Yasuaki Harabuchi

Chronic epipharyngitis is associated with a wide variety of symptoms, including local symptoms such as postnasal drip, sore throat, lump sensation of the pharynx, headache, chronic cough, nasal obstruction, tinnitus/ear fullness, chronic phlegm and dysphonia due to inflammation of the epipharynx, functional somatic symptoms such as chronic fatigue, dizziness, insomnia, brain fog, abdominal discomfort, and depression caused by dysfunction of the hypothalamus-limbic system via disturbances of vagal response and cerebrospinal fluid outflow, and distant organ symptoms such as immunoglobulin A nephropathy and palmoplantar pustulosis caused by the epipharyngeal lymphoid tissue as an etiologic organ. In the past, chronic inflammation in the epipharynx was difficult to prove by gross findings, now, direct observation of the epipharyngeal inflammation by endoscopy has become easier for the diagnosis. For the treatment of chronic epipharyngitis, epipharyngeal abrasive therapy (EAT), epipharyngeal application of a 1% zinc chloride solution intranasally or orally was popular since the 1960s, recently, endoscopic EAT (E-EAT), in which epipharynx is safely and accurately observed and abraded under clear vision using an endoscope, has been developed. The mechanisms of EAT effects can be classified into anti-inflammatory/antiviral effect, bloodletting effect, and vagus nerve stimulation effect. Recently, the effectiveness of EAT for post-acute sequelae of coronavirus disease 2019 (COVID-19), known as long COVID, has come into the limelight, and the number of patients for whom EAT is expected to increase. In 2019, the Japan Society of Stomato-pharyngology established the EAT Review Committee to accumulate evidence on the efficacy of EAT and to establish indications and techniques for its use. In this article, the EAT Review Committee outlines its symptoms, pathogenesis, and diagnosis of chronic epipharyngitis, technique of E-EAT, mechanisms of EAT effects, past reports for the efficacy of EAT, and a multicenter prospective study.

Novel insights into Epstein–Barr virus (EBV) pathogenicity were presented at the “19th International Symposium on Epstein-Barr Virus and Associated Diseases” in Asahikawa, Japan. In addition, basic and translational findings on EBV-associated tumors, including natural killer (NK)/T-cell lymphoma, gastric cancer, and nasopharyngeal cancer, were presented by an international group of scientists and clinicians.

Hematuria is an essential symptom of immunoglobulin A nephropathy (IgAN). Although the etiology of hematuria in IgAN has not been fully elucidated, it is thought that the rupture of the glomerular basement membranes caused by intra-capillary leukocyte influx, so-called glomerular vasculitis, is the pathological condition responsible for severe hematuria. Glomerular vasculitis are active lesions that exist in the glomeruli of acute phase IgAN and it is important because it is suspected to make the transition to segmental glomerular sclerosis (SGS) as a repair scar lesion in the chronic phase, and the progression of SGS would eventually lead to glomerular obsolescence. Worsening of hematuria concomitant with acute pharyngitis is common in patients with IgAN; therefore, elucidating the relationship between the immune system of Waldeyer’s ring, including the palatine tonsil and epipharyngeal lymphoid tissue, and the glomerular vasculitis may lead to understanding the nature of IgAN. The epipharynx is an immunologically activated site even under normal conditions, and enhanced activation of innate immunity is likely to occur in response to airborne infection. Hyperactivation of innate immunity via upregulation of Toll-like receptors in the interfollicular area of the palatine tonsil and epipharyngeal lymphoid tissue, followed by enhanced fractalkine/CX3CR1 interactions, appears to play an important role in the development of glomerular vasculitis in IgAN. As latent but significant epipharyngitis is present in most patients with IgAN, it is plausible that acute upper respiratory infection may contribute as a trigger for the innate epipharyngeal immune system, which is already upregulated in a chronically inflamed environment. Given that epipharyngitis and its effects on IgAN are not fully understood, we propose that the so-called “epipharynx–kidney axis” may provide an important focus for future research.

Extranodal NK/T-Cell Lymphoma, nasal type (ENKTL-NT) has some salient aspects. The lymphoma is commonly seen in Eastern Asia, has progressive necrotic lesions in the nasal cavity, makes midfacial destructive lesions, and shows poor prognosis. The lymphoma cell is originated from either NK- or γδ T-cells, which express CD56. Since the authors first demonstrated the existence of Epstein–Barr virus (EBV) DNA and EBV oncogenic proteins in lymphoma cells, ENKTL-NT has been recognized as an EBV-associated malignancy. Because the angiocentric and polymorphous lymphoma cells are mixed with inflammatory cells on a necrotic background, the diagnosis of ENKTL-NT requires CD56 immunostaining and EBER in situ hybridization. In addition, serum the EBV DNA level is useful for the diagnosis and monitoring of ENKTL-NT. Although ENKTL-NT is refractory lymphoma, the prognosis is improved by the development of therapies such as concomitant chemoradiotherapy. The basic research reveals that a wide variety of intracellular/cell surface molecules, cytokines, chemokines, and micro RNAs are involved in lymphomagenesis, and some of them are related to EBV. Understanding lymphoma behavior introduces new therapeutic strategies, such as the usage of immune checkpoint inhibitors, peptide vaccines, and molecular targeting therapy. This review addresses recent advances in basic and clinical aspects of ENKTL-NT, especially its relation to EBV features.

Head and neck squamous cell carcinoma (HNSCC) originates from squamous epithelium of the upper aerodigestive tract and is the most common malignancy in the head and neck region. Among HNSCCs, oropharynx squamous cell carcinoma (OSCC) has a unique profile and is associated with human papillomavirus infection. Recently, anti-programmed cell death-1 monoclonal antibody has yielded good clinical responses in recurrent and/or metastatic HNSCC patients. Therefore, programmed death-ligand 1 (PD-L1) may be a favorable target molecule for cancer immunotherapy. Although PD-L1-expressing malignant cells could be targeted by PD-L1-specific CD8+ cytotoxic T lymphocytes, it remains unclear whether CD4+ helper T lymphocytes (HTLs) recognize and kill tumor cells in a PD-L1-specific manner. The expression levels of PD-L1 and HLA-DR were evaluated using immunohistochemical analyses. MHC class II-binding peptides for PD-L1 were designed based on computer algorithm analyses and added into in vitro culture of HTLs with antigen-presenting cells to evaluate their stimulatory activity. We found that seven of 24 cases of OSCC showed positive for both PD-L1 and HLA-DR and that PD-L1241-265 peptide efficiently activates HTLs, which showed not only cytokine production but also cytotoxicity against tumor cells in a PD-L1-dependent manner. Also, an adoptive transfer of the PD-L1-specific HTLs significantly inhibited growth of PD-L1-expressing human tumor cell lines in an immunodeficient mouse model. Importantly, T cell responses specific for the PD-L1241-265 peptide were detected in the HNSCC patients. The cancer immunotherapy targeting PD-L1 as a helper T-cell antigen would be a rational strategy for HNSCC patients.