Development of allergic antibody to an enzyme in a body lotion: results of an 18-month clinical study.

Use of enzymes in cosmetic products is novel and the safety of these products is not well understood. The safety of a prototype enzyme-containing body moisturizer lotion was tested via measures of skin compatibility and potential to induce protease-specific IgE antibody in a clinical study. Female, atopic subjects (n = 1,100) used body lotion containing 100 ppm protease (Y217L BPN') for 5 consecutive days per month, for 18 months. Regular lotion was used the remaining days of each month. Skin evaluation and skin prick tests (SPT) were conducted every 3 months. Measures of skin hydration were made in a subset of subjects at 3-month intervals: skin biopsies occurred at baseline and at the first 3-month timepoint. Serum from SPT positive subjects was tested for specific IgE in an immunoCAP assay. Clinical evaluation and histopathology showed no skin irritation and increased hydration of the skin over time. Three of 864 subjects completing the study developed IgE antibody to the enzyme: 1 subject after 6 months product use and 2 subjects after 15 months product use. A fourth subject was found with IgE antibody 3 months after study termination. None had allergic symptoms associated with product use. Intermittent exposure to a low level of protease enzyme in a body lotion led to the development of specific IgE antibody in 0.46% of subjects. While this study showed favorable skin compatibility of the protease containing lotion, the occurrence of allergic antibody to the enzyme was unacceptable for product commercialization.