Joint Indian Chest Society-National College of Chest Physicians (India) guidelines for spirometry

Clinical Significance of Aspergillus Sensitisation in Chronic Pulmonary Aspergillosis

OBJECTIVE

Aspergillus sensitisation (AS) is seen in many patients with chronic pulmonary aspergillosis (CPA). However, the clinical relevance of AS in CPA remains unclear. In this study, we assess the clinical significance of AS in CPA.

METHODS

We retrospectively analysed the data of CPA subjects, defining AS as Aspergillus fumigatus-IgE ≥ 0.35 kUA/L. We excluded subjects with asthma, allergic bronchopulmonary aspergillosis, chronic obstructive pulmonary disease (COPD) and diffuse parenchymal lung diseases (DPLD). The primary objective was to compare the demographic and clinical characteristics, lung functions (via spirometry) and treatment outcomes in CPA subjects with or without AS. The secondary objective was to explore the association between AS and airflow obstruction on spirometry using multivariable logistic regression analysis.

RESULTS

We included 232 CPA subjects (119 females, 113 males) with a mean ± SD age of 42.1 ± 13.7 years. AS was present in 92 (39.7%) CPA patients (CPA-AS group). CPA-AS patients had higher SGRQ total scores, a higher prevalence of fungal ball, more frequent airflow obstruction and experienced more CPA relapses during follow-up compared to those without AS. Airflow obstruction was seen in 77/232 (33.2%) CPA patients. On multivariable logistic regression analysis, we found AS, increasing age and chronic fibrosing pulmonary aspergillosis independently associated with airflow obstruction on spirometry after adjusting for sex and other CPA categories. The relapse-free survival was significantly shorter in the CPA-AS group than in the CPA group.

CONCLUSION

AS is common in CPA and is independently associated with airflow obstruction. More studies are required to confirm our findings.

Efficacy and safety of Once-Daily Vilanterol/Fluticasone furoate MDI in persistent asthma: Phase 3 OD-INHALE Study

INTRODUCTION

Once-daily inhalers have been shown to improve adherence leading to lesser discontinuation compared to twice- or thrice-daily inhalers in management of asthma. Combination of Vilanterol and Fluticasone Furoate (VI/FF) is approved for management of asthma and COPD and is available as a dry powder inhaler. Pressurized-Metered Dose Inhalers (pMDIs) offer ease-of-use and therapy alternatives for patients with low inspiratory flow. This study assessed the efficacy and safety of a new once-daily pMDI containing VI/FF in individuals diagnosed with persistent asthma.

METHODS

This phase 3, double-blind, randomized controlled study assessed the non-inferiority of VI/FF (12.5 mcg/50 mcg & 12.5 mcg/100 mcg; 2 puffs once-daily) over Formoterol Fumarate and Fluticasone Propionate (FOR/FP, 6 mcg/125 mcg & 6 mcg/250 mcg; 2 puffs twice-daily) in patients with persistent asthma. Primary outcome was change from baseline in trough FEV1 at the end of study (12 weeks). Adverse events and number of exacerbations were used to evaluate safety.

RESULTS

A total of 330 patients were randomized into VI/FF (165) and FOR/FP (165). Trough FEV1 significantly improved in both the groups at week 12, with a mean difference (VI/FF minus FOR/FP) being 54.75 mL (95% CI, 8.42-101.08 mL, p = 0.02). The low dose VI/FF had similar efficacy to that of low dose FOR/FP and high dose VI/FF had similar efficacy to high dose FOR/FP. No serious adverse events were reported during the study.

CONCLUSION

Once daily VI/FF pMDI was non-inferior to twice daily FOR/FP pMDI in patients with persistent asthma.

Population prevalence of aspergillus sensitization and allergic bronchopulmonary aspergillosis in COPD subjects in North India

BACKGROUND

Sensitization to Aspergillus fumigatus (AS) has been recently described in chronic obstructive pulmonary disease (COPD) patients. However, there is no data on the community prevalence of AS in COPD.

OBJECTIVES

To assess the prevalence of AS among COPD subjects. The secondary objectives were to (1) assess the prevalence of allergic bronchopulmonary aspergillosis (ABPA) in COPD and (2) compare the lung function in COPD subjects with and without AS.

METHODS

We conducted a cross-sectional study in rural (29 villages) and urban (20 wards) communities in North India. We identified individuals with respiratory symptoms (IRS) through a house-to-house survey using a modified IUATLD questionnaire. We then diagnosed COPD through specialist assessment and spirometry using the GOLD criteria. We assayed A.fumigatus-specific IgE in COPD subjects. In those with A. fumigatus-specific IgE ≥0.35 kUA/L (AS), ABPA was diagnosed with raised serum total IgE and raised A.fumigatus-specific IgG or blood eosinophil count.

RESULTS

We found 1315 (8.2%) IRS among 16,071 participants >40 years and diagnosed COPD in 355 (2.2%) subjects. 291 (82.0%) were men and 259 (73.0%) resided in rural areas. The prevalence of AS and ABPA was 17.7% (95% CI, 13.9-21.8) and 6.6% (95% CI, 4.4-8.8). We found a lower percentage predicted FEV1 in COPD subjects with AS than those without (p =.042).

CONCLUSIONS

We found an 18% community prevalence of AS in COPD subjects in a specific area in North India. Studies from different geographical areas are required to confirm our findings. The impact of AS and ABPA on COPD requires further research.

Sculpting - A Modern Menace

Background

Sculpting is a common occupation in India. However, there have been no studies from India on sculpting-related silicosis.

Aims

The aims of this study were to evaluate- 1. awareness of disease related to sculpting. 2. Clinical, radiological, and physiological parameters in "sculpting workers" suffering from silicosis.

Settings and Design

This was a retrospective evaluation of data collected during compensation visits for silicosis in workers of the sculpting industries.

Methods and Material

The data were collected between January 2021 to April 2023. A total of 114 patients were evaluated. All patients underwent clinical evaluation including awareness about the disease, chest radiography, high-resolution computed tomography (HRCT) scan of the chest, and spirometry.

Results

The majority of patients (109) (95%) did not use any personal protective equipment while at work and did not have any awareness regarding preventive measures. On chest radiography, small opacities (rounded or irregular) and large opacities were seen in 84 (73.7%) and 26 (22.8%) patients, respectively. The size of large opacities was significantly proportionate with duration of job (P = 0.019). HRCT chest was more sensitive compared to chest radiographs. 94 (82.4%) patients were having abnormal spirometric findings.

Conclusions

The benefits of prevention of silica dust exposure and patient education considerably outweigh the benefits of early detection and treatment of silicosis, as there was an increase in the size of lesions with increasing duration of exposure. There should be a national health program on silicosis to protect worker's health.

Pulmonary Function and Diffusing Capacity of Carbon Monoxide in Hypersensitivity Pneumonitis: An Observational Study of 152 Patients

OBJECTIVE

Hypersensitivity pneumonitis (HP) is an inflammatory and/or fibrotic lung disease. The restrictive lung function with low diffusing capacity of carbon monoxide (DLCO) is common in interstitial lung diseases (ILD). There are limited data on pulmonary function test (PFT) in HP and its role for diagnosis is questionable. We analyzed the data of 152 HP patients for type of defect, lung volume, and DLCO.

MATERIAL AND METHODS

The present study is a retrospective analysis of 152 patients at one of the tertiary chest institutes in India. All diagnosed cases with at least spirometry were included. PFT findings were classified and graded as obstructive, restrictive, and mixed patterns. The correlation of PFT was calculated with disease duration and 6MWT distance.

RESULTS

The majority were female [106 (70%)], with a mean age of 47.8 ± 12.3 years. Spirometry with lung volume data were available for 97% patients. PFT was abnormal in 118 (80%) cases. Among the patterns of abnormality, the most common type was restrictive (74%) followed by mixed (15%) and obstructive (11%) with the majority in the severe to very severe grade. The mean total lung capacity (TLC) and residual volume (RV) were reduced, with the grade more severe when the pattern of abnormality was restrictive while the RV/ TLC was higher suggestive of air tapping. DLCO data were available for 132 (87%) cases, with levels decreased in 67%. The severity of DLCO was highest when the pattern of abnormality was restrictive. One of the PFT parameters was abnormal in 137 (90%) cases, with isolated decreased DLCO levels seen in 16 (10%) cases. Forced vital capacity (FVC), TLC, and DLCO showed positive correlation with 6MWT distance (FVC r = .22, P = .02; TLC r = .28, P = .003; DLCO r = .30, P = .002).

CONCLUSION

The PFT abnormality is seen in >80% of HP patients. All types of abnormality were seen, with the restrictive pattern being the most common. Isolated decreased DLCO levels were seen in 10% of cases. We advised to do full PFT for diagnosis and followup of HP.

High-dose (40 mg) versus low-dose (20 mg) prednisolone for treating sarcoidosis: a randomised trial (SARCORT trial)

BACKGROUND

Current guidelines recommend 20-40 mg·day-1 of oral prednisolone for treating pulmonary sarcoidosis. Whether the higher dose (40 mg·day-1) can improve outcomes remains unknown.

METHODS

We conducted an investigator-initiated, single-centre, open-label, parallel-group, randomised controlled trial (ClinicalTrials.gov identifier NCT03265405). Consecutive subjects with pulmonary sarcoidosis were randomised (1:1) to receive either high-dose (40 mg·day-1 initial dose) or low-dose (20 mg·day-1 initial dose) oral prednisolone, tapered over 6 months. The primary outcome was the frequency of relapse or treatment failure at 18 months from randomisation. Key secondary outcomes included the time to relapse or treatment failure, overall response, change in forced vital capacity (FVC, in litres) at 6 and 18 months, treatment-related adverse effects and health-related quality of life (HRQoL) scores using the Sarcoidosis Health Questionnaire and Fatigue Assessment Scale.

FINDINGS

We included 86 subjects (43 in each group). 42 and 43 subjects completed treatment in the high-dose and low-dose groups, respectively, while 37 (86.0%) and 41 (95.3%), respectively, completed the 18-month follow-up. 20 (46.5%) subjects had relapse or treatment failure in the high-dose group and 19 (44.2%) in the low-dose group (p=0.75). The mean time to relapse/treatment failure was similar between the groups (high-dose 307 days versus low-dose 269 days, p=0.27). The overall response, the changes in FVC at 6 and 18 months and the incidence of adverse effects were also similar. Changes in HRQoL scores did not differ between the study groups.

INTERPRETATION

High-dose prednisolone was not superior to a lower dose in improving outcomes or the HRQoL in sarcoidosis and was associated with similar adverse effects.

Reference equations for evaluation of spirometry function tests in South Asia, and among South Asians living in other countries

BACKGROUND

There are few data to support accurate interpretation of spirometry data in South Asia, a major global region with a high reported burden of chronic respiratory disease.

METHOD

We measured lung function in 7453 healthy men and women aged ≥18 years, from Bangladesh, North India, South India, Pakistan and Sri Lanka, as part of the South Asia Biobank study. First, we assessed the accuracy of existing equations for predicting normal forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and FEV1/FVC ratio. Then, we used our data to derive (n=5589) and internally validate (n=1864) new prediction equations among South Asians, with further external validation among 339 healthy South Asians living in Singapore.

RESULTS

The Global Lung Initiative (GLI) and National Health and Nutrition Examination Survey consistently overestimated expiratory volumes (best fit GLI-African American, mean±sd z-score: FEV1 -0.94±1.05, FVC -0.91±1.10; n=7453). Age, height and weight were strong predictors of lung function in our participants (p<0.001), and sex-specific reference equations using these three variables were highly accurate in both internal validation (z-scores: FEV1 0.03±0.99, FVC 0.04±0.97, FEV1/FVC -0.03±0.99) and external validation (z-scores: FEV1 0.31±0.99, FVC 0.24±0.97, FEV1/FVC 0.16±0.91). Further adjustment for study regions improves the model fit, with highest accuracy for estimation of region-specific lung function in South Asia.

CONCLUSION

We present improved equations for predicting lung function in South Asians. These offer the opportunity to enhance diagnosis and management of acute and chronic lung diseases in this major global population.

Environmental monitoring and health assessment in an industrial town in central India: A cross-sectional study protocol

Background

Textile industry has been widely implicated in environmental pollution. The health effects of residing near manufacturing industries are not well documented in India, especially in central India. Hence, a cross-sectional environmental monitoring and health assessment study was initiated as per directions of the local authorities.

Methods

Comprehensive exposure data about the concentrations of relevant pollutants in the ambient air and ground water samples in the study area will be collected over one year. Using stratified random sampling, 3003 apparently healthy adults will be selected from the study area. Sociodemographic and anthropometric information, relevant medical and family history, and investigations including spirometry, electrocardiogram, neurobehavioral tests, and laboratory investigations (complete blood count, lipid profile and random blood glucose) will be conducted. Finally Iodine azide test and heavy metal level detection in urine and blood samples respectively will be conducted in a subset of selected participants to assess individual pollution exposure. Ethics approval has been obtained from the Institutional Ethics Committee of the National Institute for Research in Environmental Health (No: NIREH/IEC-7-II/1027, dated 07/01/2021).

Discussion

This manuscript describes the protocol for a multi-disciplinary study that aims to conduct environmental monitoring and health assessment in residential areas near viscose rayon and associated chemical manufacturing industries. Although India is the second largest manufacturer of rayon, next only to China, and viscose rayon manufacturing has been documented to be a source of multiple toxic pollutants, there is a lack of comprehensive information about the health effects of residing near such manufacturing units in India. Therefore implementing this study protocol will aid in filling in this knowledge gap.

Evaluation of Simpler Criteria for Diagnosing Allergic Bronchopulmonary Aspergillosis Complicating Asthma

Background

The modified International Society for Human and Animal Mycology (ISHAM) allergic bronchopulmonary aspergillosis (ABPA) working group (AWG) criteria lists up to five components for diagnosing ABPA in asthmatics. Whether eliminating specific components of the existing criteria would have the same diagnostic utility as the original remains unknown.

Objective

To evaluate the performance of several simplified criteria for diagnosing ABPA.

Methods

We compared the performance of seven new criteria (after excluding or modifying one or more of the components of the ISHAM-AWG criteria) with the modified ISHAM-AWG criteria in asthmatic subjects using latent class analysis (LCA). We also tested the performance of the newer criteria using accuracy measures against a multidisciplinary team (MDT) diagnosis of ABPA. We considered the diagnostic accuracy of the newer criteria to be acceptable if the correct classification and false-negative rates were >95% and <5%, respectively, on an MDT evaluation.

Results

We analyzed data from 543 asthmatic subjects (58.8% women; mean age, 36.8 years). Using LCA, the sensitivity of the A.fumigatus-specific IgE-based criteria ranged from 92-99%, while the specificity varied between 92% and 100%. The MDT diagnosed ABPA in 106 (19.5%) subjects. Using MDT as the reference standard, the correct classification and false-negative rates were >95% for three of the seven and <5% for four of the seven newer criteria.

Conclusions

We found several of the newly developed criteria to perform, like the modified ISHAM-AWG criteria, for diagnosing ABPA complicating asthma. A prospective study in current clinical algorithms is required for validating our observations.

Lung Function Impairment In Patients Treated For Pulmonary Tuberculosis and Associated Factors in Puducherry, South India

Context

After completion of treatment, a proportion of pulmonary tuberculosis (TB) (PTB) patients experience lung function impairment (LFI) which can influence their quality of life.

Aim

This study was aimed to determine the prevalence of LFI in patients treated for PTB and the associated factors.

Settings and Design

A cross-sectional study was conducted among patients treated for PTB in eight primary health centers in Puducherry.

Subjects and Methods

The study was carried out among 118 patients. Those aged 18 and above whose PTB treatment outcomes were declared as cured or completed between 2018 and 2019 were included. Demographic data, respiratory symptoms before TB diagnosis, comorbidities, and chest radiography findings before TB treatment were collected. All participants underwent spirometric tests before and after dilatation with salbutamol nebulization.

Statistical Analysis

Multivariable analysis identified smear-negative TB and indoor exposure to biomass for cooking as significant independent risk factors for LFI.

Results

Of 118 participants interviewed, 70.3% were male and the median age of the participants was 47.7 years. The prevalence of LFI was 62.7% (95% confidence interval: 53.3-71.4).

Conclusion

LFI was frequent in patients treated previously for TB. Creating awareness about the possible LFI among these patients along with the awareness for seeking health care for this condition is the need of the hour.

Epidemiology and outcomes of allergic bronchopulmonary aspergillosis in the elderly

BACKGROUND

The prevalence and outcomes of allergic bronchopulmonary aspergillosis (ABPA) in the elderly remain unknown.

METHODS

We reviewed our database to identify the proportion of subjects diagnosed with ABPA at ≥60 years of age (ABPA-elderly). We compared the clinical features, treatment and outcomes of ABPA-elderly versus the non-elderly (ABPA diagnosed at <60 years of age).

RESULTS

Between 2007 and 2019, we encountered 810 ABPA subjects with a mean age of 34.9 years (49.4% women). Of these, 43 (5.3%) were aged ≥60 years (ABPA-elderly). There was a trend towards lower median (interquartile range [IQR]) serum total IgE (4900 [2659-10000] vs. 7156 [23360-11963] IU/mL; P = .06) and Aspergillus fumigatus-specific IgE (12.3 [4.8-29.6] vs. 22.4 [7.7-41.5] kUA/L; P = .06) in the elderly than the non-elderly. Eosinophil counts were similar in the two groups. The median [IQR] number of segments involved by bronchiectasis (5 [2-9] vs. 7 [4-11]) was significantly lower in the ABPA-elderly (P = .001). The proportion of subjects experiencing ABPA exacerbations was significantly (P = .047) lower in the elderly (25.6%) vs. the non-elderly (40.8%). There was also a tendency towards a lower mean number of exacerbations in the elderly (155 vs. 208 exacerbation per 1000 person-years) than the non-elderly (P = .09). There was also a trend towards longer mean time to first exacerbation in the ABPA-elderly than the non-elderly (1612 vs. 1159 days).

CONCLUSION

ABPA was uncommon in the elderly. The bronchiectasis is less extensive with a trend towards lower immunological severity and fewer exacerbations in the elderly than the non-elderly subjects with ABPA.

Sensitization to A fumigatus in subjects with non-cystic fibrosis bronchiectasis

BACKGROUND

Patients with chronic lung diseases, including cystic fibrosis (CF), are frequently sensitized to Aspergillus fumigatus. Whether patients with non-CF bronchiectasis develop sensitization to A fumigatus remains unknown.

OBJECTIVE

To evaluate the prevalence of sensitization and chronic infection with A fumigatus in subjects with bronchiectasis. We also performed a multivariate logistic regression analysis to identify factors predicting sensitization and chronic A fumigatus infection.

METHODS

Subjects with bronchiectasis were investigated with serum A fumigatus-specific IgE and IgG, and sputum cultures for bacteria, fungus and mycobacteria. We defined A fumigatus sensitization and chronic A fumigatus infection as serum A fumigatus-specific IgE and IgG > 0.35 kUA/L and >27 mgA/L, respectively. We excluded subjects with bronchiectasis secondary to allergic bronchopulmonary aspergillosis.

RESULTS

We included 258 subjects (TB [n = 155], idiopathic [n = 66] and other causes [n = 37]) with bronchiectasis. The prevalence of Aspergillus sensitization, chronic Aspergillus infection, and both sensitization and chronic infection was 29.5% (76/258), 76% (196/258) and 26% (68/258), respectively. In a multivariate logistic regression analysis, TB-related bronchiectasis was an independent risk factor for Aspergillus sensitization. Chronic Aspergillus infection was predicted by the duration of symptoms and specific aetiologies (tuberculosis and idiopathic) of bronchiectasis. The growth of Aspergillus species was also frequent in the TB group compared with other causes (32% vs 2%; P < .001).

CONCLUSIONS

We found a significant occurrence of Aspergillus sensitization and chronic infection in non-CF bronchiectasis, especially in TB bronchiectasis. In addition to Aspergillus sensitization, investigations for chronic Aspergillus infection should be routinely performed in non-CF bronchiectasis, both at diagnosis and during follow-up.

A mixed-methods community-based participatory research to explore stakeholder's perspectives and to quantify the effect of crop residue burning on air and human health in Central India: study protocol

Background

Crop residue burning adversely affects air quality and consequently human health. India, being one of the largest agro-economies of the world, produces around 500 Million tonnes of crop residue annually most of which is burnt on-farm. However, integrated studies that simultaneously quantify the effects of crop residue burning while exploring the subjective determinants of the practice are lacking in India. This paper describes the protocol for a longitudinal mixed methods research study employing a community-based participatory approach to fill this gap.

Methods

Both quantitative and qualitative data will be collected in a rural setting of the central Indian province of Madhya Pradesh, over 1 year. A steering committee comprising of the research team and community representatives will be formed. The proportion of cultivable land burnt in one crop burning season will be estimated. The association between crop residue burning, level of ambient air pollutants, and pulmonary function of village residents will be determined. Focus groups, interviews, and participatory rural appraisal methods will be used to explore stakeholder perspectives about crop residue burning. Potential barriers and opportunities for substituting burning with an alternative crop residue management technique will be ascertained as the basis for future interventions. Ethics approval has been obtained from the Institutional Ethics Committee of the National Institute for Research in Environmental Health (No: NIREH/BPL/IEC/2019–20/1494, dt 06/01/2020).

Discussion

This manuscript describes the protocol for a novel community-based participatory study to investigate thoroughly the phenomenon of crop residue burning from the perspective of the agricultural community through their active collaboration. The lack of comprehensive evidence regarding the factors responsible for crop residue burning in India underlines the importance of implementing this study protocol to fill in this critical gap in knowledge. While acknowledging that findings of this study will be not generalizable to agricultural communities other than the one studied, it is expected that the study will generate baseline evidence that might be beneficial in developing and implementing an appropriate intervention strategy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-020-09844-6.

Which Are the Optimal Criteria for the Diagnosis of Allergic Bronchopulmonary Aspergillosis? A Latent Class Analysis

BACKGROUND

The ideal criteria for diagnosing allergic bronchopulmonary aspergillosis (ABPA) remain unknown because of the lack of a criterion standard. Latent class analysis using a probabilistic modeling technique can circumvent the need for a reference standard.

OBJECTIVE

To compare the diagnostic performance of various criteria used for evaluating ABPA.

METHODS

We prospectively enrolled consecutive cases of bronchial asthma and performed a series of investigations used for the diagnosis of ABPA. We used latent class analysis to analyze the performance of various existing and novel diagnostic criteria.

RESULTS

Of the 543 subjects (mean age, 37 years; 319 women), 338 (62.2%) and 205 (37.8%) were labeled as "mild-to-moderate" and "severe" asthma cases, respectively. The subjects with severe asthma had a longer duration of asthma and a higher number of exacerbations in the previous year. The prevalence of Aspergillus fumigatus sensitization was 41% and 30%, using the A fumigatus-specific IgE and skin test, respectively. The prevalence of ABPA was 16%, using both the Rosenberg-Patterson and the International Society for Human and Animal Mycology (ISHAM)-ABPA Working Group criteria. The ISHAM criteria were slightly more sensitive (89% vs 81%) and specific (99% vs 98%) than the Patterson criteria. We obtained optimal diagnostic performance by altering the existing ISHAM criteria (serum total IgE >500 international units/mL, excluding the skin test, and using computed tomography of thorax instead of chest radiograph).

CONCLUSIONS

The ISHAM-ABPA Working Group criteria were only marginally better than the Patterson criteria in diagnosing ABPA among patients with asthma younger than 66 years. The diagnostic performance however improved by modifying the prevailing ISHAM criteria, but with increased cost.

Role of recombinant Aspergillus fumigatus antigens in diagnosing Aspergillus sensitisation among asthmatics

BACKGROUND

The diagnosis of Aspergillus-sensitised asthma (ASA) and allergic bronchopulmonary aspergillosis (ABPA) is made using IgE against crude antigens of A fumigatus (cAsp). However, the IgE against cAsp has limitations due to cross-reactivity with other fungi.

OBJECTIVE

To evaluate the utility of recombinant A fumigatus (rAsp) antigens in detecting ASA and their role in differentiating true from cross-sensitisation.

METHODS

We performed IgE against rAsp (f 1, f 2, f 3, f 4 and f 6), cAsp and other fungal (Alternaria, Candida, Cladosporium, Malassezia and Trichophyton) antigens in subjects with A fumigatus-unsensitised asthma (Af-UA [n = 51]), ASA (n = 71) and ABPA (n = 123). The diagnoses were made using cAsp-IgE and compared using rAsp-IgE. Subjects with elevated cAsp-IgE, but negative rAsp f 1 and f 2, were presumed to lack true A fumigatus sensitisation.

RESULTS

The prevalence of any rAsp antigen positivity (cut-off, 0.35 kUA/L) varied from 2%-22%, 32%-73% and 84%-98% for Af-UA, ASA and ABPA, respectively. The prevalence of sensitisation to other fungi ranged from 29%-65%, 59%-85% and 87%-95%, respectively, among subjects with Af-UA, ASA and ABPA. Nineteen subjects of ASA and one subject with ABPA were positive with cAsp-IgE but negative for rAsp f 1 and f 2 and were also cross-sensitised to at least one of the other fungi. Five subjects of Af-UA (cAsp-IgE negative) were rAsp f 1 or f 2 positive.

CONCLUSIONS

Crude Aspergillus antigens may misclassify Aspergillus sensitisation among asthmatics. IgE against rAsp antigens (f 1 and f 2) potentially detect true Aspergillus sensitisation and could be used for this purpose.

Diagnostic Cutoffs and Clinical Utility of Recombinant Aspergillus fumigatus Antigens in the Diagnosis of Allergic Bronchopulmonary Aspergillosis

BACKGROUND

The clinical utility of IgE against recombinant Aspergillus fumigatus (rAsp)-specific antigens in allergic bronchopulmonary aspergillosis (ABPA) remains unclear.

OBJECTIVE

To identify the optimal diagnostic cutoffs of rAsp-specific IgE in differentiating ABPA from A fumigatus-sensitized asthma (ASA), and define their utility in the diagnosis of ABPA.

METHODS

We enrolled consecutive subjects with ASA and ABPA. IgE against rAsp f1, f2, f3, f4, and f6 was assayed in all the subjects. We evaluated 3 fixed cutoffs (0.35, 0.5, and 1.0 kU_A/L) for their diagnostic performance in the entire cohort. We also divided the study population into derivation and validation cohorts. Cutoffs for rAsp-specific IgE were obtained using the receiver-operating characteristic analysis in the derivation cohort. We then evaluated the diagnostic performance of these cutoffs in the validation cohort. We further correlated rAsp-specific IgE levels in ABPA with asthma control, spirometry, imaging, and immunologic markers.

RESULTS

We included 194 subjects (123 ABPA and 71 ASA). The statistically derived cutoffs proved superior to fixed cutoffs. IgE against rAsp f1 yielded the best combination of sensitivity (89%) and specificity (100%). The sensitivity and specificity of IgE against either rAsp f1 (cutoff, 4.465 kU_A/L) or f2 (cutoff, 1.300 kU_A/L) for diagnosing ABPA were 100% and 81%, respectively. The correlation between rAsp-specific IgE and most clinical parameters of ABPA was weak.

CONCLUSIONS

IgE against rAsp f1 and f2 (using receiver-operating characteristic-derived cutoffs) were found to be the most useful in differentiating ABPA from ASA. Because this study was conducted at a single center, our results require further validation.