The predictive value of segmentation metrics on dosimetry in organs at risk of the brain

BACKGROUND

Fully automatic medical image segmentation has been a long pursuit in radiotherapy (RT). Recent developments involving deep learning show promising results yielding consistent and time efficient contours. In order to train and validate these systems, several geometric based metrics, such as Dice Similarity Coefficient (DSC), Hausdorff, and other related metrics are currently the standard in automated medical image segmentation challenges. However, the relevance of these metrics in RT is questionable. The quality of automated segmentation results needs to reflect clinical relevant treatment outcomes, such as dosimetry and related tumor control and toxicity. In this study, we present results investigating the correlation between popular geometric segmentation metrics and dose parameters for Organs-At-Risk (OAR) in brain tumor patients, and investigate properties that might be predictive for dose changes in brain radiotherapy.

METHODS

A retrospective database of glioblastoma multiforme patients was stratified for planning difficulty, from which 12 cases were selected and reference sets of OARs and radiation targets were defined. In order to assess the relation between segmentation quality -as measured by standard segmentation assessment metrics- and quality of RT plans, clinically realistic, yet alternative contours for each OAR of the selected cases were obtained through three methods: (i) Manual contours by two additional human raters. (ii) Realistic manual manipulations of reference contours. (iii) Through deep learning based segmentation results. On the reference structure set a reference plan was generated that was re-optimized for each corresponding alternative contour set. The correlation between segmentation metrics, and dosimetric changes was obtained and analyzed for each OAR, by means of the mean dose and maximum dose to 1% of the volume (Dmax 1%). Furthermore, we conducted specific experiments to investigate the dosimetric effect of alternative OAR contours with respect to the proximity to the target, size, particular shape and relative location to the target.

RESULTS

We found a low correlation between the DSC, reflecting the alternative OAR contours, and dosimetric changes. The Pearson correlation coefficient between the mean OAR dose effect and the Dice was -0.11. For Dmax 1%, we found a correlation of -0.13. Similar low correlations were found for 22 other segmentation metrics. The organ based analysis showed that there is a better correlation for the larger OARs (i.e. brainstem and eyes) as for the smaller OARs (i.e. optic nerves and chiasm). Furthermore, we found that proximity to the target does not make contour variations more susceptible to the dose effect. However, the direction of the contour variation with respect to the relative location of the target seems to have a strong correlation with the dose effect.

CONCLUSIONS

This study shows a low correlation between segmentation metrics and dosimetric changes for OARs in brain tumor patients. Results suggest that the current metrics for image segmentation in RT, as well as deep learning systems employing such metrics, need to be revisited towards clinically oriented metrics that better reflect how segmentation quality affects dose distribution and related tumor control and toxicity.

[Possible Significance of Bronchoalveolar Lavage Cytology at Initial Diagnosis and Follow-up of Lung Cancer]

Bronchoalveolar lavage [BAL] is an important procedure in the diagnosis of a variety of lung diseases. While it has enormous value in the diagnostics of inflammatory parenchymal diseases, its significance in lung cancer is unclear. Keeping in mind that immune therapy (e. g. application of checkpoint inhibitors) is gaining importance in the management of lung carcinoma, it is important to know if there are typical cellular patterns in BAL of lung cancer patients. Methods In a retrospective proof of principle-study, we analyzed 38 patients who underwent BAL at the initial diagnosis of lung cancer. Results We observed an elevated level of CD25 lymphocytes as well as an increased expression of DR antigen, both signaling lymphocyte activation. We could not find a typical cytologic pattern of inflammatory cells in lung carcinoma patients. Sensitivity of BAL to malignant cells was rare, thus confirming earlier analysis. Conclusion We could not demonstrate typical cellular patterns in BAL of lung cancer patients. Evaluation of specific microRNA patterns might play a supporting role in the initial diagnosis as well as follow-up of lung cancer patients.

Therapeutic drug monitoring of tricyclic antidepressants: how does it work under clinical conditions?

Therapeutic drug monitoring (TDM) of tricyclic antidepressants (TCA) is established in the treatment of depression to optimize outcome and safety. However, there are few reports on TDM under naturalistic clinical conditions. In the present study, we investigated a TDM group (TDM) and a randomly assigned parallel group without TDM (no-TDM) while on TCA treatment. Serum levels were analyzed in both cohorts, but feedback and dose recommendation were only provided for the TDM group. Serum levels of TCA were assessed by high-performance liquid chromatography (HPLC). The outcome was measured weekly using the Hamilton Depression Rating Scale (HAMD), the Clinical Global Impressions Scale (CGI), and the UKU side-effect scale. 84 patients with depressive disorder according to DSM-IV were recruited in three centers (TDM, n = 43; no-TDM, n = 41; mean age 49.9 +/- 13.2 years, 63.1 % female). Patients were treated with either amitriptyline (n = 69) or doxepin (n = 15); the mean dosage at endpoint was 126 +/- 35 mg and 155 +/- 47 mg, respectively. The mean study duration was 21 +/- 8 days. Both groups improved according to HAMD (from 25.2 +/- 8.4 at baseline to 12.0 +/- 7.4 at endpoint) and CGI scores (68 % responders). Moderately severe or severe side effects occurred in 16 % of patients. Adequate dose adjustment was significantly higher in the TDM group (60 % vs. 46 %, p < 0.05); this led to a significantly higher rate of therapeutic serum levels in the TDM group (58 % vs. 44 %, p < 0.05). Direct effects of TDM were not found for effectiveness. Therapeutic TCA serum levels over weeks one to three, however, were associated with significantly better outcome at endpoint (p < 0.05) as measured with changes in the HAMD or CGI response rates from baseline to endpoint. Finally, considerable side effects occurred significantly more often when serum levels were above the therapeutic range (27 % vs. 11 %; p < 0.01). We conclude that treating depression with TCA can be optimized by early TDM, which is superior to clinical judgment on its own. Since the psychiatrists in charge were less than completely "compliant" to the recommendations provided together with serum levels, the effect could be more pronounced than this study shows. The results encourage further studies in order to optimize antidepressant pharmacotherapy when using TDM appropriately.

CpG motifs induce Langerhans cell migration in vivo

Cytosine-guanosine (CpG) oligonucleotide (CpG-oligo) sequences are immunostimulatory motifs that are present in bacterial DNA and their presence in plasmids might contribute to the immune response generated by DNA vaccination. The cell targets of CpG motifs in vivo have not been characterized yet. In this report we assessed the in vivo effects of CpG motifs on Langerhans cells (LC) migration. We showed that intradermal injection of 10 microg of CpG-containing oligonucleotides in mouse ear induced the local depletion of LC within 2 h of exposure as shown by CD11c and Ia immunohistological staining. To demonstrate that LC depletion was due to LC migration, CpG oligonucleotides were injected into the explants ex vivo, and the CD11c(+) cells emigrating from the cultured isolated skin within medium were evaluated by immunostaining and FACS analysis. Our findings demonstrate that CpG motifs induce LC/dendritic cell (DC) migration out of the skin. To assess whether CpG motifs may act directly on LC/DC to induce their emigration we next analyzed the effects of CpG motifs in vitro on the expression of adhesion molecules involved in LC/DC migration. The results of these experiments show that alpha(6) integrins, E-Cadherin, ICAM-1, CD11b and CD11c were differentially regulated upon CpG-oligo treatment of immortalized DC. CpG treatment (10 microg/ml for 8 h) resulted in a 100% increase in ICAM-1 staining intensity, a 50% decrease in E-Cadherin staining and a 25% decrease in alpha(6) integrins staining, while no changes in the levels of CD11b and CD11c expression were recorded. Changes in adhesion molecule expression were mirrored by concomitant changes in the cell morphology that included cell depolarization, the appearance of filopods and loss of adherence. This study provides the first in vivo evidence that CpG motifs signal the migration of LC from the epidermis.

Interleukin-16 inhibits human immunodeficiency virus type 1 entry and replication in macrophages and in dendritic cells

Recombinant interleukin-16 (rIL-16) has been found to inhibit human immunodeficiency virus type 1 (HIV-1) replication in acutely or endogenously infected CD4(+) T cells. However, the effect of rIL-16 on HIV-1 replication in antigen-presenting cells (APCs) is still unknown. We show here a potent HIV-suppressive activity of rIL-16 in acutely infected monocyte-derived macrophages and dendritic cells determined by the levels of viral RNA transcripts or of viral reverse transcriptase in culture supernatants. The observed effect was dependent on the presence of rIL-16 early after infection and could not be induced by a 24-h treatment of cells with the cytokine prior to infection. Using macrophage-tropic and dually tropic primary isolates, we also showed that the addition of rIL-16 to cell cultures only during the infection period was effective in blocking virus entry and reducing proviral DNA levels in APCs. However, the anti-HIV activity of rIL-16 could not be linked to the induction of virus-suppressive concentrations of beta-chemokines or to the inhibition of HIV-enhancing cytokines. These findings establish a critical role for rIL-16 in protecting APCs against HIV-1 infection and lend further support to its potential use in the treatment of HIV disease.

Recombinant interleukin-16 selectively modulates surface receptor expression and cytokine release in macrophages and dendritic cells

Interleukin-16 (IL-16), a natural ligand for the CD4 receptor, has been found to modulate T-lymphocyte function and to inhibit human immunodeficiency virus type 1 (HIV-1) replication. Antigen-presenting cells (APC), including macrophages and dendritic cells, are known to express functional surface CD4 molecules, to be susceptible to HIV-1 infection and to play a critical role in different immune processes. Therefore, we evaluated the ability of recombinant IL-16 (rIL-16) to regulate receptor expression and cytokine release in monocyte-derived macrophages (MDM) and monocyte-derived dendritic cells (MDDC). Recombinant IL-16 was found to up-regulate CD25 and CD80 but to down-regulate CD4 and CD86 surface expression in MDM cultures. However, no change could be observed on the level of CD4, CD80 and CD86 expression in IL-16-stimulated MDDC, although a significant up-regulation of CD25 and CD83 was consistently detected. Furthermore, the level of gene expression of the chemokine receptors CCR5 and CXCR4 was significantly reduced in rIL-16-treated MDM and costimulation with IL-2 did not modify the activity of the recombinant cytokine. The effects on chemokine receptor gene expression were less evident in MDDC and only a transient down-regulation of weak intensity could be detected following stimulation with rIL-16. Analysis of supernatants from rIL-16-stimulatedcultures revealed a different profile of released cytokines/chemokines among the two cell populations studied. These findings establish an important role for IL-16 in modulating the activity of APC and may have relevance regarding the protection of reservoir cells against HIV-1 infection.

Recombinant human IL-16 inhibits HIV-1 replication and protects against activation-induced cell death (AICD)

The chemoattractant cytokine IL- 16 has been reported to suppress lymphocyte activation and to inhibit HIV-1 replication in acutely infected T cells. We have cloned and expressed human IL-16 in Escherichia coli and investigated whether the recombinant protein could regulate the level of lymphocyte apoptosis from HIV-1-infected subjects. After purification and refolding, only 2-10% of the recombinant cytokine was present in a biologically active homotetrameric form. This could explain the need for high concentrations of the bacterially derived IL- 16 to induce significant inhibition of HIV-1 replication. Addition of IL-16 to unstimulated peripheral blood mononuclear cell (PBMC) cultures from HIV-1-infected subjects did not modify the observed level of spontaneous lymphocyte apoptosis. In contrast, IL-16 added to PBMC cultures stimulated with anti-CD3, anti-CD95 or dexamethasone reduced significantly the percentage of lymphocytes undergoing AICD. This effect was found to correlate with the ability of the cytokine to decrease CD95 expression on activated CD4+ T cells. Comparative studies on PBMC from healthy individuals indicated that the regulation of apoptosis levels by IL-16 is a complex phenomenon and could depend on the nature of the activator used and/or the immune status of lymphocytes tested. The outcome of CD4 cross-linking on T cells by various ligands is discussed in the context of the observed beneficial activities of IL- 16 and its potential role in the treatment of HIV disease.

Role of nitric oxide in the regulation of lymphocyte apoptosis and HIV-1 replication

Nitric oxide (NO) has been implicated in certain immunopathogenetic mechanisms during the course of infection with human immunodeficiency virus (HIV). We have evaluated the levels of NO release and lymphocyte apoptosis in peripheral blood mononuclear cell (PBMC) cultures from HIV-1 infected subjects and healthy controls. We have also examined these 2 parameters in parallel cultures maintained under conditions where either NO synthesis was inhibited or high level of NO was present. Nitrite contents in culture supernatants were measured as the stable end products of the released NO. Levels of spontaneous apoptosis and activation-induced cell death (AICD) by anti-CD3 or by phytohemagglutinin were evaluated using flow cytometry. Additional experiments were also aimed at addressing a potential link between NO synthesis and HIV-1 replication in human monocyte-derived macrophages (MDMs). Acutely infected MDMs with HIV-1Bal were maintained in culture, without any additional activation signal, for a period of 14 days. Nitrites in the supernatants and mRNA accumulation of the inducible NO synthase (iNOS) in infected cells were assessed over the whole culture period. In addition, the effect of blocking NO synthesis during and after infection of MDMs, using an inhibitor of NO, was evaluated on the level of viral replication as measured by the presence of P24 antigen in the supernatants. Similarly, the effect on HIV replication of high NO levels in MDM cultures, supplied by a donor of NO during the 24 h period of infection, was also studied. We conclude that no elevation in NO release could be detected in PBMC cultures from HIV-1 infected subjects and that modulation of NO content may slightly regulate the level of spontaneous lymphocyte apoptosis but not that of AICD. Infection of MDMs with HIV-1 does not seem to induce detectable NO release or iNOS mRNA accumulation. Similarly, neither inhibition of NO synthesis nor the presence of high NO levels during the infection period could modify the outcome of virus replication in macrophages.

Complete reversal of FK 506 induced diabetes in a liver transplant recipient by change of immunosuppression to cyclosporine A

We report the case of a 41-year old patient who underwent orthotopic liver transplantation because of decompensated liver cirrhosis due to chronic HCV-infection. Severe acute allograft rejection was insufficiently controlled by cyclosporine A, steroids and a 6-day regimen of OKT 3 monoclonal antibody therapy. As a consequence immunosuppressive therapy was switched to FK 506 in a dose of 3 mg bid. The FK 506 concentration in whole blood consistently ranged between 5.1 and 7.8 ng/ml. Seven weeks after the onset of FK 506 therapy the patient developed severe diabetes mellitus with fasting blood glucose levels up to 640 mmol/l. The C-peptide was elevated reflecting a higher than normal insulin secretion. Intravenous insulin therapy with application of up to 85 units regular insulin per day was initiated. Because of the severe diabetes immunosuppression was changed back to cyclosporine A. After six weeks the patient did no longer require insulin and showed an entirely normal glucose tolerance test, C-peptide and Hb A1-level. This case shows that the diabetogenic side effect of FK 506 is more pronounced than that of cyclosporine A. We propose to change immunosuppressive therapy to cyclosporine A in cases of FK 506 induced severe diabetes mellitus, since long-term prognosis of many transplant recipients may depend on side effects of the immunosuppressive agents.

A patient-derived cytotoxic T-lymphocyte clone and two peptide-dependent monoclonal antibodies recognize HLA-B27-peptide complexes with low stringency for peptide sequences

HLA-B27 molecules expressed on the T2 mutant cell line do not have peptides. Such empty HLA-B27 molecules were not recognized by an HLA-B27-restricted cytotoxic T-lymphocyte (CTL) clone (auto-1) derived from synovial fluid. To test for peptide dependency of the clone, B27-T2 cells were incubated with a panel of 48 different peptides. This lack of stringency was compared with that of a peptide-dependent monoclonal antibody, B27.M2. Positive B27.M2 reactivity resulted when the B27-T2 cells were incubated with two peptides: RRKAMFEDI and RRMGPPVGHR, derived from Chlamydia HSP60 and human ribonucleoprotein, respectively. Because of the limited availability of CTL versus monoclonal antibody, the specificity of B27.M2 was studied in greater detail. The importance of the HLA-B27 heavy chain in antibody recognition of class I-peptide complexes was demonstrated by site-directed mutagenesis. The stringency of the peptide residues was tested by making analogs of each of the nine residues in RRKAMFEDI, creating a panel of 180 analogs. Although stringency was highest for the sixth position, as many as six different amino acids provided positive reactivity. These results indicate that immune recognition of HLA-B27-peptide complexes might have rather low stringency for the peptide sequences. In theory, then, pathogen-derived peptides which induce autoimmunity by generating autoreactive CTL might not share much sequence similarity with the responsible self peptides.

Tolerance exists towards resident intestinal flora but is broken in active inflammatory bowel disease (IBD)

Hyporesponsiveness to a universe of bacterial and dietary antigens from the gut lumen is a hallmark of the intestinal immune system. Since hyperresponsiveness against these antigens might be associated with inflammation, we studied the immune response to the indigenous intestinal microflora in peripheral blood, inflamed and non-inflamed human intestine. Lamina propria monocuclear cells (LPMC) isolated from inflamed intestine but not peripheral blood mononuclear cells (PBMC) of IBD patients with active inflammatory disease strongly proliferated after co-culture with sonicates of bacteria from autologous intestine (BsA). Proliferation was inhibitable by anti-MHC class II MoAb, suggesting that it was driven by antigen. LPMC from adjacent non-inflamed intestinal areas of the same IBD patients and PBMC or LPMC isolated from non-inflamed intestine of controls and patients with IBD in remission, in contrast, did not proliferate. PBMC or LPMC which had been tolerant to bacteria from autologous intestine, however, strongly proliferated after co-culture with bacterial sonicates from heterologous intestine (BsH). This proliferation was associated with an expansion of CD8+ T cells, increased expression of activation markers on both CD4+ and CD8+ lymphocyte subsets, and production of IL-12, interferon-gamma (IFN-gamma), and IL-10 protein. These results show that tolerance selectively exists to intestinal flora from autologous but not heterologous intestine, and that tolerance is broken in intestinal inflammation. This may be an important mechanism for the perpetuation of chronic IBD.

Klebsiella pneumoniae-reactive T cells in blood and synovial fluid of patients with ankylosing spondylitis. Comparison with HLA-B27+ healthy control subjects in a limiting dilution study and determination of the specificity of synovial fluid T cell clones

OBJECTIVE

To study the frequency of Klebsiella pneumoniae-responsive T cells in the peripheral blood (PB) of ankylosing spondylitis (AS) patients compared with that in healthy HLA-B27+ donors, and to examine T lymphocyte clones (TLC) derived from AS patient synovial fluid (SF) for the presence of Klebsiella reactivity.

METHODS

Limiting dilution analysis of PB T cells in 8 patients with active AS and in 8 HLA-B27+ healthy subjects was used to determine the frequency of PB T cells responsive to K pneumoniae and Escherichia coli GroEL. SF T cells from a patient with active AS were cloned, and 125 TLC were characterized in proliferation assays.

RESULTS

There were fewer T cells in the PB of AS patients that reacted with K pneumoniae than in the PB of healthy HLA-B27+ subjects. The frequencies of E coli GroEL-responsive T cells were approximately 5-10 times lower in all subjects tested (healthy donors and AS patients), but without significant differences between the 2 groups. Two CD4+ TLC that recognized K pneumoniae (1 cross-reactive with E coli) as well as 3 TLC that recognized GroEL (2 CD4+, 1 T cell receptor gamma/delta+) were isolated from the SF of a patient with actige AS.

CONCLUSION

Our results indicate that there is a quantitative reduction of K pneumoniae-responsive T cells in the PB of AS patients as compared with healthy controls. This may reflect a defective peripheral T cell defense in the immune response to Klebsiella and may allow bacterial antigens to reach the synovium, where they initiate specific T cell responses.

[Tubulointerstitial nephritis-uveitis syndrome (TINU syndrome)]

For 10 weeks a 25-year-old man had been suffering from tiredness, fatigue, nausea and a 16 kg weight loss. Erythrocyte sedimentation rate (83/133 mm), serum C-reactive protein (5.5 mg/dl) and creatinine (5.05 mg/dl) were all elevated. He also had proteinuria (1120 mg daily), sterile leukocytosis and a creatinine clearance of 10 ml/min. Renal biopsy showed interstitial nephritis and bone marrow biopsy revealed non-caseous epithelioid-cell granulomas. 14 days after admission he developed acute iritis in the right eye. Other causes having been excluded, the diagnosis of tubulo-intestinal nephritis with uveitis (TINU syndrome) was made. The clinical symptoms and laboratory findings improved within a few days of the start of glucocorticoid treatment (initially, 100 mg prednisone daily, reduced to 5 mg within 30 days). The patient was discharged after 8 days in good general condition.

Synovial fluid MHC-unrestricted gamma delta-T lymphocytes contribute to antibacterial and anti-self cytotoxicity in the spondylarthropathies

OBJECTIVE

In reactive arthritis (ReA), synovial fluid-derived bacteria-specific CD4+ and CD8+ T cells have been studied intensively in recent years. We have addressed the question whether gamma delta-TCR+ lymphocytes could contribute to antibacterial or anti-self cytotoxicity in the affected joints of patients, with spondylarthropathies.

METHODS

T cell clones were derived by random cloning from the synovial fluids of one patient with Yersinia-induced ReA, one patient with a Yersinia-induced flare up of pre-existing ankylosing spondylitis, and one patient with ankylosing spondylitis. Eight clones with a CD3+, alpha beta-TCR-, CD4-, CD8- and gamma delta-TCR+ phenotype (all expressing V gamma 9) were tested in a standard 52Cr-release assay using autologous or allogeneic B cell lines, CIR-B27, Daudi cells, and RJ.225 cells.

RESULTS

Four gamma delta-TCR+ clones killed both autologous and allogeneic target cells when infected with live Yersinia or Salmonella and also uninfected Daudi cells expressing GroEL heatshock protein. One clone was specific for Yersinia-infected targets. Three gamma delta-TCR+ clones were cytotoxic when uninfected autologous or allogeneic targets were employed. Polymorphic "classical" MHC class I or class II molecules were not used as restriction elements.

CONCLUSION

We conclude that, upon in vivo contact with bacteria such as Yersinia and Salmonella, synovial gamma delta-T lymphocytes are activated and contribute to antibacterial immunity via specific target cell lysis. Furthermore, anti-self cytolytic gamma delta-T cells could participate in the clearance of stressed and detrimental cells in the arthritic joint or, alternatively, could support the chronicity of autoimmune arthritis.

[Value of antigen, antibody and pathogen-specific lymphocyte detection in diagnosis of pathogen-induced arthritis]

In the differential diagnosis of infection-related arthritis (infectious arthritis, viral arthritis, reactive arthritis or Reiter's syndrome, Lyme disease) various laboratory methods are applied for the detection of the inciting antigen, specific antibodies or microbe-specific T-lymphocytes. In infectious (septic) bacterial or fungal arthritis, the definitive diagnosis can be made only by recovering the organism from the synovial fluid or membrane. Also, in reactive arthritis following extraarticular infection with Yersinia, Salmonella, Shigella, Campylobacter, or Chlamydia, one of the major shifts in perception of disease pathogenesis has been the detection of bacterial determinants by immunological methods and polymerase chain reaction (PCR) actually within the joint. In sexually acquired reactive arthritis, the etiologic diagnosis should be based on the direct detection of the pathogen (mainly C. trachomatis) from the urogenital smear specimen. For clinical routine, serological tests for bacteria specific antibodies (IgM and IgA class) are often necessary to show recent or persistent infection with the triggering pathogen. However, a cautionary note regarding the diagnostic significance of antibacterial antibody profiles has been sounded in several studies because of the high prevalence of bacteria-specific antibodies in the healthy population. The same problem may arise in the interpretation of virus-specific antibodies in the differential diagnosis of acute polyarthritis. Antigen-specific proliferation of synovial fluid lymphocytes can confirm the clinical diagnosis in patients with reactive arthritis and Lyme disease, although unspecific proliferation to several bacteria can also be observed in reactive arthritis as well as in many other arthritis.

Thymoma and pure red cell aplasia in a patient with systemic lupus erythematosus

We present the case of a female patient with a diagnosis of systemic lupus erythematosus (SLE) at the age of 54 years. At the age of 63 years, she suffered from malignant thymoma and 3 years after removal of the thymoma a diagnosis of pure red cell aplasia (PRCA) was established. This is, to our knowledge, the first report of the occurrence of SLE, thymoma and PRCA in the same patient. The case is discussed with regard to the already known associations between these diseases.

The effect of mutant beta 2-microglobulins on the conformation of HLA-B27 detected by antibody and by CTL

The arthritis-predisposing HLA-B27 consists of a heavy chain, a small peptide, and the monomorphic beta 2-microglobulin (beta 2-m). CTLs and a mAb, Ye-2, which recognize the complex with specificities both for the heavy chain and for the peptide, are available. The beta 2-m is in noncovalent association with the heavy chain at multiple points and is exchangeable with free beta 2-m outside of the complex. The purpose of our experiments was to test whether mutant beta 2-m capable of modulating HLA-B27 activity could be created. Eighteen recombinant mutants of the human beta 2-m were experimentally generated. In 14 of these, mutations were at or near residues that are either contact residues or interface residues with the heavy chain. Relative to the parent beta 2-m, two-thirds of the mutants showed reduced ability to exchange into HLA-B27 complexes. However, at least four of them induced more than 80% decrease in Ye-2 Ab reactivity. Two mutants were able to induce a minor decrease in susceptibility to lysis by four CTL clones. One of the CTL clones was autoreactive. Two of the CTL clones were specific for HLA-B27 cells experimentally infected with arthritis-causing Yersinia enterocolitica. These results indicate that certain beta 2-m residues play an indirect role in peptide presentation, although they are not directly associated with the peptide residues.

The effect of mutant beta 2-microglobulins on the conformation of HLA-B27 detected by antibody and by CTL

The arthritis-predisposing HLA-B27 consists of a heavy chain, a small peptide, and the monomorphic beta 2-microglobulin (beta 2-m). CTLs and a mAb, Ye-2, which recognize the complex with specificities both for the heavy chain and for the peptide, are available. The beta 2-m is in noncovalent association with the heavy chain at multiple points and is exchangeable with free beta 2-m outside of the complex. The purpose of our experiments was to test whether mutant beta 2-m capable of modulating HLA-B27 activity could be created. Eighteen recombinant mutants of the human beta 2-m were experimentally generated. In 14 of these, mutations were at or near residues that are either contact residues or interface residues with the heavy chain. Relative to the parent beta 2-m, two-thirds of the mutants showed reduced ability to exchange into HLA-B27 complexes. However, at least four of them induced more than 80% decrease in Ye-2 Ab reactivity. Two mutants were able to induce a minor decrease in susceptibility to lysis by four CTL clones. One of the CTL clones was autoreactive. Two of the CTL clones were specific for HLA-B27 cells experimentally infected with arthritis-causing Yersinia enterocolitica. These results indicate that certain beta 2-m residues play an indirect role in peptide presentation, although they are not directly associated with the peptide residues.

Bacteria-specific cytotoxic CD8+ T cells: a missing link in the pathogenesis of the HLA-B27-associated spondylarthropathies

The term seronegative spondylarthropathies is used for an entity of rheumatic syndromes of peripheral joints and the spine (ankylosing spondylitis, reactive arthritis, Reiter's syndrome, arthritis in psoriasis and in inflammatory bowel disease) which are strongly associated with the MHC class I molecule HLA-B27. However, the mechanisms whereby HLA-B27 confers disease susceptibility have so far remained unknown. There is strong evidence that gut inflammation and infection with gram-negative bacteria play a role in the induction of B27-associated disease. HLA-B27, like other MHC class I molecules, physiologically binds antigenic peptides in its binding groove and presents them to CD8+ T lymphocytes. Consequently, if the disease association with HLA-B27 arises from its role as a T-cell restriction element, synovial fluid CD8+ rather than CD4+ T cells should play a prominent pathogenetic role and should be detectable within the affected joints. In this paper, recent studies on bacteria-specific cytotoxic T cells and on peptide binding to HLA-B27 are reviewed. Particular emphasis is laid on the role of HLA-B27 restricted synovial CD8+ T cells with specificity for bacterial antigens or autoantigens. These cytotoxic T cells could provide a missing link in the pathogenesis of the spondylarthropathies and could now serve as tools to identify the critical antigenic epitopes of bacterial and self peptides which are involved in disease induction.

Role of bacteria-specific T cells in the immunopathogenesis of reactive arthritis

Reactive arthritis is a usually self-limited sterile inflammation of joints that follows certain bacterial gastrointestinal or urogenital infections. The immunopathogenesis involves CD4+ T cells, which mediate an antigen-specific TH1 response to bacterial constituents within the joint. Properties of the arthritogenic bacteria and the physicochemical characteristics of the bacterial antigens may contribute to the development of reactive arthritis.

T cells involved in psoriasis vulgaris belong to the Th1 subset

Although the pathogenesis of psoriasis vulgaris is still unknown, several characteristics point to an immunologically mediated process. Epidermal psoriatic lesions are characterized by a hyperproliferation of keratinocytes and an infiltration of T lymphocytes and granulocytes. Because the former may be mediated in part by lymphokines secreted by T cells, we have focused our interest on the in vivo and in vitro cytokine secretion patterns of T lymphocytes from psoriatic lesions. In five patients T lymphocytes were obtained from epidermal specimens. The cells were propagated with lectin and irradiated feeder cells and subsequently cloned by limiting dilution. The resulting T-cell clones were phenotypically and functionally characterized. Our data show that the majority of T-cell clones were CD4+ (74%), whereas only 25% were CD8+ and 1% were CD4-/CD8-. Also, we have further investigated the cytokine secretion pattern of T-cell lines or CD4+ T-cell clones, respectively. All cells tested produced interferon-gamma whereas only a minority secreted interleukin (IL)-4. Moreover, these cells produced high amounts of IL-2 but only little or no IL-10 or tumor necrosis factor-alpha. To correlate these data with the in vivo situation, biopsies from psoriatic lesions of five patients were investigated for the presence of the mRNA of IL-4, IL-10, and interferon-gamma using the polymerase chain reaction. In these biopsies only the mRNA for the Th1 cytokine interferon-gamma but not for the Th2 cytokines IL-4 and IL-10 could be detected. Identical experiments were performed to test the in vivo cytokine production of synovial fluid mononuclear cells of two patients with arthropathia psoriatica. Again, only the mRNA for interferon-gamma but not IL-4 could be detected. This indicates that T cells involved in psoriasis exhibit a Th1-like cytokine secretion profile.

Differential effects of IL-10 on proliferation and cytokine production of human gamma/delta and alpha/beta T cells

Gamma/delta TCR bearing T lymphocytes represent a T-cell subset whose functional relevance remains unclear. Nevertheless these T cells may play a role in the early immune response against bacteria. Until now the regulatory mechanisms on this response have not been investigated. The study described here evaluated the immunoregulatory effects of Interleukin-10 on gamma/delta and alpha/beta TCR-positive T-cell clones and freshly isolated peripheral-blood mononuclear cells (PBMC). IL-10 has been shown previously to inhibit lectin and antigen-induced proliferation and cytokine production by alpha/beta T cells. The results outlined below show that rhIL-10 strongly inhibits lectin-induced production of IFN-gamma, TNF-alpha, IL-2, and to a lesser degree proliferation and IL-4 production of both T-cell subsets. As IL-10 did not inhibit proliferation but at the same time strongly suppressed cytokine production in various experiments, the hypothesis that it could function as a growth factor for human T cells as has been described for murine thymocytes was tested. The data demonstrate that, although the gamma/delta T-cell clones tested do not produce IL-10 they can use it as a growth factor in combination with IL-2, IL-4 or alone. Furthermore, IL-10 has the same properties on human alpha/beta T-cell clones and PBMC. In summary, it is shown that IL-10 has pleiotropic effects on gamma/delta and alpha/beta TCR+ T cells by inhibiting lectin-induced cytokine production and by acting as a growth factor for these cells alone or in combination with IL-2 or IL-4.

Identification of the Yersinia enterocolitica urease beta subunit as a target antigen for human synovial T lymphocytes in reactive arthritis

The local T-cell response to bacterial antigens is involved in the pathogenesis of reactive arthritis (ReA). Here, we have identified a 19-kDa antigen of Yersinia enterocolitica O:9 recognized by Yersinia-specific synovial fluid CD4+ T cells in two patients with Yersinia-induced ReA. N-terminal amino acid sequencing of this protein revealed that it was identical to the 19-kDa urease beta subunit of Y. enterocolitica O:9. This protein has previously been shown to be arthritogenic in preimmunized rats after intra-articular injection. Analysis of the T-cell response to this protein showed that it contains several T-cell epitopes, one of which cross-reacts with other enterobacteria not able to induce ReA. This indicates that the arthritogenicity of the 19-kDa antigen is not a property of the 19-kDa protein alone but is dependent on its expression in bacteria able to induce ReA.

HLA-B27-restricted CD8 T cells derived from synovial fluids of patients with reactive arthritis and ankylosing spondylitis

Ankylosing spondylitis and seronegative spondylarthropathies such as Reiter's syndrome and reactive arthritis are strongly associated with HLA-B27. However, the mechanisms by which HLA-B27 is involved in disease susceptibility and pathogenesis are unknown. If the disease association is a consequence of HLA-B27's physiological function in antigen presentation, the disease should be mediated by cytotoxic T lymphocytes (CTLs) that recognise bacterial or self peptides presented by HLA-B27. Proof of this arthritogenic peptide model requires isolation of B27-restricted CD8 T cells from arthritic joints of patients with spondylarthropathies. An important question is whether "arthritogenic" bacteria such as yersinia or salmonella can generate HLA-B27-restricted bacteria-specific CTLs. We describe such HLA-B27-restricted CTLs. We tested a panel of 354 alpha beta-TCR CD8 T lymphocyte clones (TLCs) that had been derived from the synovial fluid of 4 patients with reactive arthritis and 2 patients with ankylosing spondylitis. In 1 patient with yersinia-induced arthritis, 2 TLCs were identified that killed specifically yersinia-infected B27 target cells. In another patient with salmonella-induced arthritis, 1 B27-restricted CD8 TLC that recognised both salmonella and yersinia was identified. In 5 of the 6 patients autoreactive CTLs were found, 5 of which showed B27-restricted killing of uninfected cell lines. B27-restricted CTLs with specificity for arthritogenic bacteria or autoantigens provide a missing link in the pathogenesis of the HLA-B27-associated spondylarthropathies.

Interstitial alveolitis as early manifestation of anti-Jo-1 positive polymyositis

Polymyositis (PM), dermatomyositis (DM) and inclusion-body myositis belong to a heterogenous group of inflammatory myopathies. Pulmonary manifestations occur in a minority of PM patients due to infiltration of diaphragmatic and thoracic muscles or more rarely due to interstitial lung disease. Here, we report on the case of a 67-year-old patient who developed an interstitial idiopathic alveolitis as an early and rare manifestation of anti-Jo-1-positive polymyositis. Clinical and pathogenetical features of the PM associated interstitial alveolitis are discussed.

Remission of severe rheumatoid arthritis following liver transplantation

We present the case of a 32-year-old male who suffered from severe RA from the age of 21 years. After 9 years of active disease and poor response to therapy the patient developed severe hepatitis induced by the NSAID pirprofen. He went into fulminant hepatic failure necessitating emergency liver transplantation. Liver transplantation was followed by clinical and laboratory remission of his RA and he has remained virtually asymptomatic for more than 3.5 years. The possibility that this favourable clinical course was due to the immunosuppressive effect of the liver transplant rather than the ensuing immunosuppressive therapy is discussed.

Expression of the 60 kDa heat shock protein in normal and inflamed liver

The 60 kDa heat shock proteins (HSP 60) have been well conserved throughout evolution and are highly immunogenic. Cross-reactivity between bacterial and mammalian HSP 60 is considered a likely mechanism in the pathogenesis of autoimmune diseases. T cell and B cell reactivity to HSP 60 is found in patients with rheumatoid or juvenile arthritis, and the expression of HSP 60 in the inflamed joint is found to be increased. In this study the presence of HSP 60 was demonstrated in normal and inflamed lives. HSP 60 was found to be predominantly expressed in hepatocytes and Kupffer cells, and mainly localized in mitochondria. Heat stress in the form of a 1 h incubation at 42 degrees C increased HSP 60 expression. The expression of HSP 60 in chronic active hepatitis was found to be markedly increased, with predominant expression in areas of inflammatory infiltrates. This increased expression in the inflamed liver was found both in viral and autoimmune hepatitis. High expression of HSP 60 in chronic active hepatitis was entirely due to self (i.e. human) HSP 60; no additional bacterial HSP 60 could be detected. Increased expression of HSP 60 in chronic active hepatitis suggests that immune reactions to HSP 60 may play a role in the immunopathogenesis and perpetuation of chronic inflammatory liver disease.

Pneumatoceles and pneumothoraces complicating staphylococcal pneumonia: treatment by synchronous independent lung ventilation

A 54 year old man with a staphylococcal sepsis developed staphylococcal pneumonia complicated by multiple pneumatoceles and bilateral tension pneumothoraces caused by bronchopleural fistulae. Excessive enlargement of the right sided pneumatoceles and a tension pneumothorax not improved by drainage led to mediastinal shift and compression of the right lung. Reversal of the mediastinal shift and closure of the bronchopleural fistulae was achieved by assisted independent lung ventilation.

T cells in reactive arthritis

T cells appear to play a major role in the development, maintenance and also resolution of reactive arthritis (ReA). Recent advances in understanding the processes involved in T cell activation now allow us to examine the peripheral blood and synovial fluid T cell responses to given "arthritogenic" microorganisms in terms of antigen specificity, epitope identification, cytokine secretion patterns, HLA restriction and the role of different T cell subsets in ReA. Peripheral blood bulk proliferation and limiting dilution studies provide evidence that the peripheral T cell response against arthritis-associated gram-negative bacteria is decreased in patients developing immunological sequelae such as ReA after gastrointestinal infection. Using clonal analysis of synovial fluid CD4+ T cells it has been shown that a polyclonal rather than an oligoclonal response to a variety of bacterial antigens is induced at the site of synovitis and that these CD4+ T cells produce a Th1-type of cytokine. 65 kD heat shock protein may represent one of the possible linkages of anti-infectious and autoimmune reactions. Furthermore, a spectrum of killer cells is present in the synovial fluid of patients with ReA. This spectrum of cytotoxic T cells includes antigen-specific, class I-restricted alpha beta-TCR+CD8+ lymphocytes, antigen-specific, apparently non-MHC-restricted alpha beta-TCR+CD8+ lymphocytes and gamma delta-TCR+ cells with braod cytolytic activity directed against bacteria-infected target cells. HLA-B27-restricted Yersinia- or Salmonella-specific synovial fluid CD8+ T cells may provide the missing link between genetic disposition (HLA-B27) and extra-articular infection with arthritogenic bacteria in these patients.

Induction of an anti-vaccine response by T cell vaccination in non-human primates and humans

Experimental and spontaneous autoimmune disease in animals can effectively be prevented and treated by application of pathogenic autoreactive T cells in an attenuated form. This approach has become known as T cell vaccination. T cell vaccination exploits specifically the ability of the immune system to regulate its autoreactive T cells by mechanisms of network control. The success of T cell vaccination in a variety of rodent animal models has raised hopes for its use as an effective and specific therapy in human autoimmune disease. The aim of this study was to induce an anti-T cell response by T cell vaccination in humans and primates as a pre-clinical study into the feasibility and toxicity of T cell vaccination. Using bulk cultures of T cells from the peripheral blood or an inflamed joint, it was possible to induce a T cell response specific for the injected vaccine and its activation state both in rhesus monkeys and in two patients with active rheumatoid arthritis. In one of the patients there was already a spontaneous T cell response against a mitogen driven T cell line from the peripheral blood, but not against a control T cell line specific for tetanus toxoid, suggesting that regulatory T cell networks are operative in patients with autoimmune disease. Significant clinical effects or side-effects were not observed. The results suggest that T cell vaccination in humans is feasible and non-toxic. It is likely to influence an already ongoing regulatory process. Conditions for making T cell vaccination an effective therapy need still to be worked out by further studies both in primates and in less complex human immune processes.

Multiclonal synovial T cell response to Yersinia enterocolitica in reactive arthritis: the Yersinia 61-kDa heat-shock protein is not the major target antigen

The T cell response to bacterial antigens plays a major role in the pathogenesis of reactive arthritis (ReA) following enteric infections with Yersinia enterocolitica. To study the antigen specificity of the T cells at the site of inflammation, the response of cloned T cells from the synovial fluid of 2 patients with ReA to partially purified antigens of Yersinia enterocolitica was determined. The clones showed different patterns of response to various fractions, indicating a multiclonal response to Yersinia antigens, and these specificities differed in the 2 patients. Some T cells were specific for Y. enterocolitica; some cross-reacted with other enterobacteria. Proteins of 14 and 19 kDa could be identified as target antigens for the T cell clones, but no clone could be unequivocally found that reacted with the highly purified Yersinia 61-kDa heat shock protein. Thus, the inflammatory T cell response in the synovial fluid in ReA is multiclonal and not predominantly directed against the bacterial heat shock 61-kDa protein.

Predominance of Th1-type T cells in synovial fluid of patients with Yersinia-induced reactive arthritis

The pathogenetic mechanisms underlying the development of reactive arthritis and the functional capacities of synovial T cells specific for Yersinia enterocolitica are still unclear. In this study we have determined the cytokine secretion patterns of 24 CD4+ synovial fluid (SF)-derived T cell clones from 2 patients with Yersinia-induced reactive arthritis, 16 clones specific for different Yersinia antigens and 8 clones as controls. The clones specific for Yersinia antigens predominantly belong to the T helper cell 1 (Th1) subset with production of interferon (IFN)-gamma and interleukin (IL)-2, but no IL-4, whereas SF T cells not reactive with Yersinia antigens produce IL-2, IL-4 and IFN-gamma and thus belonged to the Th0 subset. Moreover, short-term T cell lines established from SF and peripheral blood showed the same pattern. To further analyze the functional relevance of these data we investigated the influence of IFN-gamma and IL-4 on the intracellular killing of Yersinia in a human glioblastoma cell line. Our data show that the Th1 cytokine IFN-gamma promotes intracellular killing of Yersinia, whereas this effect is antagonized by the Th2 cytokine IL-4. Furthermore, the Th2 cytokine IL-10 inhibited the antigen-specific proliferative response and IFN-gamma and IL-2 production by the Th1 cells. These results provide insight into the antibacterial mechanisms at work in reactive arthritis after infection with Yersinia enterocolitica and, for the first time, reveal the cross-regulatory properties of cytokines derived from Th1 and Th2 cells in a human immune response to bacterial antigens.

MHC-unrestricted recognition of bacteria-infected target cells by human CD8+ cytotoxic T lymphocytes

A CD8+ alpha beta TCR+ T cell clone (A35) was isolated from the synovial fluid of a patient with post-enteric reactive arthritis caused by Yersinia enterocolitica. This clone efficiently killed autologous and allogeneic target cells that had been preincubated with live but not with heat-killed bacteria. There was no restriction by polymorphic parts of HLA-A, -B, or -C molecules and a HLA class II-deficient mutant cell line was lysed as efficiently as its normal counterpart, whereas infected HLA class I-deficient cells (Daudi cells) were not. The clone showed crossreaction between Yersinia enterocolitica, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pyogenes, but did not lyse target cells preincubated with Staphylococcus epidermidis. MAb to CD2, CD3, and CD8 efficiently blocked A35, whereas the addition of mAb to HLA class II or to HLA class I did not. This clone apparently represents a novel effector mechanism against bacteria-infected or -modified cells that could be involved in the immunopathology of reactive arthritis.

Stimulation of synovial fluid mononuclear cells with the human 65-kD heat shock protein or with live enterobacteria leads to preferential expansion of TCR-gamma delta+ lymphocytes

T lymphocyte responses to heterologous or self 65-kD heat shock protein (hsp) have been implicated in the pathogenesis of various forms of arthritis. To delineate the relationship of 65-kD hsp to different synovial fluid (SF) T cell subsets, we stimulated synovial fluid (SFMC) and peripheral blood mononuclear cells (PBMC) from patients with different inflammatory rheumatic diseases and from healthy controls with human or mycobacterial 65-kD hsp, tetanus toxoid (TT), heat-killed or live Yersinia enterocolitica. Phenotyping of the resulting T cell lines revealed an increase of up to 97% TCR-gamma delta+ lymphocytes in the 65-kD hsp-stimulated SF-derived lines. This expansion of TCR-gamma delta+ cells was less pronounced with cultures of PBMC. A preferential expansion of TCR-gamma delta+ cells was also shown after SFMC stimulation with live, but not with heat-killed Yersinia or with TT. We conclude that a common mechanism is involved in the selective expansion of TCR-gamma delta+ lymphocytes upon SFMC infection with live Yersinia or upon contact with 65-kD hsp. Out of a panel of TCR-gamma delta+ T lymphocyte clones (TLC) derived from a human 65-kD hsp-stimulated line, only a minority of TLC proliferated weakly upon restimulation with this antigen in the presence of autologous monocytes, whereas TCR-alpha beta+ TLC responded vigorously to the human 65-kD hsp and in some cases also cross-recognized the mycobacterial hsp homologue and/or heat-killed Yersinia. This implies that additional factors or cells may be present in the milieu of SFMC cultures that propagate the expansion of TCR-gamma delta+ cells in response to 65-kD hsp or live bacteria.

HLA-DP restricted Chlamydia trachomatis specific synovial fluid T cell clones in Chlamydia induced Reiter's disease

Synovial fluid (SF) mononuclear cells from a patient with Chlamydia trachomatis induced acute Reiter's disease were directly by limiting dilution in a representative protocol using phytohemagglutinin in the cloning medium. Out of 76 alpha beta-TCR+ CD4+ T lymphocyte clones, 7 were shown to specifically recognize C. trachomatis in a proliferation assay. The antigen recognition of these clones was HLA-DP restricted. Unexpectedly, 2 HLA-DR restricted clones showed a proliferative response to Yersinia enterocolitica O3, though the patient had no history of yersinia infection. The high frequency of SF derived T cells with specificity for species-specific chlamydial antigens and the limited diversity of HLA class II restriction of these clones may indicate an oligoclonal synovial T cell response to persistent intraarticular chlamydia.

Antibodies to cathepsin G in Crohn's disease

Antibodies directed against antigens in human neutrophils have proved to be of great diagnostic value in certain systemic vasculitides. Recent reports have focused the attention on these antigens as targets of antibodies in sera of patients with inflammatory bowel disease. We investigated the sera drawn from 60 patients suffering from biopsy proven Crohn's disease and 15 patients with active ulcerative colitis. Using sensitive enzyme-linked immunosorbent assays with purified antigens and Western blotting the following antibodies could be demonstrated: cathepsin G (cat-G) antibodies IgG 38.3%, IgM 13.3%, IgA 23.3% and antibodies against human leucocyte elastase (HLE) IgG, IgA, IgM 3.3%. Low but significant correlations could be found for cat-G antibodies (IgG) and the van HEES index of activity. 73.9% of the cat-G (IgG) positive patients had colon involvement. In the sera of patients with ulcerative colitis no antibodies to cat-G or HLE were detectable. Only 8.3% of the patients with Crohn's disease had antibodies against proteinase 3 (C-ANCA). Our data indicate that cat-G among other myeloid lysosomal enzymes seems to be an important target antigen of antibodies in sera of patients with Crohn's disease. Cat-G antibodies might be helpful to distinguish Crohn's disease from ulcerative colitis.

Reactivity of infiltrating T lymphocytes with microbial antigens in Crohn's disease

Intestinal T lymphocytes are normally unresponsive to microbial and recall antigens in vitro, whereas the same antigens induce strong immune responses in peripheral-blood-derived T cells. We obtained T lymphocytes from peripheral blood and from the non-inflamed and inflamed intestinal mucosa of 6 patients (3 male, 3 female; mean age 33 years) with Crohn's disease. The T cells were stimulated in vitro with a range of microbial antigens. Whereas T cells from normal mucosa were unresponsive, those from inflamed mucosa had a proliferative response comparable to that of the peripheral-blood-derived T cells. These findings suggest that physiologic unresponsiveness to luminal antigens is abrogated in the inflammatory lesions of Crohn's disease patients. Infiltrating T lymphocytes may therefore mediate chronic inflammation on encountering the many antigens present in the intestine.

Candida arthritis: cellular immune responses of synovial fluid and peripheral blood lymphocytes to Candida albicans

A case of septic Candida albicans arthritis of the knee in a patient with systemic candidiasis is presented. Systemic and intra-articular cellular immune responses to C albicans and various bacterial antigens were monitored for 15 weeks. It is shown that the candida induced blastogenesis of synovial fluid lymphocytes was much more stimulated than that of peripheral blood lymphocytes, and that the proportion of activated cells expressing HLA class II antigens was markedly increased in the synovial fluid. Strong cellular immune responses to Candida albicans could still be shown many weeks after the synovial fluid aspirates had become sterile. For the first time synovial fluid derived, CD4 positive T lymphocyte clones with specificity for candida antigens were characterised and further propagated in vitro.

A human renal cancer line as a new antigen source for the detection of antibodies to cytoplasmic and nuclear antigens in sera of patients with Wegener's granulomatosis

Autoantibodies directed against cytoplasmic antigens of neutrophils (ANCA), especially proteinase 3 (C-ANCA), have proved to be a useful clinical tool to support the diagnosis or to monitor disease activity in Wegener's granulomatosis (WG). Till now, human neutrophil granulocytes have represented the major antigen source used to detect antibodies in WG by the immunofluorescence technique (IFT). We have tested serum samples of 164 patients with different connective tissue diseases (50 suffering from clinically active WG) performing IFT on a human renal cancer line (SK-RC11) and have found antibodies against the nuclear and cytoplasmic antigens in 39 patients. C-ANCA+ sera displayed a characteristic diffuse cytoplasmic staining pattern. Antibody titers measured with human granulocytes were comparable to titers obtained using culture cells. Antibody binding could be inhibited by preabsorption with an extract of human granulocytes or purified proteinase 3. A protein of 29 kDa MW could be isolated by affinity purification using a SK-RC11 extract and a high-titer C-ANCA+ serum and antigenic identity was further confirmed by IFT using a monoclonal antibody to proteinase 3. Treatment of tumor cells with cytokines (interferon, tumor necrosis factor) led to a time dependent translocation of the antigen into the nucleus and back to the cytoplasm. The antigen was also expressed on the surface of live cells colocalized with MHC II. In addition, 21 WG patients had antibodies to cytoplasmic organelles identified by laser scanning microscopy as secretory vesicles of the Golgi complex, and five had antibodies to nuclear antigens. This is, to the best of our knowledge, the first report of proteinase 3 in human non-leukemic cells. Our data demonstrate, that the repertoire of antigens recognized by antibodies in WG sera is not limited to human neutrophils and monocytes and indicates a possible functional role of the antigenic proteins.

Synovial fluid-derived Yersinia-reactive T cells responding to human 65-kDa heat-shock protein and heat-stressed antigen-presenting cells

Humoral and cellular immune reactions to heat-shock proteins have been implicated in the pathogenesis of arthritis. Heat-shock proteins occur in bacteria as well as all eukaryotes and have been highly conserved during evolution. Cross-reactivity between bacterial and human heat-shock proteins induced at the site of inflammation may underlie the pathogenesis of some forms of arthritis. In order to test this hypothesis, we raised and cloned a Yersinia-specific T cell line from the synovial fluid lymphocytes of a patient with Yersinia-induced reactive arthritis. From this line we obtained a CD4+ T cell clone that proliferated in response to Yersinia antigens and both to the mycobacterial and the human 65-kDa heat-shock protein. This T cell clone also proliferated in response to autologous heat-stressed antigen-presenting cells as well as to synovial fluid mononuclear cells from the inflamed joint, thus showing true autoreactivity against endogenously synthetized self-antigen. These results demonstrate the induction of an autoimmune T cell response by a natural bacterial infection and support the important role of heat-shock proteins in the pathogenesis of immune-mediated arthritis.

[Rheumatologic and radiologic symptoms of secondary hyperparathyroidism: retrospective long-term study of 175 chronic hemodialysis patients]

Despite recent improvements of hemodialysis (HD) techniques, symptoms due to secondary hyperparathyroidism (HPT) contribute to longtime complications of HD patients. The aim of the present retrospective study was to determine the incidence and localization of radiological joint and bone lesions in 175 patients on chronic HD. In 108 patients the diagnosis of HPT was made by radiologic criteria. 56% had radiomorphologic lesions of the hands, 45% of the acromio-clavicular (AC) joint, 31% of the shoulder, and 27% of the pelvis. No sex difference was found for prevalence of HPT in these patients, nor was one found for any of the underlying renal diseases. There was a negative correlation between elevated serum parathyroid hormone and serum aluminum concentrations. In 111 patients the history of bone and joint pain was evaluated. 54% of these patients suffered from bone pain, arthralgia, and morning stiffness. Radiological lesions of AC-joint correlated with shoulder pain in 38%. Our data show that even in the predialytic phase of renal insufficiency x-rays of the shoulder are helpful in early diagnosis of HPT. Skeletal manifestations specific for one of the underlying renal diseases do not exist. Elevated PTH levels are a good indicator of HPT in these patients, whereas low levels of PTH do not exclude radiological manifestations. In contrast to beta 2-microglobulin amyloidosis, pain does not occur during rest and is not worsened during HD. Treatment with non-steroidal antiinflammatory drugs led to pain relief in the majority of patients. Pain history in patients on chronic HD provides important information concerning the differential diagnosis of HPT/beta 2-microglobulin amyloidosis.