Importance of albumin in cross-reactivity among cat, dog and horse allergens

Different allergenic proteins have been involved in crossreactivity among a nimals. Albumins seem to be cross-sensitizing allergenic components. The ai m of this study was to assess the importance of albumin as a cross-reactive allergen in patients sensitized to cat, dog and horse. One hundred and sev enteen patients sensitized to cat were tested for IgE reactivity using skin prick tests and RAST assays with cat, dog and horse hair/dander extracts a nd their purified albumin extracts. RAST-inhibition studies were carried ou t to assess cross-reactivity among cat, dog and horse and among their purif ied albumins. It was found that 22% of patients exhibited specific IgE to c at albumin; 41% of patients sensitized to cat were also sensitized to dog a nd horse. Out of these patients, 21% had IgE to three albumins and 17% to t wo. Reciprocal inhibitions were observed among cat, dog and horse albumins and also among cat, dog and horse hair/dander extracts, using in the latter experiment sera from patients not sensitized to albumins. IgE binding to h orse extract was inhibited 30% by its homologous albumin and IgE binding to cat and dog extracts in almost 15% by their respective albumins. It was co ncluded that albumins from these three animals share some epitopes that acc ount for the cross-reactivity observed in around one-third of patients sens itized to cat, dog and horse. Nevertheless, more than 50% of specific IgE t hat cross-reacts among these three animals is directed to allergens other t han albumin.