title: Reproducibility of counting immunoglobulin-containing cells in colonic mucosal biopsies.
abstract: Counting immunoglobulin (Ig)-containing cells in colonic mucosal biopsies can help to objectively support the differential diagnosis of ulcerative colitis and Crohn's disease. Before a method for counting Ig-containing cells can be applied in a clinical setting, however, its reproducibility must be determined. This study investigated the reproducibility of two different methods for counting such cells. The use of a light microscope with an ocular grid resulted in a slightly better reproducibility than did the use of a projection microscope with a graphics tablet. Moreover, the ocular grid method had a higher efficiency. The counting of IgM- and IgG-containing cells had a considerably higher reproducibility than did the counting of IgA-containing cells. To determine the minimal number of cells to be counted in order to ascertain a stabilized mean number of Ig-containing cells, the running means of counts of Ig-containing cells were calculated for two observers. When at least 600 Ig-containing cells (i.e., two to four fields) were counted, the interobserver variation of the running means was less than 10% for IgA and IgG counts and less than 5% for IgM counts. Since earlier studies showed differences in the counts of IgA-, IgG- and IgM-containing cells between ulcerative colitis and Crohn's disease to be, respectively, 3%, 25% and 28%, the results of the present study suggest that the proposed counting method can be useful in the differentiation between these entities.
authors.affiliation: Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: C A
authors.initials: CA
authors.lastname: Seldenrijk
authors.forename: G
authors.initials: G
authors.lastname: Hendriks
authors.forename: A W
authors.initials: AW
authors.lastname: Smeulders
authors.forename: J P
authors.initials: JP
authors.lastname: Baak
authors.forename: J P
authors.initials: JP
authors.lastname: van Spreeuwel
authors.forename: S G
authors.initials: SG
authors.lastname: Meuwissen
authors.forename: C J
authors.initials: CJ
authors.lastname: Meijer
mesh_terms: D002452:Cell Count / Q000379:methods; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis*; D007413:Intestinal Mucosa / Q000166:cytology* / Q000276:immunology; D013048:Specimen Handling
chemical_list: D007136:Immunoglobulins