Erratum: Diagnosis of Hypersensitivity Pneumonitis in Adults: An Official ATS/JRS/ALAT Clinical Practice Guideline

Relative incidence of interstitial lung diseases in Brazil

OBJECTIVE

To assess the relative frequency of incident cases of interstitial lung diseases (ILDs) in Brazil.

METHODS

This was a retrospective survey of new cases of ILD in six referral centers between January of 2013 and January of 2020. The diagnosis of ILD followed the criteria suggested by international bodies or was made through multidisciplinary discussion (MDD). The condition was characterized as unclassifiable ILD when there was no specific final diagnosis following MDD or when there was disagreement between clinical, radiological, or histological data.

RESULTS

The sample comprised 1,406 patients (mean age = 61 ± 14 years), and 764 (54%) were female. Of the 747 cases exposed to hypersensitivity pneumonitis (HP)-related antigens, 327 (44%) had a final diagnosis of HP. A family history of ILD was reported in 8% of cases. HRCT findings were indicative of fibrosis in 74% of cases, including honeycombing, in 21%. Relevant autoantibodies were detected in 33% of cases. Transbronchial biopsy was performed in 23% of patients, and surgical lung biopsy, in 17%. The final diagnoses were: connective tissue disease-associated ILD (in 27%), HP (in 23%), idiopathic pulmonary fibrosis (in 14%), unclassifiable ILD (in 10%), and sarcoidosis (in 6%). Diagnoses varied significantly among centers (c2 = 312.4; p < 0.001).

CONCLUSIONS

Our findings show that connective tissue disease-associated ILD is the most common ILD in Brazil, followed by HP. These results highlight the need for close collaboration between pulmonologists and rheumatologists, the importance of detailed questioning of patients in regard with potential exposure to antigens, and the need for public health campaigns to stress the importance of avoiding such exposure.

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.

A case of development of autoimmune pulmonary alveolar proteinosis during the treatment of hypersensitivity pneumonitis

Herein, we report the case of a 73-year-old woman with an occupational history of plaster grinding who developed autoimmune pulmonary alveolar proteinosis (PAP) during the treatment of fibrotic hypersensitivity pneumonitis with steroids and immunosuppressive drugs. Based on the changes in computed tomography imaging findings, poor response to steroid therapy, and markedly elevated KL-6 levels, PAP was suspected and diagnosed by bronchoscopy. Repeated segmental bronchoalveolar lavage under high-flow nasal cannula oxygen therapy resulted in slight improvement. Steroids and immunosuppressive treatments for other interstitial lung diseases may cause PAP or exacerbate latent PAP.

The impact of bronchoalveolar lavage on the diagnosis of undifferentiated interstitial lung disease alongside a multidisciplinary discussion

BACKGROUND AND OBJECTIVE

Cellular analysis of bronchoalveolar lavage (BAL) fluid may aid diagnosis in patients with undifferentiated interstitial lung disease (ILD). The utility of this test in the diagnostic process in conjunction with a multidisciplinary discussion (MDD) is not known. We aim to assess and compare interobserver agreement and diagnostic confidence before and after presenting BAL results in an ILD-MDD.

METHODS

Patients undergoing investigations for ILD at Waikato Hospital were recruited. At the ILD-MDD two respiratory physicians and one respiratory radiologist participated in the discussion, and their diagnosis and diagnostic confidence were assessed at four sequential time points. Assessors were blinded to each others diagnosis and diagnostic confidence scores. The four sequential time points were (1) after clinical and radiology presentation; (2) after subsequent MDD; (3) after reviewing BAL results; (4) after final MDD with all results. Interobserver agreements were calculated using Fleiss κ statistic.

RESULTS

36 patients were recruited, and 77.8% were male. In the first step, the interobserver agreement was substantial κ = 0.622 (95% CI 0.47-0.77), improving in step 2 following MDD to κ = 0.78 (95% CI 0.624-0.935), in step 3 κ = 0.776 (95% CI 0.614-0.937) and step 4 achieved almost perfect agreement of κ = 0.969 (95% CI 0.828-1.11). The diagnostic confidence for individual and group diagnosis increased with the presentation of BAL with and without multidisciplinary MDD.

CONCLUSION

We found that BAL cellular analysis improves interobserver agreement and confidence in diagnosis following MDD, thus aiding decision-making in cases with undifferentiated ILD.

Granulocyte colony-stimulating factor in bronchoalveolar lavage fluid is a potential biomarker for prognostic prediction of idiopathic pulmonary fibrosis

BACKGROUND/AIMS

Neutrophilia is frequently observed in bronchoalveolar lavage fluid (BALF) of idiopathic pulmonary fibrosis (IPF) patients. Granulocyte colony-stimulating factor (G-CSF) is a potent neutrophil-activating glycoprotein. However, the clinical implications of G-CSF remain poorly understood.in patients with IPF. Therefore, we evaluated the relationship between the G-CSF concentration in BALF and the progression of fibrosis, including in terms of the decline in lung function and long-term survival rate.

METHODS

G-CSF concentrations were measured in BALF using enzyme-linked immunosorbent assay (ELISA). The survival rate was estimated using Kaplan-Meier survival analyses.

RESULTS

G-CSF protein levels were significantly higher in IPF (n = 87; 1.88 [0 to 5.68 pg/mL]), nonspecific interstitial pneumonia (n = 22; 0.58 [0 to 11.64 pg/mL]), and hypersensitivity pneumonitis (n = 19; 2.48 [0.46 to 5.71 pg/mL]) patients than in normal controls (n = 33; 0 [0 to 0.68 pg/mL]) (all p &lt; 0.01). A receiver operating characteristic curve showed a difference in G-CSF levels between IPF and NC (area under the curve, 0.769): The G-CSF cut-off of 0.96 pg/mL indicated 84.9% specificity and 63.2% sensitivity for IPF. The survival rate was significantly lower in the group with G-CSF &gt; 2.872 pg/mL than in the group with ≤ 2.872 pg/mL (hazard ratio, 2.69; p = 0.041). The annual decline in diffusing capacity of the lung for carbon monoxide was positively correlated with the G-CSF level (p = 0.018).

CONCLUSION

G-CSF may participate in the development of IPF and be useful for predicting the prognosis of IPF. Therefore, G-CSF should be analyzed in BALF, in addition to differential cell counts.

Prevalence of latent tuberculosis infection among patients with interstitial lung disease requiring immunosuppression

Objective

To characterize the prevalence of latent tuberculosis infection (LTBI) in patients with interstitial lung diseases (ILDs) requiring immunosuppression. Only 5 to 10% of individuals infected with Mycobacterium tuberculosis develop tuberculosis, and certain groups of patients have an increased risk of illness, such as the immunocompromised. Patients with ILDs are frequently treated with immunosuppressants and, therefore, might have a higher risk of developing the disease.

Methods

Prospective study conducted at the ILD reference center of the Federal University of Paraná from January 2019 to December 2020. The screening of LTBI was performed with the use of the tuberculin skin test (TST).

Results

The sample consisted of 88 patients, of whom 64.8% were women, with a mean age of 61.4 years. The most frequent diagnoses were autoimmune rheumatic disease ILD (38.6%) and hypersensitivity pneumonitis (35.2%). The most common immunosuppressant in use at the time of the TST was prednisone, either in combination with mycophenolate (19.3%) or alone (17.1%). The majority of participants had fibrotic lung disease, characterized by a reticular interstitial pattern on chest computed tomography (79.5%) and moderate to severe functional impairment (mean FVC 69.2%). A prevalence of LTBI of 9.1% (CI 95%, 2.1%-15.1%) was found, with a TST median of 13.

Conclusion

Patients with ILD who are treated with immunosuppressants are not commonly screened for LTBI, despite being under a greater risk of progression to active disease. This study suggests the need for a more cautious approach to these patients.