Silk waste

Code: k73
Source material: Waste from cultured and wild silk
Silk is produced from the cocoons of silk moths and end-parts of cocoons, short fibres, etc, are combined to form silk waste and are utilized as filling material for e.g. bed quilts and winter clothes. 

Allergen Exposure

Silk threads to be used for the production of fabrics go through several processes that remove allergenic proteins. The silk waste, however, is less carefully processed and retains allergens of the original sources. Silk is a well-known occupational allergy in silk-industry workers (1). Silk waste from wild silk has become an important indoor inhalant allergen due to its use for filling bed quilts and pillows (2-5). 

Potential Cross-Reactivity

Silk allergens may share epitopes with the dust from silk-moth wings and possibly with other insects (8). 

Clinical Experience

IgE antibodies against silk waste (k73) were found in 99% of 111 patients with immediate type reactions to silk (4). Mulberry silk may also be included in silk waste (3, 4, 6). IgE antibodies were detected in 38/45 (84%) asthmatics with symptoms in the winter season (6). A Chinese silk waste product intended for filling bed matresses and rugs was shown to contain several IgE-binding allergens in the range 14 to 70 kD (7). Elimination of the allergen source from the patient's environment is an effective treatment that leads to complete recovery from the respiratory symptoms (9).
 
Review
Silk is produced from the cocoons of silk moths. Cultivated mulberry silk (Bombyx mori) and wild silk (Antheraea spp), also called oak-leaf silk or tussah, are the major types. Silk fibres, up to several hundred meters long, are rolled off each cocoon after an initial heating step to kill the pupae. Both types of fibres consist of fibroin, a fibrous protein, and sericin, a sticky proteinaceous material, that holds the fibres together. By-products from the silk production, end-parts of cocoons, short fibres, etc, are combined to form silk waste and are utilized as filling material for e.g. bed quilts and winter clothes.

Silk threads to be used for the production of fabrics go through several processes that remove allergenic proteins. The silk waste, however, is less carefully processed and retains allergens of the original sources.

Silk is a well-known occupational allergy in silk-industry workers (1). Silk waste from wild silk has become an important indoor inhalant allergen due to its use for filling bed quilts and pillows (2-5). IgE antibodies against silk waste (k73) were found in 99% of 111 patients with immediate type reactions to silk (4). Mulberry silk may also be included in silk waste (3, 4, 6). IgE antibodies were detected in 38/45 (84%) asthmatics with symptoms in the winter season (6).

A Chinese silk waste product intended for filling bed matresses and rugs was shown to contain several IgE-binding allergens in the range 14 to 70 kD (7). Silk allergens may share epitopes with the dust from silk-moth wings and possibly with other insects (8).

Elimination of the allergen source from the patient's environment is an effective treatment that leads to complete recovery from the respiratory symptoms (9).

References

  1. Harindranath N, Prakash O, Subba Rao PV. Prevalence of occupational asthma in silk filatures. Ann Allergy 1985;55(3):511-5.
  2. Hacki M, Wuthrich B, Hanser M. [Wild silk: a strong inhalation allergen (author's transl)]. Dtsch Med Wochenschr 1982;107(5):166-9.
  3. Johansson SG, Wuthrich B, Zortea-Caflisch C. Nightly asthma caused by allergens in silk-filled bed quilts: clinical and immunologic studies. J Allergy Clin Immunol 1985;75(4):452-9.
  4. Wuthrich B, Dietschi R, Keter A, Zortea-Caflisch C. [So-called "wild silk" asthma--an ever current inhalation allergy to silk waste]. Schweiz Med Wochenschr 1985;115(40):1387-93.
  5. Ebner H, Kraft D. [Wild silk-induced asthma. A contribution to the knowledge of inhalation allergies caused by wild and tussah silk-filled bed quilts]. Wien Klin Wochenschr 1987;99(15):542-6.
  6. Wen CM, Ye ST, Zhou LX, Yu Y. Silk-induced asthma in children: a report of 64 cases. Ann Allergy 1990;65(5):375-8.
  7. Dewair M, Baur X, Ziegler K. Use of immunoblot technique for detection of human IgE and IgG antibodies to individual silk proteins. J Allergy Clin Immunol 1985;76(4):537-42.
  8. Suzuki M, Itoh H, Sugiyama K, Takagi I, Nishimura J, Kato K, et al. Causative allergens of allergic rhinitis in Japan with special reference to silkworm moth allergen. Allergy 1995;50(1):23-7.
  9. Eng PA, Wuthrich B. [Silk waste--a further allergen in the bedroom]. Schweiz Rundsch Med Prax 1994;83(14):402-6.

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.