T and NK cell subset changes with microbial extracts and human HSP60-derived peptides in Behçet's disease.

OBJECTIVE: Microorganisms such as streptococcus and autoantigens such as 60 kD heat-shock protein (HSP60) are implicated in the etiopathogenesis of Behçet's disease (BD). METHODS: Peripheral blood mononuclear cells from patients with BD (n = 16) and healthy controls (HC) (n = 11) were cultured for 5 days with extracts of S. sanguis-KTH-1 (SS), E. coli (EC) and a mixed peptide combination from human HSP60 (aa 136-50, 179-97, 224-58 and 336-51) reported to be associated with BD. T and NK cell subset changes were determined by flow cytometry. RESULTS: In unstimulated 5-day cultures gammadelta+ (both CD4+gammadelta+ and CD8+gammadelta+), CD8+alphabeta+, CD4+CD56+ and CD8+CD11b+ cells were increased in BD compared to HC. In antigen-stimulated cultures of BD patients CD3+ and alphabeta+ T cells responded to HSP60 peptides whereas EC stimulated only CD16/ CD56+ NK cells. In the control group, similar to BD, alphabeta+ and CD4+ T cells responded to HSP60 peptides, however SS and EC mainly activated cytotoxic T cell subsets (CD8+CD11b and CD4+CD56+ T cells). CONCLUSION: Significant increases in unstimulated T cell subsets suggest the presence of an in vivo T cell activation in BD. In both patients and controls similar patterns of responses were observed against different microorganisms, however the role of human HSP60 peptides as immunodominant, crossreactive antigens could not be demonstrated.

Neutrophil activation in Behçet's disease.

OBJECTIVE: Neutrophils are implicated in the pathogenesis of Behçet's disease (BD). Various functions of neutrophils are studied to clarify this role. METHODS: The oxidative burst and phagocytic functions of neutrophils and surface molecules associated with neutrophil activation (CD10, CD14 and CD16) were investigated in BD patients by flow cytometric methods. Patients with inflammatory arthropathies, sepsis and healthy controls were also studied. RESULTS: In the oxidative burst experiments, after fMLP and PMA stimulation, stimulation index was found to be significantly decreased in patients both with BD and sepsis compared to healthy controls and inflammatory arthropathies (p < 0.001 and p < 0.01, respectively). The phagocytosis of labelled E. coli particles in patients with BD was not different from that of the healthy controls, while it was decreased in diseased controls (p < 0.001). The surface density of neutral endopeptidase (CD10) and the mean percentage of LPS receptor (CD14) was found to be significantly higher in both BD patients and diseased controls (p < 0.001). The mean percentage of CD16 expression was only low in patients with sepsis (p < 0.001), whereas CD16 intensity on cells was found to be lower in patients with BD as well as in sepsis (p < 0.01). CONCLUSION: These findings indicate the presence of in vivo pre-activated neutrophils in BD. A similar activation was also a feature of severe inflammatory disorders.

Role of hepatocyte growth factor in the development of dendritic cells from CD34+ bone marrow cells.

BACKGROUND AND OBJECTIVE: Hepatocyte growth factor (HGF) is known to augment the effects of stem cell factor, interleukin-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoetin, and granulocyte colony-stimulating factor, all of which are involved in hematopoiesis. HGF is also known to have a role in immune responses. The aim of this study was to investigate whether HGF is involved in the development of dendritic cells (DC) from CD34+ bone marrow cells. DESIGN AND METHODS: CD34+ cells obtained from three healthy donors were incubated in various combinations of HGF, GM-CSF, and tumor necrosis factor (TNF) for 12 days. Developing cell populations were analyzed for surface markers, morphology and functional capacities by flow cytometry, light microscopy and mixed lymphocyte reaction, respectively. RESULTS: Incubation with HGF alone generated greater number of dendritic cells from CD34+ bone marrow cells than incubation with GM-CSF, or a combination of GM-CSF with TNF. HGF was also found to potentiate the effect of GM-CSF on DC and monocyte development. The effects of HGF were inhibited by the concurrent use of TNF. INTERPRETATION AND CONCLUSIONS: HGF appears to be a significant factor in the development of dendritic cells from CD34+ bone marrow cells.

Oligoclonal T cell expansions in patients with Behçet's disease.

Behçet's disease (BD) is a multisystem disorder with oral and genital ulcers, mucocutaneous, ocular, joint, vascular and central nervous system involvement. In this study, the peripheral T cell repertoire was analysed in patients with BD with MoAbs against T cell receptor (TCR) Vbeta gene products in CD4+ and CD8+ T cell compartments, and these were compared with rheumatoid arthritis (RA) patients and healthy controls (HC). In the CD4+ T cell compartment, oligoclonal TCR Vbeta expression was observed in 56% of BD (10/18), 71% of RA (5/7) patients and 21% (3/14) of HC. In the CD8+ T cell group 50% of BD (9/18), 57% of RA patients and 28% of HC (4/14) had an oligoclonal TCR repertoire. An increase of TCR Vbeta5.1 subset was observed in five BD patients among CD8+ T cells. Other elevations of TCR Vbeta subsets were heterogeneously distributed with one to three different Vbeta subsets. Our results suggest an antigen-driven oligoclonal increase of T cells in BD. There was no overall increase in any Vbeta group to suggest a superantigen effect. Analysis of the responsible antigens causing the increase in T cell subsets may give insights into the aetiopathogenesis of BD and immunomodulation of these T cells may lead to new treatments.

Phenotypic characteristics of B cells in Behçet's disease: increased activity in B cell subsets.

OBJECTIVE: Increased numbers of spontaneous Ig secreting B cells and elevated immunoglobulin levels have been described in Behçet's disease (BD), in addition to changes in numbers and activities of T cells, natural killer cells, and monocyte-macrophages. We investigated other characteristics of B cells in BD. METHODS: B lymphocyte subsets (CD19+CD5+, CD19+CD13+, CD19+CD28+, CD19+CD33+, CD19+CD80+, CD5+CD19+CD45RA+, CD5+CD19+CD45RO+) were phenotypically evaluated in 50 patients with BD, 80 healthy subjects, and 20 other patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and sepsis. RESULTS: Although the B cell number (CD19+) was normal, CD13 and CD33 positive B cells were more numerous in BD and sepsis compared to healthy controls and patients with RA and SLE. The percentage of CD45RO positive B cells was higher in both BD and sepsis, while the percentage of CD80 positive B cells was high only in BD. There was no increase in the CD5+CD19+ B cell subset, previously shown to be increased in several autoimmune diseases. Naive (CD45RA) and memory (CD45RO) status of CD5+CD19+ and CD5-CD19+ B cells showed that CD45RA expression was higher in CD5+CD19+ B cells, whereas expression of both CD45RA and CD45RO was higher in the CD5-CD19+ B cell group compared with healthy controls. CONCLUSION: Although the total B cell number was normal, increased levels of activated and memory B cell subsets suggest a modified B cell function in BD, which may be related to a weak stimulus by an unknown external antigen.