title: Interferon-gamma and T-bet expression in a patient with toxoplasmic lymphadenopathy.
abstract: Infection with Toxoplasma gondii (TG) presents in some individuals as a self-limited disease with a predominant lymphadenopathy characterized by prominent B-cell activation. As this is in contrast to the in vitro based concept of a T(h)1-immune response against TG, we investigated native lymphoid tissue and peripheral blood of a patient with serologic evidence of toxoplasmosis to verify which cells show T(h)1-response features. High-level expression of T-bet in monocytoid B-cells, in germinal center B-cells, and in a lesser amount in T cells could be demonstrated by immunohistochemistry. In vitro stimulation of lymph node cells with either TG, staphylococcus enterotoxin B, or phorbol 12-myristate 13-acetate/ionomycin revealed an interferon-gamma expression in T-bet(+) B cells only in the patient and not in controls. Similar results were found for T-bet(+) T cells which were also present in controls. CD4(+) peripheral blood cells stimulated with TG antigens showed a TG-specific but attenuated T(h)1-reactivity in the patient associated with a reduced expression of IL-2 when compared with controls. We conclude that the pathogenesis and course of toxoplasmic lymphadenopathy is based on a T(h)1-cell defect, which becomes compensated by the B cells mounting a T(h)1-like immune response.
authors.affiliation: Charité-University Medicine Berlin, Campus Benjamin Franklin, Hindenburgdamm, Berlin, Germany. korinna.joehrens@charite.de
authors.forename: Korinna
authors.initials: K
authors.lastname: Jöhrens
authors.forename: Verena
authors.initials: V
authors.lastname: Moos
authors.forename: Thomas
authors.initials: T
authors.lastname: Schneider
authors.forename: Harald
authors.initials: H
authors.lastname: Stein
authors.forename: Ioannis
authors.initials: I
authors.lastname: Anagnostopoulos
mesh_terms: D000293:Adolescent; D000953:Antigens, Protozoan / Q000276:immunology / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D015704:CD4 Antigens / Q000096:biosynthesis; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007114:Immunization; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000378:metabolism; D008206:Lymphatic Diseases; D008213:Lymphocyte Activation; D008221:Lymphoid Tissue / Q000473:pathology; D020825:T-Box Domain Proteins / Q000096:biosynthesis* / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D014122:Toxoplasma / Q000276:immunology* / Q000472:pathogenicity; D014123:Toxoplasmosis / Q000097:blood / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D000098815:T-bet Transcription Factor
chemical_list: D000953:Antigens, Protozoan; D015704:CD4 Antigens; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D007371:Interferon-gamma