Unusual B cell morphology in inflammatory bowel disease.
ABSTRACT B lymphocytes express various different types of surface immunoglobulins that are largely unrelated to other hematological lines, although some reports have described a relationship between malignant B cells and other cells such as macrophages. Multiple genes of hematopoietic lineage, including transcription factors, are co-expressed in hematopoietic stem cells and progenitors, a phenomenon referred to as "lineage priming". Changes in the expression levels and timing of transcription factors can induce the lineage conversion of committed cells, which indicates that the regulation of transcription factors might be particularly critical for maintaining hierarchical hematopoietic development. The aim of this study was to evaluate the surface markers of particular IgM-positive and irregularly nucleated cells detected in patients with inflammatory bowel disease (IBD), and to assess their association with diagnosis and inflammatory cell recruitment. Small intestine, colon and rectal biopsy specimens of 96 IBD patients were studied. Immunoglobulin-producing cells (IPCs) were analyzed by means of immunofluorescence using polyclonal rabbit anti-human Ig and goat anti-human IgM. The specimens positive for B cells with irregular nuclei were assessed using monoclonal antibodies specific for CD79, and λ and κ chains in order to confirm their B cell nature. CD15+ cells, an important marker of inflammatory cell recruitment, were also evaluated. Statistical correlations were sought between the histological findings and clinical expression. 34 (35.4%) of the 96 patients (64 with ulcerative colitis and 32 with Crohn's disease) presented a periglandial localization of IPCs with irregular nuclei, which showed surface markers specific for the B cell subset, such as IgM and CD79, but quantitative differences in λ and κ chains. These specimens also contained CD15-positive cells, which are usually absent in healthy controls. The quantitative aspects and localization of the CD15-positive cells correlated with the distribution of the IPCs with irregular nuclei. IPCs with irregular nuclei were significantly more frequent in those patients with Crohn's disease than in those with ulcerative colitis (p<0.001). The finding of a subpopulation of cells that simultaneously showed irregular nuclei and B cell markers, such as functional surface IgM, in patients with IBD suggests that an unusual subgroup of B cells that correlates with CD15 expression and a diagnosis of Crohn's disease may be observed in the inflammatory process.
- SourceAvailable from: europepmc.org[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: We have recently investigated the localisation of immunoglobulin-producing cells (IPCs) in inflamed intestinal tissue samples from patients with inflammatory bowel disease (IBD), and identified two main patterns of B lymphocyte infiltration: one characterised by the moderate strong stromal localisation of small B1 cell-like IgM+/CD79+/CD20-/CD21-/CD23-/CD5 +/- IPCs, and the other by the peri-glandular localisation of IPCs with irregular nuclei that had surface markers specific for a B cell subset (IgM and CD79), but quantitative differences in their lamda and kappa chains. The same patients were also tested for CD15+ receptors, which were localised on inflammatory cell surfaces or in the crypts of the intestinal epithelium. CD15+ receptor distribution in inflamed tissues was limited to the cell structures. The aim of the study was to analyse variations in IPCs and CD15+ cell morphology or distribution in bowel biopsy specimens taken from patients with pre-malignant polyps or adenocarcinomas. METHODS: IPCs were analysed by means of immunofluorescence using polyclonal goat anti-human mu chains. The pre-malignant polyp specimens were tested for B cell surface phenotype lamda and kappa chains, CD79, CD20, CD21 and CD23 using an immunoperoxidase method. CD15+ cells were evaluated using the immunoperoxidase method and monoclonal anti-CD15 IgM. RESULTS: The study involved 14 patients (four with pre-malignant polyps and 10 with colorectal adenocarcinomas). The distribution of mu chains and CD15 markers varied in all of the biopsies, but delineated normal cell structures in the pre-malignant polyp specimens. B cell surface phenotype analysis of mu chain-positive cells identified a subset of CD79+/CD20-/CD21-/CD23- IPCs. The IPCs in certain areas showed the sporadic disintegration of inflammatory cell membranes or the accumulation of fluorescence in individual cells. IPC membrane disintegration was particularly marked in all of the adenocarcinoma samples, in which the CD15 markers also showed epithelial cell involvement. Furthermore, six of the ten adenocarcinoma samples had atypical and reorganised membranes that expressed an excess of both receptors and isolated small portions of tissue within the tumour. CONCLUSION: The findings of this preliminary morphological study suggest the presence of membrane disintegration and remodelling mechanisms in the tumours. The newly-formed membranes expressed high concentrations of inflammatory cell receptors that can confer adhesive properties.BMC Clinical Pathology 03/2013; 13(1):8.