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Expression of heat shock protein (HSP)-65 as well as infiltration of T-cells in arterial lesions and raised levels of circulating antibodies against mycobacterial HSP65 (mHSP65) led us to the concept that mHSP65 or its human homologue (hHSP60) might be involved in the etiopathogenesis of Takayasu's arteritis (TA). Therefore, we investigated mHSP65 and hHSP60 reactive peripheral blood T-cell subsets by BrdU incorporation assay and flow cytometry as well as investigating the different isotypes of anti- mHSP65 and hHSP60 antibodies by ELISA. Eighty-four percent (22/26) of the TA patients were observed to show T-cell proliferation to mHSP65 and hHSP60 whereas only 16% (3/18) healthy controls showed such proliferation (P <0·001). Both HSPs induced proliferation of exclusively CD4+ T-cells and not CD8+ T-cells. We also observed a significantly higher prevalence of only the IgG isotype reactive to mHSP65 and hHSP60 in TA as compared to HC (mHSP65: 92% TA versus 11% HC, P < 0·0001 and hHSP60: 84% versus 22%, P < 0·001). Our data show a significant correlation between mHSP65 and hHSP60 reactive T-cells (CD3+: r = 0·901; CD4+: r = 0·968) as well as anti-mHSP65 and anti-hHSP60 IgG antibodies (r = 0·814) suggesting an infection induced autoimmunity in TA, possibly induced by molecular mimicry between mHSP65 and hHSP60 or other tissue specific antigens. [ABSTRACT FROM AUTHOR]

We have investigated constitutive and phytohaemagglutinin (PHA)+ phorbol 12-myristate 13-acetate (PMA)-induced gene expression of tumour necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-3, IL-4, IL-10, IL-12 and granulocyte macrophage colony-stimulating factor (GM-CSF) in peripheral blood mononuclear cells (PBMCs) of 10 patients with Takayasu's arteritis (TA) and 10 healthy controls by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR). The constitutive mRNA expression of TNF-α (69·0 ± 4·0%versus27·5 ± 18·0%;P = 0·001) and IL-4 (60·0 ± 10·0%versus0%;P = 0·001) was significantly higher in patients than controls; that of IL-3 was comparable in both groups (38·0 ± 6·0%versus32·0 ± 5·0%;P = 0·651) while no constitutive mRNA expression was observed for the other cytokines studied. The stimulated PBMCs of patients, as compared with the controls, had higher mRNA gene expression of TNF-α (127·0 ± 16·0%versus54·0 ± 6·0%;P = 0·001), IFN-γ (93·0 ± 13·0%versus57·0 ± 5·0%;P = 0·032), IL-2 (109·0 ± 13·0%versus68·0 ± 6·0%;P = 0·015), IL-3 (60·0 ± 8·0%versus21·2 ± 3·0%;P = 0·045) and IL-4 (68·0 ± 7·0%versus27·0 ± 7·2%;P = 0·01) The mRNA expression of IL-10 was lower in patients than controls (35·0 ± 8·0%versus75·0 ± 12·0%;P = 0·022). The GM-CSF mRNA was similar (102·0 ± 6·0%versus89·0 ± 5·0%;P = 0·475) in both groups. Stimulation of cells with PHA + PMA showed no IL-12 expression but stimulation with lipopolysaccharide induced higher IL-12 mRNA in patients than controls (83·0 ± 14·0%versus33·0 ± 4·0%;P = 0·005). Our data suggest that an inflammatory cytokine signature exists in TA with a key role for TNF-α, IL-4, IL-10 and IL-12 in different pathological processes of the disease. [ABSTRACT FROM AUTHOR]

Annexin V has an important role in the regulation of apoptosis and antibodies directed against it have been shown to lead to apoptosis of vascular endothelial cells. To evaluate the role of anti-annexin V antibodies (AA5A) in Takayasu's arteritis (TA), we investigated these antibodies in the sera of 66 TA patients, 50 healthy controls and in the follow-up sera of 12 active TA patients by enzyme-linked immunosorbent assay. The AA5A-positive patients were analysed further for the presence of anti-endothelial cell antibodies (AECA) and anticardiolipin antibodies (ACLA) to determine the relationship of AA5A with these autoantibodies. AA5A were observed in 36% (24/66) of the patients versus 6% (3/50) of the controls ( P < 0·001) and in 53% (19/36) of patients with active TA versus 17% (5/30) of those with inactive disease ( P < 0·01). Levels of AA5A were also observed to be significantly higher in patients with TA compared to controls (0·557 ± 0·362 versus 0·259 ± 0·069; P < 0·0001) and in patients with active disease compared to those with inactive disease (0·700 ± 0·403 versus 0·385 ± 0·205; P < 0·0001). In the follow-up study, 6/12 patients who became inactive during follow-up also showed normalization of AA5A levels. AECA and ACLA were detected in 54% (13/24) and 12% (3/24) of the AA5A-positive patients, respectively. Our results show that a significant proportion of TA patients have AA5A, which exhibit an association with AECA and because they have a correlation with disease activity thus appear to be involved in the disease pathogenesis. [ABSTRACT FROM AUTHOR]

Takayasu's arteritis (TA) is a chronic large vessel vasculitis with a predilection for the aortic arch and its branches. T lymphocytes may be important in the pathogenesis as they have been found to initiate the vascular lesions. To elucidate further the role of T cells in thc disease, we studied circulating CD4+ and CD8+ T cells, expression of the activation marker (HLA-DR). marker for naive (CD45RA) and primed (CD45RO) cells and the different variable α/β (AV/BV) gene segments on them. The TCR AV/BV repertoire was studied using a panel of 15 T cell receptor (TCR) V-specific MoAbs by flow cytometry in 18 patients and 23 age- and sex-matched controls. Patients had a higher percentage of AV12S1 (P<0.05), BV6S7 (P<0.05) and BV9 (P<0.05)-bearing CD4+ cells. Patients also had a higher frequency of expansions, i.e. of T cell populations with an abnormally high TCR AV/BV gene usage. In patients' CD4+ subset of cells, there were 22 expansions out of 231 analyses (9.5%), whereas in controls, four were expanded out of 310 analyses (1%) (P<0.01). For CD8+ cells, the frequency of expansions was 32 in 231 analyses (14%) in patients and nine out of 304 analyses in controls (3%) (P<001). In addition, there was a correlation between CD4+ expansions and disease activity; nine out of 10 patients with active disease in comparison with two out of eight patients with inactive disease (P<0.01) had an expansion. Some of the expanded populations in patients were phenotypically characterized and observed to be HLA-DR+, CD28+, CD45RA+ and CD45RO+, with a greater proportion being CD45RO+. Patients had a higher percentage of expression of KLA-DR on both CD4+ and CD8+ T cells (P < 0.01). The percentages of naive and primed CD4+ and CD8+ T cells, γδ+ T cells and natural killer cells were comparable to those in the control group. [ABSTRACT FROM AUTHOR]

Wegener's granulomatosis (WG) and polyarteritis nodosa (PAN) are systemic necrotizing vasculitides of unknown etiology. These disorders run a fatal course if untreated. T lymphocytes are implicated in the pathogenesis of WG, since they have been found to infiltrate affected organs, and sIL-2R correlates with disease activity. To elucidate further the role of T cells in necrotizitig vasculitis, we have used a panel of 12 TCR V-specific MoAbs to investigate the number of cells expressing certain Vα and Vβ gene segments in the CD4+ and CD8+ subsets of altogether II patients with WG or PAN. In the group of patients, we found abnormal expansions of T cells using particular TCR V α or V β gene products. These T cell expansions were more numerous, of a dramatically higher magnitude, and frequently more often found in the CD4 subset, compared with T cell expansions identified in healthy individuals. In long-term studies of the T cell expansions for up to 18 months, a heterogeneous pattern was revealed, with no obvious correlation to clinical features such as disease activity or treatment. Studies of TCR V gene usage in this group of patients may help in understanding the pathogenesis of necrotizing vasculitis, and in the identification of unknown antigens, and may open the possibility to a highly selective immunotherapy by targeting disease-mediating T cells. [ABSTRACT FROM AUTHOR]