title: T-lymphocyte subset distribution in human spleen.
abstract: BACKGROUND
  When analyzing human cellular immune responses, most focus is placed on the peripheral blood (PB) and, to a lesser extent, the lymph nodes. To date the spleen has not been analyzed with regard to its role in adaptive cellular immunity and more notably not with respect to T-cell immune responses.
  
  
  METHODS
  We analyzed the splenic lymphocyte compartment in comparison with the PB lymphocyte compartment regarding the number of NK cells, B cells, CD4(+), CD8(+) T cells and CMV-specific CD8(+) T cells. Furthermore, we analyzed the distribution of naive, memory and effector subsets of CD4(+) and CD8(+) T cells in these compartments.
  
  
  RESULTS
  The spleen contains proportionally more B cells and less CD4(+) and CD8(+) T cells than PB. The percentage of CD8(+) T cells is greater in the spleen, leading to an inverse CD4/CD8 ratio. Both splenic CD4(+) and CD8(+) T-cell populations show a greater number of activated cells, and splenic CD8(+) T cells show a more differentiated cytotoxic CD27(-)CD45RA(+) memory phenotype.
  
  
  CONCLUSIONS
  Our findings show that the distribution of the different lymphocyte subsets is markedly different between the spleen and the PB, thus inferring an important and distinct role for the spleen in CD4(+) and CD8(+) T-cell activation.
authors.affiliation: Laboratory for Experimental Immunology, University of Amsterdam, the Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Langeveld
authors.forename: L E
authors.initials: LE
authors.lastname: Gamadia
authors.forename: I J M
authors.initials: IJ
authors.lastname: ten Berge
mesh_terms: D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000473:pathology; D016516:CD4-CD8 Ratio; D016022:Case-Control Studies; D003586:Cytomegalovirus Infections / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007111:Immunity, Cellular; D007156:Immunologic Memory; D007694:Killer Cells, Natural / Q000473:pathology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D013154:Spleen / Q000276:immunology*; D018709:Statistics, Nonparametric; D016176:T-Lymphocyte Subsets / Q000473:pathology*