Response to bronchoalveolar lavage and high-resolution computed tomography in interstitial lung disease.

Thanks for the interest shown in our article titled “Bronchoalveolar lavage cellular analyses in conjunction with high-resolution computed tomography imaging as a diagnostic intervention for patients with suspected interstitial lung diseases.”[1] Find below the response to the queries raised:

The study has been based on ATS guidelines, which recommend bronchoalveolar lavage (BAL) cellular analysis for supporting the diagnosis of a specific interstitial lung diseases (ILDs) and narrowing down the differential diagnosis. Authors have not only followed the guidelines correctly but also have misinterpreted them. They have classified ILD's such as idiopathic pulmonary fibrosis (IPF), chronic hypersensitivity pneumonitis into acute, subacute with superimposed infection based on a cellular analysis which needs to be clarified. The usage of terms such as “acute IPF,” “subacute IPF with bronchitis,” “bilateral subacute exacerbation of chronic hypersensitivity pneumonitis with allergic bronchitis,” “bilateral subacute rheumatoid arthritis induced ILD” in conjunction with BAL findings again requires clarification from authors.

Response: Documenting the diagnosis of a disease should not only help in its identification but also in its management. In our work, we utilized the ATS guidelines[2] to narrow down and refine the diagnosis to improve the management strategy. The acute, subacute, bronchitis, allergy, and infection terminologies were used based on the differential cell count of neutrophils, lymphocytes, and eosinophils as per the guidelines of ATS [Table 1IIb]. In patients with ILD, if the neutrophil count is more than 3%, the list of disease conditions has been provided in Table 1 (IIa). Further, based on Table 1 (IIb), if the neutrophil count amounted to greater or less than 50% we added acute or subacute sub types. The final diagnosis of “bilateral, acute IPF with bronchitis, and probable infection” was a collective decision of our clinical, radiological, and BAL findings (bilateral – clinical and radiological test; acute – BAL neutrophil count; IPF – radiological and BAL neutrophil count; bronchitis – BAL neutrophil count and radiological test; probable infection – BAL neutrophil count). Similarly for the “bilateral subacute exacerbation of chronic hypersensitivity pneumonitis with allergic bronchitis” the diagnosis was based on bilateral – clinical and radiological test; subacute – BAL neutrophil count; chronic hypersensitivity – clinical, radiological, and BAL lymphocyte count; allergic BAL eosinophil count; bronchitis – BAL eosinophil count and radiological test. In the same way, other disease diagnosis was interpreted.

In results, authors have classified ILD's based on clinical findings. They have included the entity named as “aspiration bronchiolitis,” which needs to be clarified.

Response: The patient had psychiatric illness with repeated history of aspiration pneumonia. The high-resolution computed tomography (HRCT) showed bilateral lower lobular nodules and interstitial septal thickening. The diagnosis of aspiration bronchiolitis was made based on clinical history, HRCT, and BAL findings. Pathologists use the term diffuse panbronchiolitis for bronchiolitis secondary to oropharyngeal aspiration. Since the condition is included in the classification of ILDs, this patient was included in the study.

In results, the percentage variability is too high which loses significance in view of small sample size.

As BAL is an invasive procedure small sample size for this study is justifiable. Small sample size may not be the only cause for higher variability in cell counts; we need to understand that it could also be due to inter- and intra-disease severity pattern among patients.

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Conflicts of interest

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