Fibrosis is scarring due to the replacement of tissue architecture by extracellular matrix (ECM), which consists largely of collagen. Scarring progressively destroys organ structure and thereby impairs function. Accumulation of collagen is thought to be due to an increase in production, a reduction in degradation of collagen or a combination of both.1 If so, we might expect the ratio of production to degradation to increase with increasing fibrosis. Biomarkers of type III and VI collagen production (PRO-C3 and PRO-C6) and degradation (C3M and C6M), called neoepitopes, have been developed to measure these processes.1 In diseases such as idiopathic pulmonary fibrosis, where fibrosis is the dominant pathophysiological feature, neoepitope levels align closely with disease progression.2 Whether these collagen markers are relevant in other diseases has been less well explored. In sarcoidosis, fibrosis in affected organs, especially the lungs and heart, accounts for most of the long-term morb

The mechanism of thrombocytopenia during acute pulmonary hypertension (PH) decompensation may be partly due to platelet aggregation in the lung. Platelet aggregates in explanted lung from 16 lung transplant patients during acute PH decompensation with and without thrombocytopenia were identified by immunohistochemistry. Scanning electron microscopy (SEM) was performed. 7 explant lung controls without PH and thrombocytopenia were also examined. Compared with controls, the median number of platelet aggregates was higher in patients with acute PH decompensation with thrombocytopenia (19.4 [IQR 3.4–38.3] vs 147.5 [IQR 26.5–203.2]). SEM showed capillaries filled with platelet aggregates. Our study suggests that platelets may aggregate in the lungs during acute PH decompensation.

A 38-year-old woman was admitted for uterine fibroid surgery. A routine preoperative CT chest scan identified bilateral patchy, high-density shadows, with unclear boundaries, more evident in the upper lobes (figure 1A). She had no respiratory symptoms, such as coughing or expectoration, and was an office worker with allergies to seafood and mango. She denied having comorbidities including diabetes, renal disease, liver disease, malignancy or HIV. In March 2023, she received cefuroxime anti-infective treatment during her hospitalisation for gynaecological surgery and did not continue antibiotics after discharge. Six months later, in November 2023, a follow-up CT chest revealed radiographic progression of bilateral upper lobe changes (figure 1B). Despite being asymptomatic, she was prescribed moxifloxacin at the outpatient clinic for presumed bilateral bacterial pneumonia. A subsequent CT chest a week later showed no noticeable improvement in her lung condition. Therefore, she was hospit

Primary ciliary dyskinesia (PCD), an inherited motile ciliopathy, is characterised by recurrent upper and lower respiratory tract infections, organ laterality defects, subfertility and neonatal respiratory distress due to impaired ciliary function.1 Over 50 PCD disease-causing genes have been identified that impact the structure and function of the cilia (figure 1, originally in Despotes et al 1). Significant clinical heterogeneity is associated with PCD, in part driven by genotype; genotype–phenotype relationships are an emerging area of great importance within this rare disease.2–4 However, clinical heterogeneity has also been reported among patients with the same genetic variants,3 suggesting that genetic modifiers may play an important role in disease manifestations. In their Thorax paper, Pifferi and colleagues have helped uncover our incomplete understanding of this heterogeneity by evaluating the impact of TAS2R38 polymorphisms within specific PCD genotypes. The authors specific

Objective Primary ciliary dyskinesia (PCD) severity has been related to genotype and levels of nasal nitric oxide (nNO). The most common TAS2R38 haplotypes (PAV/PAV, PAV/AVI, AVI/AVI) encoding the bitter taste receptor can affect nNO levels and thus could play a role in the susceptibility to respiratory infections. We assessed the impact of these polymorphisms on nNO production and Pseudomonas aeruginosa ( P.a .) infections in different PCD genotypes. Methods Prospective, longitudinal, single-centre study in patients with PCD with known genotype and one of three TAS2R38 haplotypes evaluated for up to 10 years. We related nNO values to TAS2R38 haplotypes in all patients, and in the three most frequent genotypes ( CCDC39/CCDC40 , DNAH5 , DNAH11 ). In the genetic group(s) with different mean trends of nNO in relation to the polymorphism, we evaluated longitudinal lung function as a clinical outcome measure. We also studied any associations between the prevalence of chronic P.a . infection