Moving Towards Precision Medicine in United Airways Disease: Unraveling Inflammatory Patterns in Asthmatic Patients With or Without Nasal Polyps

1. Background Both, asthma and chronic rhinosinusitis (CRS) are inflammatory conditions of the airways. The prevalence of asthma - with its cardinal symptoms wheezing, breathlessness, chest tightness, and coughing - has risen over the past decades not only in industrial but also in developing countries. For instance, about 8% of the United States' population and 8.2% of Europeans are diagnosed with asthma. Chronic rhinosinusitis with (CRSwNP) and without nasal polyps (CRSsNP) is a condition affecting up to 16% and 11% of the US and European population, respectively3. Both diseases, asthma and CRS, can severely impair quality of life as well as productivity and therefore embody an immense socioeconomic burden. Despite the distinction of the respiratory tract in the upper and lower airways, both parts are anatomically and immunologically related. This led to the concept of "United airway diseases" assuming that upper and lower airways form a single organ. Consequently, inflammation in the upper affects the lower respiratory tract and vice versa. This concept initially described in the context of allergic respiratory disease can also be extended to the link between sinonasal and lower airway diseases. Accordingly, the association between asthma and CRS prevalence has been unambiguously shown in epidemiological studies: around 20% of CRSsNP patients and around 48% of CRSwNP patients suffer from asthma. Conversely, nasal polyposis is detected in 19 to 25% of asthmatics. In cases of severe asthma, even up to 54% of patients were reported to have a history of nasal polyposis. However, the pathophysiological mechanism underlying the association of asthma and CRS has been poorly investigated so far. Based on the predominant inflammatory profile, asthma can be separated into T2-high and T2-low endotypes. Thereby, around 60% of severe asthma patients show a T2-high profile. The picture is becoming even more complex regarding classifications of CRS. Phenotypically we distinguish between CRSsNP and CRSwNP. However, up to 10 different endotypes of CRS can be defined based on various different inflammatory markers in nasal polyps or nasal secretions. Approaches to characterize endotypes describing conditions involving both asthma and CRS have barely been made so far. On a cellular and protein level, it seems that higher concentrations of Staphylococcus enterotoxin-specific IgE, total IgE and eosinophil cationic protein in nasal polyp tissue are indicators for a higher risk of asthma. Furthermore, it was observed that patients with CRS and eosinophilic asthma (as determined by FeNO levels only) show high numbers of eosinophils in their nasal polyps. This nasal polyp eosinophilia was associated with a more severe asthma phenotype as well as larger polyps and a significantly higher nasal polyp recurrence rate compared to non-eosinophilic patients. However, up to this point, no study investigated whether inflammatory profiles in polyps and asthmatic lungs correspond and how inflammatory profiles of patients suffering from asthma with or without polyps may differ. Novel antibody-based therapies targeting mediators of type 2 immune response are constantly emerging as new treatment options for patients with severe chronic airway diseases. Therapeutic antibodies targeting IgE or IL-4/IL-13, IL-5, or IL-5 receptor-mediated pathways are currently licensed for the treatment of asthma but have also successfully been used to treat CRSwNP to some extent. In this respect, anti-IgE (omalizumab) and anti-IL4α receptor (dupilumab) specific monoclonal antibodies have recently been licensed for the treatment of nasal polyps and CRSwNP respectively. Antibodies targeting molecules further upstream in the inflammatory cascade such as TSLP or IL-33 are currently under development. Anti-TSLP antibodies showed first promising results in clinical trials including patients suffering from uncontrolled asthma. Despite targeting molecular pathways involved in the pathogenesis of both diseases, some monoclonal antibodies such as reslizumab are effective in treating asthma but fail to significantly ameliorate nasal polyposis. Interestingly, a post-hoc responder analysis showed that the group of patients with high baseline IL-5 levels in nasal secretions improved upon reslizumab treatment, while the other patient groups did not. These findings illustrate the urgent need to better understand the pathomechanism and potential links underlying both diseases in order to choose the right therapy for the right patient. 2. Study rationale In this study, we aim to unravel the pathophysiological mechanisms underlying T2-high asthma with or without nasal polyposis. Therefore, we plan to thoroughly examine T2-high asthmatic patients with and without nasal polyposis at the cellular and molecular level and compare them to patients suffering from eosinophilic polyps in the absence of asthma. Deep analysis of nose, oropharynx, and lung samples will yield information on inflammatory patterns at protein and mRNA level, cellular tissue architecture in the different disease subtypes as well as microbiome composition. This pilot study will help to unravel underlying pathomechanisms in these united airway diseases and, therefore, provide a rationale for new therapy approaches including biologicals. 3. Study objectives In this study we plan to: * evaluate the inflammatory profile in different sections of the airways; * evaluate the endotype and immunological profile of CRSwNP (when applicable); * determine the microbiome composition in nose, oropharynx, and bronchi in T2-high asthmatic patients with and without CRSwNP, N-ERD compared to patients with CRSwNP in absence of asthma