title: Role of the spleen in peripheral memory B-cell homeostasis in patients with autoimmune thrombocytopenia purpura.
abstract: The effect of splenectomy on circulating memory B cells in autoimmune thrombocytopenia purpura (AITP) patients has not yet been addressed. We therefore analyzed the distribution and phenotypic characteristics of B-cell subsets in non-splenectomized and splenectomized AITP patients and controls, as well as CD95 expression after B cell activation. Decreased frequencies of memory B cells in splenectomized individuals were observed, with a rapid decline of CD27+IgD+ and a slower decrease of CD27+IgD- and CD27-/IgD- cells. Similar results were noted following splenectomy in healthy donors (HD). CD95+ B cells were substantially increased in all subsets in patients with active AITP, indicating their enhanced activation status. After splenectomy, the percentage of CD95+ B cells were further increased in the CD27+IgD- post-switch memory population in AITP, but not in HD. CD95+CD27+ memory B cells largely reside in the region in the human spleen analogous to the murine marginal zone. Thus, the spleen plays a fundamental role in controlling peripheral memory B cell homeostasis in both AITP and HD and regulates activated CD95+ B cells in patients with AITP.
authors.affiliation: Charité Center 14 for Tumor Medicine, Institute for Transfusion Medicine and Immune Hematology, Charité University Hospital, Berlin, Germany.
authors.forename: Lorena
authors.initials: L
authors.lastname: Martinez-Gamboa
authors.forename: Henrik
authors.initials: H
authors.lastname: Mei
authors.forename: Christoph
authors.initials: C
authors.lastname: Loddenkemper
authors.forename: Boris
authors.initials: B
authors.lastname: Ballmer
authors.forename: Arne
authors.initials: A
authors.lastname: Hansen
authors.forename: Peter E
authors.initials: PE
authors.lastname: Lipsky
authors.forename: Florian
authors.initials: F
authors.lastname: Emmerich
authors.forename: Andreas
authors.initials: A
authors.lastname: Radbruch
authors.forename: Abdulgabar
authors.initials: A
authors.lastname: Salama
authors.forename: Thomas
authors.initials: T
authors.lastname: Dörner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006706:Homeostasis / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D013154:Spleen / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D013156:Splenectomy