Immunohistochemical characterization of lymphocytes in microscopic colitis

• Background and Aims: Microscopic colitis (MC), encompassing the subgroups collagenous colitis (CC) and lymphocytic colitis (LC), is characterized by macroscopically normal or near-normal colonic mucosa, and an increased number of intraepithelial lymphocytes (IELs) and mononuclear cell infiltration in the underlying lamina propria (LP), in addition to an increased collagen layer in CC. This study aimed to characterize the inflammatory cells involved in mucosal inflammation, using immunohistochemistry.Methods Paraffin-embedded biopsies from 23 untreated patients with MC (CC = 13, LC = 10) and 17 controls were stained with antibodies against CD3, CD4, CD8, CD20, CD30, Foxp3, CD45RO and Ki67. Computerized image analysis was used to calculate areas of stained lymphocytes in the surface and crypt epithelia as well as in the LP.Results In CC and LC, an increase of predominantly CD8+ lymphocytes was seen in both the epithelium and the lamina propria, whereas a decreased amount of CD4+ lymphocytes was found in the lamina propria. CD45RO+ and Foxp3+ cells were more abundant in all areas in both patient groups compared to controls, as were CD20+ areas, although more scarce. Ki67+ areas were only more abundant in the epithelium, whereas CD30+ areas were more abundant in the lamina propria of both patient groups compared to controls.Conclusions This study confirms an increased amount of CD8+ lymphocytes in the epithelium. Lymphocytic proliferation and activation markers were more abundant, whereas a decreased amount of CD4+ lymphocytes was seen in the LP. Further studies are needed to reveal the underlying mechanism(s).

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinsk bioteknologi -- Biomedicinsk laboratorievetenskap/teknologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Medical Biotechnology -- Biomedical Laboratory Science/Technology (hsv//eng)

Nyckelord

Collagenous colitis

Lymphocytic colitis

Microscopic colitis

Lymphocytes

Immunohistochemistry

Biomedicin

Biomedicine

Publikations- och innehållstyp

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