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Biomedical subjects

A G Tzioufas

Publications and source records attributed to A G Tzioufas.

At least 19 recordsLinked to original sources
PubMed2007

Analysis of parotid glands of primary Sjögren's syndrome patients using proteomic technology reveals altered autoantigen composition and novel antigenic targets.

Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration, destruction of the salivary and lacrimal glands and production of autoantibodies against a variety of cellular proteins. The aberrant immune response against these autoantigens may begin or extend to other proteins that are not yet defined. Several studies have shown that autoantibody production is taking place in the affected salivary glands. In the present study, using proteomic approaches, we aimed to: (a) identify new autoantigens in the salivary glands of primary SS (pSS) patients and (b) evaluate the epigenetic changes of known autoantigens. Total parotid gland extracts of pSS patients were analysed using two-dimensional gel electrophoresis, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot with pSS patients' sera or purified autoantibodies and immunoprecipitation using homologous IgG. Identification of the unknown proteins was performed using mass spectrometry (MS). Immunoblot analysis on two-dimensional gels using purified anti-La/SSB antibodies revealed that pSS salivary glands contain high levels of post-translationally modified La/SSB autoantigen, while the native form of the protein is recognized faintly, in contrast to normal controls. Moreover, salivary glands of pSS patients contain post-translationally modified actin that becomes immunogenic in the microenviroment of the affected tissue. The alteration of the physicochemical properties of self-proteins could thus contribute to the break of immune tolerance against them.

Actins↗
PubMed2006

Thrombocytopaenia in lupus as a marker of adverse outcome--seeking Ariadne's thread.

OBJECTIVE: To assess the role of thrombocytopaenia as an independent predictor of outcome in patients with systemic lupus erythematosus (SLE). METHODS: This was a single-centre, retrospective, matched case-control study (1:2). Fifty consecutive Greek SLE patients were selected at random who had developed thrombocytopaenia during the disease course (cases) were compared with 100 SLE patients with no history of thrombocytopaenia, and matched for age, sex and disease duration (controls). Overall damage was assessed at the end of follow-up, using Systemic Lupus International Collaborating Clinics index. Total number of irreversible organ-damage events for both groups were recorded. Rates for specific outcomes and incidence-rate ratios (IRRs) for damage were estimated. Multivariate analysis estimating influential clinical and immunological factors for outcome, including thrombocytopaenia, was performed. RESULTS: After 583 person-years of follow-up for cases and 1155 for controls, we found that thrombocytopaenic individuals have a higher risk for damage (IRR 1.96, 1.52-2.53) compared with their matched controls and this effect persists throughout the course of their disease. They also have a predilection to certain types of damage involving heart and kidneys. Among other significant factors associated with damage in multivariate analysis (disease activity, serositis, anti-cardiolipin antibodies, central nervous system involvement), thrombocytopaenia appears as the most influential. CONCLUSION: Thrombocytopaenia is a quantitive and qualitative marker of impending damage in SLE patients.

Adolescent↗
PubMed2006

Bone marrow histological findings in systemic lupus erythematosus with hematologic abnormalities: a clinicopathological study.

BACKGROUND: The histopathologic features characterizing the involvement of the bone marrow (BM) in systemic lupus erythematosus (SLE) have not been systematically analyzed to date. OBJECTIVES: The aim of this study was to assess morphologic and immunohistochemical characteristics of BM involvement in SLE. PATIENTS AND METHODS: Clinical and serological data of 40 SLE patients with unexplained cytopenias were studied. Ten patients with myelodysplasia of refractory anemia (RA) were used as controls. BM aspiration, BM biopsy (BMB), and immunohistochemistry were carried out in patients and controls. BM fibrosis, BM necrosis, stromal edema, and abnormal localization of immature precursors (ALIP) were assessed according to standard criteria. RESULTS: Dyserythropoiesis and megakaryocytic atypias were uniform findings in SLE patients. The disruption of the normal BM architecture was a predominant SLE BM feature affecting cells of all three hemopoietic lineages, with both erythroid and megakaryocytic precursors tending to assume paratrabecular locations and ALIP aggregates being present in 27 cases. In addition, BM was hypocellular in 23 cases. BM necrotic alterations were evident in 90% of the cases. The density of reticulin content was generally increased. Vascular changes including dilatation of sinuses were manifest and were associated with the presence of necrotic alterations (P = 0.008). Hemoglobin levels correlated inversely with the presence of ALIP (P = 0.016). Upon comparing BMB features between SLE and RA controls there were striking similarities. CONCLUSIONS: BMB in patients with SLE and unexplained cytopenias presents a variety of histopathologic findings including BM necrosis, stromal alterations, hypocellularity, dyspoiesis, and distortion of normal BM architecture, characterized primarily by the presence of ALIP aggregates.

Adolescent↗
PubMed2006

Preferential recognition of the phosphorylated major linear B-cell epitope of La/SSB 349-368 aa by anti-La/SSB autoantibodies from patients with systemic autoimmune diseases.

Sera from patients with primary Sjögren Syndrome (pSS) or Systemic Lupus Erythematosus (SLE) often contain autoantibodies directed against La/SSB. The sequence 349-368 aa represents the major B-cell epitope of La/SSB, also it contains, at position 366, a serine amino acid residue which constitutes the main phosphorylation site of the protein. In this study we investigated the differential recognition of the 349-368 aa epitope and its phosphorylated form by antibodies found in sera from patients with systemic autoimmune diseases. Peptides corresponding to the sequence of the unphosphorylated (pep349-368 aa) and the phosphorylated form (pep349-368 aa Ph) of the La/SSB epitope 349-368 aa, as well as to a truncated form spanning the sequence 349-364 aa and lacking the phosphorylation site (pep349-364 aa), were synthesized. Sera from 53 patients with pSS and SLE with anti-La/SSB specificity, 30 patients with pSS and SLE without anti-La/SSB antibodies, 25 patients with rheumatoid arthritis and 32 healthy individuals were investigated by ELISA experiments. Autoantibodies to pep349-368 aa Ph were detected in sera of anti-La/SSB positive patients with a higher prevalence compared to the pep349-368 aa (66%versus 45%). Pep349-368 aa Ph inhibited the antibody binding almost completely (92%), while pep349-368 aa inhibited the binding only partially (45%). Anti-La/SSB antibodies presented a higher relative avidity for the phosphorylated than the unphosphorylated peptide. Immunoadsorbent experiments using the truncated peptide pep349-364 aa indicated that the flow through showed a selective specificity for pep349-368 aa Ph, while the eluted antibodies reacted with both peptide analogues of the La/SSB epitope. These data suggest that sera from pSS and SLE patients with anti-La/SSB reactivity possess autoantibodies that bind more frequently and with a higher avidity to the phosphorylated major B-cell epitope of the molecule.

Antibody Affinity↗
PubMed2006

Suspects in the tale of lupus-associated thrombocytopenia.

Immunologically mediated thrombocytopenia is a frequent clinical manifestation in patients with systemic lupus erythematosus (SLE). Autoantibodies targeting platelet membrane glucoproteins have a central role in peripheral platelet destruction. Autoantibodies against thrombopoietin are also present in about one-third of patients, but their pathogenetic role is obscure. Thirty-eight serum samples from SLE patients were tested for anti-platelet antibodies, anti-thrombopoietin antibodies and levels of circulating thrombopoietin. Bone marrow histology was also assessed. Thirty-nine per cent of sera displayed anti-thrombopoietin antibodies and 29% had circulating anti-platelet antibodies. Anti-thrombopoietin antibodies were associated with lower thrombopoietin concentrations, and lower mean platelet values in long-term follow-up. Anti-platelet antibodies were present in about 40% of thrombocytopenic and non-thrombocytopenic individuals but were absent in patients who had recovered from thrombocytopenia, supporting their pathogenetic role. Both autoantibodies were absent in control sera from patients with rheumatoid arthritis and primary Sjögren's syndrome. Decreased bone marrow cellularity, normal or low number of hypolobulated, pyknotic megakaryocytes and stromal alterations were prominent findings in thrombocytopenic SLE patients, suggesting a defect in megakaryopoiesis. These findings were not evident in specimens from patients with idiopathic thrombocytopenic purpura who had increased megakaryocytes, normal cellularity and absence of stromal alterations. In conclusion, peripheral destruction due to platelet autoantibodies, anti-thrombopoetin antibodies, lower effective circulating thrombopoetin and impaired compensatory response due to bone marrow damage interact in SLE and thrombocytopenia ensues.

Adult↗
PubMed2006

Post-translational modifications of the major linear epitope 169-190aa of Ro60 kDa autoantigen alter the autoantibody binding.

Ro60 kDa is a member of the Ro/LaRNP ribonucleoprotein complex and its major linear B cell epitope, corresponding to the region 169-190aa, has been found to be the initial target of the autoimmune response in patients with systemic lupus erythematosus. This sequence contains one serine and two arginine amino acid residues, which can potentially be modified post-translationally by phosphorylation or citrullination, respectively. The aim of this study was to develop an immunoassay for anti-Ro60 kDa epitope antibody detection and to investigate the changes in the antigenicity of the Ro60 kDa epitope when it is post-translationally modified, by either citrullination or phosphorylation. Peptide analogues corresponding to the unmodified form of the epitope, its phosphorylated form, and a form with both arginine residues citrullinated were synthesized. The peptide coating conditions were investigated and it was found that the use of highly hydrophilic surfaces increase the efficiency of the coating, as well as the sensitivity of the method for anti-peptide antibody detection. All peptides were tested by the optimized enzyme-linked immunosorbent assay (ELISA) against 119 sera from patients with primary Sjögren's syndrome, systemic lupus erythematosus and rheumatoid arthritis with anti-Ro/SSA reactivity, 20 sera from patients with systemic diseases without anti-Ro/SSA immune reactivity, as well as against 65 sera from normal individuals. A large proportion of the tested sera reacted against all three peptide analogues, although with a preference for the unmodified form of the epitope. In conclusion, post-translational modifications of the major Ro60 kDa B cell epitope can alter the autoantibody binding.

Amino Acid Sequence↗
PubMed2005

Long term remission of Sjögren's syndrome associated aggressive B cell non-Hodgkin's lymphomas following combined B cell depletion therapy and CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone).

BACKGROUND: Primary Sjögren's syndrome (SS) is associated with an increased frequency of non-Hodgkin's lymphomas (NHLs), mainly of low histological grade. However, aggressive diffuse large B cell lymphomas (DLBCL) characterised by poor treatment outcome can also be encountered in SS. It has recently been shown that rituxan has significant therapeutic activity in this type of lymphoma. OBJECTIVE: To evaluate the efficacy of CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine, prednisone) in combination with rituxan in SS patients with DLBCL, and to determine the outcome in such patients. METHODS: In an open, single case trial, six SS patients with DLBCL were assigned to receive eight cycles of CHOP every three weeks plus rituxan given on day 1 of each cycle. In a retrospective study, conducted by the European Concerted Action for SS, nine cases were diagnosed as DLBCL, all of whom had been treated with CHOP alone. These patients were used as historical controls. RESULTS: The difference in the overall survival between the two treatment groups was significant. The group treated with rituxan plus CHOP had a 100% two year overall survival rate, while the historical controls had only a 37% survival rate. Extraglandular manifestations serving as predictors for lymphoma development such as palpable purpura and peripheral neuropathy disappeared. The remission of these signs was accompanied by a decrease in both circulating monoclonal cryoglobulins and rheumatoid factor activity and an increase in C4 levels. Clinically relevant toxicity was not detected. CONCLUSIONS: The addition of rituxan to standard CHOP chemotherapy results in improved treatment outcome in SS patients with aggressive DLBCL, without increasing toxicity.

Adult↗
PubMed2005

Complete heart block in a patient with systemic sclerosis.

We describe a patient with diffuse systemic sclerosis and presyncopal episodes where the electrocardiogram revealed complete atrioventricular heart block associated with left posterior and right heart bundle block. The patient underwent implantation of a permanent pacemaker.

Aged↗
PubMed2005

Anaemia in systemic lupus erythematosus: from pathophysiology to clinical assessment.

Haematological abnormalities are common in systemic lupus erythematosus. Anaemia is found in about 50% of patients, with anaemia of chronic disease being the most common form. Impaired erythropoietin response and presence of antibodies against erythropoietin may contribute to the pathogenesis of this type of anaemia. Patients with autoimmune haemolytic anaemia usually belong to a distinct category, which is associated with anticardiolipin antibodies, thrombosis, thrombocytopenia, and renal disease, often in the context of secondary antiphospholipid syndrome. Autoantibodies, T lymphocytes, and deregulation of the cytokine network can affect bone marrow erythropoiesis, leading to anaemia.

Anemia, Hemolytic, Autoimmune↗
PubMed2005

Cross-reaction between antibodies to the major epitope of Ro60 kD autoantigen and a homologous peptide of Coxsackie virus 2B protein.

Coxsackie virus RNA has recently been detected in biopsy specimens of minor salivary glands from patients with primary Sjögren's Syndrome (pSS). A peptide derived from Coxsackie virus 2B protein (pepCoxs) presents 87% sequence homology with the 222-229 region of the major linear B-cell epitope of Ro60 kD autoantigen (pep216-232). Synthetic peptides corresponding to pep216-232: (216)KALSVETEKLLKYLEAV(232) and pepCoxs: (31)MVTSTITEKL LKNLVKI(47), were prepared. Sera from 42 patients with pSS and 43 patients with systemic lupus erythematosus (SLE) as well as sera from 27 healthy individuals (normal controls) and sera from 30 patients with rheumatoid arthritis (disease controls) were tested against the two homologous peptides. Twenty-five percent of SLE sera and 33.3% of pSS sera reacted against pep216-232, whereas 28% of SLE sera and 37% of pSS sera recognized the pepCoxs. The sera reacting with pep216-232 were apparently the same as those reacting with pepCoxs. Normal sera and disease control sera presented only a limited reactivity against both peptides (ranging from 3.7% to 10%). Both peptides reacted more prominently with anti-Ro/La (+) sera from pSS patients. Thus, pep216-232 was recognized by 17% of the anti-Ro (+) sera and by 42% of the anti-Ro/La (+) sera, whereas pepCoxs was recognized by 28.5% and 38% of the a-Ro(+) and a-Ro/La(+) sera, respectively. Purified anti-pep216-232 antibodies readily reacted with both peptides while inhibition experiments revealed the specificity of this reaction. These results suggest a possible cross-reaction between antibodies to the major linear B-cell epitope of Ro60 kD autoantigen and the homologous pepCoxs in pSS patients. This cross-reaction might potentially play a role in autoantibody formation and the perpetuation of the autoimmune response against Ro/SSA and La/SSB.

Antigens, Viral↗
PubMed2005

Cross-recognition between histones and La/SSB may account for anti-DNA reactivity in SLE patients.

Antibodies to La/SSB are detected in sera of patients with primary Sjogren's syndrome (pSS) and systemic lupus erythematosus (SLE). The vast majority of anti-La/SSB positive sera contain antibodies directed towards a linear B-cell epitope of La/SSB spanning the sequence 349-364aa (pep349-364). The aim of this study was to evaluate the fluctuation of antibody levels to major B-cell epitopes of La/SSB over time and investigate for their possible crossreactions. Sequential sera from 15 SLE and 15 pSS patients, followed from 3 to 10 years were obtained. All patients with SLE were positive for anti-Ro/SSA, anti-La/SSB and anti-dsDNA antibodies and patients with pSS were positive for anti-Ro/SSA and anti-La/SSB antibodies. Sera from 30 patients with SLE without anti-La/SSB antibodies and 30 healthy individuals served as disease and negative control respectivelly. All sera tested for the presence of anti-pep349-364 antibodies, using a specific ELISA. Specific anti-pep349-364 IgG was purified from sera of SLE patients and evaluated for cross reactivity against dsDNA and histones. In all SLE sera the levels of anti-pep349-364 antibodies varied in time and fluctuated in parallel with anti dsDNA antibodies. Anti-pep349-364 IgG purified from 7 SLE patients. Five out of 7 were found to react with calf thymus DNA in ELISA. All purified (7/7) anti-pep349-364 IgG preparations reacted with histone H1 and failed to produce a positive immunofluorescence pattern in Crithidia luciliae anti-dsDNA assay which lacks histones. Competative inhibition experiments demonstrated that histone H1 could inhibit completely the binding of anti-pep349-364 IgG to pep349-364 while pep349-364 inhibited by 70% the binding of anti-pep349-364 IgG to histone H1. These findings indicate that a subgroup of SLE patients possess cross-reacting anti-histone H1 antibodies and anti-pep349-364 antibodies, which can be faulty considered as anti-dsDNA reactivity in regular ELISA techniques.

Animals↗
PubMed2005

Lupus thrombocytopenia: clinical implications and prognostic significance.

OBJECTIVES: To clarify clinical manifestations, association with disease activity, and prognostic impact of thrombocytopenia using simple and reliable indices. METHODS: 632 patients were reviewed retrospectively. Fifty patients with thrombocytopenia were included as cases and matched with 100 control patients. Clinical manifestations at first thrombocytopenic episode were recorded. Classification criteria at diagnosis, basic immunological profiles, disease activity (ECLAM), and end organ damage (SLICC) were recorded. RESULTS: 29/50 (58%) had thrombocytopenia at diagnosis of lupus. Haemorrhagic manifestations were associated with the degree of thrombocytopenia (p<0.001). Anticardiolipin antibodies were not related to the degree of thrombocytopenia or the severity of haemorrhagic manifestations. Megakaryocytes were normal or increased in 26/28 (93%) bone marrow specimens, indicating peripheral platelet destruction. Patients with high disease activity were more thrombocytopenic than controls (OR = 2.61, 95% CI 1.13 to 5.96, p = 0.009). Patients with low C3 or CH50 were more likely to be thrombocytopenic (OR = 2.36, 95% CI 1.05 to 5.26, p = 0.029). Median SLICC for lupus patients with thrombocytopenia was 2 (range 0-11) compared with 1 (range 0-12) for controls (p<0.001). No deaths occurred during thrombocytopenic episodes. CONCLUSIONS: Thrombocytopenia is not directly associated with end organ damage and mortality, but defines a subgroup of patients with higher morbidity and is thus a major complication of systemic lupus erythematosus, affecting overall prognosis.

Adult↗
PubMed2004

Primary Sjögren's syndrome: new clinical and therapeutic concepts.

Sicca features are the central clinical manifestations of Sjögren's syndrome (SS), but recent studies have confirmed that primary SS has a systemic expression, including extraglandular manifestations. Patients with a predominantly extraepithelial expression should be managed differently from patients with predominantly periepithelial or sicca limited disease. In coming years treatment will be based on muscarinic agonists for sicca features and immunosuppressive/biological agents for extraglandular features.

Humans↗
PubMed2004

Antibody response to the human stress protein BiP in rheumatoid arthritis.

OBJECTIVES: The human stress protein BiP (immunoglobulin binding protein) has been implicated in the pathogenesis of rheumatoid arthritis (RA) since BiP was found to stimulate synovial T-cell proliferation and anti-BiP antibodies are present in the serum of RA patients. The aim of this study was the development of a rapid and reproducible enzyme-linked immunosorbent assay (ELISA) to determine the specificity and sensitivity of anti-BiP antibodies in RA. METHODS: An ELISA was developed that detected antibodies to BiP. The prevalence of anti-BiP antibodies was determined in sera from patients with early and established RA, sera antedating the onset of RA and sera from patients with other inflammatory and autoimmune diseases and healthy controls. RESULTS: We have confirmed the increased prevalence of antibodies to BiP in the sera of a large cohort of patients with established RA (specificity 71% and sensitivity 73%) and early RA (specificity 65% and sensitivity 66%). In pre-disease sera, median 2.5 yr (interquartile range 1.1-4.7) before symptoms of joint disease, the sensitivity for anti-BiP antibodies was 45% and the specificity was 65% for the development of RA. CONCLUSION: Antibodies to BiP are found in the sera of patients with RA and in sera antedating the onset of RA.

Adult↗
PubMed2004

Impaired elastic properties of ascending aorta in patients with giant cell arteritis.

OBJECTIVE: To investigate the elastic properties of the ascending aorta in untreated patients with giant cell arteritis compared with age and sex matched normal controls. METHODS: Distensibility of the ascending aorta and aortic strain were measured in 22 patients with a recent diagnosis of giant cell arteritis (documented by a positive temporal artery biopsy) before initiation corticosteroid treatment, and in 44 age and sex matched healthy subjects. Aortic distensibility was calculated as 2x[pulsatile change in aortic diameter]/[(diastolic aortic diameter)x(aortic pulse pressure)], and aortic strain as [pulsatile change in aortic diameter]/[diastolic aortic diameter]. Aortic diameters were measured by echocardiography. Aortic pressures were obtained by external sphygmomanometry. RESULTS: Distensibility of the ascending aorta and aortic strain were both lower in patients with giant cell arteritis than in the controls (p<0.01). In the patients with giant cell arteritis, aortic distensibility was inversely correlated with white blood cell count (p<0.05), but not with erythrocyte sedimentation rate or C reactive protein. CONCLUSIONS: Compared with healthy subjects, aortic distensibility and aortic strain are decreased in patients with giant cell arteritis before initiation of corticosteroid treatment. There was an association between the degree of reduction of aortic distensibility and the white blood cell count in the patient group.

Aged↗
PubMed2004

Combined therapy with rituximab plus cyclophosphamide/doxorubicin/vincristine/prednisone (CHOP) for Sjögren's syndrome-associated B-cell aggressive non-Hodgkin's lymphomas.

OBJECTIVE: To determine the safety and therapeutic response of a regimen consisting of cyclophosphamide/doxorubicin/vincristine/prednisone (CHOP) plus rituximab in patients with Sjögren's syndrome (SS) and aggressive non-Hodgkin's lymphoma (NHL). METHODS: Four SS patients with aggressive marginal zone NHL were enrolled in this trial. All patients were classified according to the newly proposed revised European-American classification of lymphoid neoplasms. Three out of four patients also had mixed cryoglobulinaemia (MC) of type II. They were treated every 3 weeks for eight cycles of CHOP. Patients also received rituximab, at a dose of 375 mg per square metre, on day 1 of each of the eight cycles of CHOP. Four weeks after completion of the eighth course of CHOP plus rituximab and every 6 months thereafter, patients were re-evaluated for response. RESULTS: Complete remission of lymphoma was achieved in all four patients. The lymphoma patients remained in remission for a period of 23, 15, 12 and 10 months respectively, while certain signs and symptoms of MC type II (purpura, peripheral neuropathy and arthralgias) significantly improved with treatment. In addition, the titres of circulating cryoglobulins and RF decreased, while C4 levels returned to normal. CONCLUSION: CHOP plus rituximab was well tolerated and proved effective in SS patients with aggressive NHL. Our observations may warrant a larger controlled trial to assess the effectiveness of this regimen in such patients.

Adult↗