Microbial allergy/hypersensitivity
Fungal allergens have long been known. However, in recent years,
non-fungal microbial allergens are increasingly being
found[163,164]. A common bacterial plant pathogen, Pantoea
agglomerans causes human respiratory diseases such as asthma and
HP[165]. Farm environments have Archaea[166] that are capable of
causing immune reactions[167]. IgE-mediated responses to viruses
(i.e., HIV[94], varicella zoster[168,169], influenza
virus[170] and parvovirus[171]) are also being found.
In Bachert et al’s[172] review of chronic rhinosinusitis (CRS), the
concept of bacterial allergy and colonization was one component of their
proposed immune barrier hypothesis. Calenoff et al[173] found an
elevated level of bacterial allergy in CRS.
Microbial allergies are potentially increased by exposure to damp
environments due to increased fungi and bacteria. Damp environments have
been associated with the development or exacerbation of a range of
respiratory diseases, such as asthma, hypersensitivity pneumonitis,
allergic rhinitis and chronic rhinosinusitis[174].
Although dampness has been associated with increased disease rates,
Mendell et al[174] found no clear relationships between disease
features and measured microbial exposures. The PHM hypothesis suggests
that low abundance PHMs would increase in damp environments and might be
an important missing factor.
Researchers have noted inadequate research on bacteria in damp
buildings[175,176]. Mycobacteria can cause greater immune responses
and be just as serious a threat as molds[176]. A study of showerhead
microbial biofilms found high levels of non tuberculous mycobacteria and
other potential pathogens[177].