Schwarz, Marvin I.

Abstract Rationale Idiopathic pulmonary fibrosis (IPF) is a complex and heterogeneous disease. Given this, we reasoned that differences in genetic profiles may be associated with unique clinical and radiologic features. Computational image analysis, sometimes referred to as radiomics, provides objective, quantitative assessments of radiologic features in subjects with pulmonary fibrosis. Objectives To determine if the genetic risk profile of patients with IPF identifies unique computational imaging phenotypes. Methods Participants with IPF were included in this study if they had genotype data and computed tomography (CT) scans of the chest available for computational image analysis. The extent of lung fibrosis and the likelihood of a usual interstitial pneumonia (UIP) pattern were scored automatically using two separate, previously validated deep learning techniques for CT analysis. UIP pattern was also classified visually by radiologists according to established criteria. Results Among 329 participants with IPF, MUC5B and ZKSCAN1 were independently associated with the deep learning–based UIP score. None of the common variants were associated with fibrosis extent by computational imaging. We did not find an association between MUC5B or ZKSCAN1 and visually assessed UIP pattern. Conclusions Select genetic variants are associated with computer-based classification of UIP on CT in this IPF cohort. Analysis of radiologic features using deep learning may enhance our ability to identify important genotype–phenotype associations in fibrotic lung diseases.

Abstract Rationale Disability guidelines are often based on pulmonary function testing, but factors other than lung function influence how an individual experiences physiologic impairment. Age may impact the perception of impairment in adults with chronic lung disease. Objectives To determine if self-report of physical functional impairment differs between older adults with chronic lung disease compared with younger adults with similar degrees of lung function impairment. Methods The Lung Tissue Research Consortium provided data on 981 participants with chronic obstructive pulmonary disease and interstitial lung disease who were well characterized with clinical, radiological, and pathological diagnoses. We used multiple logistic regression to determine if responses to health status questions (from the Short Form-12 and St. George’s Respiratory Questionnaire) related to perception of impairment differed in older adults (age ≥ 65 yr, n = 427) compared with younger adults (age < 65 yr, n = 393). Measurements and Main Results Pulmonary function was higher in older adults (median FEV1 %, 70) compared with younger adults (median FEV1 %, 62) (P < 0.001), whereas the median 6-minute-walk distance was similar between groups (372 m vs. 388 m, P = 0.21). After adjusting for potential confounders, older adults were less likely to report that their health limited them significantly in performing moderate activities (odds ratio [OR], 0.36; 95% confidence interval [CI], 0.22–0.58) or climbing several flights of stairs (OR, 0.51; 95% CI, 0.34–0.77). The odds of reporting that their physical health limited the kinds of activities they performed were reduced by 63% in older adults (OR, 0.37; 95% CI, 0.24–0.58), and, similarly, the odds of reporting that their health caused them to accomplish less than they would like were also lower in older adults (OR, 0.39; 95% CI, 0.25–0.60). The OR for reporting that their breathing problem stops them from doing most things or everything was 0.35 (95% CI, 0.22–0.55) in older adults versus younger adults. Conclusions Older adults with chronic lung disease were less likely to report significant impairment in their activities compared with younger adults, suggesting they may perceive less limitation.

Abstract The early stage of idiopathic pulmonary fibrosis (IPF) is thought to involve a smaller number of alveoli and to be characterized predominantly by cellularity and minimal fibrosis, whereas advanced disease involves a large number of alveoli and is characterized predominantly by fibrosis with minimal cellularity. In addition, correlative studies have indicated that prognosis and response to therapy is determined in part by the extent of fibrosis and cellularity. This study was undertaken to determine whether pulmonary function assessment would help distinguish between the cellular and fibrotic phases of this disorder, as determined by a semiquantitative pathology scoring system that comprised four factor scores: fibrosis, cellularity, granulation/connective tissue, and desquamation. Ninety-six untreated patients with biopsy-confirmed IPF (27 never smokers, 32 current smokers, and 37 ex-smokers) were evaluated. In the group as a whole, there was no significant relationship between the fibrosis or the connective/granulation tissue factor scores and any of the physiologic parameters. The Dl co correlated with the “desquamation” and the total pathology scores, whereas the TLC and FVC correlated with the cellularity factor score. In the current smokers, the coefficient of elastic retraction, Dl co/Va, and FEV1/FVC ratio were significantly lower than in never smokers and ex-smokers, and TLC and FVC were higher than in never smokers. Also, the mean cellularity and granulation/connective tissue factor scores were significantly lower, and the desquamation factor score was significantly higher than those in never smokers and ex-smokers. Both age and smoking status were significant for the cellularity factor score, whereas for the connective/granulation tissue factor score, age was not significant but smoking status was. For the desquamation factor score, age was significant but smoking status was not. There were significant differences between never smokers and ever smokers in the relationship between the pathology factors and measurements of respiratory function, and this may explain some of the difficulty in assessing structure-function correlation in patients with IPF. In the never smokers, the correlations between structure and function were likely the direct result of IPF per se. In the current smokers, bronchiolar and/or emphysematous changes associated with cigarette smoking may have complicated the pathologic alterations caused by IPF, as well as influencing the functional derangements.

Abstract We report two patients with systemic necrotizing vasculitis (microscopic polyarteritis) and associated recurrent pulmonary capillaritis, in whom progressive irreversible airway dysfunction began approximately 10 yr after disease onset. Their course was characterized by repeated episodes of diffuse alveolar hemorrhage, glomerulonephritis, palpable purpura, and splinter hemorrhages. The lung revealed intraalveolar hemorrhage, neutrophilic infiltration and cellular fragmentation, fibrinoid necrosis of the alveolar interstitium, and parenchymal hemosiderin deposits. No medium-sized vessel involvement, granulomatous inflammation, or bronchiolar obliteration were seen. Renal biopsies revealed focal segmental necrotizing glomerulonephritis, and a cutaneous biopsy in one case showed a leukocytoclastic vasculitis. Immunofluorescent studies of lung and kidney showed minimal or no immunoreactivity. The clinical course and serologic tests did not support another systemic vasculitis, connective tissue disease, or antiglomerular basement membrane antibody disease. The acute episodes responded to antiinflammatory and immunosuppressive therapy. Symptoms, serial pulmonary function tests, and chest imaging documented the development of a progressive irreversible obstructive airway disease. No other predisposing factors were identified. These cases demonstrate the unexpected appearance of an irreversible obstructive airway disease with lung parenchymal hyperinflation after systemic necrotizing vasculitis associated with recurrent pulmonary capillaritis and diffuse alveolar hemorrhage.

Abstract It is hypothesized that the extent and severity of fibrosis and cellularity found on lung biopsy determine the prognosis and response to therapy in idiopathic pulmonary fibrosis (IPF). The objective of this study was to determine which histopathologic features predict survival in IPF. We prospectively studied 87 patients with usual interstitial pneumonia (UIP) confirmed by surgical lung biopsy. Four pathologists independently graded the extent and severity of specific histopathologic features. We used Cox proportional-hazards models to assess the effect of histopathologic patterns on patients' survival. The effects of age, sex, and smoking were also included in the analysis. Sixty-three patients died during the 17-yr study period. Survival was longer in subjects with lesser degrees of granulation/connective tissue deposition (fibroblastic foci). The degree of alveolar space cellularity, alveolar wall fibrosis, and cellularity did not affect survival. A history of cigarette smoking, the level of dyspnea, and the degree of lung stiffness at presentation were also shown to be independent factors predicting survival. The extent of fibroblastic foci present on lung biopsy predicts survival in IPF. These findings support the hypothesis that the critical pathway to end-stage fibrosis is not “alveolitis” but rather the ongoing epithelial damage and repair process associated with persistent fibroblastic proliferation. Controlling these processes, rather than stopping inflammation, appears most important in preventing progressive disease and the fatal outcome common in IPF.