Background: Hypersensitivity pneumonitis (HP) is an interstitial lung disease characterized by immune-mediated inflammation and variable degrees of fibrosis. Aims: To evaluate the clinical, radiological, and hematological features of patients diagnosed with HP. Study Design: Retrospective cross-sectional study. Methods: We included 100 patients diagnosed and followed for HP between 2020 and 2024. Demographic characteristics, pulmonary function test results, diffusing capacity, six-minute walk test findings, antigen exposure history, and high-resolution computed tomography (HRCT) patterns were retrospectively analyzed. Results: The mean age was 63 ± 14 years, with equal sex distribution. Sixty-five percent of patients had identifiable antigen exposure, predominantly related to birds or bird products (86.4%). Surgical lung biopsy confirmed the diagnosis in 29% of cases. The most common HRCT findings were reticulation (87%), ground-glass opacities (84.7%), and centrilobular nodules (75%); fibrotic features were present in 48% of patients. Glucocorticoids were the main treatment (77%), and antifibrotic therapy was used in 20% of cases. Neutrophil count showed a modest positive correlation with honeycombing (r = 0.27, p = 0.025). Basophil count demonstrated a mild association with bird-related antigen exposure (r = 0.26, p = 0.035). Conclusions: Peripheral neutrophil and basophil counts showed weak but statistically significant associations with fibrotic HRCT features and exposure patterns. These exploratory findings suggest that routinely available hematologic parameters may provide supportive information alongside radiologic and clinical data. Prospective studies are needed to validate their diagnostic and prognostic relevance in HP.

Background: Pre-Chronic Obstructive Pulmonary Disease (pre-COPD) and Preserved Ratio Impaired Spirometry (PRISm) phenotypes represent important components of the early obstructive lung disease spectrum, characterized by respiratory symptoms and structural lung abnormalities prior to the development of overt airflow limitation. Emphysema is considered one of the major structural phenotypes underlying airway disease and the COPD spectrum. Although cigarette smoking is the best recognized risk factor for these conditions, non-tobacco exposures may also contribute to early structural lung changes. In this study, we evaluated the radiological features, pulmonary function parameters, and dyspnea severity of CT-detected emphysema in symptomatic patients classified as having pre-COPD or PRISm, with particular attention paid to the potential influence of smoking status on disease characteristics. Methods: In this retrospective, single-center study, symptomatic patients aged 20–50 years classified as having pre-COPD or PRISm and in whom emphysema was detected on high-resolution computed tomography (HRCT) were evaluated. Only symptomatic patients who underwent HRCT for clinical indications and in whom emphysema was identified were included. Demographic characteristics, emphysema type and quantitative emphysema severity, pulmonary function parameters, and Modified Medical Research Council (mMRC) dyspnea scores were analyzed. The PRISm and pre-COPD groups were compared in terms of clinical and symptomatic characteristics. In addition, smoking-related clinical and radiological characteristics were also evaluated. Results: A total of 232 patients were included in the study. The median age was 43 years (38–48), and 84.1% of the participants were male. Among the study population, 68.5% were classified in the pre-COPD group and 31.5% in the PRISm group. The most frequently identified emphysema patterns were paraseptal (44.4%) and centrilobular (40.5%). The median total lung emphysema area was 18% (13–22). A weak negative correlation was observed between the degree of emphysema and FEV₁ (r = −0.185; p = 0.005), whereas a weak positive correlation was found between emphysema extent and the mMRC dyspnea score (r = 0.214; p = 0.001). Dyspnea severity was significantly higher in the PRISm group compared with the pre-COPD group (p < 0.001). In the smoking-status subgroup analysis, ever-smokers demonstrated significantly greater dyspnea severity and lower FEV₁ values, whereas never-smokers had a significantly higher proportion of emphysema extent > 18% (all p < 0.05). Conclusions: Radiologically detected emphysema in symptomatic patients without airflow limitation was associated with statistically significant but weak alterations in pulmonary function and dyspnea burden. Dyspnea severity was significantly higher in the PRISm phenotype. In a smoking-status subgroup analysis, ever-smokers had significantly greater dyspnea severity, whereas never-smokers showed a significantly higher proportion of extensive emphysema (>18%), despite similar functional impairment across groups. These findings underscore the importance of non-tobacco exposures in the development of emphysema within pre-obstructive spirometric phenotypes. Multicenter prospective studies incorporating healthy controls and systematic exposure documentation are needed to confirm these observations.

Although emphysema is typically associated with older age and the presence of airflow limitation, it can also be detected in young adults prior to the development of obstructive impairment. In this study, we aimed to investigate the relationship between the radiological characteristics of emphysema, pulmonary function test results, and symptom severity in patients aged 20 to 50 years who presented with complaints of dyspnea. In this retrospective study, patients with emphysema detected on computed tomography (CT) but without airflow limitation on spirometry were evaluated. Demographic characteristics, type and extent of emphysema, pulmonary function tests, and Modified Medical Research Council (mMRC) dyspnea scores were assessed. Patients were classified into preserved ratio impaired spirometry (PRISm) and pre-COPD groups, and these groups were compared in terms of clinical and symptomatic features. The mean age of the patients was 44 years, and 84.6% were male. The most common type of emphysema was paraseptal (43.6%), and the extent of emphysema was less than 5% in the majority of cases (78.4%). A negative correlation was found between the degree of emphysema and both FEV₁ (Forced Expiratory Volume in 1 Second) and FVC (Forced Vital Capacity), while a positive correlation was observed with the mMRC (Modified Medical Research Council) dyspnea score. Dyspnea was more pronounced in the PRISm group (p< 0.001). Emphysema detected in young adults without airflow limitation may have significant effects on symptom burden and pulmonary capacity. The PRISm phenotype, in particular, is notable for its association with increased symptom severity and a history of smoking, highlighting the importance of early identification of these individuals. Our findings underscore the value of early detection; however, further studies are needed to better understand the follow-up and management of this patient population.