Immune checkpoint inhibitors-induced eosinophilic pneumonia: A case report

Dupilumab and the potential risk of eosinophilic pneumonia: case report, literature review, and FAERS database analysis

Eosinophilic pneumonia (EP) is a rare but noteworthy adverse effect linked to dupilumab, an interleukin-4 (IL-4) and IL-13 inhibitor used in the managing atopic diseases. The underlying mechanisms, potential predisposing factors, clinical characteristics, and optimal management strategies for dupilumab-induced EP remain unclear. We report a 71-year-old patient who developed acute EP after the first 600-mg dose of dupilumab. Eosinophils (EOSs) were also transiently increased (up to 1,600 cells/μl). After the acute EP was effectively treated with glucocorticoids, dupilumab treatment was continued. Rash, itching, and immunoglobulin E levels continued to decrease in the patient, and no further pulmonary adverse events occurred. We combined this case with a literature review of nine articles and analyzed data from 93 cases reported in the FDA Adverse Event Reporting System (FAERS) database of patients developing EP after dupilumab use. Our findings imply that dupilumab may induce EP, particularly in individuals over 45 years old, those with a history of respiratory diseases, and those who have previously used inhaled or systemic steroids. Vigilance is required, especially when there is a persistent elevation in peripheral blood EOSs during treatment. Although steroid treatment can effectively manage EP, more data are needed to determine the safety of resuming dupilumab treatment after controlling pneumonia.

Characterization of immunomodulatory factors and cells in bronchoalveolar lavage fluid for immune checkpoint inhibitor-related pneumonitis

As immune checkpoint inhibitors (ICIs) are widely used, a series of immune-related adverse events (irAEs) have been reported, including immune checkpoint inhibitor-related pneumonitis (ICI-pneumonitis). The incidence of ICI-pneumonitis is higher in reality than in clinical trials. The diagnosis is challenging, mainly based on clinical and imaging features, and requires the exclusion of other causes. The data on the biological mechanisms of ICI-pneumonitis are scarce, resulting in little knowledge of the best treatment for ICI-pneumonitis. Bronchoalveolar lavage (BAL) may be helpful to identify the biological differences or find predictive biomarkers, and may in turn help to develop phenotype-specific targeted drugs to treat ICI-pneumonitis. Herein, we outline the characterization of immunomodulatory factors and cells in bronchoalveolar lavage fluid for ICI-pneumonitis. Through careful sorting and literature review, we find crosstalk between pathogenic Th17/Th1 cells (i.e., Th17.1) and pro-inflammatory monocytes, and activation of Th17(/Th1)/IL-17A (/IFN-γ) pathways may play a key role in the pathogenesis of ICI-pneumonitis. Disruption of the interaction between pathogenic Th17/Th1 cells and pro-inflammatory monocytes (such as, anti-IL-23) may be a potential treatment for ICI-pneumonitis. We first describe the possible pathophysiological mechanisms of ICI-pneumonitis, hoping to contribute to the optimization of diagnosis and treatment, as well as provide readers with research inspiration.

A case of eosinophilic bronchiolitis after the initiation of immune checkpoint inhibitor

A 50-year-old Japanese woman with advanced breast cancer presented with productive cough and dyspnea while she was receiving a sixth cycle of chemotherapy including atezolizumab. Chest computed tomography revealed bronchiolitis and transbronchial lung cryobiopsy revealed eosinophilic bronchiolitis. Corticosteroid therapy successfully resolved her symptoms. Eosinophilic bronchiolitis is a rare but important immune-related adverse event; herein, we discuss its diagnosis and possible pathophysiology.

Immune checkpoint inhibitors-induced eosinophilic pneumonia: A case report

A 78‐year‐old male with renal cell carcinoma was treated with combined immunotherapy of nivolumab and ipilimumab. After four courses of the treatment, a chest computed tomography (CT) revealed newly formed ground‐glass opacities (GGOs) in both the lower lung lobes; drug‐induced pneumonia was speculated. Eosinophil counts were elevated in both peripheral blood and bronchoalveolar lavage fluid. Both the immune checkpoint inhibitors (ICIs) were discontinued, following which the chest CT findings improved. Based on these findings, a diagnosis of ICI‐induced eosinophilic pneumonia was made. Hence, clinicians should be wary of the risk of eosinophilic pneumonia during ICI‐anticancer therapy.