A. G. Tzioufas

The Th1/Th2 cytokine balance changes with the progress of the immunopathological lesion of Sjogren's syndrome.

Expression of type‐1 and type‐2 cytokines at the mRNA level in labial salivary glands (LSG) of patients with Sjogren’s syndrome (SS), as reported by several groups, have generated conflicting results. In the present study we have directly examined the production of IL‐4, IL‐13 and IFN‐γ by lymphocytes infiltrating the LSG of 44 consecutive patients referred for SS evaluation. Cytokines production was evaluated following in vitro culture of LSG in the presence of IL‐2. IFN‐γ and IL‐13 were detected in the majority of SN (24/44 and 26/44, respectively) while IL‐4 was present in 5/44 SN. The presence of IFN‐γ was significantly higher in SS patients, as opposed to patients who did not fulfil the criteria for SS (P < 0·01). In addition, almost all cultured lymphocytes expressed mRNA for IFN‐γ (17/19 cultures) and IL‐13 (18/19) while IL‐4 mRNA was also expressed at high frequency (14/19 cultures). Interestingly, the IFN‐γ mRNA copies in cultured lymphocytes correlated significantly with the intensity of lymphocytic infiltration as evaluated by Chisholm’s score (P < 0·01). Furthermore, RT‐PCR of RNA extracted from whole LSG from 14 SS patients also demonstrated the presence of all cytokines in the majority of the cases and the prevalence of IFN‐γ in LSG with high‐grade infiltration. Because IL‐13 was produced by the majority of the cultured LSG, IgE production was also evaluated. Interestingly, IgE was detected in 21/44 LSG culture SN and mainly in those biopsies that had Chisholm’s score less than 0·5 (P < 0·05). We conclude that lymphocytes infiltrating the LSG are capable of producing both Th1 and Th2 cytokines and that the balance between them shifts in favour of Th1 in LSG with high infiltration score and in patients with SS.

Expression of functional Toll-like receptors by salivary gland epithelial cells: increased mRNA expression in cells derived from patients with primary Sjögren's syndrome

Toll‐like receptors (TLR) play an essential role in the activation of both innate and adaptive immune responses. Salivary gland epithelial cells (SGEC) may participate in the development of glandular inflammatory reactions that characterize primary Sjögrens syndrome (pSS). In this study we sought to assess the expression and function of several TLR molecules in cultured non‐neoplastic SGEC obtained from pSS patients and disease controls. Long‐term cultured non‐neoplastic SGEC derived from pSS patients (SS‐SGEC) and disease controls (control‐SGEC), as well as the monocytic cell line THP‐1 (positive control cell line), were examined by reverse transcription–polymerase chain reaction (RT–PCR) analysis and quantitative real‐time PCR for mRNA expression of TLR1, ‐2, ‐3 and ‐4 molecules. TLR function was assessed by the induction of the expression (flow cytometry) of the immunoregulatory molecules CD54/intercellular adhesion molecule‐1 (ICAM‐1), CD40, CD86/B7·2, major histocompatibility complex (MHC) class I and MHC class II following treatment with the TLR ligands: Staphylococcus aureus peptidoglycan (TLR2), the synthetic dsRNA analogue polyinosinic:cytidylic acid (TLR3) and Escherichia coli lipopolysaccharide (TLR4). SGEC were found to express functional TLR2, ‐3 and ‐4 molecules, as attested by dose‐dependent up‐regulation of surface ICAM‐1, CD40 and MHC‐I expression (as well as of reciprocal TLR mRNA) following treatment with the respective TLR‐ligands. SS‐SGEC lines displayed significantly higher constitutive expression of TLR1 (P = 0·0027), TLR2 (P = 0·01) and TLR4 (P = 0·03) mRNA compared to control‐SGEC. This study demonstrates that cultured SGEC express functional TLR molecules; the high constitutive TLR expression by SS‐SGEC is probably suggestive of the intrinsic activation of epithelial cells in pSS and further supports the role of this type of tissue in pathogenesis of the disorder.

The clinical relevance of antibodies to ribosomal-P common epitope in two targeted systemic lupus erythematosus populations: a large cohort of consecutive patients and patients with active central nervous system disease

OBJECTIVES To develop an enzyme linked immunosorbent assay (ELISA) using as substrate a synthetic 22-aminoacid peptide, corresponding to the ribosomal P0, P1 and P2 common epitope. To study the specificity and sensitivity of the method and evaluate the frequency and clinical associations of anti-P antibodies in two groups of systemic lupus erythematosus (SLE) patients: (a) unselected SLE patients and (b) SLE patients with central nervous system (CNS) involvement. PATIENTS AND METHODS The C-terminal 22 aminoacid peptide of the ribosomal P proteins (Lys-Lys-Glu-Glu-Lys-Lys-Glu-Glu-Lys-Ser-Glu-Glu-Glu-Asp-Glu-Asp-Met-Gly-Phe-Gly-Leu-Phe-Asp) was synthesised according to Merrifields solid phase procedure. Purification of the peptide was performed by preparative high performance liquid chromatography and confirmed by amino acid analysis. Using this peptide, in a concentration 5 μg/ml, an ELISA was developed. The presence of anti-P antibodies was evaluated by western blot using purified ribosomal proteins from rat liver. Sera from 178 consecutive patients with SLE and 28 patients with SLE and CNS manifestations were tested. Sera from 58 patients with rheumatoid arthritis and 57 patients with primary Sjögrens syndrome were used as controls. The cut off point of the assay was defined using 124 normal sera. RESULTS The specificity of the assay was evaluated by homologous inhibition. Pretreatment of positive sera with soluble 22mer peptide of the ribosomal P proteins resulted in 88% inhibition. The concordance between the peptide assay and western blot was found to be 83%. Thirty three of 178 (18.6%) of the unselected SLE patients had antibodies to P-protein common epitope. Their presence was associated with more active disease (European Consensus Lupus Activity Measurement, ECLAM scoring system) (p<0.001), higher levels of anti-ds DNA antibodies (p<0.05) and lower levels of the C4 component of complement (p<0.01). Eleven of 28 (39.3%) patients with SLE and active CNS involvement had antibodies to P-protein. The overall prevalence of anti-P antibodies in active CNS disease patients was statistically significantly higher, as compared with unselected SLE patients (χ2=6.04, p<0.05). These antibodies were found in a high proportion of patients without anticardiolipin antibodies (52.4%) and they were associated with diffuse CNS involvement (psychiatric disorders (71%) and epilepsy (75%)). CONCLUSIONS A synthetic analogue of the common epitope of ribosomal P-proteins can be use as an antigen for the detection of anti-P antibodies. These antibodies are associated with active SLE and CNS involvement particularly in patients without anticardiolipin antibodies.

European therapeutic trials in ANCA-associated systemic vasculitis: disease scoring, consensus regimens and proposed clinical trials EUROPEAN COMMUNITY STUDY GROUP ON CLINICAL TRIALS IN SYSTEMIC VASCULITIS ECSYSVASTRIAL (BMHl-Cr93-1078)

In previous phases of this project, proteinase 3 (PR3) and myeloperoxidase (MPO), the main antigenic target molecules of antineutrophil cytopiasmic antibodies, were isolated and applied in standardized ELISAs. In this study, standardized ELISAs with three PR3 preparations (from Copenhagen (CO), Raisdorf (RS) and Leiden (LF)) and one MPO preparation (from Copenhagen), were evaluated in a large retro-and prospective clitiical study. New patients (n=174) with primary systemic vasculitis (Wegeners granulomatosis, microscopic polyangiitis and idiopathic rapidly progressive glomerulonephritis, classical PAN and Churg-Strauss Syndrome) were included. Retrospectively, another 190 patients were evaluated. Furthermore control sera were obtained from patients with other forms of vasculitis, glomerulonephritis or granulomatous diseases (disease controls, n = 184) and healthy donors (healthy controls, n = 728). All patients were categorized by a system based on clinical and histoiogical data. Patients were followed up for at least 1 year after diagnosis in order to evaluate a possible correlation between ANCA levels and disease activity. The sensitivity of the anti-PR3 assays for histologically proven WG was between 59% and 69% in new patients, with a sensitivity of 22% for the anti-MPO assay. Similar figures were found for patients with clinically suspected WG. This was comparable with the results of the IIF test. In MPA and IRPGN a larger percentage of patients had antiMPO antibodies than in WG. Only a few patients with PAN and CSS were investigated, and most of these were negative in the ELISAs. The specificity ofthe assays for disease controls was 89-91% for the anti-PR3 assays and 95% for the anti-MPO assay. In the healthy controls the specificity was 98-99%. The specificity of the IIF test was 97% for a cANCA pattern and 81 % for a pANCA pattern in disease controls. The combination of cANCA with anti-PR3 and pANCA with anti-MPO both had a specificity of 99%. Further details will be presented during the meeting, in addition to the results of a follow-up study with correlation ofdisease activity and ANCA level. From this study we can conclude that ELISAs using purified PR3 or MPO are not more sensitive than the IIF test. However, the anti-MPO assay is more specific for systemic vascuitis as compared to disease controls with related diseases. Furthermore, the combination of the IIF test with antigen-specific ELISAs is very specific for the diagnosis Wegetiers granulomatosis, microscopic polyangiitis and idiopathic rapidly progressive gtomerulonephritis.

Myelodysplasia-associated autoimmunity: clinical and pathophysiologic concepts.

Myelodysplastic syndrome (MDS), an acquired clonal disorder of haemopoietic progenitor cells, is characterized by haemopoietic insufficiency associated with cytopenias, leading to serious morbidity plus the additional risk of leukaemic transformation. In MDS an acquired insult to the haemopoietic stem cell leads to impaired differentiation and myelodysplasia. However, there is increasing evidence that the marrow failure of MDS is immune‐mediated. A model of MDS pathophysiology suggests that transformation of normal stem cells induces an autoimmune T‐cell response with the bone marrow as the target organ. This autoimmune attack results in chronic overproduction of pro‐apoptotic cytokines, especially tumour necrosis factor alpha (TNFα). In addition, several reports have revealed that approximately 10% of MDS patients have clinical autoimmune disorders. This review illustrates the cellular/molecular mechanisms and the implication of the tumour suppressor gene interferon regulatory factor‐1 (IRF‐1) in the pathophysiology of MDS‐associated autoimmune deregulation.

Preliminary classification criteria for the cryoglobulinaemic vasculitis

Background To develop preliminary classification criteria for the cryoglobulinaemic syndrome or cryoglobulinaemic vasculitis (CV). Methods Study part I developed a questionnaire for CV to be included in the formal, second part (study part II). Positivity of serum cryoglobulins was defined by experts as an essential condition for CV classification. In study part II, a core set of classification items (questionnaire, clinical and laboratory items, as agreed) was tested in three groups of patients and controls—that is, group A (new patients with the CV), group B (controls with serum cryoglobulins but lacking CV) and group C (controls without serum cryoglobulins but with features which can be observed in CV). Results In study part I (188 cases, 284 controls), a positive response to at least two of three selected questions showed a sensitivity of 81.9% and a specificity of 83.5% for CV. This questionnaire was employed and validated in study part II, which included 272 patients in group A and 228 controls in group B. The final classification criteria for CV, by pooling data from group A and group B, required the positivity of questionnaire plus clinical, questionnaire plus laboratory, or clinical plus laboratory items, or all the three, providing a sensitivity of 88.5% and a specificity of 93.6% for CV. By comparing data in group A versus group C (425 controls), the same classification criteria showed a sensitivity 88.5% and a specificity 97.0% for CV. Conclusion Classification criteria for CV were developed, and now need validation.

Fine specificity of autoantibodies to La/SSB: epitope mapping, and characterization

The B cell epitope mapping of La/SSB was performed using 20 mer synthetic peptides overlapping by eight amino acids covering the whole sequence of the protein. IgG, purified from sera of five patients with systemic lupus erythematosus (SLE) and four sera from patients with primary Sjögrens syndrome (pSS) were tested against the overlapping synthetic peptides. Peptides highly reactive with purified IgG were those spanning the regions 145–164, 289–308, 301–320 and 349–368 of the La protein. Determination of the minimum required length of the antigenic determinants disclosed the following epitopes:147HKAFKGSI154, 291NGNLQLRNKEVT302, 301VTWEVLEGEVEKEALKKI318 and 349GSGKGKVQFQGKKTKF364. Predicted features and molecular similarities of the defined epitopes were investigated using protein databases. The La epitope 147HKAFKGSI154 presented 83.3% similarity with the 139HKGFKGVD146 region of human myelin basic protein (MBP) and 72% similarity with the fragment YKNFKGTI of human DNA topoisomerase II. Peptides corresponding to these sequences cross‐reacted with anti‐La/SSB antibodies. Sixty‐three sera with anti‐La/SSB antibodies from patients with pSS or SLE, 35 sera without anti‐La/SSB antibodies from patients with SS or SLE and 41 sera from age/sex‐matched healthy blood donors were tested against biotinylated synthetic epitope analogues in order to determine their sensitivity and specificity for the detection of anti‐La/SSB antibodies. Anti‐La/SSB were detected with various frequencies ranging from 20% to epitope 147HKAFKGSI154 to 100% to epitope 349GSGKGKVQGKKTKF364. The overall sensitivity and specificity using all assays with the synthetic peptides were found to be 93.6% and 85.6%, respectively. In conclusion, antibodies to La/SSB constitute a heterogeneous population, directed against different linear B cell epitopes of the molecule. The epitope 147HKAFKGSI154 presents molecular similarity with fragments of two other autoantigens, i.e. human MBP and DNA topoisomerase II. Finally, synthetic epitope analogues exhibit high sensitivity and specificity for the detection of anti‐La/SSB antibodies.

Calreticulin binds preferentially with B cell linear epitopes of Ro60 kD autoantigen, enhancing recognition by anti-Ro60 kD autoantibodies.

Calreticulin is a molecular chaperone to newly synthesized polypeptides. Previous studies suggested that calreticulin is probably a protein member of the Ro/La RNP complex. The aims of this study were (a) to investigate whether linear B cell epitopes of the Ro/La RNP complex are bound to calreticulin and (b) if the complex peptide–calreticulin is recognized specifically by anti‐Ro autoantibodies. Calreticulin was isolated from either human or pig spleen using a multi‐step purification method and found to interact preferentially with biotinylated peptides derived from the sequence of the Ro60 kD 175–184aa(10p) and 216–232aa(17p). The interaction of the peptide–calreticulin complex was favoured by the combination of heat treatment, divalent cations and ATP. La/SSB epitopes did not react with calreticulin. Peptides corresponding to La/SSB epitopes as well as the common epitope of Sm did not interact with calreticulin. Thirty‐eight anti‐Ro60 KD positive and 23 anti‐Ro60 kD negative sera of patients with systemic lupus erythematosus (SLE) and primary Sjögrens syndrome (pSS) were tested. All anti‐Ro60 kD positive sera bound the complex calreticulin‐17p, while 95% of the same sera had activity against the complex calreticulin − 10p. Tested individually, calreticulin, pep10p and pep17p presented very low reactivity (8%, 11% and 29%, respectively) against anti‐Ro60 kD positive sera. Anti‐Ro60 KD negative sera did not exhibit significant reactivity either with calreticulin, 10ρ and 17ρ or with the complexes calreticulin − 10p and calreticulin‐17p (<5%). These results suggest that calreticulin can induce conformation‐dependent recognition of the Ro60 kD epitopes, leading eventually to their recognition by autoantibodies. This is the first time that such a relationship is shown between a chaperone protein and fragments of an intracellular autoantigen. This work also provides insights into the understanding of mechanisms for autoantibody production. Furthermore, this association can be proved useful for the development of new sensitive assays for autoantibody detection.

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 Sjögrens 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: 216KALSVETEKLLKYLEAV232 and pepCoxs: 31MVTSTITEKL LKNLVKI47, 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.

Epitope mapping of the Ro/SSA60KD autoantigen reveals disease-specific antibody-binding profiles

Anti‐Ro60KD autoantibodies are commonly found in sera from patients with primary Sjögrens syndrome (SS) and systemic lupus erythematosus (SLE). In order to identify the epitopes of this autoantigen, 22 ‐mer, synthetic peptides overlapping by eight residues, and covering the entire sequence of the Ro60KD autoantigen were prepared. Three groups of sera were evaluated according to their autoantibody specificities. The first group consisted of monospecific anti Ro60KD sera from four patients with SLE and one with SS, the second one was composed of anti‐Ro60KD + anti‐La(SSB)‐positive sera from four patients with SS and the third group included three normal sera and one anti Ro52KD serum. It was found that sera from SLE patients interact with a common antigenic site spanning the sequence TKYKQRNGWSHKDLLRSHLKP (169–190) of the Ro60KD protein. On the other hand, sera from SS patients recognise the ELYKEKALSVETEKLLKYLEAV (211–232) region of this autoantigen. Determination of the minimal required peptide length for optimal antibody recognition showed that the defined epitopes can be shortened to the NGWSHKDLLR (175–184) and KALSVETEKLLKYLEAV (216–232) sequences respectively. Inhibition experiments using the Ro60KD antigen and soluble peptides corresponding to the 175–184 and 216–232 segments further confirmed the specific antibody binding. These results, although only a small number of sera were used, indicate that the Ro60KD autoantigen, which is not charac‐ terized by disease specificity, contains two discrete epitopes specifically recognized from SLE and SS patient sera. Finally, the sequence similarity of the NGWSHKDLLR (175–184) epitope with some of the HLA haplotypes, associated with anti‐Ro response, deserves to be noted.