Toxic and other non-IgE-mediated effects of fungal exposures

Mold and human health: separating the wheat from the chaff

The term "mold" is utilized to define the ubiquitous fungal species commonly found in household dust and observed as visible multicellular filaments. Several well-defined human diseases are known to be caused or exacerbated by mold or by exposure to their byproducts. Among these, a solid connection has been established with infections, allergic bronchopulmonary aspergillosis, allergic fungal rhinosinusitis, hypersensitivity pneumonitis, and asthma. In the past decades, other less-defined and generally false conditions have also been ascribed to mold. We will herein review and critically discuss the available evidence on the influence of mold on human health.

The fungal profile of cotton lint from diverse sources and implications for occupational health

There is mounting evidence that inhalation of fungal spores and their fragments and toxins may cause respiratory illness, particularly in indoor environments and industrial settings. However, analysis of these organisms on cotton has not been carried out in detail and, hence, further examination may prove important in identifying sources of these organisms and assessing the risks posed to cotton workers. This study identified fungi from cotton lint samples originating in 12 world regions and revealed six different fungal genera, with the following rank order of sample isolation incidence: Aspergillus > Cladosporium > Fusarium > Rhizopus > Penicillium > Alternaria. Aspergillus was the most common genus and Aspergillus niger in particular was the pecies most frequently identified. Improved understanding of the variety of organisms that contaminate cotton may help to reduce prevalence of organic dust-related lung diseases.

Mold hysteria: origin of the hoax

The topic of building related illness came into the public's eye as a major health issue in the mid 1970s, when several cases of pneumonia were found to be associated with an infectious agent in Philadelphia. This agent was subsequently found to be a gram-positive bacterium known as Legionella pneumoniae. During the ensuing 30 years, a myriad of symptom constellations, disorders, clinical syndromes and illnesses have been attributed to indoor living or working environments. Over time, there appeared to be no limit to claims of building related illness, and it was "reported" that almost any kind of clinical symptom, real or imaginary, could be blamed on indoor environments. As society became more and more litigious, many of these disorders were erroneously played out in courtrooms rather than medical offices, creating a circus atmosphere surrounding this class of disorders. With the advent of the internet, as well as other advances in telecommunications, these issues eventually became part of a media frenzy, and all truths could be thrown out the window as issues became more and more decided upon by emotions and unfounded beliefs, rather than scientific data and logical thinking.

Indoor air quality and human health: truth vs mass hysteria

Indoor air quality is an important issue, because anything we breathe can potentially affect our health. To determine if there is a real health risk, well-designed scientifically valid studies must be performed. Although much attention has focused on sick building syndrome, chemical sensitivities, and mycotoxicosis, there actually is very little evidence that these conditions have an adverse effect on human health. In contrast, real health issues have been shown to exist regarding indoor air triggers of allergies and asthma. Outdoor allergens are difficult to avoid because the pollen grains we encounter outdoors, which are the size that can cause allergies, are windborne and can travel for miles. However, indoor allergens can cause severe allergic symptoms and may also have a priming effect on an individual’s susceptibility to simultaneous or subsequent exposure of other outdoor allergens. Therefore, it is important to minimize exposure to indoor allergens. Determination of individual susceptibility can be paired with knowledge of the patient’s indoor exposure pattern to produce a customized management plan of avoidance, which can be used in conjunction with pharmacological treatment of allergies and asthma, as well as immunotherapy.

The production and characterization of monoclonal antibodies to the fungus Aspergillus versicolor

Fungal exposure measurements in indoor environments require accurate and precise monitoring methods. Such techniques may be based on monoclonal antibodies (Mabs) and enzyme-linked immunosorbent assays (ELISA) and here we report the cross-reactivity patterns of Mabs produced against Aspergillus versicolor. Balb/c mice were immunized with the particulate fraction of homogenized spores and 46 Mabs (35 IgM, nine IgG3, two IgG1) were produced and tested for cross-reactivity against 55 fungal species. None of the Mabs was found to be species-specific for A. versicolor. Several Mabs strongly cross-reacted with most Aspergillus, Penicillium and Eurotium species and some Mabs also cross-reacted with Paecilomyces variotii and several Cladosporium and Stachybotrys species. Our results show that antibody responses in mice against spores of A. versicolor are dominated by highly cross-reactive antibodies of the IgM isotype. The widespread cross-reactivity suggests that the specificity of antibodies to be used for the detection of fungi in environmental samples need to be thoroughly characterized in order to avoid ambiguities in the interpretation of monitoring results. Furthermore, accurate estimates of spore concentrations may require the application of species-specific Mabs in order to avoid bias in result interpretation because of the differential reactivity of cross-reactive Mabs with different fungi.

PRACTICAL IMPLICATIONS

Producers of monoclonal or polyclonal antibodies for the detection of fungi in environmental or clinical samples need to verify antibody reactivity patterns and accurately report that information to potential users. Furthermore, immunoassays based on mouse or human serum or purified immunoglobulin fractions need to consider antibody cross-reactivity as a potential confounding factor during interpretation of results.