HLA-C mismatching improves outcomes following lung transplantation.

HLA (HLA) are a major barrier to transplant success, as HLA-A and -B molecules are principal ligands for T-cells, and HLA-C for Killer cell Immunoglobulin-like Receptors (KIR), directing Natural Killer (NK) cell function. HLA-C molecules are designated "C1" or "C2" ligands based on residues 77 and 80, which determine the NK cell responses. Here, we investigated donor/recipient HLA-C mismatch associations with the development of chronic lung allograft dysfunction (CLAD) following lung transplantation (LTx). 310 LTx donor/recipient pairs were Next Generation Sequenced and assessed for C1 and C2 allotypes. PIRCHE scores were used to quantify HLA mismatching between donor/recipients at amino acid level and stratify recipients into low, moderate or highly mismatched groups (n = 103-104). Associations between C ligands and freedom from CLAD was assessed with Cox regression models and survival curves. C2/C2 recipients (n = 42) had less CLAD than those with C1/C1 (n = 138) or C1/C2 genotypes (n = 130) (p < 0.05). Incidence of CLAD was lower in C2/C2 recipients receiving a mismatched C1/C1 allograft (n = 14), compared to matched (n = 8) or heterozygous (n = 20) allografts. Furthermore, ~80% of these recipients (C2/C2 recipients receiving C1/C1 transplants) remained CLAD-free for 10 years post-LTx. Recipients with higher HLA-C mismatching had less CLAD (p < 0.05) an observation not explained by linkage disequilibrium with other HLA loci. Our data implicates a role for HLA-C in CLAD development. HLA-C mismatching was not detrimental to LTx outcome, but potentially beneficial, representing a paradigm shift in assessing donor/recipient matching. This may inform better selection of donor/recipient pairs and potentially more targeted approaches to treating CLAD.

Platelet Activating Factor Receptor and Intercellular Adhesion Molecule-1 Expression Increases in the Small Airway Epithelium and Parenchyma of Patients with Idiopathic Pulmonary Fibrosis: Implications for Microbial Pathogenesis.

Background: Idiopathic pulmonary fibrosis (IPF) is an irreversible lung fibrotic disorder of unknown cause. It has been reported that bacterial and viral co-infections exacerbate disease pathogenesis. These pathogens use adhesion molecules such as platelet activating factor receptor (PAFR) and intercellular adhesion molecule-1 (ICAM-1) to gain cellular entry, causing infections. Methods: Immunohistochemical staining was carried out for lung resections from IPF patients (n = 11) and normal controls (n = 12). The quantification of PAFR and ICAM-1 expression is presented as a percentage in the small airway epithelium. Also, type 2 pneumocytes and alveolar macrophages were counted as cells per mm2 of the parenchymal area and presented as a percentage. All image analysis was done using Image Pro Plus 7.0 software. Results: PAFR expression significantly increased in the small airway epithelium (p < 0.0001), type 2 pneumocytes (p < 0.0001) and alveolar macrophages (p < 0.0001) compared to normal controls. Similar trend was observed for ICAM-1 expression in the small airway epithelium (p < 0.0001), type 2 pneumocytes (p < 0.0001) and alveolar macrophages (p < 0.0001) compared to normal controls. Furthermore, the proportion of positively expressed type 2 pneumocytes and alveolar macrophages was higher in IPF than in normal control. Conclusions: This is the first study to show PAFR and ICAM-1 expression in small airway epithelium, type 2 pneumocytes and alveolar macrophages in IPF. These findings could help intervene microbial impact and facilitate management of disease pathogenesis.

TGF-ß1, pSmad-2/3, Smad-7, and ß-Catenin Are Augmented in the Pulmonary Arteries from Patients with Idiopathic Pulmonary Fibrosis (IPF): Role in Driving Endothelial-to-Mesenchymal Transition (EndMT).

Background: We have previously reported that endothelial-to-mesenchymal transition (EndMT) is an active process in patients with idiopathic pulmonary fibrosis (IPF) contributing to arterial remodelling. Here, we aim to quantify drivers of EndMT in IPF patients compared to normal controls (NCs). Methods: Lung resections from thirteen IPF patients and eleven NCs were immunohistochemically stained for EndMT drivers, including TGF-ß1, pSmad-2/3, Smad-7, and ß-catenin. Intima, media, and adventitia were analysed for expression of each EndMT driver in pulmonary arteries. Computer- and microscope-assisted Image ProPlus7.0 image analysis software was used for quantifications. Results: Significant TGF-ß1, pSmad-2/3, Smad-7, and ß-catenin expression was apparent across all arterial sizes in IPF (p < 0.05). Intimal TGF-ß1, pSmad-2/3, Smad-7, and ß-catenin were augmented in the arterial range of 100-1000 µm (p < 0.001) compared to NC. Intimal TGF-ß1 and ß-catenin percentage expression showed a strong correlation with the percentage expression of intimal vimentin (r' = 0.54, p = 0.05 and r' = 0.61, p = 0.02, respectively) and intimal N-cadherin (r' = 0.62, p = 0.03 and r' = 0.70, p = 0.001, respectively). Intimal TGF-ß1 and ß-catenin expression were significantly correlated with increased intimal thickness as well (r' = 0.52, p = 0.04; r' = 0.052, p = 0.04, respectively). Moreover, intimal TGF-ß1 expression was also significantly associated with increased intimal elastin deposition (r' = 0.79, p = 0.002). Furthermore, total TGF-ß1 expression significantly impacted the percentage of DLCO (r' = -0.61, p = 0.03). Conclusions: This is the first study to illustrate the involvement of active TGF-ß/Smad-2/3-dependent and ß-catenin-dependent Wnt signalling pathways in driving EndMT and resultant pulmonary arterial remodelling in patients with IPF. EndMT is a potential therapeutic target for vascular remodelling and fibrosis in general in patients with IPF.

Multi-Locus Microsatellite Typing of Colonising and Invasive Aspergillus fumigatus Isolates from Patients Post Lung Transplantation and with Chronic Lung Disease.

Aspergillus fumigatus can cause different clinical manifestations/phenotypes in lung transplant (LTx) recipients and patients with chronic respiratory diseases. It can also precipitate chronic lung allograft dysfunction (CLAD) in LTx recipients. Many host factors have been linked with the severity of A. fumigatus infection, but little is known about the contribution of different A. fumigatus strains to the development of different phenotypes and CLAD. We used multi-locus microsatellite typing (MLMT) to determine if there is a relationship between strain (i.e., genotype) and phenotype in 60 patients post LTx or with chronic respiratory disease across two time periods (1 November 2006-31 March 2009 and 1 November 2015-30 June 2017). The MLMT (STRAf) assay was highly discriminatory (Simpson's diversity index of 0.9819-0.9942) with no dominant strain detected. No specific genotype-phenotype link was detected, but several clusters and related strains were associated with invasive aspergillosis (IA) and colonisation in the absence of CLAD. Host factors were linked to clinical phenotypes, with prior lymphopenia significantly more common in IA cases as compared with A. fumigatus-colonised patients (12/16 [75%] vs. 13/36 [36.1%]; p = 0.01), and prior Staphylococcus aureus infection was a significant risk factor for the development of IA (odds ratio 13.8; 95% confidence interval [2.01-279.23]). A trend toward a greater incidence of CMV reactivation post-A. fumigatus isolation was observed (0 vs. 5; p = 0.06) in LTx recipients. Further research is required to determine the pathogenicity and immunogenicity of specific A. fumigatus strains.

Multi-omics integration reveals a nonlinear signature that precedes progression of lung fibrosis.

Objectives: Idiopathic pulmonary fibrosis (IPF) is a devastating progressive interstitial lung disease with poor outcomes. While decades of research have shed light on pathophysiological mechanisms associated with the disease, our understanding of the early molecular events driving IPF and its progression is limited. With this study, we aimed to model the leading edge of fibrosis using a data-driven approach. Methods: Multiple omics modalities (transcriptomics, metabolomics and lipidomics) of healthy and IPF lung explants representing different stages of fibrosis were combined using an unbiased approach. Multi-Omics Factor Analysis of datasets revealed latent factors specifically linked with established fibrotic disease (Factor1) and disease progression (Factor2). Results: Features characterising Factor1 comprised well-established hallmarks of fibrotic disease such as defects in surfactant, epithelial-mesenchymal transition, extracellular matrix deposition, mitochondrial dysfunction and purine metabolism. Comparatively, Factor2 identified a signature revealing a nonlinear trajectory towards disease progression. Molecular features characterising Factor2 included genes related to transcriptional regulation of cell differentiation, ciliogenesis and a subset of lipids from the endocannabinoid class. Machine learning models, trained upon the top transcriptomics features of each factor, accurately predicted disease status and progression when tested on two independent datasets. Conclusion: This multi-omics integrative approach has revealed a unique signature which may represent the inflection point in disease progression, representing a promising avenue for the identification of therapeutic targets aimed at addressing the progressive nature of the disease.

Utility of the Stanford Integrated Psychosocial Assessment for Transplant in predicting outcomes before and after lung transplantation.

BACKGROUND: Optimizing donor use and achieving maximal survival following lung transplantation (LTx) require a pretransplant assessment that identifies clinical, physiological, and psychosocial patient factors associated with both poor and optimal post-LTx survival. We examined the utility of a psychosocial tool, the Stanford Integrated Psychosocial Assessment for Transplant (SIPAT), to identify patient suitability for LTx, as well as its association with clinical outcomes before and after LTx. METHODS: This was a retrospective single-center study analyzing LTx assessment clinical variables (age, gender, diagnosis, functional capacity, nutrition, renal function), with a particular focus on the utility of the SIPAT score, to predict patient suitability for LTx. The same variables were analyzed against LTx waitlist mortality, as well as post-LTx survival. RESULTS: Over an 8-year period dating from December 2012, 914 patients (male 54.4%, mean age 55.2 years) underwent LTx assessment. Patients declined for LTx (n = 152, 16.6%) were older and had reduced functional capacity, nutritional markers, and renal function but had a higher SIPAT score. Once listed for LTx, a higher SIPAT score was not associated with waitlist mortality or reduced post-LTx survival. CONCLUSIONS: The SIPAT tool measures psychosocial suitability for transplantation that can be incorporated into a standardized assessment of LTx suitability. While patients with higher SIPAT score were more likely to be declined for LTx, the SIPAT score did not predict outcome in transplanted patients. A subgroup of patients with high SIPAT scores were successfully transplanted, suggesting that unfavorable psychosocial variables are potentially modifiable with a well-resourced multidisciplinary LTx team.

Examining the impact of immunosuppressive drugs on antibody-dependent cellular cytotoxicity (ADCC) of human peripheral blood natural killer (NK) cells and gamma delta (γδ) T cells.

BACKGROUND: Human natural killer (NK) cells and gamma delta (γδ) T cells may impact outcomes of solid organ transplantation (SOT) such as lung transplantation (LTx) following the differential engagement of an array of activating and inhibitory receptors. Amongst these, CD16 may be particularly important due to its capacity to bind IgG to trigger antibody-dependent cellular cytotoxicity (ADCC) and the production of proinflammatory cytokines. While the use of immunosuppressive drugs (ISDs) is an integral component of SOT practice, their relative impact on various immune cells, especially γδT cells and CD16-induced functional responses, is still unclear. METHODS: The ADCC responses of peripheral blood NK cells and γδT cells from both healthy blood donors and adult lung transplant recipients (LTRs) were assessed by flow cytometry. Specifically, the degranulation response, as reflected in the expression of CD107a, and the capacity of both NK cells and γδT cells to produce IFN-γ and TNF-α was assessed following rituximab (RTX)-induced activation. Additionally, the effect of cyclosporine A (CsA), tacrolimus (TAC), prednisolone (Prdl) and azathioprine (AZA) at the concentration of 1 ng/ml, 10 ng/ml, 100 ng/ml, and 1000 ng/ml on these responses was also compared in both cell types. RESULTS: Flow cytometric analyses of CD16 expresion showed that its expression on γδT cells was both at lower levels and more variable than that on peripheral blood NK cells. Nevertheless functional analyses showed that despite these differences, γδT cells like NK cells can be readily activated by engagement with RTX to degranulate and produce cytokines such as IFNg and TNF-a. RTX-induced degranulation by either NK cells or γδT cells from healthy donors was not impacted by co-culture with individual ISDs. However, CsA and TAC but not Prdl and AZA did inhibit the production of IFN-γ and TNF-α by both cell types. Flow cytometric analyses of RTX-induced activation of NK cells and γδT cells from LTRs suggested their capacity to degranulate was not markedly impacted by transplantation with similar levels of cells expressing CD107 pre- and post-LTx. However an impairment in the ability of NK cells to produce cytokines was observed in samples obtained post LTx whereas γδT cell cytokine responses were not significantly impacted. CONCLUSIONS: In conclusion, the findings show that despite differences in the expression levels of CD16, γδT cells like NK cells can be readily activated by engagement with RTX and that in vitro exposure to CsA and TAC (calcineurin inhibitors) had a measurable effect on cytokine production but not degranulation by both NK cells and gdT cells from healthy donors. Finally the observation that in PBMC obtained from LTx recipients, NK cells but not γδT cells exhibited impaired cytokine reponses suggests that transplantation or chronic exposure to ISDs differentially impacts their potential to respond to the introduction of an allograft and/or transplant-associated infections.

Chronic lung allograft dysfunction is associated with an increased number of non-HLA antibodies.

BACKGROUND: Chronic lung allograft dysfunction (CLAD) is the major cause of adverse outcomes in lung transplant recipients. Multiple factors, such as infection, alloimmunity, and autoimmunity, may lead to CLAD. Here, we aim to examine the role of non-human leukocytes antigen (HLA) antibodies in CLAD in a large retrospective cohort. METHODS: We analyzed non-HLA antibodies in the pre- and post-transplant sera of 226 (100 CLAD, 126 stable) lung transplant recipients from 5 centers, and we used a separate cohort to confirm our findings. RESULTS: A panel of 18 non-HLA antibodies was selected for analysis based on their significantly higher positive rates in CLAD vs stable groups. The panel-18 non-HLA antibodies (n > 3) may be positive pre- or post-transplant; the risk for CLAD is higher in the latter. The presence of both non-HLA antibody and HLA donor-specific antibody (DSA) was associated with an augmented risk of CLAD (HR=25.09 [5.52-14.04], p < 0.001), which was higher than that for single-positive patients. In the independent confirmatory cohort of 61 (20 CLAD, 41 stable) lung transplant recipients, the risk for CLAD remained elevated in double-positive patients (HR=10.67 [0.98-115.68], p = 0.052). After adjusting for nonstandard immunosuppression, patients with double-positive DSA/Non-HLA antibodies had an elevated risk for graft loss (HR=2.53 [1.29-4.96], p = 0.007). CONCLUSIONS: Circulating non-HLA antibodies (n > 3) were independently associated with a higher risk for CLAD. Furthermore, when non-HLA antibodies and DSA were detected concomitantly, the risk for CLAD and graft loss was significantly increased. These results show that humoral immunity to HLA and non-HLA antigens may contribute to CLAD development.

Self-reported engagement in everyday activities following bilateral lung transplantation in paediatric cystic fibrosis: a single centre study.

INTRODUCTION: Following lung transplantation, it is unknown how children/adolescents self-assess their performance in everyday activities, importance of these activities, and whether resumption of everyday activities influences self-reported quality of life. The aim was to examine the effect of bilateral lung transplantation on children's/adolescent's perception of engagement in everyday activities over the first 18 months post-transplant. METHODS: A multiple-single-case-study pre-post test design was conducted at a National Paediatric Lung Transplant Service. Participants were aged under 18 years and were 3 months post first bilateral lung transplant at the time of recruitment. Outcomes were self-reported quality of life (Paediatric Quality of Life Inventory (PedsQL), Transplant Module and engagement in meaningful life roles (Child Occupational Self-Assessment (COSA) Scale) measured at 3 months and 18 months post-transplant from participants, and their parent(s) (PedsQL). Analysis included paired between-time differences and descriptive analysis. RESULTS: Seven participants were recruited to the trial with a mean age of 13 (SD 4) years and a diagnosis of cystic fibrosis. The total mean scores on PedsQL remained stable between 3 months and 18 months for both participants and parents. The PedsQL transplant module total mean scores of participants significantly increased from 3 months (M=66.58, SD=11.83) to 18 months (M=80.25, SD=11.56), t(5) = 2.91, p=0.03 whereas parents' scores remained stable. COSA responses reported 'big problems' with self-care tasks, family engagement and coping with worries at 3 months. At 18 months, the 'big problem' activities shifted to community engagement and independence. CONCLUSION: Time influences self-reported quality of life and engagement in meaningful life roles for children/adolescents and their parents 3 months to 18 months post-lung transplant. Our findings highlight the importance of focusing on occupational roles and occupational performance of children and adolescents when designing post-transplant interventions, suggesting a key role for occupational therapy after transplantation.

Comparison of human leukocyte antigen immunologic risk stratification methods in lung transplantation.

Outcomes after lung transplantation (LTx) remain poor, despite advances in sequencing technology and development of algorithms defining immunologic compatibility. Presently, there is no consensus regarding the best approach to define human leukocyte antigen (HLA) compatibility in LTx. In this study, we compared 5 different HLA compatibility tools in a high-resolution HLA-typed, clinically characterized cohort, to determine which approach predicts outcomes after LTx. In this retrospective single-center study, 277 donor-recipient transplant pairs were HLA-typed using next generation sequencing. HLA compatibility was defined using HLAMatchmaker, HLA epitope mismatch algorithm (HLA-EMMA), predicted indirectly recognizable HLA epitopes (PIRCHE), electrostatic mismatch score (EMS), and amino acid mismatches (AAMMs). Associations with HLA mismatching and survival, chronic lung allograft dysfunction (CLAD), and anti-HLA donor-specific antibody (DSA) were calculated using adjusted Cox proportional modeling. Lower HLA class II mismatching was associated with improved survival as defined by HLAMatchmaker (P < .01), HLA-EMMA (P < .05), PIRCHE (P < .05), EMS (P < .001), and AAMM (P < .01). All approaches demonstrated that HLA-DRB1345 matching was associated with freedom from restrictive allograft syndrome and HLA-DQ matching with reduced DSA development. Reducing the level of HLA mismatching, in T cell or B cell epitopes, electrostatic differences, or amino acid, can improve outcomes after LTx and potentially guide immunosuppression strategies.

Clinical outcomes following cessation of parenteral immunoglobulin therapy following lung transplantation.

Broad use of parenteral immunoglobulin (IgG) therapy in lung transplant (LTx) patients occurs without robust clinical evidence or guidelines. Main indications include secondary hypogammaglobulinemia, antibody-mediated rejection (AMR), and treatment or prevention of graft rejection where the use of conventional immunosuppressive therapies is contraindicated. As part of routine auditing of IgG use in our LTx service, we assessed for adverse clinical outcomes related to IgG therapy cessation between November 2017 and February 2022. Of 220 LTx recipients receiving IgG therapy at our center during this period (approximately 20% of our total LTx cohort), 48 patients ceased therapy. No adverse outcomes were experienced in 83.3% patients. About 10.4% recommenced therapy for the same indication within 6 months with no longer term sequelae. One AMR patient developed progressive Chronic lung allograft dysfunction and died within 12 months, where therapy cessation was patient-initiated and associated with general noncompliance. These data provide reassurance that physician-directed cessation of IgG therapy is safe when based on sound clinical information and part of a robust clinical auditing process.

Defining a natural killer cell-enriched molecular rejection-like state in lung transplant transbronchial biopsies.

In lung transplantation, antibody-mediated rejection (AMR) diagnosed using the International Society for Heart and Lung Transplantation criteria is uncommon compared with other organs, and previous studies failed to find molecular AMR (ABMR) in lung biopsies. However, understanding of ABMR has changed with the recognition that ABMR in kidney transplants is often donor-specific antibody (DSA)-negative and associated with natural killer (NK) cell transcripts. We therefore searched for a similar molecular ABMR-like state in transbronchial biopsies using gene expression microarray results from the INTERLUNG study (#NCT02812290). After optimizing rejection-selective transcript sets in a training set (N = 488), the resulting algorithms separated an NK cell-enriched molecular rejection-like state (NKRL) from T cell-mediated rejection (TCMR)/Mixed in a test set (N = 488). Applying this approach to all 896 transbronchial biopsies distinguished 3 groups: no rejection, TCMR/Mixed, and NKRL. Like TCMR/Mixed, NKRL had increased expression of all-rejection transcripts, but NKRL had increased expression of NK cell transcripts, whereas TCMR/Mixed had increased effector T cell and activated macrophage transcripts. NKRL was usually DSA-negative and not recognized as AMR clinically. TCMR/Mixed was associated with chronic lung allograft dysfunction, reduced one-second forced expiratory volume at the time of biopsy, and short-term graft failure, but NKRL was not. Thus, some lung transplants manifest a molecular state similar to DSA-negative ABMR in kidney and heart transplants, but its clinical significance must be established.

Cytomegalovirus Immunity Assays Predict Viremia but not Replication Within the Lung Allograft.

Cytomegalovirus (CMV) infection causes significant morbidity and mortality in lung transplant recipients. Current guidelines use pretransplant donor and recipient CMV serostatus to predict the risk of subsequent CMV replication and length of antiviral prophylaxis. Immunological monitoring may better inform the risk of CMV infection in patients, thereby allowing for improved tailoring of antiviral prophylaxis. In this study, we compared 2 commercially available assays, the QuantiFERON-CMV (QFN-CMV) and T-Track-CMV (enzyme-linked immunosorbent spot assay), to predict the risk of CMV disease in lung transplant recipients. Methods: We performed CMV immunity assays on 32 lung transplant recipients at risk of CMV disease as defined by serostatus (CMV-seropositive recipients, n = 26; or CMV-seronegative lung transplant recipient receiving a CMV-seropositive donor organ, n = 6). QFN-CMV and T-Track were performed on peripheral blood mononuclear cells, and episodes of CMV replication in both serum and bronchoalveolar lavage were found to be correlated to the CMV immune assays. The predictive ability of the assays was determined using Kaplan-Meier curves. Results: There was a degree of concordance between tests, with 44% of recipients positive for both tests and 28% negative for both tests; however, test results were discordant in 28% of cases. A negative result in either the QFN-CMV (P < 0.01) or T-Track (P < 0.05) assays was obtained in a significantly higher number of recipients who experienced CMV replication in the blood. Using these assays together gave higher predictability of CMV replication, with only 1 recipient experiencing CMV replication in the blood who obtained a positive test result for both assays. Neither assay was able to predict recipients who experienced CMV replication in the lung allograft. Conclusions: Our study demonstrates that CMV immunity assays can predict viremia; however, the lack of association with allograft infection suggests that CMV-specific T-cell immunity in the circulation is not associated with the control of CMV replication within the transplanted lung allograft.

Endothelial-to-mesenchymal transition: a precursor to pulmonary arterial remodelling in patients with idiopathic pulmonary fibrosis.

Background: We have previously reported arterial remodelling in patients with idiopathic pulmonary fibrosis (IPF) and suggested that endothelial-to-mesenchymal transition (EndMT) might be central to these changes. This study aims to provide evidence for active EndMT in IPF patients. Methods: Lung resections from 13 patients with IPF and 15 normal controls (NCs) were immunostained for EndMT biomarkers: vascular endothelial cadherin (VE-cadherin), neural cadherin (N-cadherin), S100A4 and vimentin. Pulmonary arteries were analysed for EndMT markers by using computer- and microscope-assisted image analysis software Image ProPlus7.0. All the analysis was done with observer blinded to subject and diagnosis. Results: Increased expression of mesenchymal markers N-cadherin (p<0.0001), vimentin (p<0.0001) and S100A4 (p<0.05) was noted with downregulation of junctional endothelial VE-cadherin (p<0.01) in the intimal layer of the arteries from patients with IPF compared to NCs. Cadherin switch was observed in IPF patients, showing increase in endothelial N-cadherin and decrease in VE-cadherin (p<0.01). There was also VE-cadherin shift from junctions to cytoplasm (p<0.01), effecting endothelial cell integrity in patients with IPF. In IPF, individual mesenchymal markers vimentin and N-cadherin negatively correlated with diffusing capacity of the lungs for carbon monoxide (r'= -0.63, p=0.03 and r'= -0.66, p=0.01). Further, N-cadherin positively correlated with arterial thickness (r'=0.58, p=0.03). Conclusion: This is the first study to demonstrate active EndMT in size-based classified pulmonary arteries from IPF patients and potential role in driving remodelling changes. The mesenchymal markers had a negative impact on the diffusing capacity of the lungs for carbon monoxide. This work also informs early origins of pulmonary hypertension in patients with IPF.

Major technological advances will enhance Australian donor-recipient matching and improve transplant outcomes.

In recent times, numerous and significant technological and supportive changes have taken place in Australian transplantation. These changes are often deployed without the wider clinical community having a full understanding of what has brought about these changes and the impacts they have. Here, we aim to clarify the reasoning behind these changes and shed light on potential future endeavours to improve patient outcomes.

Clinical utility of a standardized chronic hypersensitivity pneumonitis exposure questionnaire.

BACKGROUND AND OBJECTIVE: Identification of an exposure is integral to the diagnosis, management, and prognostication of chronic hypersensitivity pneumonitis (CHP). Standardized questionnaires may aid in the identification of exposures, however, there currently are no evidence-based patient-validated questionnaires available. Key qualifiers (including duration and frequency) which indicate exposure relevance are also poorly defined. This study assessed the use of a standardized CHP exposure questionnaire in the identification of exposures and diagnostic confidence of CHP. METHODS: People with a multi-disciplinary meeting (MDM) diagnosis from five Australian interstitial lung disease (ILD) expert centres who provided informed consent were included. Participants completed a previously developed standardized CHP Exposure Questionnaire. Responses were collected with the participant's MDM data, including diagnosis, diagnostic confidence, and clinician-elicited exposures. RESULTS: One hundred thirty participants (IPF = 58, CHP = 24, CTD-ILD = 17, unclassifiable = 19, other = 12) were included. In 33% of CHP participants, a standardized questionnaire elicited an exposure where the clinician did not. 63% of these had provisional low confidence CHP; and an exposure history would have increased the diagnostic confidence in these cases. Using the standardized questionnaire, 96% of CHP participants reporting any exposure, compared with 75% of non-HP ILD participants. CHP participants were 3.5 times more likely (p = 0.004) to report their symptoms improved on avoidance, and 2.3 times more likely (p = 0.018) to report daily frequent exposure, compared with non-HP ILDs. CONCLUSION: A standardized questionnaire which elicits exposure characteristics in addition to presence or absence of relevant exposures can increase the diagnostic confidence of CHP and reduce the proportion of antigen-indeterminate CHP.

Determining Clinical Thresholds for Donor HLA Eplet Compatibility to Predict Best Outcomes Following Lung Transplantation.

Currently, the assessment of immunological risk in lung transplantation (LTx) does not completely consider HLA compatibility at the molecular level. We have previously demonstrated the association of HLA eplets in predicting chronic lung allograft dysfunction following LTx; however, the associations between HLA eplet mismatch (epMM) loads and overall survival are unknown. Methods: In this retrospective, single-center study, 277 LTx donor-recipient pairs were high resolution HLA typed and analyzed for HLA epMMs using HLAMatchmaker (version 3.1). LTx pairs were also assessed for the presence of the previously described risk epitope mismatches DQ2-DQA1*05 and DQ7-DQA1*05. Results: HLA class I epMMs were not associated with deleterious outcomes; however, lower HLA class II (≤19), DQA1 (≤2), and combined HLA class I and II (≤29) epMM demonstrated an association with increased time to chronic lung allograft dysfunction and improved overall survival. The presence of a risk epitope mismatch was not associated with worse clinical outcomes. Conclusions: HLA epMM can risk-stratify LTx recipients and potentially guide donor-recipient matching and immunosuppression strategies.

Cytomegalovirus in the transplant setting: Where are we now and what happens next? A report from the International CMV Symposium 2021.

The CMV Symposium in September 2021 was an international conference dedicated to cytomegalovirus (CMV) infection after solid organ or hematopoietic stem cell transplantation. This review provides an overview of the presentations given by the expert faculty, supplemented with educational clinical cases. Topics discussed include CMV epidemiology and diagnosis, the burden of CMV infection and disease, CMV-specific immunity and management of CMV in transplant settings. Major advances in the prevention and treatment of CMV in the past decade and increased understanding of CMV immunity have led to improved patient outcomes. In the future, management algorithms may be individualized based on the transplant recipient's immune profile, which will mark the start of a new era for patients with CMV.

Matrix metalloproteinase-7 is increased in lung bases but not apices in idiopathic pulmonary fibrosis.

Introduction: Idiopathic pulmonary fibrosis (IPF) is a progressively fibrotic lung condition with poor prognosis. Matrix metalloproteinase-7 (MMP7) is a protein secreted by epithelial cells in IPF lungs. It is not known if MMP7 expression correlates with fibrotic changes in lung tissue. Methods: Tissue samples from lung apices and bases were obtained from 20 IPF patients and 14 non-diseased control (NDC) donors. In formalin-fixed paraffin-embedded sections, histological assessment of fibrosis was performed; overall MMP7 positivity was assessed by immunohistochemistry and MMP7+ cells were quantified using multiplex immunohistochemistry. Protein expression of MMP7 in whole lung lysates was quantified by Western blotting. Bulk tissue transcriptomic profiles of 101 samples were analysed using RNA sequencing technologies. Results: Lung tissue from IPF bases was more fibrotic than in apices. MMP7 protein is elevated in IPF lung base tissue. In IPF whole lung lysates, MMP7 protein levels are increased compared to NDC donors and was increased in IPF lung bases compared to apices. MMP7 protein levels correlated with MMP7 gene expression levels in lung tissue. MMP7 transcript levels were increased in IPF base compared to NDC base lung tissue and increased in IPF base tissue compared to IPF apex tissue. Conclusions: Our cross-sectional study suggests that lung epithelial MMP7 expression increases as the tissue becomes more fibrotic and identifies a potentially nonepithelial or immune-cell source. Mechanisms of disease progression in IPF are still unclear, and our study suggests aberrant MMP7 production may be a histological starting point of lung tissue fibrosis.

The molecular features of chronic lung allograft dysfunction in lung transplant airway mucosa.

BACKGROUND: Many lung transplants fail due to chronic lung allograft dysfunction (CLAD). We recently showed that transbronchial biopsies (TBBs) from CLAD patients manifest severe parenchymal injury and dedifferentiation, distinct from time-dependent changes. The present study explored time-selective and CLAD-selective transcripts in mucosal biopsies from the third bronchial bifurcation (3BMBs), compared to those in TBBs. METHODS: We used genome-wide microarray measurements in 324 3BMBs to identify CLAD-selective changes as well as time-dependent changes and develop a CLAD classifier. CLAD-selective transcripts were identified with linear models for microarray data (limma) and were used to build an ensemble of 12 classifiers to predict CLAD. Hazard models and random forests were then used to predict the risk of graft loss using the CLAD classifier, transcript sets associated with rejection, injury, and time. RESULTS: T cell-mediated rejection and donor-specific antibody were increased in CLAD 3BMBs but most had no rejection. Like TBBs, 3BMBs showed a time-dependent increase in transcripts expressed in inflammatory cells that was not associated with CLAD or survival. Also like TBBs, the CLAD-selective transcripts in 3BMBs reflected severe parenchymal injury and dedifferentiation, not inflammation or rejection. While 3BMBs and TBBs did not overlap in their top 20 CLAD-selective transcripts, many CLAD-selective transcripts were significantly increased in both for example LOXL1, an enzyme controlling matrix remodeling. In Cox models for one-year survival, the 3BMB CLAD-selective transcripts and CLAD classifier predicted graft loss and correlated with CLAD stage. Many 3BMB CLAD-selective transcripts were also increased by injury in kidney transplants and correlated with decreased kidney survival, including LOXL1. CONCLUSIONS: Mucosal and transbronchial biopsies from CLAD patients reveal a diffuse molecular injury and dedifferentiation state that impacts prognosis and correlates with the physiologic disturbances. CLAD state in lung transplants shares features with failing kidney transplants, indicating elements shared by the injury responses of distressed organs.