Aerogenous infection of C57Bl/6 mice with a virulent strain of Mycobacterium tuberculosis (CL 511) leads to the formation of primary granulomas in the lung where neutrophils, macrophages and subsequently, lymphocytes accumulate progressively around an initial cluster of infected macrophages. The spread of infection through the lung parenchyma gives rise to secondary granulomas featuring numerous lymphocytes that surround a small number of infected macrophages. Afterwards, foamy macrophages add an outer layer to the granulomas, which characteristically respect the pulmonary interstitium and remain confined within the alveolar spaces. This feature, in conjunction with the constant presence of M. tuberculosis in the products of broncho-alveolar lavage, suggests that the upward bronchial migration of infected macrophages may contribute significantly to pulmonary dissemination of mycobacterial infection. The latter would be in agreement with the persistence of chronic pulmonary infection in spite of a concomitant strong T helper 1 cell response.

BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive parenchymal lung disease of unknown aetiology and poor prognosis, characterized by altered tissue repair and fibrosis. The extracellular matrix (ECM) is a critical component in regulating cellular homeostasis and appropriate wound healing. The aim of our study was to determine the expression profile of highlighted ECM proteins in IPF lungs.MethodsECM gene and protein expression was analyzed by cDNA microarrays, rt-PCR, immunohistochemistry and western-blot in lungs from idiopathic pulmonary fibrosis (IPF), hypersensitivity pneumonitis (HP), categorized as chronic (cHP) and subacute (saHP), and healthy lung tissue. Primary fibroblast cultures from normal subjects and fibrotic patients were studied to evaluate tenascin-C (TNC) synthesis.ResultsA total of 20 ECM proteins were upregulated and 6 proteins downregulated in IPF. TNC was almost undetected in normal lungs and significantly upregulated in fibrotic lungs (IPF and cHP) compared to saHP. Furthermore, it was located specifically in the fibroblastic foci areas of the fibrotic lung with a subepithelial gradient pattern. TNC levels were correlated with fibroblastic foci content in cHP lungs. Versican and fibronectin glycoproteins were associated with TNC, mainly in fibroblastic foci of fibrotic lungs. Fibroblasts from IPF patients constitutively synthesized higher levels of TNC than normal fibroblasts. TNC and α-sma was induced by TGF-β1 in both fibrotic and normal fibroblasts. TNC treatment of normal and fibrotic fibroblasts induced a non-significant increased α-sma mRNA.ConclusionsThe difference in ECM glycoprotein content in interstitial lung diseases could contribute to the development of lung fibrosis. The increase of TNC in interstitial areas of fibrotic activity could play a key role in the altered wound healing.

Cohort studies of large series of patients with sarcoidosis over a long period of time are scarce. The aim of this study is to report a 40-year clinical experience of a large series of patients at Bellvitge University Hospital, a tertiary university hospital in Barcelona, Spain. Diagnosis of sarcoidosis required histological confirmation except in certain specific situations. All patients underwent a prospective study protocol. Clinical assessment and follow-up of patients were performed by a multidisciplinary team.From 1976 to 2015, 640 patients were diagnosed with sarcoidosis, 438 of them (68.4%) were female (sex ratio F/M 2:1). The mean age at diagnosis was 43.3 ± 13.8 years (range, 14–86 years), and 613 patients (95.8%) were Caucasian. At diagnosis, 584 patients (91.2%) showed intrathoracic involvement at chest radiograph, and most of the patients had normal pulmonary function. Erythema nodosum (39.8%) and specific cutaneous lesions (20.8%) were the most frequent extrapulmonary manifestations, but there was a wide range of organ involvement. A total of 492 patients (76.8%) had positive histology. Follow-up was carried out in 587 patients (91.7%), over a mean of 112.4 ± 98.3 months (range, 6.4–475 months). Corticosteroid treatment was administered in 255 patients (43.4%), and steroid-sparing agents in 49 patients (7.7%). Outcomes were as follows: 111 patients (18.9%) showed active disease at the time of closing this study, 250 (42.6%) presented spontaneous remission, 61 (10.4%) had remission under treatment, and 165 (28.1%) evolved to chronic sarcoidosis; among them, 115 (19.6%) with mild disease and 50 (8.5%) with moderate to severe organ damage. A multivariate analysis showed that at diagnosis, age more than 40 years, the presence of pulmonary involvement on chest radiograph, splenic involvement, and the need of treatment, was associated with chronic sarcoidosis, whereas Löfgren syndrome and mediastinal lymphadenopathy on chest radiograph were indicators of good outcome.Sarcoidosis is a multisystem disease with protean clinical-radiographic manifestations. Although almost half of patients follow a spontaneous resolution or under treatment, a significant number of them may have several degrees of organ damage. This study emphasizes the value of a multidisciplinary approach and long-term follow-up by specialized teams in sarcoidosis.