Insufficient expression of Fas antigen on helper T cells in Behçet's disease

The pro-inflammatory effect of triglyceride on human CD4+ T cells and experimental autoimmune uveitis

Aberrant lipid metabolism plays a role in inflammation and progression of autoimmune diseases but the definite mechanism remains unclear. In this study we investigate lipidomic profiles in Behçet's disease (BD) and the role of triglyceride (TAG) in the pathogenesis of autoimmune uveitis. Lipidomics revealed a distinct lipid metabolite profile including increased TAG metabolites in plasma of active BD patients. TAG could stimulate the proliferation, IL-17 and IFN-γ expression by CD4⁺ T cells and Th1, Th17 cell differentiation in vitro, but did not influence neutrophils. A922500 inhibited the TAG generation, ameliorated the EAU severity, decreased Th17 frequency and IL-17 expression by CD4⁺ T cells in vivo. The proteomocis analysis showed an up-regulation of apoptosis-related protein, Pik3r2, in CD4⁺ T cells from A922500-treated mice. In conclusion, TAG can stimulate human CD4⁺ T cells and the inhibition of its generation could significantly ameliorate EAU activity in association with down-regulated Th17 cell response.

HSV-Induced Systemic Inflammation as an Animal Model for Behçet's Disease and Therapeutic Applications

Behçet’s disease (BD) affects multiple organs. It is mainly characterized by recurrent oral, skin, and genital aphthous ulcers, and eye involvement. Successful management of BD is increasing, although its etiology remains unclear. A number of etiologies have been proposed, including environmental, genetic, viral, and immunological factors. To understand its complex etiology and improve its management, animal models of BD have been used to enable more effective therapeutic applications with increased clinical significance. An herpes simplex virus (HSV) type 1-induced BD mouse model has shown disease characteristics similar to those seen in BD patients. An HSV-induced BD animal model has been used to test various therapeutic modalities. The applied modalities are several materials that are derived from natural products, conventional therapeutics, and possible biologics. In this review, we provided how they regulate inflammation in an HSV-induced BD model.

New insights into the pathogenesis of Behçet's disease

Behçet's disease (BD) is a recurrent systemic inflammatory disorder of unknown origin characterized by oral and genital mucous ulcer, uveitis, and skin lesions. Involvement of large vessels, central nervous system (CNS), gastrointestinal tract and thrombotic events are less frequent but can be life threatening. The aim of this review is to provide new insights into the pathogenesis of BD. Over the past year substantial advances have been done in the understanding of the genetic [1,2] and immunology [3] of BD. BD is at the crossroad between autoimmune and autoinflammatory syndromes. In common with autoimmune diseases BD shares class I MHC association. However, in contrast to autoimmune disorders, BD has clinical features that seem to be mostly autoinflammatory. The pathogenesis of BD is still unknown, but major determinants of the genetic and immune system abnormalities have been reported recently. Triggering infectious factors are supposed to participate in the outbreak of BD in genetically predisposed patients. Two recent large genome-wide association study (GWAS) conducted in Turkey and Japan reported association between single nucleotide polymorphism (SNP) of interleukin (IL)-10 and IL-23R/IL-12RB2 genes and BD. New insights into the perturbations of T cell homeostasis of BD recently emerged. We have recently demonstrated the promotion of Th17 responses and the suppression of regulatory T cells (Tregs) that were driven by interleukin (IL)-21 production and that correlates with BD activity. Inflammatory cells within BD inflammatory lesions included mostly neutrophils, Th1 and Th17 cells, and cytotoxic CD8+ and γδ T cells. Altogether, the recent progresses in the knowledge of BD pathogenesis pave the way for innovative therapy.

Caspase-9 expression is increased in endothelial cells of active Behçet's disease patients

BACKGROUND

Behçet's disease is a multisystem disease of unknown etiology. Caspase-9 is responsible for initiating the caspase activation cascade during apoptosis. The aim of this study was to examine caspase-9 expression in both endothelial and perivascular infiltrates of patients with active Behçet's disease.

METHODS

Fifteen patients with active Behçet's disease, attending the First Dermatology Department, Ankara Numune Hospital, Ankara, Turkey between June 2003 and December 2005, were included in the study. Oral biopsy specimens from nine healthy volunteers were taken as the healthy control group, and skin biopsies from 18 psoriasis patients were used as the inflammatory control group. The specimens were examined with caspase-9 primary antibody. Statistical analyses were performed using SPSS 11.5.

RESULTS

The mean caspase-9-positive endothelial cell counts were 7.17 +/- 2.45 in active Behçet's disease, 4.81 +/- 0.76 in healthy controls, and 4.35 +/- 1.34 in inflammatory controls. The difference between Behçet's disease and healthy controls was statistically significant, with increased endothelial staining in active Behçet's disease (P = 0.049). The difference between Behçet's disease and inflammatory controls was also statistically significant; the rate of staining was higher in Behçet's disease (P = 0.006). The mean caspase-9-positive dermal perivascular cell counts were 5.15 +/- 2.32 in Behçet's disease, 3.32 +/- 0.82 in healthy controls, and 5.54 +/- 4.95 in inflammatory controls. These values did not show any statistically significant difference (P = 0.407).

CONCLUSION

Endothelial cells are one of the key cells in Behçet's disease, and our findings support the role of endothelial cells in the etiopathogenesis of Behçet's disease.

Fas (CD95) and bcl-2 expression in active skin lesions of Behcet's disease

Over-expression of bcl-2 in lymphocytes has an important role in some immunological and inflammatory diseases. Fas (CD95) is a cell surface molecule that mediates receptor-triggered apoptosis in various cells including autoreactive T cells. In this study we investigated bcl-2 and Fas (CD95) expression in dermal lymphocytes in active skin lesions of Behçet's disease (BD) and in skin biopsy samples with chronic, non-specific inflammations. Tissue sections of 29 skin lesions of Behçet's disease and of 10 chronic non-specific inflammatory process cases from the archives of the Ondokuz Mayis University's Pathology Department were immunohistochemically stained for bcl-2 and Fas (CD95), and lymphocytes in the dermal infiltrate were evaluated for cytoplasmic staining. bcl-2 staining was observed in the skin lesions of 22 cases (75.8%) of Behçet's disease. bcl-2 staining was detected in two (20%) control skin biopsy samples with non-specific chronic inflammation. Fas (CD95) positivity was not detected in lymphocytes in Behçet's disease-related skin lesions. Fas (CD95) staining was observed in only three skin biopsy samples with non-specific chronic inflammation. bcl-2 and Fas (CD95) staining values in Behçet's and non-specific inflammation groups were significantly different (P < 0.01); differences in the bcl-2 staining values between Behçet's patients with mucocutaneous involvement only and mucocutaneous and other systemic involvements were not significant (P > 0.05). Expression of bcl-2 and loss of Fas (CD95) expression in dermal lymphocytes may play a role in the development of skin lesions and may account for the chronic course with periodic exacerbations in BD.

NF-κB protects Behçet's disease T cells against CD95-induced apoptosis up-regulating antiapoptotic proteins

OBJECTIVE

To determine whether prolongation of the inflammatory reaction in patients with Behçet's disease (BD) is related to apoptosis resistance and is associated with the up-regulation of antiapoptotic factors.

METHODS

The percentage of cell death was evaluated by flow cytometry in peripheral blood mononuclear cells from 35 patients with BD and 30 healthy volunteers. The expression levels of antiapoptotic factors and NF-kappaB regulatory proteins were measured using Western blotting and immunohistochemical analyses. To down-regulate NF-kappaB nuclear translocation, BD T lymphocytes were exposed in vitro to thalidomide and subjected to transfection with NF-kappaB small interfering RNA.

RESULTS

Although CD95 is highly expressed in BD T cells, the absence of sensitivity to CD95-induced apoptosis observed may be attributable to the inhibitory action of antiapoptotic genes. Immunoblot analysis for major antiapoptotic proteins showed considerable up-regulation of the short form of cellular FLIP (cFLIP) and Bcl-x(L) in BD activated T cells, while levels of Bcl-2, caspase 3, and caspase 8 in activated T cells from patients with BD were comparable with those in activated T cells from normal donors. Moreover, expression of IKK and IkappaB was up-regulated, whereas NF-kappaB translocated to the nucleus in BD T cells, suggesting that NF-kappaB activation may modulate the expression of antiapoptotic genes. Interestingly, thalidomide and NF-kappaB small interfering RNA down-regulated cFLIP and Bcl-x(L) expression levels and sensitized BD activated T cells to CD95-induced apoptosis.

CONCLUSION

Taken together, these results indicate that NF-kappaB contributes to the regulation of the apoptosis-related factors and death receptors leading to apoptosis resistance in BD T cell subsets. Our results suggest that NF-kappaB plays a crucial role in the pathogenesis of BD, and that its pharmacologic control could represent a key strategy in modulating specific immune-mediated disease.

Overexpression of bcl-2 in lymphocytes of psoriatic skin

Bcl-2 overexpression in lymphocytes play an important part in immunological and inflammatory diseases. In the present study, we investigated the bcl-2 expression in dermal lymphocytes of psoriatic skin biopsy samples. From the archives of the Department of Pathology, Ondokuz Mayis University Medical School (Samsun, Turkey), tissue sections belonging to 28 psoriasis cases and 10 chronic non-specific inflammatory skin disease cases were immunohistochemically stained by bcl-2. Positive staining was semiquantitatively graded from 1+ to 4+. Of the 28 psoriasis cases 20 were found to express bcl-2. Our data suggest that bcl-2-mediated inflammation plays a part in the pathogenesis and recurrent character of psoriasis.

Combined treatment with colchicine and Herba Taraxaci (Tarazacum mongolicum Hand.-Mazz.) attenuates Behcet's disease-like symptoms in mice and influences the expressions of cytokines

Herbal medicine, Herba Taraxaci (Tarazacum mongolicum Hand.-Mazz.), was administered to mice with Behcet's disease (BD)-like symptoms induced by herpes simplex virus (HSV). BD is a chronic recurrent inflammatory disease. Herba Taraxaci (6 mg) was administered alone or in combination with 2 microg of colchicine to BD-like mice. Colchicine is a drug that is widely used as a medication for BD patients. The water extracts of Herba Taraxaci were administered orally once per day for 20 days. Eighty percent (8 of 10) of mice treated with Herba Taraxaci combined with colchicine showed improvement in mucocutaneous symptoms compared to 0% (0 of 10) of the nontreated group and 30% (3 of 10) treated with colchicine alone. Cytokine expression in spleen tissue collected from treated mice was analyzed by RT-PCR and FACS. Treatment with Herba Taraxaci induced IL-4 mRNA, and spleen from mice receiving the combined treatment (Herba Taraxaci and colchicines) showed an increased number of splenocytes staining with anti-IL-10 (46.8+/-6.80) compared to Herba Taraxaci (35.4+/-2.17) (p<0.05) or colchicine alone (26.2+/-4.47) (p<0.001). These results suggest that the Herba Taraxaci may be an effective complementary agent in the treatment of BD.

Cytokine profile in Behçet's disease patients. Relationship with disease activity

OBJECTIVE

To analyse proinflammatory Th1 and Th2 cytokines in patients with Behçet's disease (BD) in relation to disease activity.

METHODS

Forty-five BD patients (25 in active stage) were investigated with ELISA for estimation of cytokines levels. Furthermore, cytokines intracellular synthesis (IL-4 and IFN-gamma) of CD4+ T cells was studied.

RESULTS

Active and in remission BD patients showed increased serum levels of Th1 (IFN-gamma, IL-12) and Th2 (IL-4, IL-6 and IL-10) cytokines. Active BD was characterized by a higher increase of IL-6, IL-10 and a striking increase of IL-17, IL-18 and IFN-gamma, compared to remission RD. Upon in vitro stimulation, the percentages of CD4+ T cells containing IFN-gamma and CD40L were higher in active BD compared to healthy controls.

CONCLUSION

Our results suggest that the microenvironment of CD4+ T cells in active BD may induce the production of more cells committed to Th1 than in BD patients in remission and healthy controls.

Expression of bcl-2 protein in active skin lesions of Behçet's disease

BACKGROUND

Expression of bcl-2 protein has been shown to play an important role in the pathogenesis of some inflammatory as well as neoplastic disorders. In this study we have investigated the presence of bcl-2 protein in active skin lesions of Behçet's disease and compared these results with normal skin samples of Behçet's disease (BD) patients and BD unrelated leukocytoclastic vasculitis.

METHODS

Active skin lesions of 23 Behçet's disease patients, normal skin samples of seven Behçet's disease patients, and archival biopsy specimens of 23 cutaneous leukocytoclastic vasculitis were investigated for the presence of bcl-2 protein by immunohistochemical methods. Results of staining were assessed semiquantitatively. Chi-square tests were used for statistical analysis.

RESULTS

Expression of bcl-2 protein were demonstrated in 16 of 23 (69.5%) and 8 of 23 (34.7%) patients with Behçet's disease and leukocytoclastic vasculitis, respectively. There were statistically significant difference between two groups (x2 = 4.27, P < 0.05). None of the normal skin samples of Behçet's disease patients showed bcl-2 expression.

CONCLUSION

Expression of bcl-2 protein may play a particular role in the development of skin lesions in Behçet's disease by causing prolonged survival of infiltrating lymphocytes.

Disturbed expression of Fas/FasL on CD4(+) and CD8(+)T cells in Behcet's disease, Vogt-Koyanagi-Harada syndrome, and idiopathic anterior uveitis

AIMS

To evaluate the expression of Fas/FasL antigen on peripheral blood T lymphocytes in patients with Behcet's disease, Vogt-Koyanagi-Harada (VKH) syndrome, and idiopathic anterior uveitis.

METHODS

The expression of Fas and FasL on peripheral blood T lymphocytes was determined using flow cytometry in 26 patients with Behcet's disease (BD), 17 patients with VKH syndrome, 25 patients with idiopathic anterior uveitis, and 43 healthy individuals (controls).

RESULTS

A higher proportion of CD4(+) T cells expressing Fas was noted in patients with Behcet's disease (25.70 +/- 7.32%), VKH syndrome (19.60 +/- 11.02%), and idiopathic anterior uveitis (20.81+/- 7.40%) compared with controls (14.02 +/- 6.30%). The expression of Fas on CD8(+) cells from patients with Behcet's disease (9.47 +/- 6.97%) and VKH syndrome (6.84+/- 5.5%) was also higher than that seen in controls (3.47+/- 2.75%). There was no difference in FasL expression on T cells between patients and controls except that a lower expression of FasL on CD8(+) T cells was noted in patients with idiopathic anterior uveitis.

CONCLUSION

A disturbed expression of Fas and FasL on T cells is present in patients with Behcet's disease, VKH syndrome, and idiopathic anterior uveitis, which may be involved in the perpetuation and recurrence of uveitis.

Th1 polarization of the immune response in Behçet's disease: a putative pathogenetic role of interleukin-12

OBJECTIVE

To investigate whether immunologic abnormalities in patients with Behçet's disease (BD) are related to abnormalities of the Th1/Th2 ratio.

METHODS

Th1/Th2 cytokine production by peripheral blood lymphocytes (PBL) from 31 patients with BD, 11 patients with inflammatory arthritis, and 10 healthy blood donors was evaluated by intracellular immunofluorescence staining. Serum interleukin-12 (IL-12) levels were measured using an enzyme amplified-sensitivity immunoassay. The effect of recombinant IL-12 (rIL-12) on spontaneous and Fas-mediated apoptosis of phytohemagglutinin (PHA)-stimulated PBL was evaluated by flow cytometry using propidium iodide (PI) staining and a bromodeoxyuridine (BrdU)/PI procedure.

RESULTS

Intracellular immunofluorescence staining of IL-2, IL-4, and interferon-gamma (IFNgamma) in CD3+ lymphocytes from BD patients demonstrated a strong polarization of the immune response toward the Th1 pathway that correlated with the progression of BD. Peripheral Th1 cells were significantly increased in patients with active disease (n = 14) as compared with those in patients in complete remission (n = 17), patients with inflammatory arthritis, and normal donors. In addition, serum IL-12 levels were correlated with peripheral Th1 lymphocytes and disease progression. Apoptotic analysis revealed that PHA-activated PBL from patients with active disease were highly sensitive to spontaneous and Fas-mediated activation-induced cell death. However, addition of rIL-12 to complete medium prevented this spontaneous and Fas-induced apoptosis and enhanced the proliferation of Th1 lymphocytes.

CONCLUSION

Taken together, these results indicate that a strong Th1 immune response occurs in active BD and suggest that IL-12 plays a substantial part in the pathogenesis of BD. By preventing spontaneous and Fas-induced cell death, in fact, it results in an abnormal growth of autoreactive Th1 lymphocytes that could contribute to the prolonged inflammatory autoimmune condition of BD.

Expression of Bcl-2 in inflammatory sites from patients with active Behçet's disease

Behçet's disease (BD) is a current systemic vasculitis of unknown aetiology. Eyes, skin, joints, the oral cavity, genital system, blood vessels, central nervous system and lung are usually involved. Defective regulation of programmed cell death (apoptosis) may play a role in the development of (BD), and the proto-oncogene Bcl-2 is involved in the control of apoptosis in immunocompetent cells. We therefore wished to investigate the expression of Bcl-2 in the peripheral lymphocytes and in two inflammatory sites of patients with active BD: bronchoalveolar lavage (BAL) and cerebrospinal fluid (CSF) lymphocytes. Levels of Bcl-2 expression in the lymphocytes of patients with BD and, for comparison, in the lymphocytes of healthy controls and non-inflammatory neurological diseases (NIND), were studied by two-colour cytofluorography and RNA analysis. In BD patients, a significant proportion of T cells expressed increased amounts of Bcl-2 protein, both in peripheral blood and in inflammatory sites. Mononuclear cells of patients with BD showed increased amount of Bcl-2 messenger RNA. The in vitro incubation of T lymphocytes with IL-10, significantly increased the Bcl-2 expression, specifically in T lymphocytes from inflammatory sites. In active BD, stimulation of HSV-1 T lymphocytes slightly increased Bcl-2 expression, not significantly different from unstimulated HSV-1 T cells. The occurrence of circulating T lymphocytes with abnormally high Bcl-2 expression in peripheral circulation and in inflammatory sites may be explained in part by the increased in vivo activation levels, and by aetiopathological agent(s): our findings seem to indicate an important role in the chronic inflammation in BD.

Anterior chamber inoculation of splenocytes without Fas/Fas-ligand interaction primes for a delayed-type hypersensitivity response rather than inducing anterior chamber-associated immune deviation

The inoculation of antigens into the anterior chamber (AC) of the eye induces an antigen-specific immune response that inhibits delayed-type hypersensitivity (DTH). This regulatory response is known as anterior chamber-associated immune deviation (ACAID). The ACAID response appears to be complex, as it can be elicited by a wide variety of soluble and cell-associated antigens, including foreign, self, tumor, and alloantigens. To evaluate the contribution of Fas/Fas ligand (FasL) interaction to the induction of ACAID to alloantigens, gld and lpr mutant mice were used in conjunction with normal C3H, MRL, and BALB/c mice. ACAID was induced by inoculation of non-irradiated splenocytes from donor mice into the AC of various recipients. After 1 week, recipients were primed intradermally with donor splenocytes. One week later DTH was measured by ear swelling. C3Hgld mutants lacking functional FasL did not develop ACAID after the AC inoculation of BALB/c splenocytes. Conversely, the AC inoculation sensitized these mutants. MRL/pr mutants, which lack Fas, developed ACAID following inoculation of BALB/c cells. AC inoculation of lpr splenocytes did not induce ACAID, but sensitized C3H recipients. Treatment of the AC inoculum with an anti-Fas antibody blocked ACAID induction in a transient manner, as the recipients developed ACAID later. These results show that interaction of the Fas and FasL is required to induce ACAID to allogeneic cells. In the absence of Fas expression on donor splenocytes, or FasL expression by the recipient, AC inoculation primes for a DTH response rather than inducing ACAID.