title: The perifollicular and marginal zones of the human splenic white pulp : do fibroblasts guide lymphocyte immigration?
abstract: We investigate the white pulp compartments of 73 human spleens and demonstrate that there are several microanatomical peculiarities in man that do not occur in rats or mice. Humans lack a marginal sinus separating the marginal zone (MZ) from the follicles or the follicular mantle zone. The MZ is divided into an inner and an outer compartment by a special type of fibroblasts. An additional compartment, termed the perifollicular zone, is present between the follicular MZ and the red pulp. The perifollicular zone contains sheathed capillaries and blood-filled spaces without endothelial lining. In the perifollicular zone, in the outer MZ, and in the T cell zone fibroblasts of an unusual phenotype occur. These cells stain for the adhesion molecules MAdCAM-1, VCAM-1 (CD106), and VAP-1; the Thy-1 (CD90) molecule; smooth muscle alpha-actin and smooth muscle myosin; cytokeratin 18; and thrombomodulin (CD141). They are, however, negative for the peripheral node addressin, the cutaneous lymphocyte antigen, CD34, PECAM-1 (CD31), and P- and E-selectin (CD62P and CD62E). In the MZ the fibroblasts are often tightly associated with CD4-positive T lymphocytes, whereas CD8-positive cells are almost absent. Our findings lead to the hypothesis, that recirculating CD4-positive T lymphocytes enter the human splenic white pulp from the open circulation of the perifollicular zone without crossing an endothelium. Specialized fibroblasts may attract these T cells and guide them into the periarteriolar T cell area.
authors.affiliation: Institute of Anatomy and Cell Biology, University of Marburg, Robert-Koch-Str. 6, D-35033 Marburg, Germany. steinigb@mailer.uni-marburg.de
authors.forename: B
authors.initials: B
authors.lastname: Steiniger
authors.forename: P
authors.initials: P
authors.lastname: Barth
authors.forename: A
authors.initials: A
authors.lastname: Hellinger
mesh_terms: D000199:Actins / Q000032:analysis; D000328:Adult; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D005260:Female; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D007633:Keratins / Q000032:analysis; D008214:Lymphocytes / Q000276:immunology / Q000502:physiology*; D008297:Male; D051379:Mice; D009218:Myosins / Q000032:analysis; D051381:Rats; D013154:Spleen / Q000098:blood supply* / Q000166:cytology* / Q000276:immunology / Q000473:pathology; D013156:Splenectomy
chemical_list: D000199:Actins; D015703:Antigens, CD; D015415:Biomarkers; D015815:Cell Adhesion Molecules; D007633:Keratins; D009218:Myosins