title: Recommendations from the INHAND Apoptosis/Necrosis Working Group.
abstract: Historically, there has been confusion relating to the diagnostic nomenclature for individual cell death. Toxicologic pathologists have generally used the terms "single cell necrosis" and "apoptosis" interchangeably. Increased research on the mechanisms of cell death in recent years has led to the understanding that apoptosis and necrosis involve different cellular pathways and that these differences can have important implications when considering overall mechanisms of toxicity, and, for these reasons, the separate terms of apoptosis and necrosis should be used whenever differentiation is possible. However, it is also recognized that differentiation of the precise pathway of cell death may not be important, necessary, or possible in routine toxicity studies and so a more general term to indicate cell death is warranted in these situations. Morphological distinction between these two forms of cell death can sometimes be straightforward but can also be challenging. This article provides a brief discussion of the cellular mechanisms and morphological features of apoptosis and necrosis as well as guidance on when the pathologist should use these terms. It provides recommended nomenclature along with diagnostic criteria (in hematoxylin and eosin [H&E]-stained sections) for the most common forms of cell death (apoptosis and necrosis). This document is intended to serve as current guidance for the nomenclature of cell death for the International Harmonization of Nomenclature and Diagnostic Criteria Organ Working Groups and the toxicologic pathology community at large. The specific recommendations are:Use necrosis and apoptosis as separate diagnostic terms.Use modifiers to denote the distribution of necrosis (e.g., necrosis, single cell; necrosis, focal; necrosis, diffuse; etc.).Use the combined term apoptosis/single cell necrosis whenThere is no requirement or need to split the processes, orWhen the nature of cell death cannot be determined with certainty, orWhen both processes are present together. The diagnosis should be based primarily on the morphological features in H&E-stained sections. When needed, additional, special techniques to identify and characterize apoptosis can also be used.
authors.affiliation: Cellular and Molecular Pathology Branch, National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA elmore@niehs.nih.gov.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Elmore
authors.affiliation: Molecular Pathogenesis Group, National Toxicology Program Laboratory, Division of the NTP, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: Darlene
authors.initials: D
authors.lastname: Dixon
authors.affiliation: Covance Inc., Chantilly, Virginia, USA.
authors.forename: James R
authors.initials: JR
authors.lastname: Hailey
authors.affiliation: The Institute of Environmental Toxicology, Joso-shi, Ibaraki, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Harada
authors.affiliation: Cellular and Molecular Pathology Branch, National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA.
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Herbert
authors.affiliation: Maronpot Consulting LLC, Raleigh, North Carolina, USA.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Maronpot
authors.affiliation: Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nolte
authors.affiliation: Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Jerold E
authors.initials: JE
authors.lastname: Rehg
authors.affiliation: Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Rittinghausen
authors.affiliation: Department of Veterinary Biosciences, Ohio State University, Columbus, Ohio, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Rosol
authors.affiliation: Iwate University, Morioka, Iwate, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Satoh
authors.affiliation: Vet Path Services Inc. (VPS), Mason, Ohio, USA.
authors.forename: Justin D
authors.initials: JD
authors.lastname: Vidal
authors.affiliation: Envigo, East Millstone, New Jersey, USA.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Willard-Mack
authors.affiliation: Envigo, East Millstone, New Jersey, USA.
authors.forename: Dianne M
authors.initials: DM
authors.lastname: Creasy
mesh_terms: D000818:Animals; D017209:Apoptosis; D008297:Male; D051379:Mice; D009336:Necrosis; D010336:Pathology / Q000592:standards*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009626:Terminology as Topic; D014116:Toxicology / Q000592:standards*
keywords: INHAND; apoptosis; cell death; guidance; necrosis; single cell necrosis