title: CD80/CD28 co-stimulation in human brucellosis.
abstract: Despite treatment, 10-30% of brucellosis patients develop chronic disease, characterized by atypical clinical picture and/or relapses. A defective T helper 1 (Th1) response and a low [corrected] percentage of CD4(+)/CD25(+) cells have been described in chronic brucellosis patients. CD80/CD28 co-stimulation is critical for an efficient Th1 response and has not been studied previously in human brucellosis. In order to investigate the role of CD80/CD28 co-stimulation, 13 acute brucellosis patients (AB), 22 chronic brucellosis patients (CB, 12/22 relapsing type-CB1 and 10/22 atypical type-CB2), 11 'cured' subjects and 15 healthy volunteers (controls) were studied. The percentage of CD4(+)/CD28(+) T lymphocytes and CD14(+)/CD80(+) monocytes were analysed by flow cytometry both ex vivo and after phytohaemagglutinin (PHA)-stimulation with or without heat-killed Brucella abortus (HkBA). Ex vivo analysis showed no differences between all groups studied. PHA stimulation up-regulated the percentage of CD80(+) monocytes in AB compared to 'cured' subjects and controls (P < 0.001), although the proportion of CD4(+)/CD28(+) cells did not alter. A higher percentage of CD80(+) monocytes was observed in the CB1 subgroup, compared to AB, 'cured' subjects and controls (P = 0.042, < 0.001 and < 0.001, respectively). CB2 was characterized by a lower percentage of CD80(+) monocytes in comparison to CB1 (P = 0.020). HkBA in PHA cultures down-regulated the percentage of CD80(+) monocytes compared to PHA alone in all groups, especially in AB and CB patients (P < 0.001 and P = 0.007, respectively). In conclusion, the diminished percentage of CD4(+)/CD25(+) T cells in CB is not associated with inadequate CD80/CD28 co-stimulation. We speculate that differential frequency of CD80(+) monocytes after PHA stimulation could serve as a qualitative parameter of disease status, related to the different clinical forms of chronic brucellosis.
authors.affiliation: Clinical Immunology Unit, 2nd Department of Internal Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Skendros
authors.forename: P
authors.initials: P
authors.lastname: Boura
authors.forename: F
authors.initials: F
authors.lastname: Kamaria
authors.forename: M
authors.initials: M
authors.lastname: Raptopoulou-Gigi
mesh_terms: D000208:Acute Disease; D000328:Adult; D018122:B7-1 Antigen / Q000097:blood / Q000276:immunology*; D002006:Brucellosis / Q000276:immunology*; D018106:CD28 Antigens / Q000097:blood / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D002908:Chronic Disease; D005260:Female; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000097:blood; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D010835:Phytohemagglutinins / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D018122:B7-1 Antigen; D018106:CD28 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D010835:Phytohemagglutinins