Lispro analog for treatment of generalized allergy to human insulin

OBJECTIVE - To evaluate the clinical usefulness of the human insulin analog lispro in a patient with generalized allergy to human insulin. RESEARCH DESIGN AND METHODS - A 34-year-old obese female patient developed systemic allergic reactions to human insulin but tolerated insulin lispro. Sequential analyses of the anti-insulin IgE and IgG immunoglobulins were performed. RESULTS - On intradermal rest, the lispro insulin produced a 50% less intense wheal-flare response, compared with human insulin, which was presumed to be due to lispro's molecular form. The intradermal reactivity to both human and lispro insulins decreased with time and disappeared by week 25. I-125-labeled lispro and human insulin binding antibody titers of both the IgE and IgG immunoglobulins were high initially, but decreased progressively, becoming very low by the end of 1 year. In in vitro immunoassay, the lispro and human insulins show a complete cross-reactivity. CONCLUSIONS - Lispro may be useful for the management of allergy to human insulin. This analog of human insulin appears to have a reduced immunogenic potency.