Pholcodine stimulates a dramatic increase of IgE in IgE-sensitized individuals. A pilot study.

A previous study showed a relation between pholcodine (PHO) consumption, prevalence of IgE-sensitization to PHO, morphine (MOR) and suxamethonium (SUX) and anaphylaxis to neuromuscular blocking agents (NMBA). The purpose of this pilot study was to explore the effect on IgE production, in IgE-sensitized and nonsensitized individuals, of exposure to cough syrup and environmental chemicals containing PHO, MOR and SUX related allergenic structures. Serum concentrations of IgE and IgE antibodies to PHO, MOR and SUX allergens measured by ImmunoCAP (Pharmacia Diagnostics, Uppsala, Sweden) were followed after intake of cough syrup, or exposure to confectionary and other household chemicals containing various amounts of substances cross-reacting with PHO, MOR and SUX. Cough syrup containing PHO gave, in sensitized individuals, within 1-2 weeks, an increase of IgE of 60-105 times and of IgE antibodies to PHO, MOR and SUX in the order of 30-80 times. The tested confectionary did not have any similar stimulating effect but seemed to counteract the expected decrease of IgE. No effect was seen in nonsensitized individuals. The PHO stimulated IgE showed a nonspecific binding to ImmunoCAP with common allergens and glycine background ImmunoCAP that was up to 10-fold higher than that of monomeric myeloma-IgE at twice the concentration. It seems as cough syrups containing PHO have a most remarkable IgE boostering effect in persons IgE-sensitized to PHO, MOR and SUX related allergens. Household chemicals containing such allergenic epitopes seem capable of some, minor, stimulation.