Heterogeneity of the IgE response to allergenic determinants of cefaclor in serum samples from patients with cefaclor-induced anaphylaxis.
BACKGROUND
Beta-lactam antibiotics, such as cefaclor, may cause IgE-mediated anaphylactic reactions. However, the clinically available serologic test has not been widely accepted, and the antigenic determinants of these drugs are unclear.


OBJECTIVE
To describe 4 cases of anaphylaxis caused by cefaclor in which a specific IgE response to cefaclor was demonstrated.


METHODS
Four patients with anaphylaxis to cefaclor and 35 nonatopic controls never exposed to cefaclor were studied. Skin tests and oral challenges with this drug were performed. The specific IgE response to the antigenic determinant of cefaclor-human serum albumin (HSA) conjugate was compared in each patient. The serum specific IgE to cefaclor-HSA conjugate was detected using enzyme-linked immunosorbent assay (ELISA). Also, ELISA inhibition studies using various concentrations of cefaclor-HSA, HSA alone, and free cefaclor were performed, as were hapten inhibition studies using cefaclor, cephalexin, cefadroxil, ampicillin, ceftriaxone, and cefotaxime.


RESULTS
Three patients showed high levels of serum specific IgE to cefaclor-HSA and marked inhibition patterns to free cefaclor and cefaclor-HSA conjugate on ELISA inhibition testing. Hapten inhibition testing in 3 individual serum samples showed 2 different patterns. In patient 3, significant dose-dependent inhibitions (up to 92%) were noted with additions of free cefaclor and cefaclor-HSA conjugate, and lesser inhibitions (up to 74%) were noted with cephalexin, which shares the aminobenzyl side chain. In patients 1 and 2, marked dose-dependent inhibitions were noted only with additions of cefaclor-HSA conjugate and free cefaclor, whereas minimal inhibitions were noted with the other 5 compounds.


CONCLUSIONS
The specific IgE response to cefaclor-HSA conjugate in patients with cefaclor anaphylaxis occurs against the hapten, in which heterogeneity of the antigenic determinant was noted to depend on the individual.
Kim
Sang-Hoon
SH
Department of Internal Medicine, Eulji Hospital, Eulji University School of Medicine, Seoul, Republic of Korea.
Choi
Jeong-Hee
JH
Park
Hae-Sim
HS
D000293:Adolescent; D000328:Adult; D000707:Anaphylaxis / Q000139:chemically induced* / Q000276:immunology*; D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000276:immunology*; D002433:Cefaclor / Q000009:adverse effects* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005260:Female; D006241:Haptens / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male
D000900:Anti-Bacterial Agents; D000939:Epitopes; D006241:Haptens; D007073:Immunoglobulin E; D002433:Cefaclor