Escalante, Patricio

Abstract Introduction Bronchiectasis (BE) is characterized by recurrent infections and dilated airways and has been associated with recurrent exacerbations and hospitalizations affecting quality of life. Approximately 40-60% of patients with BE have concomitant OSA, with an increased AHI (apnea-hypopnea index) in BE patients with Pseudomonas infections. We hypothesize that patients with BE are less tolerant of PAP therapies, contributing to worsening quality of life related to either condition. We aim to determine differences in PAP adherence and treatment response in patients with BE and OSA compared with a matched OSA-control group. Methods A retrospective cohort analysis was conducted on adult patients evaluated at Mayo Clinic Center for Sleep Medicine between January 2000 to December 2020. Inclusion criteria were patients greater than 18 years old diagnosed with BE and OSA per current guidelines and were prescribed PAP therapy. Control OSA patients were matched to BE/OSA patients by gender, BMI, and AHI severity. Exclusion criteria included cystic fibrosis, hospice enrollment, active lung transplant evaluation, and lack of sleep clinic follow-up. Follow-up visits determined PAP compliance and change in quality-of-life metrics over 3 years. Results We compared 50 patients with BE/OSA with 74 OSA matched controls. The etiology of BE in these cases included COPD (32%) or other etiologies (34%). Baseline characteristics were not statistically different in gender, BMI, and AHI severity across groups. Median treatment follow-up for the BE/OSA group was 3 years [IQR 2 to 4]. Importantly, there was no statistically significant difference in PAP adherence in patients with BE/OSA compared to OSA controls regardless of etiology of BE, but these patients more often required supplemental oxygen therapy. Interestingly, there was a statistically significant increase in MRC and decrease in FEV1 over time in BE patients compliant to therapy. Conclusion There was no significant difference in baseline OSA characteristics, treatment response, and PAP adherence, except for need of oxygen supplementation in BE patients with OSA compared with matched non-BE OSA controls. FEV1 values decreased, and dyspnea score increased in BE patients compliant to PAP therapy; however, future larger studies should include longer-term follow-up to further assess the impact of PAP therapy on BE progression and outcomes. Support (if any)

Abstract Introduction Several studies have shown a positive association between Obstructive Sleep Apnea (OSA) and malignancies such as lung cancer. However, the effects of intermittent hypoxemia in cancer-free survival following curative therapy are not known. We propose that OSA-related episodic hypoxemia and hypoxic burden are independent risk factors for accelerated lung cancer reoccurrence (< 2 years). Methods We performed a retrospective record review of patients 18 years and older from January 2016 to September 2023 with history of non-small cell lung cancer who received an overnight oximetry study (OXY) within three years prior to undergoing curative malignancy treatment. Subjects with history of central sleep apnea, baseline oxygen saturation (SpO2) below 90%, receiving supplemental oxygen or treatment for OSA were excluded. Results 403 patients met inclusion criteria (52% female vs 48% males; median age 74 y). The most common histologic subtypes were adenocarcinoma (68%) followed by squamous cell carcinoma (22%). Most patients fell into Stage IA1 (35%) followed by IA2 (24.1%) and IB (19%) as per TNM 8th edition classification. Over this period, 68 patients (22%) had lung cancer recurrence (median 19 months). A 4% oxygen desaturation index (ODI) of >15 and time spent in desaturation events were found to be a risk factor for cancer reappearance in less than 2 years (p< 0.001). Measures of hypoxic burden such as time spent below 89% SpO2, average SpO2 value below 89%, and single nadir oxygen levels, showed a similar association (p< 0.001). This was irrespective of histologic subtype, stage at diagnosis, and all studied demographic variables. Basal SpO2 demonstrated no correlation. A multivariate proportional hazard survival model showed that ODI>15 was no longer significant, however average SpO2 below 89% and single minimum oxygen level remained strongly correlated with accelerated recurrence. Conclusion This study showed a strong, positive association between accelerated lung cancer recurrence and OSA-related episodic hypoxemia and hypoxic burden on our univariate analysis. The multivariate model demonstrated correlation with hypoxic load measures only, suggesting the need for a larger sample to elucidate the involvement of this highly treatable risk factor. To our knowledge, this is the first study revealing this potential link. Support (if any)

The optimal detection strategies for effective convalescent immunity after SARS-CoV-2 infection and vaccination remain unclear. The objective of this study was to characterize convalescent immunity targeting the SARS-CoV-2 spike protein using a multiparametric approach. At the beginning of the pandemic, we recruited 30 unvaccinated convalescent donors who had previously been infected with COVID-19 and 7 unexposed asymptomatic controls. Peripheral blood mononuclear cells (PBMCs) were obtained from leukapheresis cones. The humoral immune response was assessed by measuring serum anti-SARS-CoV-2 spike S1 subunit IgG via semiquantitative ELISA, and T-cell immunity against S1 and S2 subunits were studied via IFN-γ enzyme-linked immunosorbent spot (ELISpot) and flow cytometric (FC) activation-induced marker (AIM) assays and the assessment of cytotoxic CD8+ T-cell function (in the subset of HLA-A2-positive patients). No single immunoassay was sufficient in identifying anti-spike convalescent immunity among all patients. There was no consistent correlation between adaptive humoral and cellular anti-spike responses. Our data indicate that the magnitude of anti-spike convalescent humoral and cellular immunity is highly heterogeneous and highlights the need for using multiple assays to comprehensively measure SARS-CoV-2 convalescent immunity. These observations might have implications for COVID-19 surveillance, and the determination of optimal vaccination strategies for emerging variants. Further studies are needed to determine the optimal assessment of adaptive humoral and cellular immunity following SARS-CoV-2 infection, especially in the context of emerging variants and unclear vaccination schedules.

Abstract Background Tuberculosis (TB) is an infectious disease that induces a complex response from the host immune system. Most carriers of the bacteria experience the asymptomatic, non-infectious phase, latent tuberculosis infection (LTBI), but have the potential to reactivate to active, contagious TB infection. Current diagnostics for TB are not sufficient for LTBI and are focused on using one biomarker, interferon-gamma (IFN-g). To build better diagnostics for the complex disease, multi-biomarker approaches to profile the immune system, coupled with machine learning algorithms, are necessary to diagnose LTBI and determine patients' risks of reactivation to active TB. We aim to use a multiplexed silicon photonic microring resonator sensing platform to profile thirteen biomarkers in patients with LTBI infection and use machine learning data analysis to identify biomarkers relevant for diagnosing LTBI and predicting reactivation risk. Methods We employed microring resonators coupled with a sandwich-style detection format to simultaneously detect thirteen cytokines and chemokines in plasma in under 40 minutes. Chip-integrated silicon photonic microrings are small in size and easily multiplexed with up to sixteen different capture agents. Biomolecular binding events are measured by monitoring the resonant wavelength within the sensing cavity, which shifts as binding events occur. Quantitation of each biomarker is possible with calibration curves that correlate standard protein concentrations to wavelength shifts. The multiplexed assay has been optimized for each individual biomarker, tested for cross-reactivity, and calibrated in the plasma matrix of interest. The LODs vary, depending on biomarker and matrix dilution, but range from 4.9 pg/mL to 691 pg/mL. The patient plasma samples are left over from the TB screening IFN-g release assay, QuantiFERON-TB Gold Plus (QFT), putting this method within the current clinical workflow. We use precision normalization approaches from the four QFT stimulations to account for immunologic differences among the subjects. The biomarker concentrations are evaluated using a random forest machine learning model to identify which biomarkers are important for identifying patients with LTBI and predicting their reactivation risk. Results We used this sensor method to profile 42 patients, 24 LTBI negative controls and 18 LTBI positive controls, with 13 being considered at high risk of reactivation. Using a precision normalization approach, a combination of nine normalized conditions using five of the thirteen biomarkers (CCL4, CCL8, IP-10, IL-2, IL-17) discriminated between LTBI positive and negative subjects with a ROC AUC of 0.90. Additionally, eight normalized conditions using four of the same biomarkers discriminated between high and low-risk subjects with an AUC of 0.83. Currently, we have expanded the sample cohort to include an additional 72 subjects, 25 LTBI positive and 47 LTBI negative. Preliminary analysis shows CCL8, IL-2, and IP-10 alone are able to distinguish between LTBI status (P values <0.01) using raw target concentrations prior to precision normalization. Conclusion Overall, we show the importance of multi-biomarker approaches to develop diagnostic and prognostic tools for a complex disease, such as TB. Further work to use the initial machine learning algorithm with the expanded cohort to validate biomarker importance is underway.

Abstract Optimal detection strategies for effective convalescent immunity after SARS-CoV-2 infection and vaccination remain unclear. The objective of this study was to characterize convalescent immunity targeting the SARS-CoV-2 spike protein using a multiparametric approach. At the beginning of the pandemic, between April 23, 2020, to May 11, 2020, we recruited 30 COVID-19 unvaccinated convalescent donors and 7 unexposed asymptomatic donors. Peripheral blood mononuclear cells (PBMCs) were obtained from leukapheresis cones. The humoral immune response was assessed by measuring serum anti-SARS-CoV-2 spike S1 subunit IgG semiquantitative ELISA and T cell immunity against S1 and S2 subunits were studied by IFN-γ Enzyme-Linked Immune absorbent Spot (ELISpot), flow cytometric (FC) activation-induced marker (AIM) assays and the assessment of cytotoxic CD8+ T-cell function (in the subset of HLA-A2 positive patients). No single immunoassay was sufficient in identifying anti-spike convalescent immunity among all patients. There was no consistent correlation between adaptive humoral and cellular anti-spike responses. Our data indicate that the magnitude of anti-spike convalescent humoral and cellular immunity is highly heterogeneous and highlights the need for using multiple assays to comprehensively measure SARS-CoV-2 convalescent immunity. These observations might have implications for COVID-19 surveillance, and optimal vaccination strategies for emerging variants. Further studies are needed to determine the optimal assessment of adaptive humoral and cellular immunity following SARS-CoV-2 infection, especially in the context of emerging variants and unclear vaccination schedules.

TB remains a leading cause of morbidity and mortality worldwide. However, most infected immunocompetent individuals are asymptomatic and only 5–10% of these will eventually develop active TB during their lifetime (typically within 2 years after exposure). Therefore, rapid diagnosis and efficient management of asymptomatic infected individuals who are at the highest risk of progression and transmission remain major clinical and public health challenges. In recent years, there has been important scientific progress in our understanding of the spectrum of asymptomatic Mycobacterium tuberculosis (Mtb) infections that not only includes the dynamic state of latent TB infection (LTBI), but also the preclinical state of incipient and subclinical TB. The latter is possibly as prevalent as symptomatically active TB and potentially contributes to global Mtb transmission in various settings. We summarize the latest developments and current challenges of the existing testing tools for LTBI and describe promising biomarkers and diagnostics for the spectrum of asymptomatic TB. Following the negative results of a recent clinical trial for a biomarker-guided preventive therapy approach, we also suggest some treatment options for incipient TB.

Abstract Introduction Interstitial lung disease (ILD) is a heterogenous group of parenchymal lung disorders with multiple etiologies. ILD often affects the quality of life and survival of patients. OSA is commonly diagnosed among ILD patients with reported prevalences of 50-90%, and a prevalence of moderate to severe OSA as high as 65%. There is also concern that patients with ILD may be less tolerant of PAP therapies. We aim to identify differences in PAP treatment response and adherence in patients with ILD and OSA compared with a group of matched OSA controls. Methods A retrospective cohort analysis was conducted on patients ≥ 18 years-old that were evaluated at Mayo Clinic Center for Sleep Medicine between July 2012 to June 2022. Inclusion criteria were patients with a diagnosis of ILD per ATS criteria also diagnosed with OSA by HSAT or PSG. Control OSA patients were matched to ILD/OSA patients by age, BMI, and AHI ranges. Exclusion criteria included comorbid conditions of asthma or COPD. Patients with early non-adherence to CPAP or those who didn't have sleep follow up were also excluded. Follow-up sleep visits were assessed to determine CPAP adherence, change in PAP pressure, addition of oxygen, and change in Epworth sleepiness scale. Results We compared 51 patients with ILD/OSA and 51 OSA matched-controls. Twenty-five ILD/OSA patients were diagnosed by PSG and 26 by HSAT. Median treatment follow-up for the ILD group was 7 months (IQR of 3 to 18 months). Baseline characteristics, including oxygen desaturation index (ODI), oxygen saturation, time spent below 89% during overnight oximetry, and baseline Epworth scale, were similar between ILD/OSA and non-ILD OSA patients. Importantly, there was no statistically significant difference in PAP adherence, median PAP levels, PAP pressure change, residual AHI, or change in Epworth after treatment Conclusion There was no significant difference in baseline OSA characteristics, treatment response, and PAP adherence in ILD patients with OSA compared with matched non-ILD OSA controls. Outcome assessment may be limited by sample size and the shorter follow-up period. Future studies should include longer-term follow-up with a larger ILD cohort to assess the impact of ILD progression on PAP adherence over time. Support (if any)

Abstract Rationale Candida albicans (CA) is ubiquitous and individuals are often immunized against it. However, skin testing reactivity with CA-antigens (CAAg) have been variable during latent tuberculosis infection (LTBI) screening. We hypothesized that the use of a CAAg in an ELISPOT assay would provide a positive control to study tuberculosis (TB)-antigen specific immune responses. Objective To test an ELISPOT with TB-antigens and control conditions, including a purified protein derivative of CA, CAAg, that differentiates subjects with LTBI from unexposed subjects. Methods An ELISPOT that detects interferon-γ from PBMCs (2×105 cells) after 2-day incubation with TB antigens, controls, including CAAg, and co-stimulatory antibodies. We studied two independent cohorts of subjects with LTBI diagnosis based on TST and IGRA results per clinical guidelines. Results One-hundred thirty-nine subjects were studied in 2010–12, including 27 patients with LTBI and 21 IGRA(−) unexposed subjects. ELISPOT with TB-antigens but also CAAg - nil (78 [21 – 182] vs. 9 [1 – 50] cfu) differentiated LTBI subjects from unexposed ones (P<0.005). A second cohort of 76 subjects were studied in 2015–17, including 14 patients with LTBI and 24 unexposed controls, which showed similar statistical results. Positive control (SEAB/antiCD3) did not differentiate these study groups. ELISPOT results with CAAg correlated with results of ELISPOT with TB antigens in all subjects (P<0.001), and in the LTBI and unexposed groups independently. Conclusion An ELISPOT assay that includes CAAg revealed immune reactivity that is prevalent in LTBI. The immune subsets that react to both CA and mycobacterial antigens are unclear, but may be relevant for both TB and candida immunity.

Abstract Introduction Previous studies have shown that sleep disordered breathing (SDB) is common in patients with Interstitial Lung Disease (ILD), and oximetry is often used for screening prior to further diagnostic testing. Current guidelines recommend polysomnography (PSG) for diagnosis of SDB in patients with significant pulmonary disease, however, home sleep apnea tests (HSAT) are increasingly used in clinical practice for a variety of reasons despite lack of evidence regarding accuracy in this population. In this study, we evaluate the correlation between screening oximetry, a commercial brand HSAT (WatchPAT®) and PSG to examine the diagnostic accuracy of this HSAT technology in patients with ILD. Methods The institution electronic medical record was screened for patients with a diagnosis code for ILD who underwent screening oximetry followed by PSG or HSAT using peripheral arterial tonometry from July 1, 2012 to present. Clinical review confirmed presence of ILD according to American Thoracic Society guidelines. Among the respective cohorts, Paired Wilcoxon Test was used to compare the oximetry 4% oxygen desaturation index (ODI) to the HSAT ODI and PSG apnea-hypopnea index (AHI) as well as percent time spent below oxyhemoglobin saturation of 89%. Spearman correlation was used to correlate the oximetry ODI and parameters of SDB on HSAT and PSG. Results Data was analyzed for 25 patients who had undergone oximetry/HSAT and for 25 patients who had undergone oximetry/PSG. Oximetry ODI showed no significant difference from PSG AHI (p = 0.2635) or between HSAT ODI (p = 0.0755), and no difference was seen in hypoxic time between oximetry and PSG (p = 0.9789). Hypoxic time on HSAT was significantly longer than that on oximetry (p < 0.001). Using HSAT ODI as the standard, HSAT AHI and respiratory disturbance index (RDI) showed rs of 0.9638 and 0.8913 respectively, while oximetry ODI was 0.3893. Compared to PSG AHI, the PSG RDI and oximetry ODI rs were 0.9759 and 0.7407 respectively. Conclusion Among patients with ILD, screening oximetry appears to correlate more strongly with indices of SDB and hypoxic time on PSG rather than HSAT. Further studies are warranted to evaluate efficacy of additional HSAT testing modalities in this patient population. Support (If Any)