Atypical Memory and Regulatory B Cell Subsets in Tumor Draining Lymph Nodes of Head and Neck Squamous Cell Carcinoma Correlate with Good Prognostic Factors

Research on the role of B cells in the development and modulation of antitumor immunity has increased in recent years; however, knowledge about B cell phenotype and function in tumor draining lymph nodes (TDLNs) is still incomplete. This study aimed to investigate changes in the phenotypic profile of B cells in TDLNs of head and neck squamous cell carcinoma (HNSCC) during disease progression. Mononuclear cells were isolated from TDLNs and stained with antibodies for CD19 and other B cell-related markers and analyzed by flow cytometry. CD19⁺ B cells comprised 38.6 ± 8.9% of lymphocytes in TDLNs of HNSCC. Comparison of metastatic and non-metastatic LNs disclosed no significant differences in the frequencies of B cell subsets including antigen-experienced, naïve, switched, unswitched, atypical memory, marginal zone-like B cells, and B cells with regulatory phenotypes. The percentage of atypical memory (CD27^–IgM^–IgD^–) B cells was significantly higher in patients with tongue SCC with no involved LNs (p = 0.033) and correlated inversely with the number of involved LNs. The frequency of CD24^hiCD38^hi B cells was significantly higher in non-metastatic LNs of patients with grade I compared to grade II (p = 0.016), and the percentage of CD5⁺ B cells decreased as tumors progressed from stage III to IV (p = 0.008). Our data show that in TDLNs of HNSCC, the frequency of B cells with atypical memory and regulatory phenotypes was significantly associated with good prognostic factors; however, their function remains to be investigated.