D1.326 - Behind The Scenes: Primary Immunodeficiencies in Pediatric Eosinophilic Gastrointestinal Diseases

Primary immunodeficiencies (PIDs) and eosinophilic gastrointestinal diseases (EGIDs) may share common underlying defects.  Therefore, recently, studies focusing on the prevalence of EGIDs in PIDs come to the fore. Contrary, no studies to date have investigated the frequency of PIDs among patients with EGIDs. In this study, we aimed to assess the frequency and spectrum of PIDs among our pediatric EGIDs patients.

Patients were prospectively evaluated over a two-year period. Electronic health records were screened for EGIDs' specific features, comorbidities, and previous laboratory tests. All patients were questioned according to the ten warning signs of the Jeffrey Modell Foundation. Routine laboratory tests and basic immunologic tests [serum immunoglobulin (Ig) levels (IgG, Ig A, Ig M, Ig E), isohemagglutinin titres, anti-HBs and anti-rubella Ig G titres] were performed on all participants. Advanced immunologic workup was performed in selected cases after the initial evaluation. All PID diagnoses were established according to the European Society for Immunodeficiencies (ESID)’ criterias.

A total of 88 EGID patients [76% male, mean age: 12.02 years, 78 patients (88.6%) with EoE] were included. Fourteen patients were diagnosed with predominantly antibody deficiencies [unclassified antibody deficiency (n=11), selective Ig A deficiency (n=2), transient hypogammaglobulinemia of infancy (n=1)]. Eighteen patients had altered Ig levels. Comparisons across the groups [patients with PID (n=14), without PID (n=56), and with altered immunoglobulin levels (n=18)] revealed no statistically significant differences in demographic, endoscopic and pathologic features. Only topical swallowed budesonide unresponsiveness was significantly higher among cases with PID (p = 0.038).

Primary immunodeficiencies are not rare among EGIDs patients. JMF’s warning signs alone are insufficient for establishing a diagnosis; therefore, additionally basic immunologic tests as first step and advanced evaluation in suspected cases may be appropriate. In patients with EGIDs, neither the key diagnostic endoscopic and pathological features nor the presence of strictures reliably distinguish patients with primary immunodeficiency.