Alternaria measures in inner-city, low-income housing by immunoassay and culture-based analysis.
BACKGROUND
Sensitivity to Alternaria allergens has been associated with severe asthma and life-threatening exacerbations, and a high prevalence of Alternaria sensitivity has been reported among inner-city populations. Traditionally, epidemiologic studies have measured indoor Alternaria concentrations by cultural analyses; however, the number of viable spores may not be a good proxy for allergen levels. Furthermore, other genera share epitopes with Alternaria that may contribute to the allergenic effect.


OBJECTIVE
To compare measures of Alternaria antigen by enzyme-linked immunosorbent assay with measures of Alternaria and cross-reactive genera (Ulocladium, Curvularia, Epicoccum, and Stemphylium) by cultural analysis.


METHODS
Antigen assays and cultural analyses were performed on vacuum-collected bed dust samples collected between June 18, 2002, and February 9, 2004, from 3 inner-city, low-income public housing developments.


RESULTS
Alternaria antigen was found in all bed dust samples regardless of season. However, culturable Alternaria, Ulocladium, Curvularia, Epicoccum, and Stemphylium were only found in 50%, 35%, 6%, 11%, and 0% of bed samples, respectively. No correlations were found between Alternaria antigen and culturable concentrations of Alternaria or of its cross-reactive genera except for marginal correlation with Ulocladium culturable concentrations.


CONCLUSIONS
The results confirm that exposure to Alternaria antigens and allergens can occur even in the absence of culturable Alternaria or its cross-reactive genera, so further refinement and use of assays are essential for characterizing the distribution and determinants of indoor fungal allergen levels forsensitive populations.
Peters
Junenette L
JL
Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02215, USA. jpeters@hsph.harvard.edu
Muilenberg
Michael L
ML
Rogers
Christine A
CA
Burge
Harriet A
HA
Spengler
John D
JD
D000485:Allergens / Q000032:analysis / Q000276:immunology*; D000528:Alternaria / Q000276:immunology*; D000946:Antigens, Fungal / Q000032:analysis*; D004391:Dust / Q000032:analysis / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006798:Housing; D006801:Humans; D009172:Mycology / Q000379:methods; D011203:Poverty; D018709:Statistics, Nonparametric; D014505:Urban Population
D000485:Allergens; D000946:Antigens, Fungal; D004391:Dust