Standard treatment of oropharyngeal squamous cell carcinoma (OPSCC) is associated with strong morbidity, whereas immunotherapeutic approaches using PD-1:PD-L1 checkpoint blockade only show moderate response rates in OPSCC patients. Therefore, the development of a complex therapeutic protocol combining checkpoint inhibition with other targets is needed for better responses. The significance of tumor-infiltrating B cells (TIL-Bs) in shaping antitumor immunity remains unclear; therefore, we analyzed frequency, phenotype, prognostic value and possible roles of TIL-Bs in OPSCC.
In this study, we evaluated the density and distribution of TIL-Bs in FFPE samples from 2 cohorts of OPSCC patients. Than we assessed the phenotype of TIL-Bs by means of flow cytometry in fresh tumor samples immediately after radical surgery. The acquired data were corelated with the clinical outcome of the patients.
We observed that CD20+ TIL-Bs and CD8+ T cells formed non-organized clusters with clearly interacting cells and the densities of both intraepithelial CD20+ B cells and B/CD8+ T cell interactions have prognostic significance for the overall survival of OPSCC patients. Furthermore, a high density of TIL-Bs was associated with an activated B cell phenotype and a high density of direct B cell/CD8+ T cell interactions significantly correlated with the abundance of HPV16-specific CD8+ T cells.
Our results indicate that high abundance of TIL-Bs and high density of direct B cell/CD8+ T cell interactions can preselect patients with excellent prognosis who would profit from less invasive treatment. Furthermore, including B cells as an additional target in novel immunotherapeutic protocols may help to establish the desired sustained antitumor T cell responses in OPSCC patients.
Kamila Hladikova.
Sotio a.s.
All authors have declared no conflicts of interest.