National Toxicology Program

National Toxicology Program

Recommendations to Federal Agencies on the LLNA and Agency Responses

See below for letters communicating the ICCVAM recommendations to member agencies and for ICCVAM member agency responses

The murine local lymph node assay (LLNA) is a test method for assessing the hazard potential of a test substance to induce allergic contact dermatitis. Following its original evaluation of the LLNA in 1999, ICCVAM recommended the LLNA as a valid stand-alone alternative to traditionally accepted guinea pig test methods for assessing the allergic contact dermatitis hazard potential of a substance, in most testing situations. In January 2007, the U.S. Consumer Product Safety Commission (CSPC) requested that NICEATM and ICCVAM assess the validation status of new versions and applications of the LLNA. These included evaluations of the use of the LLNA for evaluating pesticide formulations, metals, substances in aqueous solutions, and other products, and of three modified versions of the LLNA not requiring the use of radioactive markers.

The ICCVAM evaluation of these new versions and applications of the LLNA is now complete, and ICCVAM has made recommendations to Federal agencies.

  • Based on a comprehensive technical evaluation of their scientific validity, ICCVAM concluded that two of the nonradioactive LLNA methods, the LLNA: DA and the LLNA: BrdU-ELISA, can be used to identify substances that may cause allergic skin reactions.
  • ICCVAM also recommends that the LLNA may be used to test most chemicals and products for their potential to cause allergic contact dermatitis.

The links below lead to pages containing more details about the ICCVAM recommendations and other information about the ICCVAM evaluations.

ICCVAM Evaluation of the Applicability Domain for the Murine Local Lymph Node Assay

ICCVAM Evaluation of Nonradioactive Versions of the Murine Local Lymph Node Assay

Transmittal of Recommendations to Federal Agencies and Agency Responses

The ICCVAM recommendations on the use of these new versions and applications of the LLNA were communicated to Federal agencies in letters from Dr. Linda Birnbaum, Director, NIEHS. These letters and the responses from ICCVAM member Federal agencies are posted below.

NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.