Methyl methacrylate and respiratory sensitization: A Critical review

Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants.The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer

Overview of Aspergillus allergens

Fungi in general and, Aspergillus fumigatus (A. fumigatus) in particular, are able to produce complex patterns of IgE-binding molecules. Robotics-based high throughput screening of A. fumigatus cDNA libraries displayed on phage surfaces revealed at last 81 different sequences encoding structures potentially able to bind to serum IgE of sensitised individuals suffering from A. fumigatus-related complications. Although not all of these allergens have been characterised in detail, A. fumigatus still represents the best investigated allergenic source. A total of 23 A. fumigatus allergens are recorded by the official allergen list of the International Union of Immunological Societies (http://www.allergen.org) and this is by far the longest allergen list reported for a single allergenic source. The IgE-binding molecules include species-specific as well as phylogenetically highly conserved cross-reactive structures and such with unknown function. A subset of cDNAs have been used to produce and characterise the corresponding recombinant allergens which have proven to be useful diagnostic reagents allowing specific detection of A. fumigatus sensitisation and differential diagnosis of allergic bronchopulmonary aspergillosis. Structures highly conserved through different species like manganese-dependent superoxide dismutase, P2 acidic ribosomal protein, cyclophilins and thioredoxins induce, beyond sensitisation, IgE antibodies able to cross-react with the corresponding homologous self-antigens. The frequently observed cross-reactivity is traceable back to shared discontinuous B-cell epitopes as shown by detailed analyses of the crystal structures