title: Immunologic evaluation of immediate hypersensitivity to cefaclor.
abstract: OBJECTIVE
  Cefaclor is widely prescribed for various infectious diseases. As its consumption increases, the number of hypersensitivity reactions to cefaclor has increased. This study aimed to evaluate the immunologic findings of immediate hypersensitivity to cefaclor.
  
  
  METHODS
  We enrolled 47 patients with immediate hypersensitivity to cefaclor from Ajou University Hospital and Asan Medical Center. Serum specific IgE, IgG1, and IgG4 antibodies to cefaclor-human serum albumin (HSA) conjugate were measured by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The most common phenotype was anaphylaxis (Group I, 78.7%), followed by urticaria (Group II, 21.3%). The detection of specific IgE, IgG1, and IgG4 to cefaclor-HSA conjugate by ELISA tended to be higher in Group I (40.5%, 41.7%, 21.6%) than in Group II (20.0%, 20.0%, 0%) with no statistical significance. Significant associations were found between specific IgE and IgG1 or IgG4 (p<0.001, p=0.019). ELISA inhibition tests showed significant inhibitions by both free cefaclor and cefaclor-HSA conjugate. For basophil activation tests in patients having no specific IgE antibody, the CD63 expression level on basophils increased with incubations of free cefaclor.
  
  
  CONCLUSIONS
  The most common manifestation of immediate hypersensitivity to cefaclor was anaphylaxis, most of which was mediated by IgE; however, a non-IgE mediated direct basophil activation mechanism was suggested in a subset of anaphylaxis patients.
authors.affiliation: Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Hye-Soo
authors.initials: HS
authors.lastname: Yoo
authors.affiliation: Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Division of Allergy and Clinical Immunology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hyouk-Soo
authors.initials: HS
authors.lastname: Kwon
authors.affiliation: Division of Allergy and Clinical Immunology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Tae-Bum
authors.initials: TB
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Young-Hee
authors.initials: YH
authors.lastname: Nam
authors.affiliation: Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Ye
authors.affiliation: Department of Allergy and Clinical Immunology, Ajou University School of Medicine, Suwon, Korea. hspark@ajou.ac.kr.
authors.forename: Hae-Sim
authors.identifier: http://orcid.org/0000-0003-2614-0303
authors.initials: HS
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000139:chemically induced* / Q000276:immunology; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000276:immunology*; D001491:Basophils / Q000378:metabolism; D002433:Cefaclor / Q000009:adverse effects* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000139:chemically induced / Q000175:diagnosis / Q000276:immunology*; D007073:Immunoglobulin E / Q000097:blood*; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012882:Skin Tests; D060149:Tetraspanin 30; D014581:Urticaria / Q000139:chemically induced / Q000175:diagnosis / Q000276:immunology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; C554586:CD63 protein, human; D007074:Immunoglobulin G; D060149:Tetraspanin 30; D007073:Immunoglobulin E; D002433:Cefaclor
keywords: Cefaclor; IgE; IgG; anaphylaxis; hypersensitivity; immediate; urticaria