title: CD3 immunohistochemical staining in diagnosis of lymphocytic colitis.
abstract: Microscopic colitis (MC) is a common cause of chronic watery diarrhea. Traditionally, MC encompasses the 2 subgroups lymphocytic colitis (LC) and collagenous colitis, but recently, an additional subgroup, MC incomplete, has been introduced. Distinguishing between the subgroups relies exclusively on histopathologic evaluation. In the present study, 4 pathologists evaluated 156 archived biopsies originally diagnosed as LC or LC incomplete (LCi). Each pathologist assigned a diagnosis of LC, LCi, or nonspecific inflammation to all cases at 2 independent assessments. At the first assessment, hematoxylin and eosin (HE) stainings were available. At the second assessment, a supplementary CD3 immunohistochemical staining was also available. The aim was to evaluate whether a supplementary CD3 would increase the diagnostic agreement among pathologists, and whether a CD3 stain would change the diagnosis based on HE staining only. After the complete assessment, the cases were divided into 3 groups, that is, full agreement, partial agreement, and disagreement. The CD3 staining increased the number of cases with full agreement from 60 to 78. One hundred thirty-one cases with agreement or partial diagnostic agreement based on HE + CD3 were compared with the HE diagnoses. In 44 (34%) of 131 cases, CD3 changed the diagnosis. Cases assigned to the LCi category based on HE were often changed by a supplementary CD3. Conclusively, it is recommended to use a CD3 before giving the histopathologic diagnosis of LCi.
authors.affiliation: Department of Pathology, Roskilde Hospital, 4000 Roskilde, Denmark; Department of Pathology, Rigshospitalet, 2100 Copenhagen, Denmark. Electronic address: ankf@regionsjaelland.dk.
authors.forename: Anne-Marie Kanstrup
authors.initials: AM
authors.lastname: Fiehn
authors.affiliation: Department of Pathology, University Hospital of Copenhagen, 2650 Hvidovre, Denmark.
authors.forename: Ulla
authors.initials: U
authors.lastname: Engel
authors.affiliation: Department of Pathology, University Hospital of Copenhagen, 2650 Hvidovre, Denmark.
authors.forename: Susanne
authors.initials: S
authors.lastname: Holck
authors.affiliation: University of Copenhagen, Faculty of Health Medical Sciences, 2200 Copenhagen, Denmark; Department of Gastroenterology, Koege Hospital, 4600 Koege, Denmark.
authors.forename: Lars Kristian
authors.initials: LK
authors.lastname: Munck
authors.affiliation: Department of Pathology, Roskilde Hospital, 4000 Roskilde, Denmark; University of Copenhagen, Faculty of Health Medical Sciences, 2200 Copenhagen, Denmark.
authors.forename: Peter Johan Heiberg
authors.initials: PJ
authors.lastname: Engel
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D017252:CD3 Complex / Q000032:analysis*; D046730:Colitis, Lymphocytic / Q000175:diagnosis*; D006801:Humans; D007150:Immunohistochemistry; D015588:Observer Variation
chemical_list: D014408:Biomarkers, Tumor; D017252:CD3 Complex
keywords: CD3; Immunohistochemistry; Lymphocytic colitis; Lymphocytic colitis incomplete; Microscopic colitis