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Keywords:

  • β-(1,3)-glucan;
  • feather;
  • pillows;
  • synthetic

Pillows are a recognized source of exposure to indoor allergens. Specifically, synthetic pillows are known to contain higher amounts of house dust mite allergen (1) and animal allergens (2) compared with feather pillows. These higher levels of allergens may explain the association between synthetic pillows use and asthma symptoms (3).

Recently, Woodcock et al. (4) demonstrated that pillows are a substantial source of fungi. They found that synthetic pillows contained a greater variety of fungal species and more colony forming units than feather pillows. The authors concluded that fungal contamination of pillows could have important implications for asthmatic patients.

A major component of the fungal cell wall is β-(1,3)-glucan, which in itself is nonallergenic but is proinflammatory and shows some associations with airway inflammation and respiratory symptoms (5). In light of the previous finding of fungal contamination of pillows we determined the β-(1,3)-glucan content of synthetic and feather pillows.

Five pairs of synthetic and feather pillows, each pair having been on the same mattress for at least 3 months, were collected and dust samples obtained by vacuuming each side of the pillow for 1 min. The dust samples were extracted with 0.3 N NaOH and β-(1,3)-glucan content of the supernatants were estimated by a modified Limulus amebocyte lysate kinetic assay specific for β-(1,3)-glucan (Glucatell; Cape Cod Inc., Falmouth, MA). Results were log transformed and results expressed as geometric means (95% confidence interval), both as ng/g dust and total ng/pillow. Differences between types of pillow were assessed by Student's t-test with statistical significance set at the P < 0.05 level.

Expressed per gram of dust β-(1,3)-glucan levels were similar between the two types of pillows but when expressed as total amount of β-(1,3)-glucan recovered, synthetic pillows contained about fourfold higher levels compared with feather pillows (Table 1). In all five pairs total β-(1,3)-glucan was higher from the synthetic pillow than the feather pillow (data not shown).

Table 1.   Geometric mean (95% CI) β-(1,3)-glucan from synthetic and feather pillows
Pillow typeng/gRatio*Total ng/pillowRatio*
  1. *Ratio synthetic : feather.

Synthetic71449 (42893–119016)1.2 (0.5–2.8)31987 (16783–60965)3.9 (1.6–10.0)
Feather59980 (27177–132376) 8115 (4249–15497) 
P0.30 0.0074 

We have recovered about fourfold higher total amounts of β-(1,3)-glucan from synthetic pillows than from feather pillows. Various cross-sectional studies have consistently shown that synthetic bedding is associated with reported asthma symptoms (4). It has been suggested that these findings are due to the higher levels of indoor allergens on synthetic bedding. β-(1,3)-glucan could also explain these findings as β-(1,3)-glucan apparently increases peak expiratory flow variability in asthmatic children (5). Thus given our findings of higher β-(1,3)-glucan content of synthetic pillows and the recent finding of significant fungal contamination of pillows (4), this may also be relevant for the reported associations of synthetic bedding with asthma symptoms, such as wheeze (6).

A limitation of our study is that we only studied five pairs of pillows. However, in all five pairs total β-(1,3)-glucan content was higher from synthetic pillows. Similarly, the previous finding of higher Der p 1 levels from synthetic pillows was evident on eight pillow pairs (1) and more A. fumigatus on synthetic pillows was evident from five pillow pairs (4).

As we spend about a third of our lives in bed further studies are warranted on β-(1,3)-glucan content of individual bedding items. It has been shown, for instance, that synthetic duvets also have much higher levels of Der p 1 than feather duvets (7). Given the close proximity of bedding to the airways, potentially higher levels of β-(1,3)-glucan from other synthetic bedding items could be of relevance for asthmatics.

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