Allergies arise from aberrant Th2 responses to allergens. The processes involved in the genesis of allergic sensitization remain elusive. Some allergens such as derived from house dust mites have proteolytic activity which can induce oxidative stress in vivo. A reduced capacity of the host to control oxidative stress might prime for allergic sensitization.Two different strains of mice were compared for their antioxidant and immune response to HDM. Protease activity of the HDM extract was reduced to investigate its role in oxidative stress induction in the airways and whether this induction could determine allergic sensitization and inflammation. The role of oxidative stress in allergic sensitization was also investigated in humans. An occupational cohort of animal workers was followed for the development of sensitization to rodent urinary proteins. Levels of oxidative stress in serum and antioxidant responses by PBMCs were determined.Susceptibility to allergic sensitization to mite allergens in mice was highly dependent on host genetic background and was associated with oxidative stress in the lungs before allergen exposure and poor antioxidant response after allergen exposure. Reduction in mite protease activity limited its capacity to induce oxidative stress and allergic inflammation in mice. We showed that also in human subjects, oxidative stress before allergen exposure and poor antioxidant responses were associated with predisposition to occupational allergy.Our study indicates that oxidative stress condition before allergen exposure due to an inadequate antioxidant response may prime for allergic Th2 responses.
Analysis of induced sputum supernatant is a minimally invasive approach to study the epithelial lining fluid and, thereby, provide insight into normal lung biology and the pathobiology of lung diseases. We present here a novel proteomics approach to sputum analysis developed within the U-BIOPRED (unbiased biomarkers predictive of respiratory disease outcomes) international project. We present practical and analytical techniques to optimize the detection of robust biomarkers in proteomic studies. The normal sputum proteome was derived using data-independent HDMSE applied to 40 healthy nonsmoking participants, which provides an essential baseline from which to compare modulation of protein expression in respiratory diseases. The "core" sputum proteome (proteins detected in ≥40% of participants) was composed of 284 proteins, and the extended proteome (proteins detected in ≥3 participants) contained 1666 proteins. Quality control procedures were developed to optimize the accuracy and consistency of measurement of sputum proteins and analyze the distribution of sputum proteins in the healthy population. The analysis showed that quantitation of proteins by HDMSE is influenced by several factors, with some proteins being measured in all participants' samples and with low measurement variance between samples from the same patient. The measurement of some proteins is highly variable between repeat analyses, susceptible to sample processing effects, or difficult to accurately quantify by mass spectrometry. Other proteins show high interindividual variance. We also highlight that the sputum proteome of healthy individuals is related to sputum neutrophil levels, but not gender or allergic sensitization. We illustrate the importance of design and interpretation of disease biomarker studies considering such protein population and technical measurement variance.
Introduction: Growing evidence suggests that patients with severe COPD are at a higher risk of pulmonary aspergillosis (PA), especially during an exacerbation. The levels of GM in exhaled breath condensate (EBC) might allow earlier diagnosis and extend the diagnostic yield of noninvasive mycological tests. Objective: Evaluate the role of GM in EBC for early diagnosis of PA in severe COPD patients at exacerbation. Methods: Serum and EBC were collected from 15 severe or very severe COPD patients at exacerbation and tested for GM using a Platelia® Aspergillus Ag test. Sera/EBC fluids with an index >0.5 were considered positive. Double diffusion in agarose gel (DD) for antibody response to Aspergillus was also determined. Results: Two patients had probable, 7 possible and 6 had no evidence of PA according to the criteria proposed by Bulpa. Serum positive GM assay was observed in two samples of the patients with probable PA and in one sample of two patients with possible PA. In patients with probable PA also serum precipitins was positive ( A. fumigatus ). EBC analysis yielded GM positive results (range, 0.8–7.5) in one patient with probable PA, in 2 patients with possible PA and in 2 patients without PA. In a patient with probable PA, positivity of the GM in EBC, preceded that of the serum of 4 days. GM in EBC was negative in 5 out of 7 cases with possible PA and in 5 out of 6 without PA. The sensitivity of GM in EBC was lower for the diagnosis of probable and possible PA compared to serum GM. However, considering the discordant results in serum and in EBC of four patients with possible PA we suggest that EBC GM levels can expand the diagnostic yield of PA.
In asthma, reactive oxygen species induce damage to biomolecules like proteins. This oxidative stress can promote inflammation, but its contribution to asthma pathology is controversial, not in the least because antioxidant interventions have proven rather unsuccessful. Recent studies indicate that the oxidative stress at baseline can be predictive of the fall in FEV1 upon an allergen challenge and of sensitization to an allergen. Interestingly, this baseline oxidative stress correlated with the capacity of antioxidant and cytoprotective responses to deal with reactive oxygen species, but not with inflammatory parameters. These findings have led to several considerations in relation to antioxidant trials that are discussed. Trials should be complemented by in-depth analyses of the failing antioxidant and cytoprotective responses and their consequences for cellular function in asthma.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
