Immunogenicity studies of guayule and guayule latex in occupationally exposed workers

Type I Hevea brasiliensis rubber latex allergy is managed by avoidance, using synthetic and alternative latex (such as Parthenium argentatum, guayule) products. This study investigates the ability of high-dose occupational exposure to guayule shrub/homogenate/latex to induce guayule-specific antibody responses in employees (Yulex Corporation). Participants completed an allergy history/guayule exposure questionnaire and provided annual blood samples from 2006 to 2008. Sera were analyzed for IgG and IgE anti-guayule (protein from homogenate, commercial-grade latex and non-ammoniated total plant proteins) using solid phase immunoassays (negative = IgG < 1 μg/ml, IgE < 1 ng/ml). Guayule-specific IgG antibody (range: 2.0–9.7 μg/ml) was detected in 3 of 16 (19%) highly exposed employees in the pilot plant and R&D/applications laboratory. Antibody levels related to relative cumulative-years (e.g. >3) of reported guayule homogenate/latex exposure. Equivocal IgG antibody responses (1.0–2.0 μg/ml) were detected in 2 of 5 (40%) of administrators with infrequent guayule homogenate/latex contact. No guayule-specific IgE antibody or guayule-associated allergic reactions were detected. We conclude that protein from guayule and in guayule latex can be immunogenic but not allergenic in occupationally exposed workers.