Frequently asked questions
Why it is not enough to measure the total protein level? Only some of the proteins are allergenic; total protein content does not yield reliable information about the allergenicity of a product.
Why it is not enough to measure only one allergen?
Patients can be sensitised to one or more allergens; different gloves and other NRL products can contain different allergens.
Are all proteins and antigens from the rubber tree equally allergenic?
No. During the rubber manufacturing process many of the proteins degrade, denature and lose their activity, however, some proteins retain their allergenic properties throughout the process. Latex products can have high protein but low allergen levels and vice versa.
Why have we chosen Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 to be included in the kits?
According to the current literature, these four allergens are the ones that have been unequivocally demonstrated to be present in glove extracts and to resist the glove-manufacturing process.[1]
Why do we have four separate kits?
It enables the direct measurement of each individual allergen and thus the definition of product based reference values for the customer. Alternatively, the results from the four tests can be combined.
How well does the selection of these four allergens cover the total allergenicity of the gloves?
Convincing results have been obtained showing high correlation to the allergenicity of gloves measured by currently available patient IgE-based methods. In comparison, the allergenicity of gloves has correlated only moderately or poorly to the total protein measurement method (Lowry).[1]
Which allergens are relevant for health care workers?
The two most important latex allergens are Hev b 5 and Hev b 6.02 (hevein). These allergens can resist the process of glove manufacturing and they have been demonstrated in extracts of medical gloves. [2, 3, 4]
What is the relationship between Hev b 6 and Hev b 6.02?
Hev b 6 (prohevein or hevein preprotein) is the 20 kD precursor protein of Hev b 6.02 (4.72 kD polypeptide known as mature hevein). Hevein carries the major IgE epitope of prohevein.
What is the significance of Hev b 1 and Hev b 3 in latex allergy?
Hev b 1 and Hev b 3 are the two most important latex allergens for patients with spina bifida. [5, 6, 7]
How do I prepare the product extract?
NRL products can be extracted in PBS (phosphate buffered saline). For instance, 1 g of rubber product can be cut into pieces and extracted in 5 mls of PBS. After extraction, the rubber products are removed and the extract is centrifuged.
References
1. Timo Palosuo, Harri Alenius, Kristiina Turjanmaa: Quantification of Latex Allergens . Methods 27 2002; 52-58
2. Akasawa A, Hsieh S-H, Martin BM, Liu T, Lin Y. A novel acidic allergen, Hev b 5, in latex. J Biol Chem 1996; 271:25389-25393
3. Alenius H, Kalkkinen N, Reunala T, Turjanmaa K, Palosuo T. The main IgE-binding epitope of a major latex allergen, prohevein, is present in its N-terminal 43 amino acid fragment, hevein. J Immunol 1996; 156:1618-1625.
4. Timo Palosuo, Vladimir Ovod, Tytti Kärkkäinen, Nisse Kalkkinen, Markku Kulomaa, Timo Reunala, Kristiina Turjanmaa, Hely Reinikka-Railo: The Major Latex Allergens Hev b 6.02 (hevein) and Hev b 5 are Regularly Detected in Medical Gloves with Moderate or High Allergen Content. J. Allergy Clin Immunol 2001; 107:S321
5. Czuppon AB, Chen Z, Rennert S, Engelke T, Meyer HE, Heber M, Baur X. The rubber elongation factor of rubber trees (Hevea brasiliensis) is the major allergen in latex. J Allergy Clin Immunol 1993; 92:690-697.
6. Alenius H, Palosuo T, Kelly K, Kurup V, Reunala T, Mäkinen-Kiljunen S, Turjanmaa K, Fink J. IgE reactivity to 14-kD and 27-kD natural rubber proteins in latex-allergic children with spina bifida and other congenital anomalies. Int Arch Allergy Immunol 1993; 102:61-66
7. Yeang HY, Cheong KF, Sunderasan E, Hamzah S, Chew NP, Hamid S, Hamilton RG, Cardosa J:The 14.6 kD rubber elongation factor (Hev b 1) and 24 kD (Hev b 3) rubber particle proteins are recognized by IgE from patients with spina bifida and latex allergy. J Allergy Clin Immunol 1996; 98: 628-639
