Numbers and Distribution of Immune Cells in the Tunica Mucosa of the Small and Large Intestine of Full-Thickness Biopsies from Healthy Pet Cats

Abstract

In this study, CD3(+) T lymphocytes and IgA(+) , IgG(+) and IgM(+) plasma cells were quantified in the tunica mucosa of the intestinal tract of 12 pet cats without gastrointestinal diseases. The study included full-thickness biopsies of the duodenum, jejunum, ileum and colon. The distribution and quantification of CD3(+) T cells, IgA(+) , IgG(+) and IgM(+) plasma cells within the intestinal tunica mucosa was performed by using immunohistochemical methods and computer-aided morphometry. CD3(+) T cells were significantly prominent in the villi and their numbers increased from duodenum to ileum but decreased towards the colon. The predominant type of plasma cells was IgA(+) cells, followed by IgM(+) cells. The number of IgG(+) cells was generally low compared to the other plasma cell types investigated. The results of the vertical distribution showed that IgA(+) and IgM(+) plasma cells were most numerous in the lower crypt areas, whilst IgG(+) plasma cells accumulated in the upper crypt region with a decline towards the villi and the lower crypt areas of control cats. All types of plasma cells showed a general decline from the duodenum towards the caudal sections of the intestinal tract regarding the horizontal distribution of plasma cells. This study provides a comprehensive overview on the vertical and horizontal distribution and the number of CD3(+) T cells and IgA(+) , IgG(+) and IgM(+) plasma cells in the intestinal tunica mucosa of pet cats.

Quantitative immunohistochemical assessment of IgA, IgM, IgG and antigen-specific immunoglobulin secreting plasma cells in pig small intestinal lamina propria

“…This feature is consistent with the "physiology" to concentrate IgA-secreting cells at this level: primed lymphocytes migrate here, as reported by Bimczok and Rothkötter (2006), from post-capillary venules of the lamina propria, that are numerous around the crypts. Another possible explanation is related to the distribution of the polymeric immunoglobulin receptor (pIgR) in the intestine (Marsilio et al, 2011). From the above, the importance of displaying the exact histological location of immune cells in the mucosa is clear in order to have comparative data from normal to pathologic conditions.…”

ACVIMconsensus statement guidelines on diagnosing and distinguishing low‐grade neoplastic from inflammatory lymphocytic chronic enteropathies in cats

“…Formalin fixation issues can be overcome by contemporaneous collection of biopsy specimens that are stored frozen for subsequent clonality analysis, which has been shown to improve sensitivity 184 . T‐cells are present within both the lamina propria and the epithelial layer of the mucosa of the intestine of cats and considered part of the normal resident gut‐associated lymphoid tissue 139,145,185 . Clonality analysis will amplify the T‐cell receptor gene DNA from all T‐cells present within a sample, regardless of whether they are considered clinically relevant (i.e., suspicious for LGITL) or not.…”

“… 35 , 36 , 37 , 38 , 39 On the other hand, chronic antigenic stimulation has been described to lead to monoclonal lymphocyte proliferations. 9 Commonly used antibodies for cellular phenotyping include cluster of differentiation (CD)3 to detect T‐lymphocytes, 34 , 36 , 51 , 56 , 121 , 139 , 141 , 142 CD20, CD79a, B lymphocyte antigen 36 (BLA.36), and paired box gene 5 (Pax5) for B‐lymphocytes, 34 , 36 , 51 , 138 , 140 , 143 macrophage marker antibody 387 (MAC387) for macrophages, 18 , 144 , 145 , 146 and granzyme B to detect natural killer (NK) cells. Finally, the proliferative cell fraction can be assessed using Ki67 expression, 147 , 148 a nuclear protein with maximal expression during M phase that is absent after mitosis is completed.…”

“… 184 T‐cells are present within both the lamina propria and the epithelial layer of the mucosa of the intestine of cats and considered part of the normal resident gut‐associated lymphoid tissue. 139 , 145 , 185 Clonality analysis will amplify the T‐cell receptor gene DNA from all T‐cells present within a sample, regardless of whether they are considered clinically relevant (i.e., suspicious for LGITL) or not. In emerging LGITLs or patchy disease, the DNA from T‐cells of interest may only comprise a small proportion of the total T‐cell DNA.…”

“…184 T-cells are present within both the lamina propria and the epithelial layer of the mucosa of the intestine of cats and considered part of the normal resident gut-associated lymphoid tissue. 139,145,185 Besides technical challenges, predicaments concerning the misinterpretation and overinterpretation of clonality assays are common.…”