Th17 cells provide protection at barrier tissues but may also contribute to immune pathology. The relevance and induction mechanisms of pathologic Th17 responses in humans are poorly understood. Here, we identify the mucocutaneous pathobiont Candida albicans as the major direct inducer of human anti-fungal Th17 cells. Th17 cells directed against other fungi are induced by cross-reactivity to C. albicans. Intestinal inflammation expands total C. albicans and cross-reactive Th17 cells. Strikingly, Th17 cells cross-reactive to the airborne fungus Aspergillus fumigatus are selectively activated and expanded in patients with airway inflammation, especially during acute allergic bronchopulmonary aspergillosis. This indicates a direct link between protective intestinal Th17 responses against C. albicans and lung inflammation caused by airborne fungi. We identify heterologous immunity to a single, ubiquitous member of the microbiota as a central mechanism for systemic induction of human antifungal Th17 responses and as a potential risk factor for pulmonary inflammatory diseases.

BackgroundIn Cystic Fibrosis (CF), the airways are often colonized by opportunistic fungi. The most frequently detected mold is Aspergillus fumigatus (Af). Af diseases are associated with significant morbidity and mortality. The most common clinical picture caused by Af is allergic bronchopulmonary aspergillosis (ABPA), triggered by an immunological reaction against Af. Af bronchitis and invasive aspergillosis rarely occur in CF as a result of spore colonization and germination. Since pulmonary mycoses and exacerbations by other pathogens overlap in clinical, radiological, and immunological characteristics, diagnosis still remains a challenge. The search for reliable, widely available biomarkers for Af diseases is therefore still an important task today.ObjectivesAf-specific IgG m3 is broadly available. Sensitivity and specificity data are contradictory and differ depending on the study population. In our prospective study on pulmonary Af diseases in CF, we determined specific IgG m3 in order to test its suitability as a biomarker for acute Af diseases and as a follow-up parameter.MethodsIn this prospective single center study, 109 patients with CF were screened from 2016 to 2019 for Af-associated diseases. According to diagnostic criteria, they were divided into four groups (control, bronchitis, ABPA, pneumonia). The groups were compared with respect to the level of Af-specific IgG (ImmunoCAP Gm3). We performed a receiver operating characteristic (ROC) curve analysis to determine cut-off, sensitivity and specificity. Twenty-one patients could be enrolled for a follow-up examination.ResultsOf the 109 patients, 36 were classified as acute Af-disease (Af bronchitis, ABPA, Af pneumonia). Of these, 21 patients completed follow up-screening. The median Af-specific Gm3 was higher in the acute Af-disease groups. There was a significant difference in Af-specific IgG m3 compared to the control group without acute Af-disease. Overall, there was a large interindividual distribution of Gm3. A cut-off value of 78.05 mg/L for Gm3 was calculated to discriminate controls and patients with ABPA/pneumonia with a specificity of 75% and a sensitivity of 74.6%. The follow up examination of 21 patients showed a decrease of Gm3 in most patients without statistical significance due to the small number of follow up patients.ConclusionAf specific IgG may be a useful biomarker for acute ABPA and Af pneumonia, but not for Af bronchitis in CF. However, due to the large interindividual variability of Gm3, it should only be interpreted alongside other biomarkers. Therefore, due to its broad availability, it could be suitable as a biomarker for ABPA and Af pneumonia in CF, if the results can be supported by a larger multicenter cohort.

Mycobacterium ( M .) abscessus infections in Cystic Fibrosis (CF) patients cause a deterioration of lung function. Treatment of these multidrug-resistant pathogens is associated with severe side-effects, while frequently unsuccessful. Insight on M. abscessus genomic evolvement during chronic lung infection would be beneficial for improving treatment strategies. A longitudinal study enrolling 42 CF patients was performed at a CF center in Berlin, Germany, to elaborate phylogeny and genomic diversification of in-patient M. abscessus . Eleven of the 42 CF patients were infected with M. abscessus . Five of these 11 patients were infected with global human-transmissible M. abscessus cluster strains. Phylogenetic analysis of 88 genomes from isolates of the 11 patients excluded occurrence of M. abscessus transmission among members of the study group. Genome sequencing and variant analysis of 30 isolates from 11 serial respiratory samples collected over 4.5 years from a chronically infected patient demonstrated accumulation of gene mutations. In total, 53 genes exhibiting non-synonymous variations were identified. Enrichment analysis emphasized genes involved in synthesis of glycopeptidolipids, genes from the embABC (arabinosyltransferase) operon, betA (glucose-methanol-choline oxidoreductase) and cho D (cholesterol oxidase). Genetic diversity evolved in a variety of virulence- and resistance-associated genes. The strategy of M. abscessus populations in chronic lung infection is not clonal expansion of dominant variants, but to sustain simultaneously a wide range of genetic variants facilitating adaptation of the population to changing living conditions in the lung. Genomic diversification during chronic infection requires increased attention when new control strategies against M. abscessus infections are explored.

Background: Epidemiology and potential risk factors for cystic fibrosis arthropathy (CFA) were studied in a relevant cystic fibrosis (CF) patient cohort.Methods: Cohort study of patients included in the German CF registry in 2016-2017. Descriptive analysis, exploratory tests and multivariable logistic regression were used to assess prevalence of CFA and associated potential risk factors for adult patients with/without chronic Pseudomonas aeruginosa infection.Results: 6069 CF patients aged from 0 to 78 years were analysed. CFA was observed in 4.9% of the patients. Prevalence was significantly higher in adult patients (8.4%) compared to patients < 18 years (0.7%; p < 0.0 0 01). Logistic regression analyses in adult patients (n = 3319) showed that CFA was significantly associated with increasing age (OR = 1.04; 95% CI: 1.02-1.05; p < 0.0 0 01), female gender (OR = 2.10; 95%CI:1.52-2.90; p < 0.0 0 01), number of hospitalizations (OR = 1.24; 95%CI:1.12-1.36; p < 0.0 0 01), chronic P. aeruginosa infection (OR = 1.83; 95%CI:1.28-2.61; p = 0.0 0 09), CF-related diabetes (OR = 1.69; 95%CI:1.23-2.33; p = 0.0013), pancreatic insufficiency (OR = 2.39; 95%CI:1.28-4.46; p = 0.0060) and sinusitis/polyps (OR = 1.91; 95%CI:1.39-2.62; p < 0.0 0 01). In a subgroup analysis of adults without chronic P. aeruginosa infection (n = 1550) CFA was also significantly associated with increasing age, female gender, increasing number of hospitalizations, pancreatic insufficiency as well as sinusitis/polyps; antimycotic treatment associated only in this subgroup while association with CF-related diabetes was not significant. Conclusion:CFA is a frequent and clinically relevant co-morbidity particularly in adult CF patients. CFA is significantly more common in patients with chronic P. aeruginosa colonization but associations with other indicators for a more severe disease course were identified regardless of P. aeruginosa colonization status.

Aspergillus fumigatus (Af) frequently colonizes the airways of patients with cystic fibrosis (CF) and can cause severe diseases, such as allergic bronchopulmonary aspergillosis, Af bronchitis or even Af pneumonia. However, risk factors, including environmental factors, for acquiring Af in the respiratory tract of patients with CF are rarely studied and described. The aim of this study was to investigate whether urban or rural life could affect colonization with Af in the respiratory tract of patients with CF. Due to privacy policy, registry data are usually not linked to patients´home addresses. It is therefore very difficult to analyze the influence of the patient´s residential environment. This prospective questionnaire survey was carried out in 31 German CF centers in 2018. Only completed surveys, including a clearly assigned type of residential area were included. Statistical analysis was performed by chi-squared test and logistic regression models. A total of 1016 questionnaires were analyzed (Patients`age: 23 ± 13; 0-88 years; female gender: n=492; 48%). The majority of patients with CF live in large cities (n =314; 30.9%) or urban districts (n=461; 45.4%). Prevalence of 30.2% was found for Af, within the 12 months of investigation period. Af colonization was significantly associated with urban life (p=0.004). Urban live should be considered as possible new risk factor for colonization with Af in the respiratory tract of patients with CF. These new results may raise the awareness of the influence of environmental factors on patient outcomes and should be included in patient guidance and preventive measures.

Background. The fungus Aspergillus fumigatus causes a variety of clinical phenotypes in patients with cystic fibrosis (pwCF). T-helper (Th) cells orchestrate immune responses against fungi, but the types of A. fumigatus-specific Th-cells in pwCF and their contribution to protective immunity or inflammation remain poorly characterized.Methods. We used antigen-reactive T cell enrichment (ARTE) to investigate fungus-reactive Th cells in peripheral blood of pwCF and healthy controls. Results. We show that clonally expanded, high-avidity A. fumigatus-specific effector Th-cells develop in pwCF, which are absent in healthy donors. Individual patients were characterized by distinct Th1, Th2, or Th17 dominated responses that remained stable over years. These different Th subsets target different A. fumigatus proteins, indicating that differential antigen uptake and presentation directs Th-cell subset development. Patients with allergic bronchopulmonary aspergillosis (ABPA) are characterized by high frequencies of Th2-cells that cross-recognize various filamentous fungi. Conclusion. Our data highlight the development of heterogenous Th responses targeting different protein fractions of a single fungal pathogen and identify the development of multispecies cross-reactive Th2-cells as a potential risk factor for ABPA.

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Aspergillus fumigatus (Af) frequently colonizes the respiratory tract of patients with cystic fibrosis (CF). Af is associated with loss of pulmonary function and allergic bronchopulmonary aspergillosis (ABPA), a hypersensitivity fungal lung disease. Environmental factors have impact on CF patients’ lung function variation. The aim of this nationwide questionnaire survey was to investigate the amount of CF patients with frequent pet contact including pet species and to examine the potential impact of frequent pet contact on the occurrence of Af colonization and ABPA diagnosis in these patients. The survey was carried out in 31 German CF centers in 2018. A total of 1232 who completed the surveys were included, and statistical analysis was performed by chi-squared test. Within the study cohort 49.8% of subjects (n = 614; CF patients &lt; 18years: 49.4%, n = 234; ≥ 18years: 50.1%, n = 380) reported frequent contact to pets, of which 60.7% reported frequent contact to dogs, 42.3% to cats and other animals. Of those with frequent pet contact, 71.8% (n = 441) had contact to one pet or more pets from the same family. Af colonization was not significantly associated with frequent pet contact. ABPA diagnosis was documented in 16.7% (n = 206) of all included CF patients and was significantly associated with frequent pet contact (18.9%, n = 116, p = 0.042), confirming previous single center examinations. Particularly, patients with frequent contact to dogs showed an increased ABPA prevalence of 21.3%. Frequent pet contact might be a risk factor for ABPA. CF patients who are sensitized to Af should be informed about the increased risk to develop an ABPA by frequent pet contact. Patients with recurrent onset of ABPA should be evaluated in terms of frequent pet contact.