Pyrazinone conjugates as potential cephalosporin allergens.

Cephalosporins with an alpha-amino group on the 7-beta-acyl substituent have been shown to undergo aminolysis with subsequent formation of a fluorescent pyrazinone degradation product. An analogous reaction seems to take place upon in vitro conjugation of such cephalosporins to albumins and polylysine. A corresponding pyrazinone-polylysine conjugate was able to bind IgE antibodies in sera from patients with suspected allergy to beta-lactams. These findings may have applications in the diagnosis of allergy against aminocephalosporins.