Quantification and Functional Studies of Neutrophilic Cells Identifies Distinct Papilloma Phenotypes

• Published in: The Laryngoscope Vol. 134; no. 7; pp. 3238 - 3244
• Main Authors: Bai, Ke, Clavijo, Paul E., Robbins, Yvette, Norberg, Scott M., Allen, Clint T.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2024
• Subjects: Adult; Aged; Female; Flow Cytometry; functional assays; human papillomavirus; Humans; immunosuppression; Laryngeal Neoplasms - immunology; Laryngeal Neoplasms - pathology; laryngeal papilloma; Male; Middle Aged; neutrophilic cells; Neutrophils - immunology; Neutrophils - pathology; Papilloma - immunology; Papilloma - pathology; Papillomavirus Infections - immunology; Papillomavirus Infections - pathology; Phenotype; recurrent respiratory papillomatosis; Respiratory Tract Infections - immunology; Respiratory Tract Infections - pathology; T-Lymphocytes, Regulatory - immunology; Tumor Microenvironment - immunology; functional assays; immunosuppression; recurrent respiratory papillomatosis; neutrophilic cells; human papillomavirus; laryngeal papilloma
• ISSN: 0023-852X; 1531-4995
• DOI: 10.1002/lary.31375

Objectives To characterize the distribution of immune cell subsets within laryngeal papillomas and to study the function of potentially immunosuppressive neutrophilic and regulatory T cells (Tregs). Methods Fresh clinical papilloma specimens were collected at the time of surgery and studied with multiparameter flow cytometry. Papilloma infiltrating neutrophilic cells and Tregs were sorted and studied functionally with ex vivo T cell suppression assays. Results Flow cytometric analysis of fresh laryngeal papillomas samples from 18 adult patients with recurrent respiratory papillomatosis revealed patterns in immune constituency between patients. Clearly divergent phenotypes based primarily on the degree of neutrophilic and T cell infiltration were identified. Relative neutrophilic cell enrichment and T cell depletion were observed in 50% of samples and neutrophilic cell depletion and T cell enrichment were observed in the others. Greater papilloma neutrophilic cell enrichment was positively associated with the number of clinically indicated interventions required in the 12 months prior to sample collection, linking papilloma neutrophil inflammation to disease severity. Functional assays revealed the ability of both papilloma infiltrating neutrophilic and Tregs to suppress T cell function at roughly equal magnitudes, but substantially increased infiltration of neutrophilic cells compared to Tregs across samples. Conclusion Neutrophilic cells are an important contributor to immunosuppression within the respiratory papilloma microenvironment. Given these data and the association between greater neutrophilic cell infiltration and lack of clinical response to therapeutic vaccination, additional study of strategies aimed at limiting neutrophilic cell infiltration or function within papillomas is warranted. Level of Evidence 4 Laryngoscope, 134:3238–3244, 2024 This work characterizes patterns of neutrophilic cell accumulation in respiratory papillomas from adult patients with RRP. Ex vivo functional assays demonstrate that papilloma infiltrating neutrophilic cells are immunosuppressive. This provides the scientific rationale for attempting to inhibit neutrophilic cell infiltration or function with the aim of improving local immunity within papillomas.