The aim of this study is to clarify the local immune status in the larynx affected by infection or carcinogenesis associated with HPV. Cytological samples for the detection of HPV and laryngeal secretions for the collection of immunoglobulin (Ig) were obtained from 31 patients with laryngeal diseases during microscopic surgery of the larynx. Histological results were as follows: 12 patients with squamous cell carcinomas, 4 with laryngeal papillomas and 15 with other benign laryngeal diseases.
HPV-DNA testing from cytological samples was performed with the Hybrid Capture 2 assay method. High risk HPV-DNA was detected in 25% (3⁄12 cases) of laryngeal cancers. Low risk type was detected in three laryngeal papillomas only. The mean IgM, IgG, IgA and secretory IgA concentrations in HPV-DNA positive cases were more than double compared to respective concentrations in HPV-DNA negative cases. In particular, a significant difference was observed between the concentrations of secretory IgA of the two groups. A comparison of laryngeal cancer and benign laryngeal diseases revealed that patients with laryngeal cancer had a higher concentration in each Ig isotype in laryngeal secretions than patients with benign laryngeal diseases. When the mean concentrations of each antibody isotype in the 12 cases with laryngeal cancer were compared between HPV-DNA positive (3 patients) and HPV-DNA negative (9 patients), the mean IgM, IgG, IgA, secretory IgA concentrations in HPV-DNA positive cancer showed a tendency to be higher than those in HPV-DNA negative cancer. Our results suggest that the local immune response in the larynx is activated by infection or carcinogenesis caused by HPV. It is strongly considered that secretory IgA activity inhibits infection or proliferation of HPV in the larynx.
