morbidities can be excluded with a careful history taking, physical examination and conventional laboratory tests.All patients were subjected to: Clinical evaluation: Thorough history taken.General and local abdominal examination.Laboratory investigation: after conventional laboratory investigation, measurement of serum interleukin-5 (IL-5) by ELISA (enzyme-linked immunosorbent assay) technique at Clinical and Chemical Pathology Department (Benha University Hospital) had been done.The human IL-5 kits included in this study were ELISA type and had size 48T/96T, range from 5.625-1000 pg./ml for application in quantitative detection of IL-5 in serum was done.Principle for detection based on sandwich ELISA technology.Anti-IL-5 antibody was precoated onto 80 well plates.The biotin conjugated anti-IL-5 antibody had been used as detection antibodies.Finding source: None.

Conflicts of interest:
The authors declare that they have no conflict of interest.

Acknowledgement:
The authors would thank all our colleagues who helped us.

HIGHLIGHTS
 Eosinophilic esophagitis represents unusual cause of chronic esophageal dysfunction symptoms.
 Serum biomarker for its diagnosis is required to be as an indicator and complement of histological diagnosis.
 The current study aimed to assess serum interleukin 5 as an indicator of eosinophilic esophagitis (EoE) in patients with chronic upper GIT symptoms.
 The positive relationship between the increased level of serum interleukin 5 and possibility of eosinophilic esophagitis diagnosis was reported in this study.
 However, histological diagnosis remains to be necessary and further studies are required to investigate the usage of serum interleukin 5 in follow up of and monitoring disease therapy.

Source of IL-5 kits was New Test Company. Upper GI endoscopy: Midazolam or propofol
Categorical data were compared by using Chi-square test.ROC curve was constructed to detect cutoff values of IL-5 and blood eosinophils in prediction of EoE.EoE patients (table 2).By laboratory assessment of the studied subjects (peripheral eosinophilic count), all six eosinophilic esophagitis patients had increased peripheral eosinophilic count (2.3-7.0%)thannon-EoEpatients and controls with statistically significant difference (table3 and 6).studied subjects, mucosal and sub mucosal edema, basal hyperplasia, papillae elongation, squamous cell layer thinning and infiltration lymphocytic or neutrophilic were more frequent in EoE compared with non-EoE patients (83.3, 83.3, 83.3, 66.7 and 83.3% vs 28.4,28.4,35.1, 23and 26%) with significant statistically difference.While, goblet Cell metaplasia was demonstrated only in 7 patients of non-EoE (table 5).Regarding serum IL-5 assay by ELISA, median concentration of serum IL-5 in EoE patients was 222.2pg/ml with range 187.5-307pg/ml while, it was 32.1pg/ml with RESULTS:

Table ( 1
): Demographic data in the studied subjects.

Table ( 2
): Clinical symptomatology in the studied patients.

Table ( 3
): CBC in the studied subjects.

Table ( 4
): Endoscopic findings in the studied patients.

Table ( 5
): Histopathological finding in the studied patients.