Plasma myeloperoxidase levels in acute brain ischaemia and high grade carotid stenosis

BACKGROUND AND PURPOSE

Myeloperoxidase (MPO) is an important oxidative enzyme participating in different stages of cardiovascular disease and predicts prognosis. Little is known about its role in acute cerebrovascular events and carotid plaque vulnerability. In this study, the aim was to assess plasma MPO levels in acute stroke patients and their correlation to stroke severity and stroke outcome.

METHODS

Plasma MPO levels were assessed in patients presenting with acute brain ischaemia within 36 h of symptom onset (n = 144, mean age 64.7 ± 11.6 years, 67% men) and in patients with moderate-to-severe carotid stenosis undergoing carotid artery stenting (n = 51, mean age 66.3 ± 8.4 years, 75% men). Patients presenting with acute brain ischaemia were assessed serially for stroke severity and disability.

RESULTS

Plasma MPO concentrations (ng/ml) were associated with interleukin-6 (r = 0.38, P < 0.0001) and gender (median interquartile range) of 68.6 (49.8-107.0) vs. 59.7 (42.7-85.5) in women vs. men (P = 0.02). In acute brain ischaemia, MPO concentrations were associated with non-lacunar subtype (bottom, middle and top tertiles 37.5%, 71.7% and 71.7% respectively; P = 0.001), with stroke severity (baseline National Institutes of Health Stroke Scale score > 10, bottom, middle and top tertiles 6.3%, vs. 41.7% and 31.3%, respectively; P < 0.006) as well as with stroke severity at days 1-2, days 4-5 and at discharge (P < 0.05 for all), but less with disability at discharge (modified Rankin Scale score ≥ 2, 41.7% vs. 60.4% and 58.7% for the bottom, middle and top tertiles, respectively; P = 0.096).

CONCLUSIONS

Amongst patients with acute brain ischaemia, plasma MPO concentrations were associated with stroke severity and non-lacunar subtype, but not with long-term functional disability.

Effects of anti-cardiolipin antibodies and IVIg on annexin A5 binding to endothelial cells: implications for cardiovascular disease

OBJECTIVES

Anti-phospholipid antibodies (aPL), including anti-cardiolipin antibodies (aCL), are risk factors for cardiovascular disease (CVD) in the general population and in patients with the anti-phospholipid syndrome (APS; Hughes syndrome). APS may be primary but is also common in patients with systemic lupus erythematosus (SLE). The anti-coagulant protein annexin A5 (ANXA5) is implicated in CVD by interfering with phospholipids and aPL.

METHODS

ANXA5 binding to human umbilical venous endothelial cells (HUVECs) was determined by flow cytometry.

RESULTS

When cells were cultured in serum from APS patients with a high aPL titre (aPL-S), binding of ANXA5 to HUVECs was reduced. Monoclonal immunoglobulin (Ig)G aPL against cardiolipin (mAb-CL) dose-dependently reduced ANXA5 binding to endothelium. Preincubation of intravenous (IV)Ig at therapeutically relevant doses with aPL-S and mAb-aCL restored ANXA5 binding to comparable levels when normal healthy serum (NHS) was used. By contrast, IVIg per se had the capacity to reduce ANXA5 binding to endothelium when added to NHS (but not to aPL-S).

CONCLUSIONS

Decreased ANXA5 binding to endothelium, mediated by aPL, is a novel mechanism of atherothrombosis that can be countered by IVIg in vitro. IVIg per se could, to a lesser degree, cause decreased ANXA5 binding in NHS, which raises the possibility that some antibodies in IVIg can be involved in a side-effect reported in IVIg treatment, namely atherothrombosis and CVD. Increasing ANXA5 binding, either by addition of ANXA5 or by use of neutralizing antibodies in IVIg, represents a possible therapeutic strategy that deserves further study.

TSH receptor antibody (TRAb) assays based on the human monoclonal autoantibody M22 are more sensitive than bovine TSH based assays

Measurements of TSH receptor autoantibodies (TRAb) using assays based on the human monoclonal TSH receptor autoantibody M22 or bovine TSH have been compared in 136 adult patients. They suffered from Graves' disease (GD, n=62), Hashimoto's thyroiditis (HT, n=26), or non-autoimmune hyperthyroidism (NAH, n=48) and were selected on the basis of undetectable, borderline or low TRAb levels (0.6-3 IU/l) as measured by TSH based TRAb assay (Dynotest TRAKhuman from BRAHMS). The time interval between initial diagnosis of GD and TRAb determination was high and ranged from 1 month to 3.5 years (median: 2.3 years). Using the kit manufacturer's cutoff values, 53/62 (85.5%) of the selected group of GD patients were TRAb positive (>0.4 IU/l) by M22 based TRAb ELISA (Medizym TRAb clone, Medipan) and 45/62 (72.6%) were TRAb positive (>1.5 IU/l) by TSH based TRAb assay. In the HT group, 9/26 (34.6%) sera were positive in the M22 based ELISA and all but one of these 9 were positive or borderline in the TSH based assay. ROC plot analysis of the GD group using the NAH group as reference showed that at 95% specificity, the bovine TSH based TRAb assay had a sensitivity of 62.9% (cutoff for positivity=1.64 IU/l) and the M22 based TRAb ELISA a sensitivity of 90.3% (cutoff for positivity=0.32 IU/l). Overall therefore, the M22 based Medizym TRAb clone assay is more sensitive than the bovine TSH based Dynotest TRAK human assay.

Prevalence and clinical correlations of antibodies against six beta2-glycoprotein-I-related peptides in the antiphospholipid syndrome

Two-hundred ninety five patients with the antiphospholipid syndrome (APS) were studied for the presence of antibodies against six anti-beta2GPI-related peptides Abs. The prevalence of a wide spectrum of clinical and laboratory parameters of APS was evaluated in all patients, and correlated with the presence of each anti-beta2GPI peptide antibody. The rates of the various antipeptides Abs ranged from 18.0 to 63.7%. Altogether, 87.1% of the patients had antibody reactivity against at least one of the six beta2GPI-related peptides. A high degree of simultaneous reactivity against several beta2GPI-peptides was found. Positive and negative correlations were found between several antipeptides Abs and the rates of thrombosis and fetal loss. Our results point to a heterogeneous activity of antiphospholipid Abs in APS patients, directed, often concurrently, against various epitopes of the beta2GPI molecule. Evaluation of APS patients for the presence of specific antipeptides Abs may be of a value in predicting the risk for future thrombotic and obstetrical complication, as well as for specific therapeutic purposes.

Antiprothrombin antibodies are associated with pregnancy loss in patients with the antiphospholipid syndrome

OBJECTIVE

To document the clinical association between the history of pregnancy loss in patients with the diagnosis of primary or secondary antiphospholipid syndrome (APS) and the presence of different antiprothrombin antibody subtypes [immunoglobulin G (IgG), IgM and IgA] in a cohort of patients with APS.

METHODS

Records of 170 female patients with primary APS, or APS secondary to systemic lupus erythematosus (SLE) or secondary to other autoimmune diseases were studied.

RESULTS

In female APS patients with IgG antiprothrombin antibodies (n = 105) significant associations to pregnancy loss (p < 0.0001), early pregnancy loss (p < 0.0001) and a negative association to thrombocytopenia (p < 0.01) could be identified. In the group of patients with IgG antiprothrombin antibodies and at least one pregnancy (n = 84) a significant association with pregnancy loss (p < 0.005) and especially with early pregnancy loss (p < 0.0001) was demonstrated. No association with other immunoglobulin subtypes of antiprothrombin antibodies could be documented. In the subgroup of patients with primary APS and at least one pregnancy in the history, pregnancy loss (p < 0.005) and early pregnancy loss (p < 0.0001) were found to be highly associated with the presence of IgG antiprothrombin antibodies. IgG antiprothrombin antibodies represent the highest independent risk factor for pregnancy loss with an odds ratio of 4.5. There was no statistically significant association with venous or arterial thrombosis in all IgG antiprothrombin antibody positive patients.

CONCLUSION

The results of this study document the association of IgG antiprothrombin antibodies with pregnancy loss and in particular early pregnancy loss in a large and well-characterized cohort of patients. We would recommend routine testing for antiprothrombin antibodies in young female patients with APS.

[Antiphospholipid syndrome. Pathogenesis, molecular basis and clinical aspects]

BACKGROUND

In 1983 the antiphospholipid syndrome was first described as an independent clinical entity by Graham Hughes and characterized by thrombosis, thrombocytopenia and recurrent fetal losses. In the following years evidence accumulated from various studies that the thrombotic events in the antiphospholipid syndrome correlate with elevated serum titers of antiphospholipid antibodies. These autoantibodies represent a very heterogeneous group as multiple specificities against various negatively charged phospholipids are found. Most commonly described are antibodies against cardiolipin, but also cross-reactivities between the different phospholipids are observed. Moreover, efficient binding of antiphospholipid antibodies against a phospholipid requires the presence of certain protein-cofactors which on the other hand can be antigens themselves.

PATHOGENESIS

Although numerous animal models strongly indicate that antiphospholipid antibodies play a causal role in the pathogenesis of the disease, the exact pathogenetic mechanisms are still to be elucidated. There is accumulating evidence from in vitro studies with poly- and monoclonal antiphospholipid antibodies that these autoantibodies are able to interfere with all aspects of the hemostatic balance. Influences of antiphospholipid antibodies on plasmatic processes of the coagulation cascade as well as antithrombotic and fibrinolytic mechanisms are described. Furthermore, antiphospholipid antibodies are able to exert prothrombotic effects on cells participating in hemostasis, mainly platelets and endothelial cells.

THERAPEUTIC APPROACHES

Therapeutic approaches to the antiphospholipid syndrome today are mainly restricted to the prevention of further thrombosis by permanent anticoagulation. Although 30-50% of all patients, according to the literature, with moderately to highly elevated antiphospholipid antibody titers develop the clinical symptoms of the syndrome, there are only few studies investigating the benefits of a prophylactic anticoagulation of the affected patients. There is an urgent need for prospective clinical studies to clarify this question. Therapy of nonthrombotic manifestations of the antiphospholipid syndrome are scarcely standardized. In obstetrics, treatment with aspirin, heparin and steroids is the main approach. Here also controlled studies are restricted to small numbers of patients and are therefore of limited validity.

New approaches in the diagnosis of sepsis

In diagnosing sepsis the rapid identification of bacteremia at an early stage of the disease is critical for a favorable outcome. Furthermore, it is important that exact information on the stage of the disease be obtained rapidly in order to choose and initiate the appropriate therapy. In recent years many new techniques have been added to the diagnostic tools. In this review we will focus on three new methods for the early diagnosis of sepsis. These are: polymerase chain reaction, which offers the possibility to attain detailed information about the involved bacterial (or viral) species, and the laboratory markers procalcitonin and hypophosphatemia, which are indicators of the presence of infection with gram-negative bacteria. The approaches reviewed here were developed to expedite the diagnosis of especially early sepsis and might be a further step towards the improvement of therapy for sepsis.

Simulated bone erosions in a hand phantom: detection with conventional screen-film technology versus cesium iodide-amorphous silicon flat-panel detector

PURPOSE

To assess the diagnostic performance of an active-matrix flat-panel x-ray detector for reduced-dose imaging of simulated arthritic lesions.

MATERIALS AND METHODS

A digital x-ray detector based on cesium iodide and amorphous silicon technology with a panel size of 43 x 43 cm, matrix of 3,000 x 3,000 pixels, pixel size of 143 micrometer, and digital output of 14 bits was used. State-of-the-art screen-film radiographs were compared with digital images obtained at doses equivalent to those obtained with system speeds of 400, 560, and 800. The phantom was composed of a human hand skeleton on an acrylic plate with drilled holes simulating bone erosions of different diameters and depths. Results of four independent observers were evaluated with receiver operating characteristic curve analysis.

RESULTS

The cesium iodide and amorphous silicon detector resulted in better diagnostic performance than did the screen-film combination, with the dose being the same for both modalities (P <.05). For digital images obtained at reduced doses, no significant differences were found.

CONCLUSION

The improved diagnostic performance with digital radiographs obtained with the cesium iodide and amorphous silicon detector suggests that this detector technology holds promise in terms of dose reduction for specific diagnostic tasks, without loss of diagnostic accuracy.

Isolation and characterization of two human monoclonal anti-phospholipid IgG from patients with autoimmune disease

The antigenic specificity of anti-phospholipid antibodies (APA) is a matter of intensive investigation. To further characterize these antibodies, we attempted to isolate human monoclonal APA. B-cells of patients with at least one positive test for antibodies against cardiolipin, phosphatidylserine, beta2-glycoprotein I (beta2-GPI) or the lupus anti-coagulant were immortalized by transformation with Epstein-Barr virus and screened for production of specific IgG. Positive pools were fused with a heteromyeloma cell line and APA-secreting clones were isolated by standard procedures. Two monoclonal APA, HL-5B from a 51-year-old man with primary anti-phospholipid syndrome and recurrent cerebral microinfarctions, and RR-7F from a 48-year-old women with systemic lupus erythematosus but no evidence for thrombotic events were obtained. HL-5B is of the IgG2 subtype with lambda light chains, while RR-7F is IgG2 with kappa light chains. Both monoclonals show reactivity against cardiolipin and phosphatidylserine but lack reactivity against beta2-GPI or lupus anti-coagulant activity. To yield the same OD in the cardiolipin and phosphatidylserine ELISAs RR-7F must be used in an approximately 10-fold higher concentration than HL-5B, indicating a lower affinity towards these antigens. Interestingly, both mAPA can bind to cardiolipin in the absence of beta2-GPI. They do not cross-react with dsDNA but show reactivity against oxidized low-density lipoproteins. Analysis of the heavy chain mRNA of HL-5B and RR-7F showed that both are members of the VH3 family. While HL-5B shows extensive somatic mutations in the CDR1 and 2 regions, indicating that it was derived by a T cell-dependent antigen driven process, RR-7F is apparently germline encoded. The two monoclonal APA can be used as tools in further structural and functional analyses.

A new antigenic epitope localized within human kappa light chains specific for rheumatoid arthritis and systemic lupus erythematosus

Human B cell hybridomas were established to define new autoantigens of importance for autoimmune diseases such as rheumatoid arthritis (RA). One lgG1, lambda monoclonal antibody (FKN-E12), was derived from synovial B lymphocytes of a patient with sero-negative RA. The purified lg was used to select specifically binding peptides from a random peptide phage display library. Only one epitope with the heptamer sequence HLTFGPG was detected and named RASFp1. Very similar and partly identical sequences are found in the variable region of lg kappa light chains in position 96-101, at the junction of framework 2 and the J-region. The antibody FKN-E12 was shown to detect the epitope RASFp1 also on human lgG kappa chains, but only in a specific conformation. The aim of the present study was to analyse human sera from patients with autoimmune diseases, non-autoimmune inflammatory diseases and healthy blood donors for the presence of lgG binding to RASFp1. For this purpose a 15-mer-peptide was synthesized containing RASFp1 within Vk-derived flanking regions, and an ELISA assay established. Sera of 142 individuals were studied. Only <5% of the control sera including sera from patients with non-autoimmune inflammations were positive. In contrast, 45% of sera from patients with RA or SLE contained RASFp1-binding antibodies. Within the 40 RA sera analysed so far, rheumatoid factors and RASFp1-binding antibodies have shown no correlation with each other.

Monoclonal autoantibodies from patients with autoimmune diseases: synovial fluid B lymphocytes of a patient with rheumatoid arthritis produced an IgG lambda antibody recognizing J-sequences of Ig kappa chains in a conformation-dependent way

Synovial fluid B cells from a patient with seronegative rheumatoid arthritis were immortalized by electrofusion. The specificity of clone FKN-E12 (IgG1 lambda) was analysed by screening a phage display random peptide library. One heptamer sequence was identified (RASFp1 = HLTFGPG). Three human IgG kappa antibodies contained a highly homologous sequence (xLTFGPG) at the junction of V- and J-regions. Homologies were also found in distinct humans (J kappa 3, J kappa 4) and murine (J kappa 5) J kappa-sequences (TFGPG, LTFGxG), and to a lower degree in all remaining J kappa-sequences (TFGxG). Binding and binding inhibition assays showed that FKN-E12 bound to kappa light chains tested in a conformation-dependent way: it reacted only with IgG kappa or IgA kappa chains adhered to a plastic surface, but not in soluble form. In conclusion, FKN-E12 detects a conformational epitope on probably all kappa light chains, which could be definded by screening a phage library displaying linear epitopes.

Favorable role of interleukin 10 in patients with polymyalgia rheumatica

OBJECTIVE

To determine the relationship between the antiinflammatory molecule interleukin 10 (IL-10) and disease symptoms, IL-1beta, tumor necrosis factor (TNF), and IL-1 receptor antagonist (IL-1ra) in patients with polymyalgia rheumatica (PMR).

METHODS

In 102 patients with PMR, we determined the severity of the disease by the presence of typical clinical symptoms (symptom score with a maximum of 10 points). IL-10, IL-1beta, TNF, and IL-1ra were measured in all patients and 31 age matched healthy controls by enzyme immunometric assays.

RESULTS

Compared to patients with elevated serum levels, patients with normal serum levels of IL-10 (below the mean + 3 SD of controls, 7.79 pg/ml) more often had adynamia (p = 0.045), bilateral muscular pain in shoulders, upper arms or neck (p = 0.045), bilateral muscular pain in the pelvic girdle (p < 0.001), headache (p = 0.014), morning stiffness (p < 0.001), symptoms of depression (p = 0.013), and initial weight loss (p = 0.011), and had a higher symptom score (5.5+/-0.4 vs 3.7+/-0.3; p < 0.001). The overall symptom score correlated negatively with IL-10 serum levels (Rrank = -0.421, p < 0.001). IL-10 correlated negatively with IL-1beta (p = 0.013) and TNF-alpha (p = 0.039). The association between elevated serum levels of IL-10 and low serum levels of IL-1beta and TNF was observed only in patients with corticosteroid treatment. In these patients, elevated serum levels of IL-10 were positively associated with an increased ratio of IL-1ra to IL-1beta.

CONCLUSION

Elevated serum levels of IL-10 were associated with a more mild form of PMR. This study indicates a favorable role of IL-10 in patients with PMR.

Immortalized B-lymphocytes from rheumatoid synovial tissue show specificity for bacterial HSP 60

Several studies indicate a pathogenetic role of T-lymphocytes with specificity for heat shock proteins (HSP) in rheumatoid arthritis (RA). Surprisingly, there are no experimental data for B-lymphocytes with specificity for HSP. To investigate whether B-lymphocytes from rheumatoid synovial tissue show a specificity for HSP 60 we immortalized synovial tissue B-lymphocytes by the electrofusion technique and tested the specificity of the B-cell clones for HSP 60 by ELISA. Tissue samples from four patients with classic, active RA were used in this study. The isolated cells were electrofused in strongly hypo-osmolar medium with cells either of the mouse strain X63-Ag8-653 (Ag8) or the heteromyeloma strain HAB-1. Clones positive for IgG, the IgG fraction of the supernatant of the isolated synovial cells and the IgG of the serum of the patients were tested in an ELISA for reactivity to the recombinant HSP 60 or Yersinia enterocolitica, which shows great homology with mycobacterial HSP 65 and human HSP 60. The expression of this HSP 60 was studied in normal and rheumatoid synovial tissue using a polyclonal rabbit serum against HSP 60 from Y. enterocolitica (Ye HSP 60). In this way we investigate differences in the expression of HSP 60 and compared the pattern of this HSP60 with the pattern of mycobacterial HSP65 and human HSP 60 described by others. In three of four patients 10 IgG secreting B-cell clones showing a specificity for HSP 60 were detected. IgG specific for HSP 60 was also detected in the supernatant of the isolated synovial cells before fusion and in the serum of these patients. HSP 60 was demonstrated immunohistochemically within the rheumatoid synovial tissue and showed stronger expression with a different distribution when compared with the expression in normal synovial tissue. B-cell clones from rheumatoid synovial tissue thus exhibit a specificity for bacterial HSP 60, and a monospecific rabbit serum against this HSP shows strong reactivity within the rheumatoid synovial tissue. It may be postulated that a humoral HSP 60 response, initially directed against an infectious agent, could react with cross-reactive epitopes of rheumatoid synovial tissue or with self-HSP perpetuating the local inflammatory process.

Electro-immortalization of B lymphocytes isolated from stomach carcinoma biopsy material

The advantages of electrofusion were used to immortalize the small number of B-cells from fresh biopsy material taken from a gastric carcinoma of a patient. Two stable human antibody secreting clones could be produced which exhibited functional activity against the autologous tumour cells (inhibition of cell adhesion and immunofluorescence staining of the membranes). This shows that a variety of hitherto inaccessible B lymphocyte populations from other human organ biopsies can be immortalised by the improved electrofusion technique.