T-Helper Type 9 Cells Play a Central Role in the Pathogenesis of Respiratory Epithelial Adenomatoid Hamartoma

Is Respiratory Epithelial Adenomatoid Hamartoma Related to Central Compartment Atopic Disease?

BACKGROUND

Respiratory epithelial adenomatoid hamartoma (REAH) is a benign lesion of the sinonasal tract that may mimic more concerning pathology. Clinical factors associated with REAH have not been well characterized.

OBJECTIVE

To report our findings on patients with this pathologic diagnosis.

METHODS

A retrospective chart review of patients with REAH between September 2006 and November 2019 was conducted. Data collected included clinical allergic rhinitis and asthma history, additional sinonasal diagnoses, prior sinus surgery, and the location of the REAH within the sinonasal cavity.

RESULTS

Twenty-six patients were identified (53.8% male, mean age 62 years [range, 29-93]). Bilateral REAH occurred in 50%. REAH was located at the superior nasal septum in 84.6% cases, with the remainder identified in sinus contents submitted for pathology, making definitive site uncertain. Concurrent sinonasal inflammatory disorders were identified in 18 patients (69.2%), including chronic rhinosinusitis with nasal polyps-not otherwise specified (6), chronic rhinosinusitis without nasal polyps (4), aspirin-exacerbated respiratory disease (2), allergic fungal rhinosinusitis (1), central compartment atopic disease (5), and IgG4-related sclerosing disease (1). Eight patients had isolated REAH. Adequate allergy records were available for 19 patients, of which 18 of 19 (94.7%) had clinical allergic rhinitis.

CONCLUSIONS

REAH is a benign sinonasal lesion commonly located within the central compartment of the nasal cavity, a site of significant allergen exposure. Affected patients have a high incidence of allergy along with chronic inflammatory conditions. The coexistence of REAH within inflammatory nasal mucosa in a consistent anatomic location, suggests REAH may have a similar etiology to central compartment atopic disease, with resultant respiratory glandular ingrowth within long-standing reactive changes of mucosa derived from ethmoid embryologic origin.

Chondro-Osseous Respiratory Epithelial Adenomatoid Hamartoma (COREAH): Case Report and Literature Review

Chondro-osseous respiratory epithelial adenomatoid hamartoma (COREAH) is an extremely rare lesion of the nasal cavity with only 11 reported cases in the literature. COREAH is of interest as it may be easily mistaken for other diseases of the nasal cavity with higher morbidity, which require significantly different management strategies. We report, to the best of our knowledge, the oldest documented case of COREAH in the literature: an 83-year-old female who presented with headaches and was found to have a posterior nasal septal lesion. Uniquely, the patient had sequential scans performed 1 year apart demonstrating only minor interval growth. We describe our experience in managing a patient with COREAH and review the world literature, to better define aspects of the history, presentation, and investigations that may allow differentiation from more sinister disease.

Bilateral respiratory epithelial adenomatoid hamartomas originating from the anterior olfactory clefts

A respiratory epithelial adenomatoid hamartoma (REAH) is an uncommon benign lesion often found in the sinonasal tract. We present a case of bilateral REAH originating from the anterior olfactory cleft treated with endoscopic surgical resection without recurrence. We highlight the characteristics of REAH and necessary steps to ensure proper diagnosis and treatment.

Neutralization of interleukin-9 ameliorates symptoms of allergic rhinitis by reducing Th2, Th9, and Th17 responses and increasing the Treg response in a murine model

A novel independent Th-cell subset, characterized by high expression of interleukin (IL)-9, has been recognized as the "Th9" subset. Although Th9 cells are important in many diseases, their contribution to allergic rhinitis (AR) remains unclear. We therefore first determined whether Th9 cells were present in a mouse model of AR. We then investigated the their involvement in the distribution of CD4+ T-cell subsets and the symptoms of AR by treating mice with anti-IL-9 antibodies (Abs). Anti-IL-9 Abs were administered intranasally during rechallenge of ovalbumin (OVA)-induced AR in BALB/c mice. We measured nasal rubbing motion, sneezing and eosinophils, as well as the Th1 (Th1 cell percentage, Ifn-γ mRNA/protein, T-bet mRNA), Th2 (Th2 cell percentage, Il-4 mRNA/protein, Gata3 mRNA), Th9 (Th9 cell percentages Il-9 mRNA/protein, PU.1 and Irf4 mRNA), Th17 (Th17 cell percentage, Il-17 mRNA/protein, Rorγt mRNA), and Treg (Treg cell percentage, Foxp3 mRNA) responses in the nasal mucosa. Treatment with anti-IL-9 Abs markedly reduced nasal rubbing, sneezing, eosinophil infiltration, and Th2, Th9, and Th17 responses, and increased the Treg response. Our findings emphasize the importance of IL-9/Th9 in the pathogenesis of AR, and suggest that anti-IL-9 Ab treatment may be an effective therapeutic strategy for AR.

IL-9 Signaling Pathway: An Update

Since the discovery of IL-9 almost three decades back as a growth factor, we have come a long way to understand its pleiotropic functions in the immune system. Despite its many functions, IL-9 still remains as an understudied cytokine. In the last decade, renewed emphasis has been provided to understand the biology of IL-9. Any growth factor or cytokine signals via its cognate receptor to mediate biological functions. In this chapter, we discuss the IL-9 signal transduction in different cell types, which would then exert its distinct functions.

TH9 cells in anti-tumor immunity

IL-9 was initially identified as a T cell growth factor with a potential oncogenic activity. Accordingly, IL-9 drives tumor growth in most hematological cancers. However, the links between IL-9 and cancer progression have been recently revisited following the discovery of T_H9 cells. T_H9 cells, which have been characterized in 2008 as a proinflammatory CD4 T cell subset that promotes protection against parasites and drives tissue inflammation in colitis, actually harbor potent IL-9-dependent anti-cancer properties in solid tumors and especially melanoma. While the molecular mechanisms underlying these observations are still being investigated, T_H9 cells were demonstrated to activate both innate and adaptive immune responses, thereby favoring anti-cancer immunity and tumor elimination. Human T_H9 cells have also been identified in cancer tissues, but their functions remain elusive. The present review aims to discuss the anti-cancer potential of T_H9 cells and their possible clinical relevance for cancer immunotherapy.

Respiratory Epithelial Adenomatoid Hamartomas: An Increasingly Common Diagnosis in the Setting of Nasal Polyps

Background

Respiratory epithelial adenomatoid hamartomas (REAH) are benign nose neoplasms found in the nasal cavity and sinuses. Symptoms include anosmia, nasal obstruction, facial pressure, and rhinorrhea. Although previously thought to be rare, these tumors are being increasingly recognized on pathology in patients undergoing endoscopic sinus surgery. However, REAH is difficult to diagnose before surgery because it may mimic other entities, such as nasal polyps or inverted papilloma, and is often found incidentally only after surgery.

Objective

The aims of this study were to (1) add an additional case series of REAH to the literature, (2) report unique imaging findings on computed tomography and magnetic resonance imaging, and (3) pool and summarize all available data from existing publications.

Methods

Retrospective chart review from years 2004 to 2015 and a literature review

Results

Twenty-three cases were found in our case series, which included 12 men (52%) and 11 women (48%), with a mean age of 59 years. No cases were found before 2007. Lund-Mackay scores were comparable with those found in chronic rhinosinusitis without nasal polyposis. Imaging consistently demonstrated a discoid-shaped mass at the olfactory cleft. Fifty previous publications were found (4 prospective, 11 retrospective studies, 9 case series, 26 cases reports), which included 660 patients diagnosed with REAH. Pooled data revealed a mean age of 54 years (range, 9–86 years) and a male to female ratio of 3:2.

Conclusion

The results of our study further refined the average age at which REAH diagnosis occurs as 54 years old, although it may occur at any age. There is a clear male-to-female predominance (3:2). In addition, olfactory cleft widening and discoid soft tissue at the olfactory cleft are hallmark radiographic findings. The vast majority of published cases occurred during the past 4 years, which indicated increased recognition of REAH.

Serum Interleukin (IL)-9 and IL-10, but not T-Helper 9 (Th9) Cells, are Associated With Survival of Patients With Acute-on-Chronic Hepatitis B Liver Failure

CD4 T helper (Th) cells are reported to be essential for initiating and maintaining an effective immune response to hepatitis B virus (HBV) infection. Th9 cells are a new subset of CD4 Th cells that produce interleukin (IL)-9 and IL-10. The present study aimed to investigate the percentage of Th9 cells relative to the number of CD4 cells in peripheral blood. We also measured serum IL-9 and IL-10 levels in different stages of HBV infection and their relationship with progress and prognosis of liver disease. Whole blood samples from 111 patients with HBV infection, including 39 chronic hepatitis B (CHB), 25 HBV-liver cirrhosis (HBV-LC), 21 acute-on-chronic liver failure (ACLF) patients, and 26 healthy controls were collected. The percentage of Th9 cells and serum IL-9 and IL-10 levels were determined. There was no significant difference in the percentage of Th9 cells and serum IL-9 and IL-10 levels among different groups, nor were these related to hepatitis B e antigen status, complications of cirrhosis, inflammation index, or prognosis indexes. There was no change in the percentage of Th9 cells before and after antiviral treatment in CHB patients. There was no correlation of Th9 cells with survival of ACLF patients. However, IL-9 and IL-10 levels were significantly higher in the nonsurvived ACLF patients compared to survived ACLF patients. Furthermore, baseline IL-9 level predicted the prognosis of ACLF patients with 87.5% sensitivity and 61.5% specificity.Thus, our data indicate that Th9 cells were unlikely involved in the pathogenesis of HBV infection, but elevation in IL-9 and IL-10 may signal poor prognosis for ACLF.