Retrospective evaluation of clinicaland laboratory results of patients with selective immunoglobulin E deficiency/low

INTRODUCTION Selective immunoglobulin (Ig) E deficiency is defined as a significant reduction in IgE levels (<2.5 internationalunits/mL) in a patient with normal levels of other immunoglobulins, including IgG, IgG subclassesand IgA levels. It is an unproven laboratory finding equivalent to a clinical disorderand selective IgE deficiency is not yet considered primary immune failure. MATERIAL AND METHOD This study included 135 patients under the age of 18 who applied to Yeditepe University Hospital between 2013-2023 with Ig E levels below 10 kIU/L and all other immunoglobins requested. Patients with IgE levels below 2 kIU/L and other immunoglobulin levels within normal age-appropriate limits were definedas Selective IgE deficiency. Those with IgE levels of 2-10 kIU/L were defined as having low IgE levels. 25 of 135 patients were Selective IgE deficiency and the remaining 110 patients were low-IgE. 135 patients were analyzed in terms of age, gender, atopy, allergy, frequent infections, reasons for hospital admission, infections, allergies and other diseases in their medical history until the time of hospital admission, the treatments they used, the course of the disease after diagnosis and the treatments used and the evaluation of comorbid diseases. RESULTS 110 patients (81.5%) had IgE deficiency and 25 (18.5%) had selective IgE deficiency. 15 (60%) of the patients with Selective IgE deficiency were male and 10 (40%) were female. In patients with IgE deficiency, 50 (45.4%) were male and 60 (54.6%) were female. At the time of presentation, 7(31.8%) patients with selective IgE deficiency had cough, 7(31.8%) had frequent illness, 3(13.7%) had nasal congestion, 3(13.7%) had eczema, 1(4.5%) had diarrhea and 1(4.5%) had earache. In patients with low IgE, 43(43%) had cough, 23(23%) had frequent illness, 16 (16%) had nasal congestion, 7(%7) had eczema, 6(6%) had earache and 5(5%) had diarrhea. While 68% of patients with Selective IgE deficiency had no disease at the time of diagnosis, 55% of patients with low IgE had no disease at the time of diagnosis. Allergic rhinitis was present in 5 (20%), asthma in 2 (8%), and allergic rhinitis and asthma in 1 (4%) of patients with selective IgE deficiency. In patients with low IgE, 29 (26.4%) had allergic rhinitis, 10 (9%) had asthma, 8 (7.2%) had allergic rhinitis and asthma, and 2 (1.8%) had immunodeficiency at diagnosis. While 56% of patients with selective IgE low levels had no treatment, 31.8% of IgE low levels patients received no treatment. Most patients who received treatment received more than one treatment. It was observed that antibiotic prophylaxis was used as the last option in treatments and symptomatic treatments were tried first. Among the patients with low selective IgE, 9 (81.8%) received antibiotic prophylaxis, 6 (54.5%) received inhaled corticosteroids, 5 (45.4%) received nasal steroids, 4 received montelukast (36.3%), 1 (9%) received montelukast and nasal corticosteroids combination therapy. It was found that adenoidectomy had been performed in 4 patients with low selective IgE. There was 3 patient who received both antibiotic prophylaxis and an adenoidectomy. Among the patients with low IgE who received treatment, 48 (64%) received nasal steroids, 37 (49.3%) received antibiotic prophylaxis, 36 (48%) received inhaled corticosteroids, 35 (46.7%) received montelukast, 21 (28%) received montelukast and nasal corticosteroid combination, 3 (4%) received chemotherapy and 3 (4%) received allogeneic stem cell transplantation. DISCUSSION Low IgE levels are thought to be associated with immunodeficiency, increased risk of malignancy, reactive airways, allergic rhinitis, and seasonal antibiotic prophylaxis in the frequently ill patient with low IgE levels may delay surgeries such as adenoidectomy. More research is needed to evaluate ultra-low Ig E levels as potential bioreceptors in hematology and oncology.