Antifungal Antibodies Research Articles

Perspective on receptor-associated immune response to Candida albicans single and mixed infections: implications for therapeutics in oropharyngeal candidiasis.

Oropharyngeal candidiasis (OPC), commonly known as 'thrush', is an oral infection that usually dismantles oral mucosal integrity and malfunctions local innate and adaptive immunities in compromised individuals. The major pathogen responsible for the occurrence and progression of OPC is the dimorphic opportunistic commensal Candida albicans. However, the incidence induced by non-albicans Candida (NAC) species including C. glabrata, C. tropicalis, C. dubliniensis, C. parapsilosis, C. krusei are increasing in company with several oral bacteria, such as Streptococcus mutans, Streptococcus gordonii, Staphylococcus epidermidis and Staphylococcus aureus. In this review, the microbiological and infection features of C. albicans and its co-contributors in the pathogenesis of OPC are outlined. Since the invasion and concomitant immune response lie firstly on the recognition of oral pathogens through diverse cellular surface receptors, we subsequently emphasize the roles of epidermal growth factor receptor (EGFR), ephrin-type receptor 2 (EphA2), human epidermal growth factor receptor 2 (HER2), aryl hydrocarbon receptor (AhR) located on oral epithelial cells to delineate the underlying mechanism by which host immune recognition to oral pathogens is mediated. Based on these observations, the therapeutic approaches to OPC comprising conventional and non-conventional antifungal agents, fungal vaccines, cytokine and antibody therapies, and antimicrobial peptide therapy are finally overviewed. In face of newly emerging life-threatening microbes (C. auris and SARS-CoV-2), risks (biofilm formation and interconnected translocation among diverse organs), and complicated clinical settings (HIV and oropharyngeal cancer), the research on OPC is still a challenging task.

Intestinal fungi and antifungal secretory immunoglobulin A in Crohn's disease.

The human gastrointestinal tract harbors trillions of commensal microorganisms. Emerging evidence points to a possible link between intestinal fungal dysbiosis and antifungal mucosal immunity in inflammatory bowel disease, especially in Crohn's disease (CD). As a protective factor for the gut mucosa, secretory immunoglobulin A (SIgA) prevents bacteria from invading the intestinal epithelium and maintains a healthy microbiota community. In recent years, the roles of antifungal SIgA antibodies in mucosal immunity, including the regulation of intestinal immunity binding to hyphae-associated virulence factors, are becoming increasingly recognized. Here we review the current knowledge on intestinal fungal dysbiosis and antifungal mucosal immunity in healthy individuals and in patients with CD, discuss the factors governing antifungal SIgA responses in the intestinal mucosa in the latter group, and highlight potential antifungal vaccines targeting SIgA to prevent CD.

Universal Candidacell-surface-specific monoclonal antibodies protect mice against multidrug-resistant Candida aurisbloodstream infections

Abstract Candidaspecies are the leading cause of life-threatening fungal infections in humans, especially among immunocompromised and hospitalized individuals. Of utmost concern is the emerging “superbug” Candida auriswhich has the potential to disseminate into bloodstream infections with up to 60% mortality in susceptible populations. Importantly, C. aurisis the first inherently multidrug-resistant fungal pathogen, which contributes to a delay in effective treatment and increased mortality rates. Consequently, C. aurisis the first fungal pathogen to cause a serious global public health threat. Our lab has identified and isolated a panel of universal monoclonal antibodies (mAbs) specific to Candidacell wall epitopes that share high homology among various human pathogenic Candidaspecies. Using an established murine model of disseminated infection, we showed that passive transfer of mAb C3.1 (anti-β-1,2-mannotriose) significantly extended survival and reduced fungal burdens and inflammation during early infection. We also showed that mAbs C3.1 and 9F2 (anti-phosphoglycerate kinase 1) significantly enhanced phagocytosis of C. aurisyeast by macrophages and inhibited the proliferation of multiple C. aurisclinical isolates in vitro. Since there are currently no approved antifungal vaccines or antibodies and current treatments are inadequate, critically needed antifungal antibodies can provide long-awaited effective therapies against this deadly pathogen. Our future directions include developing humanized mAbs to evaluate their protective efficacy in genetic mouse models of human immunodeficiency. We will then utilize Fc engineering to derive human IgG1 variants for enhanced complement-based effector efficacy. Supported by grants from NIH /NIAID (R21AI168929) and the Department of Defense (PR171482)

Antifungal antibodies present in intravenous immunoglobulin derived from China

Fungal infections usually occur in immunocompromised patients. Intravenous immunoglobulin (IVIG) has been used as therapeutic interventions for many infectious diseases, but seldom applied in mycosis due to unknown antifungal specificity. This study aims to determine the presence of antifungal antibodies in IVIG. Binding reactivity of IVIG with crude and recombinant antigens of Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans and Talaromyces marneffei were observed in a dose-dependent manner, similar with mixed normal human sera. The antifungal specificity was further confirmed by competitive enzyme-linked immunosorbent assays (ELISA) inhibited by rabbit specific antifungal polyclonal antibodies (PAbs) and homogenous crude antigens with inhibitions of 65.5-87.2% and 73.1-94.2%, respectively. Moreover, IVIG also reacted with fungal glycoproteins (Csa2, Cpl1 and Mp1p) in a dose-dependent way, which was inhibited by specific rabbit PAbs and homogenous antigens with different inhibitions and pulled down 72.8-83.8% of specific antibodies if preabsorption IVIG with Dynabeads® coupled with homogenous glycoproteins. These results furthermore verified the antifungal specificity of IVIG. Among four brands of IVIG, there was different antifungal IgG against C. albicans (P < 0.05) and C. neoformans (P < 0.05), while no difference for A. fumigatus (P = 0.086) and T. marneffei (P = 0.057). IVIG contained a significantly higher level of specific IgG for C. albicans than other three fungi (P <0.001). In conclusion, we proved antifungal IgG against C. albicans, A. fumigatus, C. neoformans and T. marneffei present in IVIG, which might be expected to provide a possible immunoregulation choice for mycosis and an evaluation to humoral immunity against fungi.

A Critical Role for CARD9 in Intestinal Microbiota Modulation and Colorectal Malignancies

The adaptor protein Caspase Recruitment Domain Family Member 9 (CARD9) plays an indispensable role in innate immunity. Recent studies indicate that dysregulated CARD9 is a critical risk factor in the progression of colorectal cancer (CRC). This review provides novel insights into the functions of CARD9 in CRC, particularly in delineating its role in disrupting the host microbe balance, fueling gut microbiota metabolism and inducing systemic immunoglobulin G (IgG) antifungal antibodies. These pathways provide important information that can potentially be used for therapeutic innovation in developing potential vaccines for CRC.

Fungal Infection Testing in Pediatric Intensive Care Units-A Single Center Experience.

Mycoses are diseases caused by fungi that involve different parts of the body and can generate dangerous treatment complications. This study aims to analyze fungal infection epidemiology in intensive care units (Pediatric and Cardiac Surgery Intensive Care Units—PCICU) and the Neonatal Intensive Care Unit (NICU) in one large pediatric center in the period 2015–2020 compared with 2005. The year 2005 was randomly selected as a historical time reference to notice possible changes. In 2005 and 2015–2020, 23,334 mycological tests were performed in intensive care units. A total of 4628 tests (19.8%) were performed in the intensive care units. Microbiological diagnostics involved mycological and serological testing. Of the 458 children hospitalized in the NICU, positive results in the mycological tests in the studied years were found in 21–27% of the children and out of 1056 PCICU patients, positive results were noticed in 18–29%. In both departments, the main detected pathogen was Candida albicans which is comparable with data published in other centers. Our experience indicates that blood cultures as well as the detection of antifungal antibodies do not add important information to mycological diagnostics. For the years of observation, only a few positive results were detected, even in patients with invasive fungal diseases. To our knowledge, this is one of a few similar studies over recent years and it provides contemporary reports of mycoses in pediatric ICU patients.

Advances in Antifungal Drug Development: An Up-To-Date Mini Review.

The utility of clinically available antifungals is limited by their narrow spectrum of activity, high toxicity, and emerging resistance. Antifungal drug discovery has always been a challenging area, since fungi and their human host are eukaryotes, making it difficult to identify unique targets for antifungals. Novel antifungals in clinical development include first-in-class agents, new structures for an established target, and formulation modifications to marketed antifungals, in addition to repurposed agents. Membrane interacting peptides and aromatherapy are gaining increased attention in the field. Immunotherapy is another promising treatment option, with antifungal antibodies advancing into clinical trials. Novel targets for antifungal therapy are also being discovered, allowing the design of new promising agents that may overcome the resistance issue. In this mini review, we will summarize the current status of antifungal drug pipelines in clinical stages, and the most recent advancements in preclinical antifungal drug development, with special focus on their chemistry.

Mycobiota-induced IgA antibodies regulate fungal commensalism in the gut and are dysregulated in Crohn's disease.

Secretory immunoglobulin A (sIgA) plays an important role in gut barrier protection by shaping the resident microbiota community, restricting the growth of bacterial pathogens, and enhancing host protective immunity via immunological exclusion. Here, we found that a portion of microbiota-driven sIgA response is induced by and directed towards intestinal fungi. Analysis of the human gut mycobiota bound by sIgA revealed a preference for hyphae; a fungal morphotype associated with virulence. C. albicans was a potent inducer of IgA class switch recombination (CSR) among plasma cells, through an interaction dependent on intestinal phagocytes and hyphal programming. Characterization of sIgA affinity and polyreactivity showed that hyphae-associated virulence factors were bound by these antibodies and that sIgA influenced C. albicans morphotypes in the murine gut. Furthermore, an increase of granular hyphal morphologies in Crohn’s Disease (CD) patients compared to healthy controls, correlated with a decrease of antifungal sIgA antibody titers with affinity to hyphae-associated virulence factors. Thus, in addition to their importance in gut bacterial regulation, sIgA targets the uniquely fungal phenomenon of hyphal formation. Our findings indicate that antifungal sIgA produced in the gut can play a role in regulating intestinal fungal commensalism by coating fungal morphotypes linked to virulence, thereby providing a protective mechanism that might be dysregulated in CD patients.

Gut mycobiota tunes humoral antifungal immunity.

This study shows that gut fungi, in particular Candida albicans, induce the production of systemic antifungal antibodies, which can provide protection against systemic fungal infections.

Human gut mycobiota tune immunity via CARD9-dependent induction of anti-fungal IgG antibodies

Antibodies mediate natural and vaccine-induced immunity against viral and bacterial pathogens, whereas fungi represent a widespread kingdom of pathogenic species for which neither vaccine nor neutralizing antibody therapies are clinically available. Here, using a multi-kingdom antibody profiling (multiKAP) approach, we explore the human antibody repertoires against gut commensal fungi (mycobiota). We identify species preferentially targeted by systemic antibodies in humans, with Candida albicans being the major inducer of antifungal immunoglobulin G (IgG). Fungal colonization of the gut induces germinal center (GC)-dependent B cell expansion in extraintestinal lymphoid tissues and generates systemic antibodies that confer protection against disseminated C.albicans or C.auris infection. Antifungal IgG production depends on the innate immunity regulator CARD9 and CARD9+CX3CR1+ macrophages. In individuals with invasive candidiasis, loss-of-function mutations in CARD9 are associated with impaired antifungal IgG responses. These results reveal an important role of gut commensal fungi in shaping the human antibody repertoire through CARD9-dependent induction of host-protective antifungal IgG.

Optimised production of an anti-fungal antibody in Solanaceae hairy roots to develop new formulations against Candida albicans

BackgroundInfections caused by fungi are often refractory to conventional therapies and urgently require the development of novel options, such as immunotherapy. To produce therapeutic antibodies, a plant-based expression platform is an attractive biotechnological strategy compared to mammalian cell cultures. In addition to whole plants, hairy roots (HR) cultures can be used, representing an expression system easy to build up, with indefinite growth while handled under containment conditions.ResultsIn this study the production in HR of a recombinant antibody, proved to be a good candidate for human immunotherapy against fungal infections, is reported. Expression and secretion of this antibody, in an engineered single chain (scFvFc) format, by HR from Nicotiana benthamiana and Solanum lycopersicum have been evaluated with the aim of directly using the deriving extract or culture medium against pathogenic fungi. Although both Solanaceae HR showed good expression levels (up to 68 mg/kg), an optimization of rhizosecretion was only obtained for N. benthamiana HR. A preliminary assessment to explain this result highlighted the fact that not only the presence of proteases, but also the chemical characteristics of the growth medium, can influence antibody yield, with implications on recombinant protein production in HR. Finally, the antifungal activity of scFvFc 2G8 antibody produced in N. benthamiana HR was evaluated in Candida albicans growth inhibition assays, evidencing encouraging results.ConclusionsProduction of this anti-fungal antibody in HR of N. benthamiana and S. lycopersicum elucidated factors affecting pharming in this system and allowed to obtain promising ready-to-use immunotherapeutics against C. albicans.

Thioredoxin Reductase 1 Is a Highly Immunogenic Cell Surface Antigen in Paracoccidioides spp., Candida albicans, and Cryptococcus neoformans

The increasing number of immunocompromised people has made invasive fungal infections more common. The antifungal armamentarium, in contrast, is limited to a few classes of drugs, with frequent toxicity and low efficacy pointing to the need for new agents. Antibodies are great candidates for novel antifungals, as their specificity can result in lower toxicity. Additionally, the immunomodulatory activity of antibodies could treat the underlying cause of many invasive mycoses, immune disfunction. In a previous comparative genomics study, we identified several potential targets for novel antifungals. Here we validate one of these targets, thioredoxin reductase (TRR1), to produce antibodies that could be useful therapeutic tools. Recombinant TRR1 proteins were produced by heterologous expression in Escherichia coli of genes encoding the proteins from Candida albicans, Cryptococcus neoformans, and Paracoccidioides lutzii. These proteins were then used to immunize mice, followed by detection of serum antibodies against them by ELISA and western blot. A first set of experiments in which individual mice were immunized repeatedly with TRR1 from a single species showed that all three were highly immunogenic, inducing mostly IgG1 antibodies, and that antibodies produced against one species cross-reacted with the others. In a second experiment, individual mice were immunized three times, each with the protein from a different species. The high titers of antibodies confirmed the presence of antigenic epitopes that were conserved in fungi but absent in humans. Immunofluorescence with sera from these immunized mice detected the protein in the cytoplasm and on the cell surface of fungi from all three species. These results validate TRR1 as a good target for potentially broad-spectrum antifungal antibodies.

Malassezia Is Associated with Crohn’s Disease and Exacerbates Colitis in Mouse Models

Inflammatory bowel disease (IBD) is characterized by alterations in the intestinal microbiota and altered immuneresponses to gut microbiota. Evidence is accumulating that IBD is influenced by not only commensal bacteria but also commensal fungi. We characterized fungi directly associated with the intestinalmucosa in healthy people and Crohn's disease patients and identified fungi specifically abundant in patients. One of these, the common skin resident fungus Malassezia restricta, is also linked to the presence of an IBD-associated polymorphism in the gene for CARD9, a signaling adaptor important for anti-fungal defense. M.restricta elicits innate inflammatory responses largely through CARD9 and is recognized by Crohn's disease patient anti-fungal antibodies. This yeast elicits strong inflammatory cytokine production from innate cells harboring the IBD-linked polymorphism in CARD9 and exacerbates colitis via CARD9 in mouse models of disease. Collectively, these results suggest that targeting specific commensal fungi may be a therapeutic strategy for IBD.

Murine models of Pneumocystis infection recapitulate human primary immune disorders.

Despite the discovery of key pattern recognition receptors and CD4+ T cell subsets in laboratory mice, there is ongoing discussion of the value of murine models to reflect human disease. Pneumocystis is an AIDS-defining illness, in which risk of infection is inversely correlated with peripheral CD4+ T cell counts. Due to medical advances in the control of HIV, the current epidemiology of Pneumocystis infection is predominantly due to primary human immunodeficiencies and immunosuppressive therapies. To this end, we found that every human genetic immunodeficiency associated with Pneumocystis infection that has been tested in mice recapitulated susceptibility. For example, humans with a loss-of-function IL21R mutation are severely immunocompromised. We found that IL-21R, in addition to CD4+ T cell intrinsic STAT3 signaling, were required for generating protective antifungal class-switched antibody responses, as well as effector T cell-mediated protection. Furthermore, CD4+ T cell intrinsic IL-21R/STAT3 signaling was required for CD4+ T cell effector responses, including IL-22 production. Recombinant IL-22 administration to Il21r-/- mice induced the expression of a fungicidal peptide, cathelicidin antimicrobial peptide, which showed in vitro fungicidal activity. In conclusion, SPF laboratory mice faithfully replicate many aspects of human primary immunodeficiency and provide useful tools to understand the generation and nature of effector CD4+ T cell immunity.

Multiple sclerosis and mixed microbial infections. Direct identification of fungi and bacteria in nervous tissue

Multiple sclerosis (MS) is the prototypical inflammatory disease of the central nervous system (CNS), leading to multifocal demyelination and neurodegeneration. The etiology of this incurable disease is unknown and remains a matter of intensive research. The possibility that microbial infections, such as viruses or bacteria, can trigger an autoimmune reaction in CNS tissue has been suggested. However, the recent demonstration that bacteria are present in CNS tissue points to a direct involvement of microbial infections in the etiology of MS. In the present study, we provide the first evidence of fungal infection in CNS tissue of MS patients, and demonstrate that fungal DNA from different species can be detected in the CNS. We used, nested PCR assays together with next-generation sequencing to identify the fungal species in the nervous tissue of 10 patients with MS. Strikingly, Trichosporon mucoides was found in the majority of MS patients, and particularly high levels of this fungus were found in two patients. Importantly, T. mucoides was not detected in the CNS of control subjects. We were also able to visualize fungal structures in CNS tissue sections by immunohistochemistry using specific antifungal antibodies, which also revealed the accumulation of a number of microbial cells in microfoci. Again, microbial structures were not observed in CNS sections from controls. In addition to fungi, neural tissue from MS patients was also positive for bacteria. In conclusion, our present observations point to the novel concept that MS could be caused by polymicrobial infections. Thus, mycosis of the CNS may be accompanied by opportunistic bacterial infection, promoting neuroinflammation and directly causing focal lesions, followed by demyelination and axonal injury.

Fungal infection in neural tissue of patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease and the main cause of motor neuron pathology. The etiology of the disease remains unknown, and no effective therapy exists to halt the disease or improve the quality of life. Here, we provide compelling evidence for the existence of fungal infection in ALS. Immunohistochemistry analysis using a battery of antifungal antibodies revealed fungal structures such as yeast and hyphae in the motor cortex, the medulla and the spinal cord, in eleven patients with ALS. Some fungal structures were localized intracellularly and even intranuclearly, indicating that this infection is not the result of post-mortem colonization. By contrast, this burden of fungal infection cannot be observed in several CNS areas of control subjects. PCR analysis and next generation sequencing of DNA extracted from frozen neural tissue identified a variety of fungal genera including Candida, Malassezia, Fusarium, Botrytis, Trichoderma and Cryptococcus. Overall, our present observations provide strong evidence for mixed fungal infections in ALS patients. The exact mixed infection varies from patient to patient consistent with the different evolution and severity of symptoms in each ALS patient. These novel findings provide a logical explanation for the neuropathological observations of this disease, such as neuroinflammation and elevated chitinase levels, and could help to implement appropriate therapies.

Drugs in Clinical Development for Fungal Infections.

Despite increasing rates of invasive fungal infections being reported globally, only a single antifungal drug has been approved during the last decade. Resistance, toxicity, drug interactions and restricted routes of administration remain unresolved issues. This review focuses on new antifungal compounds which are currently in various clinical phases of development. We discuss two azoles with a tetrazole moiety that allows selective activity against the fungal CYP: VT-1161 for Candida infections and VT-1129 for cryptococcal meningoencephalitis. We also discuss two glucan synthesis inhibitors: CD101, an echinocandin with an increased half-life, and SCY-078 with oral bioavailability and increased activity against echinocandin-resistant isolates. Among the polyenes, we discuss MAT023, an encochleated amphotericin B formulation that allows oral administration. Two novel classes of antifungal drugs are also described: glycosylphosphatidylinositol inhibitors, and the leading drug APX001, which disrupt the integrity of the fungal wall; and the orotomides, inhibitors of pyrimidine synthesis with the leading drug F901318. Finally, a chitin synthesis inhibitor and progress on human monoclonal antifungal antibodies are discussed.

Murine models of Pneumocystis infection recapitulate human primary immune disorders

Abstract Despite the discovery of key pattern recognition receptors and CD4+ T-cell subsets in laboratory mice, there is ongoing discussion of the value of murine models to reflect human disease. We recognize a strong parallel between human and mouse CD4+ T-cell immunity using the hallmark example of CD4+ T-cell dependent immunity, Pneumocystis pneumonia. Pneumocystis jirovecii infection was the first AIDS-defining illness and most closely tied with peripheral CD4+ T-cell counts. Due to successful control of HIV, the epidemiology of Pneumocystis infection in children is now primarily due to primary human immunodeficiencies and immunosuppressive therapies. To this end, we found that every human genetic immunodeficiency associated with Pneumocystis infection, recapitulated susceptibility in Pneumocystis infection in mice bearing similar mutations. Similar to human IL-21R deficiency, we found that IL-21R and CD4+ T-cell STAT3 signaling were required for both protective anti-fungal class-switched antibody responses and CD4+ effector T-cell mediated protection. Furthermore, we discerned that CD4+ T-cell intrinsic IL-21R/STAT3 signaling was required for inducing a Pneumocystis-specific IL-22 response, and that IL-22 inhibited trophozoite binding to alveolar epithelial cells. Moreover, recombinant IL-22 administration to Il21r−/− mice induced the expression of a fungicidal peptide, cathelicidin anti-microbial peptide which showed in vitro fungicidal activity. In conclusion, SPF laboratory mice faithfully replicate many aspects of human primary immunodeficiency and provide useful tools to understand the generation and nature of effector CD4+ T-cell immunity.

Immune responses in hibernating little brown myotis (Myotis lucifugus) with white-nose syndrome.

White-nose syndrome (WNS) is a fungal disease responsible for decimating many bat populations in North America. Pseudogymnoascus destructans (Pd), the psychrophilic fungus responsible for WNS, prospers in the winter habitat of many hibernating bat species. The immune response that Pd elicits in bats is not yet fully understood; antibodies are produced in response to infection by Pd, but they may not be protective and indeed may be harmful. To understand how bats respond to infection during hibernation, we studied the effect of Pd inoculation on the survival and gene expression of captive hibernating Myotis lucifugus with varying pre-hibernation antifungal antibody titres. We investigated gene expression through the transcription of selected cytokine genes (Il6, Il17a, Il1b, Il4 and Ifng) associated with inflammatory, Th1, Th2 and Th17 immune responses in wing tissue and lymph nodes. We found no difference in survival between bats with low and high anti-Pd titres, although anti-Pd antibody production during hibernation differed significantly between infected and uninfected bats. Transcription of Il6 and Il17a was higher in the lymph nodes of infected bats compared with uninfected bats. Increased transcription of these cytokines in the lymph node suggests that a pro-inflammatory immune response to WNS is not restricted to infected tissues and occurs during hibernation. The resulting Th17 response may be protective in euthermic bats, but because it may disrupt torpor, it could be detrimental during hibernation.

Association between spirometry controlled chest CT scores using computer-animated biofeedback and clinical markers of lung disease in children with cystic fibrosis

ABSTRACT Background: Computed tomography (CT) of the lungs is the gold standard for assessing the extent of structural changes in the lungs. Spirometry-controlled chest CT (SCCCT) has improved the usefulness of CT by standardising inspiratory and expiratory lung volumes during imaging. This was a single-centre cross-sectional study in children with cystic fibrosis (CF). Using SCCCT we wished to investigate the association between the quantity and extent of structural lung changes and pulmonary function outcomes, and prevalence of known CF lung pathogens. Methods: CT images were analysed by CF-CT scoring (expressed as % of maximum score) to quantify different aspects of structural lung changes including bronchiectasis, airway wall thickening, mucus plugging, opacities, cysts, bullae and gas trapping. Clinical markers consisted of outcomes from pulmonary function tests, microbiological cultures from sputum and serological samples reflecting anti-bacterial and anti-fungal antibodies. Results: Sixty-four children with CF, median age (range) of 12.7 (6.4–18.1) years, participated in the study. The median (range) CF-CT total score in all children was 9.3% (0.4–46.8) with gas trapping of 40.7% (3.7–100) as the most abundant finding. Significantly higher median CF-CT total scores (21.9%) were found in patients with chronic infections (N = 12) including Gram-negative infection and allergic bronchopulmonary aspergillosis (ABPA) exhibiting CF-CT total scores of 14.2% (ns) and 24.0% (p < 0.01), respectively, compared to 8.0% in patients with no chronic lung infection. Lung clearance index (LCI) derived from multiple breath washout exhibited closest association with total CF-CT scores, compared to other pulmonary function outcomes. Conclusions: The most prominent structural lung change was gas trapping, while CF-CT total scores were generally low, both showing close association with LCI. Chronic lung infections, specifically in the form of ABPA, were associated with increased scores in lung changes. Further investigation of impact of infections with different microorganisms on extent and progression of structural CF lung disease is needed.