Clinical characteristics of hypersensitivity pneumonitis: non-fibrotic and fibrotic subtypes

Xueying Chen; Xiaoyan Yang; Yanhong Ren; Bingbing Xie; Sheng Xie; Ling Zhao; Shiyao Wang; Jing Geng; Dingyuan Jiang; Sa Luo; Jiarui He; Shi Shu; Yinan Hu; Lili Zhu; Zhen Li; Xinran Zhang; Min Liu; Huaping Dai

doi:10.1097/CM9.0000000000002613

Clinical characteristics of hypersensitivity pneumonitis: non-fibrotic and fibrotic subtypes

Chin Med J (Engl). 2023 Dec 5;136(23):2839-2846. doi: 10.1097/CM9.0000000000002613.

Authors

Xueying Chen¹, Xiaoyan Yang², Yanhong Ren¹, Bingbing Xie¹, Sheng Xie³, Ling Zhao⁴, Shiyao Wang¹, Jing Geng¹, Dingyuan Jiang¹, Sa Luo¹, Jiarui He¹, Shi Shu¹, Yinan Hu¹, Lili Zhu¹, Zhen Li¹, Xinran Zhang⁵, Min Liu³, Huaping Dai¹

Affiliations

¹ Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Diseases, Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100029, China.
² Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Capital Medical University, Beijing 100029, China.
³ Department of Radiology, China-Japan Friendship Hospital, Beijing 100029, China.
⁴ Department of Pathology, China-Japan Friendship Hospital, Beijing 100029, China.
⁵ Institute of Clinical Medical Sciences, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing 100029, China.

Abstract

Background: The presence of fibrosis is a criterion for subtype classification in the newly updated hypersensitivity pneumonitis (HP) guidelines. The present study aimed to summarize differences in clinical characteristics and prognosis of non-fibrotic hypersensitivity pneumonitis (NFHP) and fibrotic hypersensitivity pneumonitis (FHP) and explore factors associated with the presence of fibrosis.

Methods: In this prospective cohort study, patients diagnosed with HP through a multidisciplinary discussion were enrolled. Collected data included demographic and clinical characteristics, laboratory findings, and radiologic and histopathological features. Logistic regression analyses were performed to explore factors related to the presence of fibrosis.

Results: A total of 202 patients with HP were enrolled, including 87 (43.1%) NFHP patients and 115 (56.9%) FHP patients. Patients with FHP were older and more frequently presented with dyspnea, crackles, and digital clubbing than patients with NFHP. Serum levels of carcinoembryonic antigen, carbohydrate antigen 125, carbohydrate antigen 153, gastrin-releasing peptide precursor, squamous cell carcinoma antigen, and antigen cytokeratin 21-1, and count of bronchoalveolar lavage (BAL) eosinophils were higher in the FHP group than in the NFHP group. BAL lymphocytosis was present in both groups, but less pronounced in the FHP group. Multivariable regression analyses revealed that older age, <20% of lymphocyte in BAL, and ≥1.75% of eosinophil in BAL were risk factors for the development of FHP. Twelve patients developed adverse outcomes, with a median survival time of 12.5 months, all of whom had FHP.

Conclusions: Older age, <20% of lymphocyte in BAL, and ≥1.75% of eosinophil in BAL were risk factors associated with the development of FHP. Prognosis of patients with NFHP was better than that of patients with FHP. These results may provide insights into the mechanisms of fibrosis in HP.

MeSH terms

Alveolitis, Extrinsic Allergic* / diagnosis
Bronchoalveolar Lavage Fluid
Carbohydrates
Fibrosis
Humans
Prospective Studies

Substances

Carbohydrates