ABSTRACT
Histological examination is an obligatory component of non-clinical toxicity evaluation as histological changes are a primary effect of toxic exposures. These changes may be expressed as quantitative or qualitative alterations in the normal structure and function of target organs. But, as histopathological diagnosis is qualitative and often represents a subjective judgement on the nature and the expected consequence of a specific lesion, a central question is to what extent histopathology can be effectively used in the nonclinical immunotoxicity evaluation of xenobiotics. Because routine histopathology is necessarily a component of conventional toxicity testing and no additional animals are required, it is often considered to be an essential component of non-clinical immunotoxicity evaluation.
