title: Interlaboratory validation of the modified murine local lymph node assay based on adenosine triphosphate measurement.
abstract: BACKGROUND
  The murine local lymph node assay (LLNA) is a well-established alternative to the guinea pig maximization test (GPMT) or Buehler test (BT) for the assessment of the skin sensitizing ability of drugs and chemicals. Daicel Chemical Industries Ltd. has developed a modified LLNA based on the adenosine triphosphate (ATP) content (LLNA-DA). We conducted 2 interlaboratory validation studies to evaluate the reliability and relevance of LLNA-DA.
  
  
  METHODS
  The experiment involved 17 laboratories, wherein 14 chemicals were examined under blinded conditions. In the first study, 3 chemicals were examined in 10 laboratories and the remaining 9 were examined in 3 laboratories. In the second study, 1 chemical was examined in 7 laboratories and the remaining 4 chemicals were examined in 4 laboratories. The data were expressed as the ATP content for each chemical-treated group, and the stimulation index (SI) for each chemical-treated group was determined as the increase in the ATP content relative to the concurrent vehicle control group. An SI of 3 was set as the cut-off value for exhibiting skin sensitization activity.
  
  
  RESULTS
  The results of the first study obtained in the experiments conducted for the 3 chemicals that were examined in all the 10 laboratories and for 5 of the remaining 9 chemicals were sufficiently consistent with small variations in their SI values. The sensitivity, specificity, and accuracy of LLNA-DA against those of GPMT/BT were 7/8 (87.5%), 3/3 (100%), and 10/11 (90.9%), respectively. In the second study, all the 5 chemicals studied demonstrated acceptably small interlaboratory variations.
  
  
  CONCLUSIONS
  In the first study, a large variation was observed for 2 chemicals; in the second study, this variation was small. It was attributed to the application of dimethylsulfoxide as the solvent for the metallic salts. In conclusion, these 2 studies provide good evidence for the reliability of the LLNA-DA.
authors.affiliation: Kyoto University School of Public Health, Japan. omori@pbh.med.kyoto-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Omori
authors.forename: Kenji
authors.initials: K
authors.lastname: Idehara
authors.forename: Hajime
authors.initials: H
authors.lastname: Kojima
authors.forename: Takashi
authors.initials: T
authors.lastname: Sozu
authors.forename: Kazunori
authors.initials: K
authors.lastname: Arima
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Goto
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Hanada
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Ikarashi
authors.forename: Taketo
authors.initials: T
authors.lastname: Inoda
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kanazawa
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kosaka
authors.forename: Eiji
authors.initials: E
authors.lastname: Maki
authors.forename: Takashi
authors.initials: T
authors.lastname: Morimoto
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Shinoda
authors.forename: Naoki
authors.initials: N
authors.lastname: Shinoda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takeyoshi
authors.forename: Masashi
authors.initials: M
authors.lastname: Tanaka
authors.forename: Mamoru
authors.initials: M
authors.lastname: Uratani
authors.forename: Masahito
authors.initials: M
authors.lastname: Usami
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamanaka
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Yoneda
authors.forename: Isao
authors.initials: I
authors.lastname: Yoshimura
authors.forename: Atsuko
authors.initials: A
authors.lastname: Yuasa
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D007509:Irritants / Q000633:toxicity*; D023441:Local Lymph Node Assay; D051379:Mice; D008808:Mice, Inbred CBA; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D018675:Toxicity Tests / Q000379:methods
chemical_list: D007509:Irritants; D012997:Solvents; D000255:Adenosine Triphosphate