Mould-specific immunoglobulin antibodies quantified by flow cytometry reflect mould exposure in Norwegian children.

BACKGROUND: Studies from many countries have shown an association between dampness in buildings and airway symptoms. Little is known about the role of mould-specific IgG antibodies in this context. Objective To examine the IgG antibody response to mould applying a new flow cytometric assay, compare the results with the standardized ImmunoCap method, and evaluate the association of IgG to IgE antibodies, dampness in buildings, and airway symptoms like wheeze and asthma. METHODS: A population of 3713 children 9-11 years of age living in Northern Norway was investigated for airway symptoms and dampness at homes by a parental questionnaire, using protocols of the International study of Asthma and Allergy in Childhood (ISAAC). Among these, a case-control study of 100 wheezers and 100 non-wheezers was established that included home inspection, a parental structured interview, and serum samples analysed for mould-specific IgG and IgE antibodies, total IgE, and specific IgE to an allergen panel (Phadiatop). RESULTS: Self-reported visible signs of mould or moisture at home during the child's first year of life were a significant risk factor for both wheeze and asthma. The levels of mould-specific IgG antibodies were associated with mould and moisture findings, but only when IgG antibodies were measured by flow cytometry. CONCLUSIONS: The results support that dampness at home can increase the risk of airway symptoms. IgG antibodies determined by flow cytometry reflect mould exposure better than antibodies measured by the conventional method. IgG antibodies measured by flow cytometry may be used as an indicator of mould exposure.

Antibody response to long-term and high-dose mould-exposed sawmill workers.

Exposure to moulds is thought to cause adverse health effects ranging from vague subjective symptoms to allergy and respiratory diseases. Until now, most studies have been emphasizing low levels of exposure. In Norwegian sawmills during the 1980s, extensively high spore counts up to 10(7) spores/m3 air were reported. By using serum samples obtained from sawmill workers during that period, in addition to control sera, we studied the antibody response of all classes and IgG subclasses to Rhizopus microsporus at different levels of exposure. Antigen specificity was further studied by Western blotting. Exposure to R. microsporus was accompanied by R. microsporus-specific antibody production against a wide range of antigenic components most likely of both protein and carbohydrate nature. Increasing levels of mould-specific IgG1, IgG2, IgG4 and IgA antibodies were associated with increased exposure, while the highest levels of exposure were associated with a somewhat reduced level of mould-specific IgE antibodies. In conclusion, the present study strongly suggests that high mould exposure can induce a strong IgG and IgA response in a dose-dependent manner.

Immunoglobulin G antibodies against environmental moulds in a Norwegian healthy population shows a bimodal distribution for Aspergillus versicolor.

Immunoglobulin G (IgG) antibodies against moulds related to indoor dampness problems are used as biomarkers to indicate exposure. In the present study, we evaluated the frequency of mould exposure in an adult healthy population by examining levels of mould-specific IgG antibodies in Norwegian blood donors. Using enzyme-linked immunosorbent assay, 106 blood donor sera were analyzed for IgG antibodies to Aspergillus versicolor, Penicillium chrysogenum, Cladosporium herbarum, Stachybotrys chartarum and Fusarium oxysporum. The levels of specific IgG antibodies to P. chrysogenum, C. herbarum and S. chartarum correlated (r = 0.46-0.62). Responses to A. versicolor were considerably stronger than to the other moulds, and another 996 blood donor sera were analyzed for IgG antibodies to this mould. Women had significantly higher levels of specific IgG antibodies to A. versicolor than men. The concentration of A. versicolor-specific IgG antibodies showed a non-Gaussian, bimodal distribution profile, in which 12.5% were defined as positive to exposure. This suggests that significant mould exposure in a healthy population can be calculated from mean + 1SD. Western blotting analyses showed that antibody responses to A. versicolor were largely directed against carbohydrate antigens of unknown saccharides.

Mould extracts increase the allergic response to ovalbumin in mice.

BACKGROUND: Exposure to moulds in indoor air is thought to induce asthma in susceptible persons. Moulds may contain several potent allergens. However, more importantly, moulds may increase the allergic response to other allergens (adjuvant effect). Previously, we have found that a beta-1,3-glucan from the cell wall of the fungus Sclerotinia sclerotiorum increases the allergic response to the model allergen ovalbumin (OVA) in a mouse model. OBJECTIVE: In the present study, we wanted to confirm the adjuvant effect of another beta-1,3-glucan, MacroGard (MG) from baker's yeast in this model. More importantly, we wished to explore the putative effects of extracts from the moulds Cladosporium herbarum (CH) and Penicillium chrysogenum (PC) using the very same model as used to explore effects of beta-glucans. METHODS: Groups of eight Balb/c mice were injected with OVA alone, OVA+extract or OVA+MG, into one footpad. On day 21, all mice were reinjected with OVA, before exsanguination on day 26. The levels of OVA-specific IgE, IgG1 and IgG2a in serum were measured by ELISA. RESULTS: Compared with OVA alone, OVA+MG, OVA+CH extract and OVA+PC extract increased OVA-specific IgE and IgG1 levels significantly. For all groups, the levels of IgG2a anti-OVA remained similar to those of the OVA-alone group. CONCLUSIONS: Our results show that extracts from CH and PC, and the beta-1,3/1,6-glucan from baker's yeast have adjuvant effects on the allergic response in mice.