P410 Aspergillus fumigatus sensitization among the patients with chronic obstructive pulmonary disease (COPD)— a cross sectional study

Abstract

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMObjectivesAllergic bronchopulmonary aspergillosis (ABPA) caused by hypersensitivity to A. fumigatus complicates the course of asthma. Fungal sensitization due to A. fumigatus among asthmatic patients and their progression to ABPA is well studied. Similar data on Aspergillus sensitization among patients with COPD and their progression are still not well established. The objective of this study was to evaluate the Total serum IgE (TIgE) and A. fumigatus specific IgE (Af sp IgE) levels among patients with COPD.MethodA total of 100 stable patients with COPD above 40 years of age from the Department of Pulmonary Medicine were included. TIgE and Af sp IgE levels were detected using VIDAS total IgE assay and M3 ImmunoCap with Phadia 100 respectively. The subjects were grouped into three (TIgE <500 IU/l, 500-1000 IU/l, and >1000 IU/l) based on the TIgE values. They were also categorized based on Af sp IgE levels as sensitization likely (AS ≥0.35 kUA/l), sensitization indeterminate (AI 0.1-0.35 kUA/l), and sensitization unlikely (AU ≤0.1 kUA/l). This categorization was based on the kit manufacturer's guidelines that sensitization is unlikely with specific IgE <0.1 kUA/l and the proposed ISHAM ABPA working group criteria of >0.35 kUA/l for diagnosis of sensitization. A comparison of Asf sp IgE with TIgE was done using the Fischer exact test.ResultAmong 100 patients, the prevalence of elevated TIgE [>150 IU/l (kit cutoff)] and Aspergillus sensitization [Af Sp IgE >0.35kUA/l (ISHAM cutoff)] was 47% and 6%, respectively. A total of 5% of subjects satisfied the criteria for serological ABPA. The results of the comparison of Asf sp IgE with total IgE using the Fischer exact test are given in Table 1.AS category: TIgE was >1000 IU/l in 5 (83.3%) of the 6 subjects. One (16.7%) had between 500-1000 IU/l. None of them had TIgE <500IU/l. Aspergillus sensitization was higher in 3/5 subjects with TIgE >1000 IU/ml (Asf sp IgE values of 2.55KUA/l, 12KUA/l, 14KUA/l, 0.38KUA/l, and 0.45KUA/l) compared with the one subject with TIgE <1000IU/l (Asf sp IgE of 0.73KUA/l). The clinical characteristics of subjects in the AS category is given in Table 2.AI category: A total of 7 (50%) of the 14 subjects had the TIgE value >1000 IU/l, 5 (35.7%) had the TIgE between 500-1000 IU/l, and 2 subjects had the TIgE <500 IU/l.AU category: In all, 1 (1.25%) had the TIgE value >1000 IU/l, 5 (6.25%) had the TIgE between 500-1000 IU/l. TIgE was <500 IU/l in 74 (92.5%) subjects.ConclusionThe study results suggest the co-existence of COPD and Aspergillus sensitization/ABPA. Patients in the AI group (Af sp IgE level 0.1-0.35 kUA/l) must be evaluated and monitored to prevent the progression of the disease. Studies involving a larger patient population are warranted.