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

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM

 

Objectives

Allergic 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.

Method

A 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.

Result

Among 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.

Conclusion

The 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.

A simple high-volume culture technique-Good substitute for polymerase chain reaction for the detection of Aspergillus species in bronchoalveolar lavage samples

BACKGROUND

Aspergillus species is the most common agent of invasive pulmonary fungal disease. Culture-based diagnosis considered as gold standard is limited by the fungal load in samples. Detection of Aspergillus by polymerase chain reaction (PCR) has been included as a diagnostic criterion by European Organisation for Research and Treatment of Cancer (EORTC). Most routine laboratories lack facilities for molecular diagnosis. Better yield using high-volume culture (HVC) technique has been reported. Studies have not compared HVC and PCR for detection of Aspergillus species in respiratory samples from patients with suspected invasive pulmonary Aspergillosis (IPA) not on antifungal therapy.

OBJECTIVE

This pilot study compared HVC and PCR for the detection of Aspergillus species in respiratory samples from treatment naïve patients.

METHODS

Bronchoalveolar lavage (BAL) samples from 30 patients with clinical suspicion of IPA were evaluated. Direct microscopy, culture both conventional (CC) and HVC and qualitative Pan Aspergillus PCR were performed. Latent class model was used for statistical analysis.

RESULTS

Sensitivity of HVC (100%) was better compared with CC (60%) and comparable to that of PCR (100%). Specificities of CC, HVC and PCR were 100%, 100% and 25%, respectively.

CONCLUSION

High-volume culture is a simple cost-effective technique with a high sensitivity and specificity. It can be easily introduced in routine microbiology laboratories. In centres with the availability of infrastructure for molecular analysis, Aspergillus PCR with other mycological techniques can be used for better diagnosis and management of patients with IPA.