On the immunochemical specificity of pyrazolinone and pyrazolidinedione reactions.

Haptenic groups based on the 1-phenyl-2,3-dimethyl-3-pyrazolin-5-one and 1,2-diphenyl-pyrazolidine-3,5-dione structures conjugated to human serum albumin gave antibody responses in rabbits which were compared with those raised against the same haptens conjugated via spacer bridges to the protein carrier. The spacing up to 12.4 A had no marked influence on the antibody specificity evaluated by haptenic inhibition of ELISA. The specificities are more pronounced than those found with e.g. anti-penicilloyl antibodies which seems in line with clinical experience involving e.g. phenylbutazone, sulfinpyrazone, propyphenazone and metamizole. It is argued that such strict specificities may lead to false negative tests in diagnostic procedures in vitro as well as in skin testing.

Diagnosis of antibody-mediated drug allergy. Pyrazolinone and pyrazolidinedione cross-reactivity relationships.

Based on the 1-phenyl-2,3-dimethyl-3-pyrazolin-5-one series and on the 1,2-diphenyl-pyrazolidine-3,5-dione series of drugs, haptenic reagents and conjugates were synthesized and evaluated by passive cutaneous anaphylaxis in guinea pigs, and by ELISA tests using rabbit antisera against the haptens. No cross-reactivity between pyrazolinone and pyrazolidinedione haptenic reagents was found in any of the test systems. But also within each series, the animal antibodies showed rather strict specificities upon interaction with related haptens or drugs. These results are somewhat unexpected, because the haptens were used in connection with long and flexible spacer arms. Furthermore, they are not typical for certain other drug allergies. The strict specificity reduces the diagnostic potential of the haptenic reagents when used in serological tests or in skin testing.

Defined test reagents for the diagnosis of drug-induced allergy. Antibody-dependent skin reactions towards pyrazolinone and pyrazolidinedione derivatives in the guinea pig.

Chemically defined haptenic reagents and haptenic conjugates were synthesized for use in clinical skin testing. One series of reagents was based on the 1-phenyl-2,3-dimethyl-3-pyrazolin-5-one structure, a second series on 1,2-diphenyl-pyrazolidine-3,5-dione. Haptens were connected via flexible spacer molecules which insert considerable distances between haptenic moieties and carriers. The skin test reagents were hexavalent conjugates prepared from the bis-penta-L-lysine carrier 'PAL'. The methodological details exemplify the application of N-hydroxysuccinimide activated ester derivatives for the preparation of peptidic conjugates. Rabbit and guinea-pig antisera against the haptens were obtained by immunization with human serum albumin conjugates. Efficacy and cross-reactivity relationships were assessed by guinea pig PCA and by testing actively immunized guinea pigs. A striking lack of cross-reactivity was found between pyrazolinone and pyrazolidinedione haptenic reagents in all test systems. On the other hand, the elicitation of homologous anaphylaxis was highly effective with the PAL conjugates. The data presented and discussed provide a basis for the evaluation of clinical tests performed in order to define drug-induced allergic reactions. They are relevant for immediate-type skin reactions as well as for serological methods.

Diagnostic reagents in drug allergy: immunochemical specificity in the 1,2-diphenyl-pyrazolidinedione series.

Chemically defined haptenic reagents and haptenic conjugates were synthesized to be used for skin tests in allergic patients and for serological tests. One series of reagents is based on an open-chain derivative which is formed by reaction of the oxidation product of phenylbutazone, 4-hydroxyphenylbutazone, with amino functions. A second series uses the intact 1,2-diphenyl-pyrazolidine-3,5-dione molecule which is substituted in the 4-position with acetic acid. Both haptens are used in conjunction with spacer molecules which provide considerable distances between haptenic moiety and carriers. The skin test reagents are hexavalent conjugates based on the bis-penta-L-lysine carrier "PAL". Rabbit and guinea-pig antisera against the haptens were obtained by immunizations with human serum albumin conjugates. Data obtained from passive cutaneous anaphylaxis and from ELISA tests show that there is generally only slight cross-reactivity between the two series of haptenic reagents. Also, there is only modest cross-reactivity between intact drugs and haptenic reagents. No measurable crossreactions were noted between 1-phenyl-2,3-dimethyl-3-pyrazolin-5-one derivatives and haptenic reagents of the 1,2-diphenyl-pyrazolidinedione series.