Baqir, M.

Abstract Background Takayasu arteritis (TA) is a rare large-vessel vasculitis that can involve pulmonary arteries, potentially leading to pulmonary hypertension (PH). Noninvasive evaluation by echocardiography is often used, but its reliability in confirming and characterizing PH in TA is unclear. We investigated the role of invasive hemodynamic testing in TA patients with suspected PH. Methods We retrospectively identified 10 patients with TA meeting 2022 ACR criteria and suspected PH based on symptoms and/or echocardiography; all underwent echocardiography followed by right heart catheterization (RHC).PH was defined as mean pulmonary artery pressure (mPAP) >20 mmHg. PH was classified as pre-capillary (pulmonary artery wedge pressure [PAWP] ≤15 mmHg), post-capillary (PAWP >15 mmHg), or combined (PAWP >15 mmHg with elevated pulmonary vascular resistance). Echocardiographic parameters were collected where available, along with invasive hemodynamics, cardiac biomarkers (BNP/NT-proBNP), inflammatory markers (ESR, CRP), NYHA functional class, and outcomes. Results Median age was 44 years (range 18-58), and 90% were female. Based on invasive hemodynamics, pre-capillary PH was present in 5 patients, combined pre-/post-capillary PH in 3, and isolated post-capillary PH in 2. Median mPAP was 38 mmHg (IQR 30-55), median pulmonary vascular resistance 3.5 Wood units (IQR 2.3-8.7), and median PAWP 15 mmHg (IQR 8-24). Echocardiography frequently underestimated disease severity. Several patients with absent or low tricuspid regurgitation velocity (≤1.0 m/s), where measurable, demonstrated severe pre-capillary PH on RHC, including pulmonary vascular resistance >6 Wood units. Among patients with available data, NT-proBNP levels ranged from 59 to 51,968 pg/mL, and inflammatory markers varied widely (CRP <0.3 to 107.9 mg/L). Among patients with available NYHA data, most were class II-III. Conclusions In this TA cohort, RHC was essential to confirm and phenotype PH, which was present in the majority of those with suspected PH. Echocardiography alone often underestimated or misclassified PH in TA - in one case missing severe pre-capillary PH due to an absent TR signal, and in another failing to discern elevated left-heart filling pressure. Invasive assessment prevented missed diagnoses and misclassification, ensuring appropriate management of TA-associated PH This abstract is funded by: None

Abstract Rationale Inflammatory bowel disease (IBD) is increasingly recognized as a systemic disorder, with extraintestinal manifestations (EIMs) involving multiple organ systems. Pulmonary involvement, particularly interstitial lung disease (ILD), remains an underrecognized manifestation of IBD. Its prevalence, clinical characteristics, and risk factors in IBD remain poorly defined. Methods We conducted a retrospective study of adults (≥18 years) with IBD who had at least one encounter in our health system between January 1, 2013 and December 31, 2023. IBD, and ILD cases were identified using ICD-9/ICD-10 codes, with ILD diagnoses confirmed by thoracic radiologists. Demographic, clinical, pulmonary, smoking, medication, and surgical data were abstracted. Associations between patient characteristics and ILD were evaluated using both a cohort design and a matched case-control design (1:3 ratio). Mortality was assessed using a Cox proportional hazards model with ILD as a time-dependent covariate. Results Among 875 patients with IBD, 109 (12%) had ILD. Radiographic patterns included nonspecific interstitial pneumonia (NSIP, 27%), indeterminate (26%), definite/probable UIP (24%), hypersensitivity pneumonitis (15%), and organizing pneumonia (8%). Pulmonary function testing demonstrated predominantly restrictive physiology and impaired diffusion capacity. In multivariable analysis, higher BMI (OR 1.04), bronchiectasis (OR 2.65), ex-smoking (OR 2.15), and use of adalimumab (OR 2.04) or infliximab (OR 2.14) were independently associated with ILD. The matched case-control design confirmed these findings and also identified older age (OR 1.04) as a significant factor. ILD was strongly associated with mortality (HR, 3.78; 95% CI, 2.50-5.72; p < 0.001). Conclusions ILD occurs in a meaningful subset of patients with IBD and is associated with older age, higher BMI, prior smoking, bronchiectasis, and TNF inhibitor use. ILD confers a markedly increased risk of death, highlighting the importance of early recognition and close monitoring in this population. This abstract is funded by: None

Abstract Rationale Lymphangioleiomyomatosis (LAM) is a rare, progressive, cystic lung disease affecting women. Sirolimus has been shown to stabilize lung function in women with LAM, but real-world data on long-term safety and efficacy are limited. Methods The NIH Multicenter Safety and Durability of Sirolimus for LAM (MIDAS, NCT02432560) observational registry was launched in 2015. All adult (≥18 years) women with LAM (treated or untreated) were eligible to enroll at any of the 20 U.S. sites and followed longitudinally with serial assessments of lung function, health-related quality of life, and treatment related adverse event (TRAEs). Baseline cohort characteristics and TRAEs are summarized using descriptive analyses. Marginal structural models (MSMs) with inverse probability of treatment weighting estimated the causal effect of sirolimus on annualized forced expiratory volume in one-second (FEV1) decline, adjusting for age at LAM diagnosis, prior treatment with sirolimus, menopausal status, race, presence of angiomyolipomas, supplemental oxygen use; time-varying covariates included diffusing capacity for carbon monoxide (DLCO) and serum vascular endothelial growth factor-D (VEGF-D) levels. Results Longitudinal data was available in 350 LAM patients, most of whom (246, 70.3%) had sporadic LAM. The median age at the baseline pulmonary function test (PFT) measurement was 46 years (range: 19 - 74) and the median (IQR) number of serial PFTs obtained per patient was 3 (1 - 5). The average follow-up duration per patient was 2.8 years. Over half of the patients (196, 56%) were treated with sirolimus during the MIDAS observation period for a median (IQR) treatment duration of 4.9 (2.4 - 7.5) years. MSM analysis demonstrated that sirolimus treatment was durably effective and reduced FEV₁ decline by 74.36 mL/year (95% CI: 15.87 - 132.85) compared with no treatment (-85.31 mL/year for the untreated group vs. -10.95 mL/year for the treated group, p = 0.01). Sirolimus was generally well tolerated; treatment interruption ≥3 months was observed in 38 (19.4%) of the 196 sirolimus treated patients. Logistic regression analysis showed that higher levels of FEV1 (odds ratio: OR = 3.12 [1.45 - 7.11], p = 0.005), VEGF-D (OR = 1.0007 [1.0004 - 1.001], p < 0.001), and DLCO (OR = 1.023 [1.0053 - 1.0413, p = 0.01]), were associated with treatment interruption. Conclusions In the MIDAS cohort, sirolimus treatment resulted in durable stabilization of lung function with a favorable safety profile over a 5-year period. These real-world data support sirolimus as a chronic suppressive therapy for LAM, demonstrating durable efficacy in slowing lung disease progression and tolerability with long-term use. This abstract is funded by: National Institutes of Health

Abstract Background: Bronchiectasis is a recognized pulmonary manifestation of ANCA-associated vasculitides (AAV). Although positive AAV workup has been observed in patients with isolated airway diseases, without other systemic involvement, AAV workup is not routinely obtained in patients presenting with bronchiectasis. Patients with bronchiectasis and positive AAV workup may represent a distinct subgroup with unique characteristics and outcomes. Objectives: To establish a cohort of patients with bronchiectasis who also have a positive AAV workup (i.e., presence of ANCA by indirect immunofluorescence AND elevated antibodies to PR3 or MPO) and to describe their characteristics. METHODS: There were 944 patients across Mayo clinic sites with bronchiectasis (J47.9, J47.0 and J 47.1) who underwent AAV workup. Of these 315 (33.36%) had evidence of ANCA on immunofluorescence and an abnormal level of antibodies to PR3 or MPO. Chest CT scans were reviewed, and 118 patients were excluded because their pulmonary disease was mostly interstitial or had no clear bronchiectasis. Co-morbidities were evaluated using respective ICD-10 codes and respiratory cultures were collected. RESULTS: A total of 197 patients were identified with Bronchiectasis (76% female; mean age 66 years, BMI 25 kg/m2), 112 (56.8%) were diagnosed before antibody detection and 85 (43.1%) after. MPO (positive [>0.9] or equivocal [0.4-0.9]) was detected in 177 (89.8%) patients; PR3 (positive [>0.9] or equivocal [0.4-0.9]) in 34 (17.2%). P-ANCA and c-ANCA patterns occurred in 185 (94%) and 15 (4%) patients, respectively. The most common antigen-target/ANCA combinations were MPO/p-ANCA (177, 89.8%), PR3/p-ANCA (22, 11.2%), and PR3/c-ANCA (14, 7.1%). Comorbidities included asthma (66, 33.5%), COPD (58, 29.4%), GERD (64, 32.5%), hypothyroidism (56, 28.4%), and autoimmune/inflammatory conditions (e.g., rheumatoid arthritis [23, 11.7%], IBD [25, 12.7%]). Neurologic (42, 23.9%) and renal (25, 14.7%) manifestations occurred. Respiratory cultures (n=122) isolated yeast (57, 46.7%), Aspergillus (34, 27.9%), and Pseudomonas (30, 24.6%); Mycobacteria and other molds (e.g., Penicillium) each appeared in 23-24 patients (∼19%). Conclusion: This work identifies a cohort of patients with bronchiectasis who also have a positive AAV workup, mostly MPO/p-ANCA. While AAV workup is not routine for patients presenting for bronchiectasis evaluation, some patients in this cohort had primarily airway disease with an abnormal AAV workup, in the absence of other common manifestations of AAV. Further research on this cohort will be conducted to determine whether these patients represent a distinct group with unique characteristics, treatment patterns, and outcomes.

Abstract Introduction: Idiopathic CD4 lymphocytopenia is a disorder with CD4 counts below 200 cells/mm3 or less than 20% of total lymphocytes without an acquired or genetic cause. Case Summary: A 41-year-old female with history of Celiac disease complicated by hyposplenism developed fevers, weight loss, sicca symptoms, widespread erythematous rash, sinusitis, multifocal pneumonia refractory to antibiotics and pulmonary embolism. Workup demonstrated isolated weakly positive PR3 antibody of 1.2 (reference range < 1.0), CD4 count of 78 with negative ANA, ENA, HIV, CMV, EBV, HTLV, fungal, mycobacterial testing and mildly low IgM. PET-CT noted FDG avidity in the paranasal sinuses, lung opacities and salivary glands. Sinus biopsy showed chronic inflammation and fibrosis. Sputum cultures were positive for MSSA and Pseudomonas. Lung biopsy noted fibrinous organizing pneumonia. Skin biopsy demonstrated pauci-inflammatory vacuolar interface dermatitis with discontinuous weak granular deposition of C3 on basement membrane. A small-intestinal biopsy noted villous blunting and polymorphous T cell infiltration of the lamina propria. Bone marrow biopsy redemonstrated polytypic T cells with inverted CD4:CD8 ratio, but neither harbored an abnormal T cell population. Treatment for presumptive GPA was undertaken with corticosteroids, Rituximab, and Avacopan with transient improvement. CRP was elevated at 65.1 mg/dL (reference range < 5.0mg/dL). However, CD4 count had increased to 260 (reference range 365-1437) with 20% CD4 cells, low B cells, normal CD8 and NK cells, and IgG4 levels elevated at 180 mg/dL (reference range 2.4-121.0). LDH was elevated at 455 U/L (reference range 122-222) but flow cytometry, SPEP, and FLC ratio were unremarkable. Rhinoscopy demonstrated purulence, nasal septal perforation, and crusting of the larynx and subglottis. Salivary gland biopsy noted chronic sialadenitis without malignancy. Repeat CD4 count was 93. Given recurrent, refractory pulmonary infections, IVIG was considered, but prior to administration the patient developed worsening hypoxemia and pressor requirements and was transitioned to comfort cares. Discussion: It is crucial to rule out conditions causing lymphopenia, such as severe sarcoidosis, Sjogren's, IgG4-related disease, cutaneous T cell lymphoma, and splenectomy. While common complications include opportunistic infections, invasive cancers and autoimmunity, their absence may be explained by normal CD3 and CD8 counts. Despite complications, mortality is generally not increased, although baseline CD4 counts of less than 150 cells/mm3 may predict death. Decreases in CD4 counts in the setting of rising immunoglobulin levels may represent antibody production against lymphocytes. While evidence on the use of IVIG is limited, it may be beneficial when hypogammaglobulinemia or life-threatening infections are present.