Activation of the JAK/STAT pathway in Behcet's disease.

Th1/Th17-type T-cell responses are upregulated in Behcet's disease (BD). However, signaling pathways associated with this aberrant immune response are not clarified. Whole-genome microarray profiling was performed with human U133 (Plus 2.0) chips using messenger RNA of isolated CD14(+) monocytes and CD4(+) T cells from peripheral blood mononucleated cell (PBMC) in patients with BD (n = 9) and healthy controls (HCs) (n = 9). Flow cytometric analysis of unstimulated (US) and stimulated (phytohaemagglutinin) signal transducer and activator of transcription (STAT3) and pSTAT3 expressions of PBMCs were also analyzed (BD and HC, both n = 26). Janus family of kinase (JAK1) was observed to be upregulated in both CD14(+) monocytes (1.95-fold) and CD4(+) T lymphocytes (1.40-fold) of BD patients. Using canonical pathway enrichment analysis, JAK/STAT signaling was identified as activated in both CD14(+) monocytes (P = 9.55E-03) and in CD4(+) lymphocytes (P =8.13E-04) in BD. Interferon signaling was also prominent among upregulated genes in CD14(+) monocytes (P = 5.62E-05). Glucocorticoid receptor signaling and interleukin (IL-6) signaling were among the most enriched pathways in differentially expressed genes in CD14+ monocytes (P = 2.45E-09 and 1.00E-06, respectively). Basal US total STAT3 expression was significantly higher in BD (1.2 vs 3.45, P < 0.05). The JAK1/STAT3 signaling pathway is activated in BD, possibly through the activation of Th1/Th17-type cytokines such as IL-2, interferon (IFN-γ), IL-6, IL-17 and IL-23.

Effects of malnutrition on oxidative burst functions and infection episodes in children with acute lymphoblastic leukemia.

INTRODUCTION: The aim of this study was to determine the effect of malnutrition on oxidative burst functions (OBF) of neutrophils in children with acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: Twenty-eight patients with ALL and thirty healthy controls were enrolled to the study. Thirteen patients with ALL were found to have malnutrition. While neutrophil OBF of ALL patients without malnutrition were studied both before induction chemotherapy and 3 months after, the same functions in ALL patients with malnutrition were studied both before induction chemotherapy and when the nutritional status improved. Control group were studied at admission and 3 months later. RESULTS: The OBF of ALL patients with and without malnutrition before induction chemotherapy were found to be significantly lower than the control group (P = 0.009), whereas the OBF were found to be similar in both patient groups with ALL (P = 0.27). The median infection episode rate and the duration of antibiotics therapy during the study period were similar in both patient groups with ALL. The repeated OBF of both patient groups with ALL were shown to increase to similar values with the control group in the third month of chemotherapy (P = 0.002). The median infection episode rate during the first month of chemotherapy was shown to decrease significantly during the third month of chemotherapy in both patient with ALL groups (P < 0.001). CONCLUSIONS: We have not been able to demonstrate an overt effect of malnutrition on OBF. However, our results still need to be verified via further larger scaled studies of OBF in leukemic children with and without malnutrition.

Dietary whey supplementation in experimental models of wound healing.

Whey is a dairy product containing milk serum proteins with diverse biological effects. In this study, the effect of dietary whey supplementation on wound healing was investigated. Rats were fed a standard or whey-supplemented diet for three weeks. Wound healing parameters, glutathione, and lipid peroxide levels were determined three days after the application of two different models of wound healing, i.e. laparotomy and colonic anastomosis. Dietary whey supplementation significantly increased glutathione levels and suppressed lipid peroxidation after experimental laparotomy and colonic anastomosis. Bursting pressures, hydroxyproline, and cytokine levels were not changed. Our results show that dietary whey supplementation increases glutathione synthesis and cellular antioxidant defense. Long-term effects of whey feeding on wound healing remains to be investigated.

CD8+CD28-, suppressive T cells in systemic lupus erythematosus.

Recent studies show that a CD8+CD28- phenotype of T-cell population inhibits the reactivity of T-helper cells either by a contact-dependent mechanism or with secreting suppressive cytokines. In this study, we have explored the peripheral blood CD8+CD28- T-cell population in 53 patients with systemic lupus erythematosus (SLE) in comparison to healthy and diseased control groups. The distribution of CD28- cells within CD8+ population has been found significantly lower in patients with SLE than in healthy individuals. While there were no significant differences in the expression of costimulatory molecules CD80 and CD86, the CD40 expression on monocytes was found significantly lower and there was a slight decrease of expression of Interleukin-10 (IL-10) in CD8+CD28- population in patients with SLE. The Transforming growth factor-beta (TGF-beta) mRNA expression was found higher in CD8+CD28- T cells. Neither activation induced nor time-dependent change in the frequency of CD8+CD28- cells has been observed following stimulation at various time-points indicating that the control of CD28 expression was not dependent on the presence of sustained stimulations. Decrease in CD8+CD28- T cells which normally produce TGF-beta and their low-level IL-10 content may reflect impaired T-cell suppression and accordingly, increased T cell help to autoreactive B cells in patients with SLE.

Thalidomide has both anti-inflammatory and regulatory effects in Behcet's disease.

Thalidomide is shown to be an effective treatment for mucocutaneous symptoms of Behcet's disease (BD). In this study, the effects of thalidomide on peripheral blood mononuclear cells were investigated ex vivo. In an open prospective study, ten patients were given 200 mg/day thalidomide for 12 weeks and cluster of differentiation 4 (CD4), CD8, CD11a, CD11b, CD16, CD18, CD28, CD44, CD45RO, CD45RA, CD56, CD120a and gammadelta+ T cells were analysed with flow cytometry at 0, 3, 7, 30 and 90 days. Two patients were excluded from the analysis for attacks of uveitis within the first 2 weeks. At day 7, tumour necrosis factor-alpha (TNF-alpha) receptor+ (CD120a; 12% vs 5%), CD8/CD11b+ (12% vs 6%) and CD16/CD56+ (16% vs 9%) cells decreased in BD patients compared to day 0. On the other hand, CD4+CD45RO+ T cells (24% vs 34%) at day 30 and gammadelta+ T cells (11% vs 21%) at day 90 increased after treatment. These results suggest that thalidomide tends to decrease TNF-alpha receptor levels, CD8/CD11b+ T cells and natural killer cells in early treatment and increases CD4+CD45RO+ memory T and gammadelta+ T cells later in BD.

Activation of neutrophils by testosterone in Behçet's disease.

OBJECTIVE: Gender differences, especially in disease severity, are observed in Behçet's disease (BD), a systemic vasculitis of unknown etiology. To determine the putative role of testosterone on neutrophil activity exhibited by patients with BD, peripheral blood neutrophils were examined in vitro before and after treatment with testosterone. METHODS: Peripheral blood neutrophils of 49 patients with BD (26M:23F), 33 patients with ankylosing spondylitis (AS) (23M:10F), 8 female patients with hirsutism and 31 healthy individuals (19M:12F) were analyzed by flow cytometry. Neutrophil-ROS-generating capacity, anti-CD66b, anti-CD16, Phi-philux and PI staining techniques were used for evaluating neutrophil activation and apoptosis. RESULTS: Gender differences were striking not only in the mean oxidative burst response but also in the rate of apoptosis. Male BD patients manifested increased burst response before testosterone treatment compared with females (8.0 +/- 4.9 vs. 4.9 +/- 3.3, p < 0.01). Consistent with oxidative burst results, baseline percentages of CD66b (99.1 +/- 0.9 vs. 94.7 +/- 5.3 p < 0.04) and CD16 expressing cells were greater in male BD patients. A decreased apoptosis ratio was observed using phi-philux and PI staining in BD patients. This was especially significant in male compared to female BD patients (2.4 +/- 1.4 vs. 6.8 +/- 5.8, p < 0.002). BD itself rather than the gender was found to be the most important predictor of this altered apoptosis ratio in BD determined by linear regression analysis. CONCLUSION: Our results suggest that a contribution of testosterone to the BD pathogenesis cannot be ruled out. However, causative factors for disturbed apoptosis especially seen in male BD patients need to be further evaluated.

The effects of iron deficiency on neutrophil/monocyte apoptosis in children.

OBJECTIVES: Iron is essential for DNA synthesis; its deficiency may lead to impaired DNA synthesis and subsequent alterations in levels of apoptosis. Here, we have aimed to investigate effects of iron deficiency anaemia (IDA) on apoptotic response of phagocytic cells and to understand whether the effect is reversible after iron supplementation. MATERIALS AND METHODS: Forty-nine IDA patients and 26 healthy controls, aged between 6 months and 12 years with similar demographic status, were considered. Neutrophil- and monocyte-apoptotic responses of IDA patients and the control group were compared by flow cytometry. Then, IDA patients were provided with oral iron supplementation. On day 15 of iron therapy, neutrophil- and monocyte-apoptotic responses of IDA patients were rechecked and were compared to those of control group. RESULTS: Neutrophil- and monocyte-apoptotic responses in terms of early and late percentages of apoptosis, and percentages of necrotic cells, were significantly less in IDA patients compared to the control group. The significantly low apoptotic responses of IDA patients rose to levels of the control group by day 15 of iron therapy. Besides, the effect of IDA on apoptotic responses was found to be more enhanced in severe IDA patients that those of mild IDA patients. CONCLUSION: Correction of differences after iron supplementation therapy implies that IDA might be a cause for changes in neutophil- and monocyte-apoptotic responses. The impact of this diminution of apoptotic cellular function in IDA should be further investigated, with longitudinal studies, in order to document the impact of any severe and/or long-lasting IDA on autoimmunity and malignancy.

L-Carnitine ameliorates methotrexate-induced oxidative organ injury and inhibits leukocyte death.

Methotrexate (MTX), a folic acid antagonist widely used for the treatment of a variety of tumors and inflammatory diseases, affects normal tissues that have a high rate of proliferation, including the hematopoietic cells of the bone marrow and the gastrointestinal mucosal cells. To elucidate the role of free radicals and leukocytes in MTX-induced oxidative organ damage and the putative protective effect of L-carnitine (L-Car), Wistar albino rats were administered a single dose of MTX (20 mg/kg) followed by either saline or L-Car (500 mg/kg) for 5 days. After decapitation of the rats, trunk blood was obtained, and the ileum, liver, and kidney were removed for histological examination and for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, and collagen content. Our results showed that MTX administration increased the MDA and MPO activities and collagen content and decreased GSH levels in all tissues, while these alterations were reversed in L-Car-treated group. The elevated serum TNF-alpha level observed following MTX treatment was depressed with L-Car. The oxidative burst of neutrophils stimulated by Annexin V was reduced in the saline-treated MTX group, while L-Car abolished this inhibition. Similarly, flow cytometric measurements revealed that leukocyte apoptosis was increased in MTX-treated animals, while L-Car reversed these effects. Severe degeneration of the intestinal mucosa, liver parenchyma, and glomerular and tubular epithelium observed in the saline-treated MTX group was improved by L-Car treatment. These results suggest that L-Car, possibly via its free radical scavenging and antioxidant properties, ameliorates MTX-induced oxidative organ injury and inhibits leukocyte apoptosis. Thus, supplementation with L-Carnitine as an adjuvant therapy may be promising in alleviating the systemic side-effects of chemotherapeutics.

Oxidative burst response to monosodium urate crystals in patients with Behçet's syndrome.

OBJECTIVE: An erythematous response to intradermal injection of monosodium urate crystals (MSU) has been demonstrated in Behçet's syndrome (BS). To further elucidate the pathogenesis of this response, the effects of MSU on in vitro oxidative burst reaction of neutrophils and monocytes were investigated. METHODS: Peripheral blood mononuclear cells from patients with Behçet's syndrome (BS), rheumatoid arthritis (RA), familial Mediterranean fever (FMF) and healthy controls (HC) were incubated with 100 ng/ml phorbol myristate acetate (PMA) and MSU at different dosages (25-500 microg/ml). Oxidative burst reaction was evaluated in neutrophils and monocytes by flow cytometry. RESULTS: In patients with BS, oxidative burst of neutrophils was significantly increased compared to HC at 125 microg/ml and 250 microg/ml dosages of MSU (p < or = 0.001 and 0.004 respectively). In patients with FMF; there was also an increased oxidative burst reaction at 75 microg/ml, 250 g/ml and 500 microg/ml (p < or = 0.007; 0.001 and 0.004 respectively). In patients with BS, oxidative burst of monocytes was increased only at 125 g/ml dosage of MSU (p < or = 0.002). However, in patients with FMF monocyte burst response was increased at 25 microg/ml, 75 microg/ml and 125 g/ml (p < or = 0.004; < 0.0001; < 0.0001 and 0.002 respectively). In RA group, stimulation with PMA resulted in a higher oxidative burst reaction than FMF and BS (p < or = 0.000 and p < or = 0.008). No correlation was observed between oxidative burst of neutrophils or monocytes and intradermal responses to MSU crystals. CONCLUSION: Oxidative burst reaction with MSU is augmented in neutrophils and monocytes of BS. However, the response is not specific and is unassociated with skin dermal test which has a high specificity for BS.

Clinical and immunological effects of azithromycin in Behçet's disease.

BACKGROUND: The aim of this study was to evaluate the effects of azithromycin on mucocutaneous manifestations, oral health and immune response in Behçet's disease (BD). METHODS: Eight BD patients with active mucocutaneous symptoms were treated with azithromycin for 4 weeks. Oral health, clinical manifestations and in vitro interleukin (IL)-12, interferon (IFN)-gamma, IL-10 and monocyte chemotactic protein (MCP)-1 responses were evaluated before and after treatment. RESULTS: The number of folliculitic lesions, healing time of oral ulcers and scores of plaque indexes (PLIs) were lower after azithromycin treatment (P<0.05). Scores of PLIs correlated positively with the healing time of oral ulcers (P=0.02). Although a trend towards increased stimulated IL-10 responses with azithromycin was observed, no statistically significant difference was found. Stimulated and unstimulated MCP-1, IFN-gamma and IL-12 responses were similar before and after treatment (P>0.05). CONCLUSION: Azithromycin was observed to be effective in decreasing folliculitic lesions and fastening the healing time of oral ulcers in BD.

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.

Expression of KIR and C-type lectin receptors in Behcet's disease.

OBJECTIVE: Behçet's disease (BD) is a multisystemic disorder with a possible underlying pathology of immune-mediated vasculitis. Genetic susceptibility associated with HLA-B*51 and B*2702 has been implicated in its pathogenesis. Considering the recently defined regulatory mechanisms of NK cells through HLA class I binding receptors, we hypothesized that interactions of NK and T cells through the NK receptors may be important in the pathogenesis of BD. METHODS: The impact of different expression patterns of HLA-recognizing receptors on NK or T cells was analysed in 51 patients with BD and 32 healthy controls. We used flow cytometry to investigate the expression of KIR3DL1 from the polymorphic killer immunoglobulin-like receptor (KIR) family, which binds a shared HLA-Bw4 motif on HLA-B51 and *2702 alleles, and CD94 from the conserved C-type lectin receptor family, which binds HLA-E. Thirty-three of the BD patients and 19 of the controls carried the same HLA-Bw4 motif. RESULTS: CD3(+) T cells were increased in patients with BD compared with controls (81 vs 75%, P = 0.001), whereas the NK cells did not show any difference between the two groups. Increased expression of CD94 in BD was observed on CD16(+)CD56(+) cells (66 vs 57, P = 0.04) and on CD3(+) (7.7 vs 4.0, P < 0.001) and CD3(+)CD56(+) (44 vs 35, P = 0.02) T cells. KIR3DL1 expression on the NK and T cells was not statistically different between the two groups. No effect of HLA-Bw4 motif was observed on the expression of CD94 and KIR3DL1 in both the patients and the controls. CONCLUSION: The absence of a correlation between KIR3DL1 expression and HLA-Bw4 motif confirms previous work reporting that the expression of these molecules is regulated separately. Increased expression of CD94 may suggest that NK receptors play a pathogenic or regulatory role in BD.

The effects of nitric oxide donors and inhibitors on neutrophil functions in Behçet's disease.

OBJECTIVE: The effects of nitric oxide donor SNAP and nitric oxide inhibitors L-NMMA and AG on the functions of neutrophils in patients with Behçet's Disease (BD) were investigated in vitro. METHODS: Oxidative burst and phagocytosis of neutrophils were evaluated by flow cytometry in patients with Behçet's disease (n = 32), inflammatory (n = 17) and healthy controls (n = 14), in the presence of L-NMMA, AG and SNAP. RESULTS: The stimulation index of oxidative burst was found to be significantly decreased following PMA stimulation in patients with active BD compared to inflammatory and healthy controls. Oxidative function of neutrophils were inhibited in all 3 groups in the presence of L-NMMA, AG and SNAP L-NMMA inhibited the oxidative burst of neutrophils obtained from healthy controls more than inflammatory controls and BD (80% vs 52% and 53% respectively, p = 0.001). No significant difference of phagocytosis inhibition was found with L-NMMA, AG and SNAP and there were also no differences between the groups (% 9-39). CONCLUSION: Nitric oxide donors and inhibitors may have a therapeutic role in Behçet's disease by suppresing neutrophil activity.

HSP 60 expression in mucocutaneous lesions of Behçet's disease.

BACKGROUND: Heat shock protein (60 kd HSP) has been implicated in the etiology of Behçet's disease, but its expression at sites of inflammation is unknown. OBJECTIVE: Our aim was to investigate local HSP 60 expression and to quantify T-cell receptor (TCR) gamma delta-positive cells, which are known to respond to HSP peptides. METHODS: Patients with active Behçet's disease (n = 21) and controls (n = 18) were included. Flow cytometric analysis was performed on peripheral blood to investigate TCR gamma delta-positive cell counts. Biopsies were performed on active skin lesions, and immunohistochemical analysis was performed by a streptavidin-biotin method using the monoclonal ML-30 antibody; HSP staining intensity and distribution were evaluated in a blinded fashion. Immunohistochemical studies were performed to quantify TCR gamma delta-positive cells at lesional sites. RESULTS: Mucocutaneous lesions of patients with Behçet's disease had statistically significantly increased expression of HSP 60/65. Peripheral blood TCR gamma delta-positive cell counts were similar in both groups. However, lesional skin of patients with Behçet's disease had significantly increased gamma delta-positive T-cell counts. CONCLUSION: Up-regulation of HSP expression was found at lesional skin sites in Behçet's disease. The increased number of TCR gamma delta-positive cells, which are known to respond to HSP peptides, may support the function of HSPs in the etiology of Behçet's disease. However, these findings may also be an epiphenomenon that needs to be further investigated.

Human HSP 60 peptide responsive T cell lines are similarly present in both Behçet's disease patients and healthy controls.

Heat shock protein (HSP, 60/65 kDa) is investigated as a candidate autoantigen in Behçet's disease (BD), a systemic vasculitis of unknown origin, and a prominent response to 'disease-specific epitopes' of mycobacterial and human HSP60/65 is described in BD patients. In this study, long-term T cell lines from peripheral blood of BD patients (n=6) and controls (n=7) were stimulated with mycobacterial recombinant HSP and purified protein derivate (PPD) and expanded with IL-2. In the BD group, 15 out 27 and in the controls, 25 out of 35 PPD specific T cell lines have responded to the synthetic peptides of the human HSP60. Out of the primarily HSP-specific T cell lines, 17/23 in patients and 8/8 in controls did recognize a peptide of human origin. T cell lines specifically reactive to 136-150, 179-197, 244-258 and 336-351 could be raised with similar frequency in both groups. In contrast to a previous report, T cells also reacted to peptide 425-441 frequently in both groups. The results demonstrate that the human proliferative response to mycobacterial HSP may also target the self-protein in both BD patients and controls. However, the responsive T cells may have different effects depending on their functional features such as cytokine secretions.

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.

Anti-MHC autoimmunity in Behçet's disease: T cell responses to an HLA-B-derived peptide cross-reactive with retinal-S antigen in patients with uveitis.

Immune response to retinal autoantigens plays a central role in the pathogenesis of uveitis. A synthetic peptide (B27PD) from a common sequence of various HLA-B molecules associated with uveitis, such as HLA-B27 and 51, which shares amino acid homologies with a retinal-S antigen (S-Ag)-derived peptide (PDSAg), was shown to be immunogenic in human and experimental uveitis in the rat. In this study we investigated T cell responses to B27PD and PDSAg in patients with Behçet's disease and posterior uveitis (BD-posterior uveitis; n = 33) in comparison with non-Behçet anterior uveitis (AU, n = 14), Behçet's patients without uveitis (BD, n = 15) and healthy controls (HC, n = 32) in a 6-day proliferation assay. Patients with BD and posterior uveitis had significantly higher responses (stimulation index (SI) 2.8 +/- 1.3) than those with AU (SI 1.5 +/- 0.4), BD without uveitis (SI 1.1 +/- 0.4) and HC (SI 1.1 +/- 0.6) for B27PD (P < 0.0001). Responses to PDSAg were also higher in BD with posterior uveitis patients (SI 3.3 +/- 1.6) than AU (SI 1.5 +/- 0.4), BD without uveitis (SI 1.2 +/- 0.3) and HC (SI 1.1 +/- 0.6) (P < 0. 0001). A significant correlation between the responses to PDSAg and B27PD (r = 0.56, P < 0.001) was observed. Elevated levels of IL-2 and tumour necrosis factor-alpha were also observed in culture supernatants obtained from peripheral blood mononuclear cells after stimulation with the peptides, but no correlation was found between the proliferative responses and cytokine levels. These results suggest that cellular immunity to cross-reactive HLA-B and S-Ag-derived peptides might play a role in the pathogenesis of posterior uveitis in BD.

T cell responses to 60/65 kDa heat shock protein derived peptides in Turkish patients with Behçet's disease.

OBJECTIVE: Sequence homology and cross reactivity between microbial and human heat shock proteins (HSP) led to the concept that HSP might be involved in the etiopathogenesis of Behçet's disease (BD). We investigated T cell responses to 8 synthetic peptides derived from the mycobacterial 65 kDa and homologous human 60 kDa HSP in patients with BD. METHODS: T cell proliferative responses to synthetic peptides were studied in 49 patients with BD and 46 disease (DC) and 34 healthy controls (HC) with 3H-thymidine uptake test. RESULTS: Positive T cell responses to one or more of the mycobacterial peptides were observed in 52% (12/23) of patients with BD compared with 17% (3/18) of DC (p = 0.02) and to homologous human peptides in 57% (13/23) of BD and 11% (2/18) of DC (p < 0.01). Responses to the mixtures of 4 mycobacterial peptides were also significantly higher in BD compared with controls (stimulation index in BD 4.7 +/- 3.5 vs DC 2.0 +/- 1.2, HC 1.6 +/- 0.4; BD vs DC and HC, p < 0.001). Similar elevated responses to the mixture of 4 human peptides was also observed in patients with BD (BD 3.4 +/- 2.3; DC 1.9 +/- 0.8; HC 1.4 +/- 0.6; BD vs DC, p < 0.01; BD vs HC, p < 0.001). CONCLUSION: These results suggest that cellular immunity against the 65 kDa mycobacterial and 60 kDa human HSP derived peptides is significantly increased in Turkish patients with BD compared to controls, as observed in the UK and Japan.