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Latex allergy affects well-recognized risk groups. The highest prevalence appears in children requiring multiple surgeries, especially those with spina bifida (SB). Natural rubber latex (NRL) contains more than 200 proteins and peptides, some of which are capable of eliciting immunoglobulin E (IgE) responses. It is known that manufacturing processing of latex can alter the structure of proteins; thus, ammoniated latex contains less allergenic determinants and has been proved to offer inferior results to those of nonammoniated extracts for the study of sensitization to latex (1). Therefore, the isolation and synthesis of recombinant allergens is becoming an important tool both for clinical and research purposes. So far, 13 latex allergens have been registered by the IUIS (2). A lipid transfer protein, Hev b 12, is one of the latest registered allergens (3), and little information is currently available concerning its allergenic importance in sensitized patients.

We studied 20 Spanish children with SB with two to nine operations, eight non-SB children with two to eight operations, and three atopic nonoperated children. All displayed NRL-specific IgE antibodies in their serum (Pharmacia CAP class ≥1), and 25 have had clinical symptoms in relation to latex. Serum IgE antibodies to recombinant Hev b 12 (rHev b 12) were analyzed by an ImmunoCAP method in leftover sera of all children. No rHev b 12-specific IgE antibodies were found (<0.3 U/l). As positive controls, rHev b 12-specific IgE responses using the same technique were recently obtained in sera of fruit-allergic patients with and without NRL-sensitization (4).

The allergenic potential of NRL varies among risk groups. In health care workers, responses are found mainly to Hev b 5 and Hev b 6.01/6.02. In children with SB, Hev b 1 is the major allergen, with frequent responses also to Hev b 3 and Hev b 7. In nonoperated NRL-sensitized children, the pattern of sensitization resembles more that of health care workers (1, 5). This seems to depend on the physical properties of the allergens, and is important in order to develop suitable products for diagnosis and treatment of latex allergy. Extracts for diagnosis should contain a mixture of all allergens, to reach the highest sensitivity, and cover all cases of latex sensitization. Extracts for immunotherapy must contain sufficient amounts of the allergens relevant for the given patient. Until individualized extracts are commercially feasible and available, products for treatment must include those allergens known to sensitize most of the patients of each risk group. Regarding this, the importance of Hev b 12 had not been studied before. Our results revealed no rHev b 12-specific IgE antibodies in the sera of our 31 children. If these results are confirmed in more atopic children and in sensitized adults, the efforts to include rHev b 12 in diagnostic NRL-extracts should be limited. However, the relevance of this allergen in a recombinant form for cross-reactivity should be further studied.

References

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  2. References
  • 1
    La Grutta S, Mistrello G, Varin E, Pajno GB, Passalacqua G. Comparison of ammoniated and nonammoniated extracts in children with latex allergy. Allergy 2003;58: 814818.
  • 2
    International Union of Immunological Societies (IUIS). Allergen nomenclature. International Union of Immunological Societies. Allergen Nomenclature Sub-Committee. http://www.allergen.org/List.htm (accessed, 3 July 2004).
  • 3
    Beezhold DH, Hickey VL, Kostyal DA, Puhl H, Zuidmeer L, Van Ree R et al. Lipid transfer protein from Hevea brasiliensis (Hev b 12), a cross-reactive latex protein. Ann Allergy Asthma Immunol 2003;90: 439445.
  • 4
    Rihs HP, Rueff F, Lundberg M, Rozynek P, Garcia-Selles J, Barber D et al. Specific IgE-binding of rHev b 12 is restricted to fruit-allergic patients. J Allergy Clin Immunol 2004;113: S76.
  • 5
    Ylitalo L, Alenius H, Turjanmaa K, Palosuo T, Reunala T et al. IgE antibodies to prohevein, hevein, and rubber elongation factor in children with latex allergy. J Allergy Clin Immunol 1998;102: 659664.