Purpose: The association between fungi and asthma is known for a long time. The variation in temperature or change of weather, pollens and mold spores, second-hand smokes, inhaled chemicals and ambient air pollutants, all lead to its exacerbation. Besides all these causative factors, one-third to one-half of severe asthmatics have history of atopic sensitization to filamentous fungi, predominantly to Aspergillus fumigatus.
Exposure to fungal elements potentially causes worsening of asthmatic symptoms, lung functions along with increased hospital admissions and asthma-related deaths. Fungi can be associated with severe asthma in a number of ways i.e. ABPA with or without bronchiectasis and severe asthma with sensitization. ABPA is the most common fungal infection among asthma patients, wherein, the fungus acts as both a source of allergen as well as pathogen. ABPA presents itself by a range of clinical features including asthma exacerbation, eosinophilia, elevated total serum IgE, elevated Aspergillus fumigatus-specific IgE or IgG, recurrent pulmonary infiltrates, central bronchiectasis and hyper-attenuation mucous plug impaction.
ABPA is diagnosed by presence of severe asthma, A.fumigatus specific IgE ≥ 0.35 kUA/L, total IgE >1000 IU/mL, elevated A.fumigatus specific IgG ≥ 27mgA/L. Currently ABPA is further classified as serological-ABPA (ABPA-S) and ABPA with bronchiectasis depending upon normal high-resolution CT or presence of bronchiectasis on HRCT. Hence this project was planned to study the prevalence of ABPA among severe bronchial asthma patients.
Methods: A total of 50 patients of severe asthma, reporting to the Pulmonary Medicine OPD, were consecutively enrolled from January 2016 to June 2017. Blood samples were taken from all these patients and serum samples were separated. All of them were tested for absolute eosinophil count, total IgE, Aspergillus fumigatus specific IgE.
Results: From these 50 patients, thirty-four patients were diagnosed as ABPA depending on their raised total IgE, Aspergillus fumigatus specific IgE. Out of these 34 patients, there were 18 females and 16 males. Eleven patients had bronchiectasis changes on HRCT and were classified as ABPA-B and 24 patients (ABPA-S) had raised Aspergillus specific IgE but no changes were observed on HRCT of thorax. The prevalence of ABPA among severe asthma patients was found to be 68% (34/50 patients). A high prevalence of ABPA-S as 70.6% was seen as compared to ABPA-B, which was 29.4%.
Conclusions: In India, Aspergillus fumigatus is the most common fungus involved among bronchial asthma patients, especially ABPA. Aspergillus is one of the most common environmental mold present in both indoor as well as outdoor air. The number of fungal spores in indoor air increases with damp and humid buildings. Along with that household dust particles play a major role in transmission of spores and other fungal elements. A lot of patients develop sensitization before development of lung changes. Patients of severe asthma with recurrent attacks and persistent asthma with irreversible lung changes are at high risk of fungal colonization and sensitization. As the numbers of fungal infections are increasing day by day, not only the Aspergillus species but role of various fungi in complicating bronchial asthma should be explored in detail.
Full conference title:
- AAA 8th (2018)