Interleukin-10 promotes activation-induced cell death of SLE lymphocytes mediated by Fas ligand

The Sjögren’s Syndrome-Associated Autoantigen Ro52 Is an E3 Ligase That Regulates Proliferation and Cell Death

Patients affected by Sjögren's syndrome and systemic lupus erythematosus (SLE) carry autoantibodies to an intracellular protein denoted Ro52. Although the serologic presence of Ro52 autoantibodies is used clinically for diagnostic purposes, the function of the protein or why it is targeted as an autoantigen in several rheumatic conditions has not been elucidated. In this study, we show that the expression of Ro52 is significantly increased in PBMC of patients with Sjögren's syndrome and SLE, and demonstrate that Ro52 is a RING-dependent E3 ligase involved in ubiquitination. Overexpression of Ro52, but not of Ro52 lacking the RING domain, in a mouse B cell line lead to decreased growth in steady state and increased cell death after activation via the CD40 pathway. The role of Ro52 in activation-mediated cell death was further confirmed as a reduction in Ro52 expression restored cell viability. These findings suggest that the increased expression of the Ro52 autoantigen in patients may be directly involved in the reduced cellular proliferation and increased apoptotic cell death observed in Sjögren's syndrome and SLE, and may thus contribute to the autoantigenic load and induction of autoimmune B and T cell responses observed in rheumatic patients.

Amelioration of murine lupus by a peptide, based on the complementarity determining region-1 of an autoantibody as compared to dexamethasone: Different effects on cytokines and apoptosis

A peptide (hCDR1) based on the sequence of the complementarity-determining region-1 of an anti-DNA autoantibody ameliorates clinical manifestations of lupus. We analyzed the beneficial effects of hCDR1 when given alone or in combination with dexamethasone, while comparing the mechanisms of action of the latter. Treatment with either hCDR1 or dexamethasone, or a combination of the latter significantly reduced titers of dsDNA-specific autoantibodies, levels of proteinuria, and intensity of glomerular immune complex deposits. Both drugs down-regulated the secretion and expression of IFN-gamma and IL-10, but only treatment with hCDR1 up-regulated TGF-beta. While both drugs reduced the expression of Fas ligand (FasL) and caspase 8, treatment with hCDR1 resulted in reduced whereas dexamethasone administration resulted in increased rate of apoptosis. Furthermore, down-regulation of FasL appeared to play a role in cytokine modulation. We conclude that specific treatment with hCDR1 ameliorates murine lupus via distinct mechanisms of action than those of dexamethasone.

Association of apoptosis-related microsatellite polymorphisms on chromosome 1q in Taiwanese systemic lupus erythematosus patients

Apoptosis is important in the pathogenesis of systemic lupus erythematosus (SLE). Several genome-wide scan studies have suggested chromosome 1q as a genetic susceptibility locus for SLE. This study investigated the association of apoptosis-related genes on chromosome 1q, Fas ligand (FasL), interleukin (IL)-10 and poly(ADP-ribose) polymerase (PARP), promoter microsatellite multi-allelic polymorphisms with SLE susceptibility and clinical characteristics in Taiwan. This study recruited 237 SLE patients and 304 healthy controls. FasL, IL-10 and PARP promoter microsatellite polymorphisms were genotyped employing gene scan. IL-10, located on 1q31-32, emerged as a significant susceptibility gene locus in Taiwanese SLE (T4 statistic = 0.01). IL-10 CA21 allele was the most common allele of 15 identified in Taiwanese, displaying skewed distribution of susceptibility in Taiwanese SLE patients. Conversely, the IL-10 CA20 allele showed a protective effect of SLE susceptibility. Additionally, the IL-10 CA26 allele displayed a negative significant association with ascites and IL-10 CA25 allele increased the occurrence of the anti-cardiolipin IgM antibody. This study identified five alleles of FasL and nine alleles of PARP of microsatellite polymorphisms in Taiwanese patients. FasL and PARP alleles displayed no skewing distribution between Taiwanese SLE patients and controls. However, FasL GT15 and PARP CA17 allele demonstrated a high discoid rash presentation (T4 statistic 0.01 and 0.03, respectively) and PARP CA12 allele displayed a significant association with anti-cardiolipin IgM antibody production (T4 statistic 0.02). IL-10, FasL and PARP microsatellite polymorphisms exhibited significant associations with SLE susceptibility and/or clinical characteristics in Taiwanese patients. Thus, SLE is a complex and multiple genetics determined autoimmune disease. Chromosome 1q23-42 is an important genetic locus for further SLE subphenotype susceptibility study.

Atherosclerosis in Patients With Autoimmune Disorders

Recent findings indicate that presence of activated immune competent cells and inflammation are typical of atherosclerosis, the main cause of cardiovascular disease (CVD). The risk of CVD is very high in a prototypic autoimmune disease, systemic lupus erythematosus (SLE), and is also raised in other autoimmune diseases such as rheumatoid arthritis. Autoimmunity-related CVD and atherosclerosis are important clinical problems. They may also shed light on interactions between immune reactions and atherosclerosis development and manifestations, not least in women, who have a much higher risk of autoimmune disease than men. In general, a combination of traditional and nontraditional risk factors, including dyslipidemia (and to a varying degree, hypertension, diabetes, and smoking), inflammation, antiphospholipid antibodies (aPLs), and lipid oxidation, contribute to CVD in autoimmune diseases. Premature atherosclerosis is likely to be a major underlying mechanism, although distinctive features, if any, of autoimmunity-related atherosclerosis compared with “normal” atherosclerosis are not clear. One interesting possibility is that factors such as inflammation, neoepitopes on endothelial cells, or aPLs make atherosclerotic lesions in autoimmune disease more prone to rupture than in “normal” atherosclerosis. Some cases of autoimmunity-related CVD may be more related to thrombosis than atherosclerosis. Whether premature atherosclerosis is a general feature of autoimmune diseases such as SLE or only affects a subgroup of patients whereas others do not have an increased risk remains to be demonstrated. Treatment of patients with autoimmune disease should also include CVD aspects and be focused on traditional risk factors as well as on disease-related factors. Hopefully novel therapeutic principles will be developed that target the causes of the inflammation present in atherosclerotic lesions.

SLE, atherosclerosis and cardiovascular disease

Atherosclerosis is an inflammatory disease and the major cause of cardiovascular disease (CVD) in general. Atherosclerotic plaques are characterized by the presence of activated immune competent cells, but antigens and underlying mechanisms causing this immune activation are not well defined. During recent years and with improved treatment of acute disease manifestations, it has become clear that the risk of CVD is very high in a prototypic autoimmune disease, systemic lupus erythematosus (SLE). SLE-related CVD and atherosclerosis are important clinical problems but may in addition also shed light on how immune reactions are related to premature atherosclerosis and atherothrombosis. A combination of traditional and nontraditional risk factors, including dyslipidaemia (and to a varying degree hypertension, diabetes and smoking), inflammation, antiphospholipid antibodies (aPL) and lipid oxidation are related to CVD in SLE. Premature atherosclerosis in some form leading to atherothrombosis is likely to be a major underlying mechanism, though distinctive features if any, of SLE-related atherosclerosis when compared with 'normal' atherosclerosis are not clear. One interesting possibility is that factors such as inflammation or aPL make atherosclerotic lesions in autoimmune disease more prone to rupture than in 'normal' atherosclerosis. Whether premature atherosclerosis is a general feature of SLE or only affects a subgroup of patients remains to be demonstrated. Treatment of SLE patients should also include a close monitoring of traditional risk factors for CVD. In addition, attention should also be paid to nontraditional risk factors such as inflammation and SLE-related factors such as aPL. Hopefully novel therapeutic principles will be developed that target the causes of the inflammation and immune reactions present in atherosclerotic lesions.

IL-15 converts human intestinal intraepithelial lymphocytes to CD94 producers of IFN-gamma and IL-10, the latter promoting Fas ligand-mediated cytotoxicity

Intestinal intraepithelial lymphocytes (IELs), T-cell receptor alphabeta(+) CD8(+) T cells located between epithelial cells, are thought to contribute to Fas ligand (FL)-mediated epithelial cell death in coeliac disease, a condition characterized by excess interleukin-15 (IL-15). This study evaluates the effects of prolonged IL-15 stimulation on IELs. Human IELs were obtained from jejunal mucosa from gastric bypass operations for morbid obesity and cultured for 3 or 10 days with IL-15. As the culture progressed, an increasing number of IELs became CD94(+) and produced massive quantities of interferon-gamma (IFN-gamma) and IL-10. There was a steady rate of transcription with no feedback regulation. Few chronically activated IELs produced IL-2, IL-4, or tumour necrosis factor-alpha (TauNuF-alpha). To determine whether the accumulation of IL-10 affected IEL functions, endogenous IL-10 was neutralized by antibody during culture with IL-15. This manipulation reduced expression of CD94, NKG2D, and FL as well as FL-mediated killing of Jurkat cells by IELs. It did not affect perforin or TNF-alpha expression or the associated cytotoxic activities. This study shows that IL-15 induces the development of CD94(+) IELs containing IFN-gamma and IL-10, and that endogenous IL-10 promotes FL-mediated cytotoxicity.

Review of ACR hematologic criteria in systemic lupus erythematosus

We have conducted a thorough literature review to evaluate the relative value of the hematologic criterion in making a diagnosis of systemic lupus erythematosus (SLE), its clinical relevance, and its prognostic significance. In the updated 1982 ACR criteria, the presence of one or more of the four elements: 1) hemolytic anemia (with reticulocytosis); 2) leukopenia (<4000/microL on two or more occasions); 3) lymphopenia (< 1500/microL on two or more occasions); or 4) thrombocytopenia (< 100,000/microL in the absence of offending drugs) is now considered as a single hematologic disorder. The sensitivity and specificity of the individual elements of the hematologic criterion range from 18 to 46% and 89 to 99%, respectively. The accuracy of the hematologic criterion requires proper interpretation. For example, many studies reported the presence of anemia that was not clearly defined and likely included anemia from etiologies other than hemolytic anemia, thereby causing an overestimation of the prevalence. In addition, medications such as corticosteroids and cytotoxic agents, and viral infections, can also contribute to a reduction in lymphocyte count. Despite these limitations, the SLICC committee recommends no change in the elements of the hematologic criterion when this criterion is properly interpreted and other causes of cytopenia are excluded.

Therapy with statins in patients with refractory rheumatic diseases: a preliminary study

We have explored the therapeutic potential of statins in patients with different inflammatory rheumatic diseases refractory to conventional therapy. We found that simvastatin (80mg o.d. for eight days) induced a rapid and significant reduction in proteinuria levels in three systemic lupus erythematosus (SLE) patients. A similar kind of therapy had a marked beneficial effect in a patient with Wegener's granulomatosis and a patient with erythema nodosum. On the other hand, five patients with rheumatoid arthritis (RA) who received atorvastatin for eight days (20mg/day) showed reduction in C-reactive protein levels and a clinical improvement that was classified as an ACR20 response. Prior to the administration of statins, all these patients had received aggressive conventional therapy with no satisfactory response. A significant reduction in spontaneous apoptosis of peripheral blood lymphocytes and expression of CD69 and HLA-DR was observed in SLE patients after simvastatin therapy. These results prompted us to perform a pilot short-time comparative (simvastatin versus chloroquine) open clinical trial in 15 patients with RA who were receiving methotrexate as a single disease modifying antirheumatic drug with no satisfactory response. Most patients (9/10) who received simvastatin (40mg/day) showed an ACR50 or better response after eight weeks, whereas such a response was not observed in any patient (0/5) treated with chloroquine. Our preliminary results indicate that statins may be an important therapeutic tool for the treatment of inflammatory rheumatic diseases.

Mitochondrial dysfunction in T cells of patients with systemic lupus erythematosus

Activation, proliferation, or programmed cell death of T lymphocytes are dependent on controlled reactive oxygen intermediates (ROI) production and ATP synthesis in mitochondria. The mitochondrial transmembrane potential (Delta Psi(m)) also plays a decisive role in cell survival by controlling activity of redox-sensitive caspases. T lymphocytes of patients with systemic lupus erythematosus (SLE) exhibit mitochondrial hyperpolarization, increased ROI production, diminished intracellular glutathione levels, cytoplasmic alkalinization, and ATP depletion that mediate enhanced spontaneous and diminished activation-induced apoptosis and sensitize lupus T cells to necrosis. These redox and metabolic checkpoints represent novel targets for pharmacological intervention in SLE.

The A-1087IL-10 allele is associated with cardiovascular disease in SLE

The risk of cardiovascular disease (CVD) in SLE patients is very high. It is therefore surprising that IL-10 has been discussed both as pathogenic in SLE and as an atheroprotective cytokine. In contrast, TNF is believed to be atherogenic and we recently reported that raised activity in the TNF-system is implicated in SLE-related CVD. Twenty-six (aged 52 +/- 8 years) female patients with SLE and a history of CVD (myocardial infarction, angina, stroke or claudication) were compared with 26 age-matched SLE patients without CVD (SLE controls) or 26 age-matched population controls. The -1087IL-10 gene polymorphism was determined by PCR with restriction endonuclease mapping. Serum IL-10 and TNF-levels were determined by ELISA. The A allele frequency of -1087IL-10 gene in SLE/CVD was higher than in SLE controls (0.62 versus 0.42, p < 0.05). Ten (38%) of 26 SLE/CVD exhibited IL-10 AA genotype compared with five (19%) of 26 SLE controls. Serum IL-10 and TNF-levels were raised in SLE/CVD compared with SLE controls or population controls (p < 0.001). Furthermore, in SLE/CVD, a significantly reduced IL-10:TNF ratio was observed in patients with IL-10 AA genotype compared with AG or GG genotype (0.56 versus 0.77 versus 1.24, p < 0.05). In SLE controls and population controls, individuals with IL-10 GG genotype tended to have higher IL-10:TNF ratio. In conclusion, the A-1087IL-10 allele which has been reported to cause a lower capacity for IL-10 production could contribute to CVD in SLE. Furthermore, the IL-10 AA genotype is associated with reduced ratio of atheroprotective to atherogenic cytokines in SLE patients with CVD.

Cyclic adenosine 5'-monophosphate response element modulator is responsible for the decreased expression of c-fos and activator protein-1 binding in T cells from patients with systemic lupus erythematosus

T cells from patients with systemic lupus erythematosus express increased levels of the cAMP response element modulator (CREM) that has been shown to bind to the IL-2 promoter and suppress its activity. In this study, we demonstrate that CREM binds to the proximal promoter of the c-fos proto-oncogene in live systemic lupus erythematosus T cells and represses its expression following stimulation in vitro. Decreased levels of c-fos protein result in decreased AP-1 activity, as determined in shift assays. Blockade of the translation of CREM mRNA with an antisense CREM vector increases the expression of c-fos and the AP-1 activity. The levels of c-fos mRNA vary with disease activity. We conclude that CREM represses the expression of c-fos and limits the activity of the enhancer AP-1. Thus, CREM is involved indirectly in the modulation of transcriptional regulation of multiple genes including IL-2.

Termination of Antigen-Specific Immunity by CD95 Ligand (Fas Ligand) and IL-10

Following elimination of a foreign invader, the immune system must return to its normal quiescent levels. This process requires removal of reactive immune cells when they are no longer needed. We have explored the role of Fas/Fas ligand (FasL) in terminating immunity and demonstrate that mice defective in these proteins have prolonged immune responses. Studies demonstrate that termination of immunity occurs via the interaction of Fas(+) lymphoid cells with FasL(+) nonlymphoid cells at the site of Ag challenge. Our results also show that FasL is absent in quiescent tissue but is rapidly up-regulated during the local immune reaction. This occurs through the production of IL-10. Thus, FasL and IL-10 work in concert to eliminate inflammatory cells and control the duration of an immune response.

Fas ligand down-regulates cytokine-induced Fas receptor expression on insulinoma (NIT-1), but not islet cells, from autoimmune nonobese diabetic mice

In the pathogenesis of autoimmune type 1 diabetes, the apoptosis receptor Fas appears de novo on the surface of insulin-producing beta-cells. Fas expression is thought to be induced by proinflammatory cytokines, such as IL-1beta, interferon-gamma (IFNgamma), and TNFalpha, released by islet-infiltrating mononuclear cells. To determine whether beta-cells can modulate their sensitivity to apoptosis at the level of Fas, we investigated the effect of Fas ligand (FasL) on surface expression of Fas in NIT-1 insulinoma cells from nonobese diabetic (NOD) mice prone to autoimmune diabetes and islet cells from NOD and nonautoimmune BALB/c mice. In NIT-1 insulinoma cells, Fas expression induced by the cytokine combination IL-1beta and IFNgamma was reduced in the presence of FasL, whereas in islet cells Fas expression was unaffected by FasL. The effect of FasL on NIT-1 cells was evident during and after the induction of Fas expression by IL-1beta and IFNgamma. Thus, FasL down-regulates cytokine-induced Fas expression in NOD mouse-derived NIT-1 cells, but not in NOD or BALB/c mouse islets. The ability of NIT-1 cells to down-regulate Fas receptor in response to ligation is similar to that of a variety of tumor cells, which may use this mechanism to escape destruction by cytotoxic T cells. Islets apparently cannot protect themselves against FasL-induced apoptosis by down-regulating the Fas receptor. Understanding how NIT-1 insulinoma cells down-regulate Fas receptor in response to ligation by FasL has therapeutic implications for protecting normal beta-cells in autoimmune type 1 diabetes.

Feline Immunodeficiency Virus Infection Phenotypically and Functionally Activates Immunosuppressive CD4+CD25+T Regulatory Cells

Disease progression of feline immunodeficiency virus (FIV) infection is characterized by up-regulation of B7.1 and B7.2 costimulatory molecules and their ligand CTLA4 on CD4(+) and CD8(+) T cells. The CD4(+)CTLA4(+)B7(+) phenotype described in FIV(+) cats is reminiscent of CD4(+)CD25(+)CTLA4(+) cells, a phenotype described for immunosuppressive T regulatory (Treg) cells. In the present study, we describe the phenotypic and functional characteristics of CD4(+)CD25(+) T cells in PBMC and lymph nodes (LN) of FIV(+) and control cats. Similar to Treg cells, feline CD4(+)CD25(+) but not CD4(+)CD25(-) T cells directly isolated from LN of FIV(+) cats do not produce IL-2 and fail to proliferate in response to mitogen stimulation. Unstimulated CD4(+)CD25(+) T cells from FIV(+) cats significantly suppress the proliferative response and the IL-2 production of Con A-stimulated autologous CD4(+)CD25(-) T cells compared with unstimulated CD4(+)CD25(+) T cells from FIV(-) cats. Flow-cytometric analysis confirmed the apparent activation phenotype of the CD4(+)CD25(+) cells in LN of chronically FIV(+) cats, because these cells showed significant up-regulation of expression of costimulatory molecules B7.1, B7.2, and CTLA4. These FIV-activated, anergic, immunosuppressive CD25(+)CTLA4(+)B7(+)CD4(+) Treg-like cells may contribute to the progressive loss of T cell immune function that is characteristic of FIV infection.

Assessment of Be1 and Be2 cells in systemic lupus erythematosus indicates elevated interleukin-10 producing CD5+ B cells

Recent studies indicate that normal B cells can be primed to differentiate into two distinct cytokine-secreting effector subsets, Be1 and Be2. The aim of this study was to analyse, for the first time, Be1 and Be2 cells at the single cell level in SLE patients using the recently developed technique of flow cytometry for intracellular cytokines. Peripheral blood mononuclear cells (PBMC) from SLE patients and age- and sex-matched normal controls were cultured for 24 h in the presence or absence of phorbal myristate acetate and ionomycin (PMA/I) or lipopolysaccharide (LPS). The production of type I (IFN-gamma, IL-2) and type 2 (IL-4, IL-5, IL-6, IL-10, IL-13) cytokines by B cells (and IL-10 production by fractionated CD5+ and CD5- B cells) was investigated using an intracellular cytokine staining technique and flow cytometry. In the absence of PMA/I stimulation, the percentage of B cells from SLE patients was significantly lower than those of normal subjects and significantly more SLE B cells spontaneously produced IL-10 than controls. Moreover, CD5+ B cells from SLE patients were enriched for cells with signs of previous in vivo activation and for high levels of IL-10 production. A significant positive correlation was observed between the percentage of IL-10- and IL-6-producing PMA/I-stimulated B cells in SLE patients, but not in controls. There were no significant differences in the production of other cytokines by B cells of SLE patients and normal subjects. In conclusion, a general alteration of type 1 and type 2 cytokine production by B cells is not observed in SLE patients. The role of B cell cytokines in the pathogenesis of SLE appears to be exerted by elevated secretion of in vivo IL-10, which may play an important role in the immune dysregulation observed in SLE patients. Moreover, the cross regulation of IL-10 and IL-6 is disrupted in SLE patients.

Association of a four-amino acid residue insertion polymorphism of the HS1 gene with systemic lupus erythematosus: Molecular and functional analysis

OBJECTIVE

To investigate whether polymorphism(s) or mutation(s) in the hematopoietic cell-specific Lyn substrate 1 (HS1) gene are involved in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

The entire coding region of the HS1 gene was analyzed by reverse transcriptase-polymerase chain reaction/single-strand conformational polymorphism analysis. HS1-transfected WEHI-231 cells or B lymphocytes from patients with SLE were studied for apoptosis, activation, and proliferation by flow cytometric analysis and MTT assay.

RESULTS

We identified a glutamic acid-proline-glutamic acid-proline insertion between codons 366 and 367 (EPEP366-367ins) and 2 amino acid substitutions (A235T and E361K). The genotype frequency among individuals homozygous for the EPEP+ allele was 0.184 in 201 patients with SLE but only 0.098 in 184 healthy individuals (P = 0.016). The allele frequency of EPEP366-367ins was 0.408 in patients with SLE; this frequency was significantly higher than that in healthy controls (0.312) (P = 0.006). WEHI-231 cells transfected with EPEP+ HS1 were 100-fold more sensitive to B cell receptor (BCR)-mediated apoptosis than were those transfected with HS1 without EPEP. B lymphocytes from SLE patients with the EPEP+ allele were significantly more apoptotic without BCR stimulation and less activated after BCR stimulation than were those from SLE patients without the EPEP allele.

CONCLUSION

These results suggest that HS1 with the EPEP insertion polymorphism transmits accelerated signals from BCR and is involved in the pathogenesis of SLE.

Increased apoptotic neutrophils and macrophages and impaired macrophage phagocytic clearance of apoptotic neutrophils in systemic lupus erythematosus

OBJECTIVE

To evaluate whether patients with systemic lupus erythematosus (SLE) have a higher rate of apoptosis in and secondary necrosis of polymorphonuclear neutrophils (PMNs) and macrophages compared with controls; to compare the rate of macrophage phagocytic clearance of apoptotic PMNs in patients with SLE and healthy controls; to evaluate whether in vitro PMN and macrophage apoptosis and secondary necrosis, and the ability of macrophages to phagocytose apoptotic bodies, are correlated with lupus disease activity; and to determine whether macrophage clearance of apoptotic bodies in patients with SLE and normal controls is related to certain serum factors.

METHODS

Thirty-six patients with SLE and 18 healthy, nonsmoking volunteers were studied. PMNs and monocytes were isolated from fresh blood and cultured in the presence of different sources of serum. Apoptotic PMNs and macrophages were examined by annexin V binding and morphology on May-Giemsa-stained cytopreparations, at different time points. The presence of secondary necrotic PMNs and macrophages was verified by staining with trypan blue. Macrophage phagocytosis of apoptotic PMNs was measured using a coded, observer-blinded, microscopically quantified phagocytosis assay. Cells were cultured in the presence of serum obtained from healthy subjects or from patients with SLE.

RESULTS

At 5 and 24 hours, the percentage of apoptotic PMNs from patients with SLE was significantly higher than that of PMNs from healthy subjects. At 24 and 48 hours, the percentage of secondary necrotic PMNs from patients with SLE was also significantly higher than the percentage of necrotic PMNs from controls. Serum from patients with SLE accelerated the rate of apoptosis in and secondary necrosis of PMNs from healthy subjects. Macrophages from SLE patients were less capable of phagocytosing apoptotic PMNs compared with macrophages obtained from controls. Macrophages from patients with active SLE were less capable of phagocytosing apoptotic PMNs than were macrophages from patients with inactive SLE, but the difference was not statistically significant. The percentage of phagocytosis of apoptotic PMNs by macrophages from SLE patients correlated negatively with the SLE Disease Activity Index, serum levels of anti-double-stranded DNA, and the erythrocyte sedimentation rate, and correlated positively with serum levels of C3, C4, and albumin, the hemoglobin level, and the leukocyte count. Serum from SLE patients not only significantly increased macrophage apoptosis in cells from healthy subjects but also remarkably down-regulated the clearance of apoptotic PMNs by macrophages from healthy subjects. In contrast, serum from healthy subjects significantly increased phagocytosis of apoptotic PMNs by macrophages from SLE patients.

CONCLUSION

The observed increase of apoptotic PMNs and macrophages and the poor ability of macrophages from patients with SLE to phagocytose apoptotic bodies may indicate an impaired clearance mechanism, which may be mediated by factors in a patient's serum.

Dual upregulation of Fas and Bax promotes alloreactive T cell apoptosis in IL-10 gene targeting of cardiac allografts

Activation-induced cell death and cytokine deprivation are demonstrated by peripheral T cell populations at the conclusion of natural immune responses, and each of these processes is modulated by the immunosuppressive cytokine interleukin (IL)-10 in vitro. This study employs a clinically relevant in vivo model of IL-10 gene transfer with heterotopically transplanted cardiac allografts to determine the mechanisms of the effects of IL-10 on T cell survival. IL-10 protein overexpression within allografts 4-5 days after gene transfer augments apoptosis of CD4+ and CD8+ graft-infiltrating lymphocytes by 7.1-fold (P < 0.001) and 6.0-fold (P < 0.001), respectively. Graft-infiltrating T cells express 10-fold more proapoptotic Fas (P < 0.01) and 30-fold more Bax (P < 0.01) than controls. The fractions of activated caspase-8 (FADD-like IL-1beta-converting enzyme) and activated caspase-9 were increased 7- and 2.3-fold, respectively, in IL-10 gene-treated allografts at postoperative day 4-5. These changes in the Fas-Fas ligand pathway and Bcl-2 mitochondrial apoptosis regulation are enhanced by complete suppression of antiapoptotic FADD-like IL-1beta-converting enzyme inhibitory protein (FLIP) (from 30.5 to 0.0%, P < 0.01) and Bcl-xL (from 22.5 to 0.1%, P = 0.03) expression among these cells from the earliest days after gene transfer. Although changes in proteins of Fas- and Bcl-2-mediated apoptosis signaling occur, only the levels of Fas and FLIP correlate to the rate of apoptosis of graft-infiltrating CD3 lymphocytes and histological rejection scores. These results indicate that dichotomous apoptosis-regulatory pathways are affected by IL-10 gene therapy, but Fas-mediated mechanisms of activation-induced cell death more substantially contribute to the greater cell death of graft-infiltrating T cells after ex vivo IL-10 gene transfer.

Role of the Fcgamma receptor IIA polymorphism in the antiphospholipid syndrome: an international meta-analysis

OBJECTIVE

To assess the impact of the FcgammaRIIA-R/H131 polymorphism on the risk for antiphospholipid syndrome (APS), both primary and secondary to systemic lupus erythematosus (SLE).

METHODS

This international meta-analysis combined data from 9 research teams. FcgammaRIIA-R/H131 genotypes were determined in 481 APS cases (206 with primary APS), 1,420 SLE controls, and 1,655 disease-free controls. Data were combined using fixed-effects and random-effects models.

RESULTS

Compared with disease-free controls, the RR genotype was enriched in the entire group of APS cases (odds ratio [OR] 1.65, 95% confidence interval [95% CI] 1.28-2.14); this was driven mostly by patients with secondary APS (OR 1.95, 95% CI 1.45-2.63). The excess of RR homozygotes but not heterozygotes among APS patients suggested a recessive mode of inheritance, rather than the additive model seen for SLE susceptibility, where RR conferred greatest risk, and RH intermediate risk, for SLE. This probably reflected the additional influence of another opposing genetic effect of HH homozygosity on APS predisposition (OR 0.72 for RH versus HH, 95% CI 0.55-0.96). Among SLE patients, those with APS were more frequently HH homozygotes than heterozygotes (OR 0.56 for RH versus HH, 95% CI 0.39-0.81). HH homozygosity also tended to predominate in primary APS compared with secondary APS (OR 0.50 for RR versus HH, 95% CI 0.25-0.99 by fixed-effects model). There was no significant between-study heterogeneity for any of these effects.

CONCLUSION

The FcgammaRIIA-R/H131 polymorphism is an important determinant of predisposition to APS, with different influences on SLE and APS susceptibility per se.

Delayed neutrophil apoptosis in chronic periodontitis patients

BACKGROUND, AIMS

Neutrophil cells constitute the first defense barrier against the oral bacterial challenge in the periodontium. Reduction of neutrophils could impair this response against periopathogenic bacteria such as Porphyromonas gingivalis. Our previous work implicates the apoptosis of neutrophils in the pathogenesis of periodontitis. We now demonstrate that granulocyte monocyte-colony stimulating factor (GM-CSF) present in the gingival crevicular fluid (GCF) and secreted during the immune response reduces the apoptosis of neutrophils.

METHOD

In this study, the presence of GM-CSF and tumor necrosis factor-alpha (TNF-alpha) in GCF was determined in samples obtained from adult patients with periodontitis and from control subjects with clinically healthy gingiva. GCF was collected for 30 s using Periopaper(R) strips, and cytokines were quantified by ELISA. We used ex vivo culture of gingival tissue biopsies for 2 and 4 days in the presence of GM-CSF. Apoptosis was determined using the terminal TdT-mediated dUTP-biotin nick end labeling (TUNEL) technique, and expression of Bax by immunohistochemistry.

RESULTS

The presence of GM-CSF and TNF-alpha was detected in the majority of sites from periodontal patients (83.3% and 63.3%, respectively), presenting a total amount of 27.65 and 42.38 pg, respectively. GM-CSF reduces the neutrophil apoptosis determined by double staining with TUNEL and myeloperoxidase and by a reduction of Bax expression.

CONCLUSIONS

These findings suggest a novel mechanism by which neutrophils specifically accumulate in adult patients with periodontitis.

Quinacrine added to ongoing therapeutic regimens attenuates anticardiolipin antibody production in SLE

The benefit of combining quinacrine (Qn) with hydroxychloroquine (HCQ) in the treatment of systemic lupus erythematosus (SLE) was previously re-evaluated by us. In our current study we observed that, in 11 active SLE patients (SLEDAI score 5-12), the addition of Qn (100 mg/day) to their existing ongoing therapeutic regimens resulted in a significant attenuation of their previously persistent anticardiolipin antibody (aCL) response. This was in comparison with a matched non-Qn treated control group composed of 14 randomly chosen aCL-positive SLE patients with a similar SLEDAI score 6-10. Prior to Qn treatment the therapeutic regimens of 12 months' duration, included in all cases HCQ (400 mg/day), in many cases prednisone (P, 10-20 mg/day) and in some additional cases immunosuppressive drugs. SLEDAI scores and aCL levels were monitored during the entire follow-up period which totaled 24 months in the study group and 15-18 months in the controls. Along with the beneficial effect of the added Qn on SLEDAI scores, aCL disappearance was documented in eight of 11 patients and remained negative during 8-12 months of follow-up (P = 0.004), compared with such a change in only three of 14 non-Qn treated aCL-positive patients (P = 0.18). We conclude that the added Qn treatment to former established therapeutic protocols may eliminate aCL response in SLE patients. Whether this agent's effect is permanent needs further elucidation.

Immunopathology and the gene therapy of lupus

Lupus is a chronic autoimmune inflammatory disease with complex clinical manifestations. In humans, lupus, also known as systemic lupus erythematosus (SLE), affects between 40 and 250 individuals, mostly females, in each 100 000 of the population. There are also a number of murine models of lupus widely used in studies of the genetics, immunopathology, and treatment of lupus. Human patients and murine models of lupus manifest a wide range of immunological abnormalities. The most pervasive of these are: (1) the ability to produce pathogenic autoantibodies; (2) lack of T- and B-lymphocyte regulation; and (3) defective clearance of autoantigens and immune complexes. This article briefly reviews immunological abnormalities and disease mechanisms characteristic of lupus autoimmunity and highlight recent studies on the use of gene therapy to target these abnormalities.

Increased T-lymphocyte apoptosis/necrosis and IL-10 producing cells in patients and their spouses in Icelandic systemic lupus erythematosus multicase families

The objective of this study was to evaluate apoptosis and production of IL-10 in SLE patients, their spouses and first-degree relatives in Icelandic SLE multicase families. Previously, increased IL-10 production has been found in all three groups. As IL-10 has been found to induce apoptosis in SLE, the percentage of lymphocytes undergoing apoptosis was evaluated, as well as the possible correlation between apoptosis and IL-10 production. Apoptosis and IL-10 production were studied in SLE patients (n = 12) from SLE multicase families and their spouses (n = 12) and a matched control group of healthy individuals (n = 10). The proportion of T and B lymphocytes undergoing apoptosis at 0, 24, 48 and 72 h was detected by flow cytometry using Annexin V and PI staining and the rate of apoptosis was calculated. IL-10 production was studied simultaneously by ELISpot analysis of freshly isolated peripheral blood mononuclear cells. In addition, T lymphocyte apoptosis at t = 0 was investigated in a group of non-household first-degree relatives (n = 10) and controls (n = 10). Antinuclear and antilymphocyte antibodies were analysed in all the groups. The SLE patients as a group had a significantly increased percentage of T lymphocytes in apoptosis at 0 and 48 h and a significantly higher number of IL-10 producing cells as compared with the healthy controls (P = 0.03, 0.02 and 0.03, respectively). The spouses also had significantly increased percentage of T lymphocytes in apoptosis (t = 0) and a significantly higher number of IL-10-producing cells when compared with healthy controls (P = 0.01 and 0.02, respectively). There were no significant differences between the patients and their spouses. For apoptosis of B lymphocytes no difference was found between the groups. The SLE patients as a group had the highest rate of apoptosis. No correlation between the degree and rate of apoptosis and the number of IL-10-producing cells was detected. The first-degree relatives did not have increased percentage of T lymphocytes undergoing apoptosis at t = 0 compared with healthy controls. The SLE patients had higher titres of ANA compared with the other groups. No correlation was detected between the ANA titre and the percentage of lymphocytes undergoing apoptosis. There was no correlation between disease activity as measured by SLEDAI and apoptosis. In conclusion, our results suggest that environmental factors common to both SLE patients and their spouses are associated both with the increased apoptosis and increased spontaneous production of IL-10, thus providing support for the notion that both environmental and genetic factors influencing apoptosis are of importance for the development of SLE.

Costimulating aberrant T cell responses by B7-H1 autoantibodies in rheumatoid arthritis

A pathogenic hallmark of rheumatoid arthritis (RA) is persistent activation of self-reactive CD4(+) T cells. The cause of this aberrant activity remains elusive. We report here detection of autoantibodies against B7-H1, a recently described member of the B7 family, in 29% of patients with RA versus 4% of healthy donors. High-level expression of cell surface B7-H1 are found on activated human CD4(+), CD8(+), and CD45RO(+) T cells. Immobilized autoantibodies to B7-H1 are capable of costimulating the proliferation of CD4(+) T cells in vitro, and the presence of these autoantibodies correlates with active disease status. Using immobilized B7-H1 mAb's and programmed death 1Ig, we demonstrate that engagement of B7-H1 on CD4(+) T cells costimulates proliferation and secretion of IL-10, and subsequently leads to programmed cell death, accompanied with upregulated expression of TNF-related apoptosis-inducing ligand and activation of caspase-3. Taken together with our previous findings, these data indicate a bidirectional signaling role of B7-H1 in T cell costimulation and apoptosis and implicate B7-H1 autoantibodies as contributing to the progression of RA by inducing aberrant T cell responses.

IL-10 regulates murine lupus

MRL/MpJ-Tnfrsf6(lpr) (MRL/MpJ-Fas(lpr); MRL-Fas(lpr)) mice develop a spontaneous lupus syndrome closely resembling human systemic lupus erythematosus. To define the role of IL-10 in the regulation of murine lupus, IL-10 gene-deficient (IL-10(-/-)) MRL-Fas(lpr) (MRL-Fas(lpr) IL-10(-/-)) mice were generated and their disease phenotype was compared with littermates with one or two copies of an intact IL-10 locus (MRL-Fas(lpr) IL-10(+/-) and MRL-Fas(lpr) IL-10(+/+) mice, respectively). MRL-Fas(lpr) IL-10(-/-) mice developed severe lupus, with earlier appearance of skin lesions, increased lymphadenopathy, more severe glomerulonephritis, and higher mortality than their IL-10-intact littermate controls. The increased severity of lupus in MRL-Fas(lpr) IL-10(-/-) mice was closely associated with enhanced IFN-gamma production by both CD4(+) and CD8(+) cells and increased serum concentration of IgG2a anti-dsDNA autoantibodies. The protective effect of IL-10 in this lupus model was further supported by the observation that administration of rIL-10 reduced IgG2a anti-dsDNA autoantibody production in wild-type MRL-Fas(lpr) animals. In summary, our results provide evidence that IL-10 can down-modulate murine lupus through inhibition of pathogenic Th1 cytokine responses. Modulation of the level of IL-10 may be of potential therapeutic benefit for human lupus.

The role of interleukin-10 in autoimmune disease: systemic lupus erythematosus (SLE) and multiple sclerosis (MS)

Interleukin-10 (IL-10) is an immunoregulatory cytokine that plays a crucial role in inflammatory and immune reactions. It has potent anti-inflammatory and immunosuppressive activities on myeloid cell functions which forms a solid basis for its use in acute and chronic inflammatory diseases. Here, we discuss the role of IL-10 in autoimmune diseases and examine its beneficial effects in cellular-based autoimmune diseases such as multiple sclerosis (MS) or its involvement in humoral-based autoimmune diseases such as systemic lupus erythematosus (SLE). Inhibition of the immune stimulatory activities of IL-10 may provide novel approaches in the treatment of humoral autoimmune diseases, infectious diseases and cancer.

Tumor-associated B7-H1 promotes T-cell apoptosis: a potential mechanism of immune evasion

B7-H1, a recently described member of the B7 family of costimulatory molecules, is thought to be involved in the regulation of cellular and humoral immune responses through the PD-1 receptor on activated T and B cells. We report here that, except for cells of the macrophage lineage, normal human tissues do not express B7-H1. In contrast, B7-H1 is abundant in human carcinomas of lung, ovary and colon and in melanomas. The pro-inflammatory cytokine interferon-gamma upregulates B7-H1 on the surface of tumor cell lines. Cancer cell-associated B7-H1 increases apoptosis of antigen-specific human T-cell clones in vitro, and the apoptotic effect of B7-H1 is mediated largely by one or more receptors other than PD-1. In addition, expression of B7-H1 on mouse P815 tumor increases apoptosis of activated tumor-reactive T cells and promotes the growth of highly immunogenic B7-1(+) tumors in vivo. These findings have implications for the design of T cell-based cancer immunotherapy.

Combination of molecular mimicry and aberrant autoantigen expression is important for development of anti-Fas ligand autoantibodies in patients with systemic lupus erythematosus

We have reported previously that circulating anti-Fas ligand (FasL) autoantibodies able to inhibit Fas/FasL-mediated apoptosis were present in patients with systemic lupus erythematosus (SLE). In the present study, we describe the epitopes recognized by these anti-FasL autoantibodies. Rabbit antihuman antibody, raised against a FasL fragment consisting of amino acids (aa) 103-179 (fragment 2.0), inhibited Fas/FasL-mediated apoptosis, whereas an antibody against a FasL aa 103-146 fragment (fragment 1.0) did not. This suggested that an epitope around aa 146-179 was important for Fas/FasL interaction. Epitope mapping of anti-FasL autoantibodies using deletion mutants indicated that the epitope was located around aa 163-179. Three-dimensional molecular modelling of the Fas/FasL complex revealed that the aa 162-169 region was located on the outermost side of FasL, which suggested that the anti-FasL autoantibody would easily have access to the epitope. FasL point mutants involving aa positions 162-169 resulted in complete loss of apoptosis-inducing capability, which suggested that the aa 162-169 region was important for Fas/FasL interaction. A synthetic FasL peptide consisting of aa 161-170 blocked the binding of anti-FasL autoantibodies to FasL fragment 2.0 (aa 103-179). The FasL aa 161-170 sequence was found to be highly homologous with aa sequences from several infectious agents. Synthetic peptides derived from some of these microorganisms cross-reacted with the epitope recognized by the autoantibodies, suggesting that several foreign infectious agent-derived proteins may share an epitope with human FasL. As lymphocytes from SLE patients aberrartly expressed FasL, it is possible that infection by one of several infectious agents may trigger cross-reactive antibody responses, after which aberrantly expressed endogenous FasL might induce the shift from a cross-reactive response to an authentic autoimmune response. Therefore, a combination of molecular mimicry and aberrant autoantigen expression may be important for the development of anti-FasL autoantibodies in SLE patients.

Persistent mitochondrial hyperpolarization, increased reactive oxygen intermediate production, and cytoplasmic alkalinization characterize altered IL-10 signaling in patients with systemic lupus erythematosus

Abnormal death signaling in lymphocytes of systemic lupus erythematosus (SLE) patients has been associated with elevation of the mitochondrial transmembrane potential (Delta psi(m)) and increased production of reactive oxygen intermediates (ROI). The resultant ATP depletion sensitizes T cells for necrosis that may significantly contribute to inflammation in patients with SLE. In the present study, the role of mitochondrial signal processing in T cell activation was investigated. CD3/CD28 costimulation of PBL elicited transient mitochondrial hyperpolarization and intracellular pH (pH(i)) elevation, followed by increased ROI production. Baseline Delta psi(m), ROI production, and pH(i) were elevated, while T cell activation-induced changes were blunted in 15 patients with SLE in comparison with 10 healthy donors and 10 rheumatoid arthritis patients. Similar to CD3/CD28 costimulation, treatment of control PBL with IL-3, IL-10, TGF-beta(1), and IFN-gamma led to transient Delta psi(m) elevation. IL-10 had diametrically opposing effects on mitochondrial signaling in lupus and control donors. Unlike healthy or rheumatoid arthritis PBL, cells of lupus patients were resistant to IL-10-induced mitochondrial hyperpolarization. By contrast, IL-10 enhanced ROI production and cell death in lupus PBL without affecting ROI levels and survival of control PBL. Ab-mediated IL-10 blockade or stimulation with antagonistic lymphokine IL-12 normalized baseline and CD3/CD28-induced changes in ROI production and pH(i) with no impact on Delta psi(m) of lupus PBL. The results suggest that mitochondrial hyperpolarization, increased ROI production, and cytoplasmic alkalinization play crucial roles in altered IL-10 responsiveness in SLE.

Localized interleukin-10 gene transfer induces apoptosis of alloreactive T cells via FAS/FASL pathway, improves function, and prolongs survival of cardiac allograft

We hypothesized that localized IL-10 gene transfer can induce alloreactive T cell apoptosis and tested this hypothesis with liposome-mediated ex vivo intracoronary IL-10 gene transfer using a functional heterotopic allograft heart transplant model in rabbits. Localized IL-10 overexpression prolonged cardiac allograft survival over three folds. In parallel with the time-course of IL-10 overexpression, the percentage of apoptotic CD3+ cells among total CD3+ cells was significantly increased in the gene therapy group (36.5+/-3.9%) compared with that in the control group (6.2+/-2.6%, P<0.01) on postoperative day (POD) 3-6, and it was further increased (45.8+/-5.7%) on POD7-10. Apoptotic CD4+ and CD8+ cells were also significantly increased in the gene group (P<0.01). In contrast, the percentage of apoptotic myocytes significantly decreased from 10.1+/-0.8% in the control group to 3.5+/-0.4% in the gene group on POD7-10 (P<0.01). This reduction was inversely correlated with the increase in the percentages of apoptotic CD4+ and CD8+ cells (P<0.01). The percentage of caspase-3 positive myocytes was significantly reduced, although percentages of caspase-3 positive CD4+ and CD8+ cells were markedly increased in the gene group (P<0.01). Moreover, about 60-80% of apoptotic T lymphocytes expressed Fas in the gene group compared with less than 10% in the control group (P<0.01). These results suggest that localized IL-10 gene transfer induces alloreactive T cell apoptosis via the Fas/FasL pathway that may contribute to the alleviated acute rejection, improved cardiac function, and prolonged survival in the IL-10 gene-treated cardiac allografts.

New therapies in systemic lupus erythematosus

A new understanding of the pathogenesis of autoimmunity, the mechanisms of action of older drugs, the advent of target-specific biological therapies and pharmacogenomics has created multiple treatment options for the patient with systemic lupus erythematosus. These include topical therapies, more selective non-steroidal anti-inflammatory agents, hormonal interventions and a new generation of immune suppressives. Currently available strategies also include the use of intravenous gamma globulin, apheresis, stem-cell transplantation and antileprosy preparations alone or in combination with immune suppressives. A handful of biologicals have been studied in clinical trials. After two decades without new options for lupus patients practitioners now have a full menu of improved therapeutic options.

Dysregulation of p56lck kinase in patients with systemic lupus erythematosus

In this study we investigated one of the possible mechanisms of p56lck down-regulation in peripheral blood lymphocytes (PBLs) from Systemic Lupus Erythematosus (SLE) patients and we correlated p56lck dysregulation with accelerated apoptosis in SLE PBLs. PBLs from SLE patients and healthy donors were isolated. p56lck protein expression and lck mRNA level were estimated by immunoblotting and RT-PCR, respectively. FACS analysis was used to evaluate the apoptosis and p56lck levels in apoptotic and non-apoptotic PBLs. A non-radioactive Tyrosine Kinase Assay Kit was used to measure p56lck activity. Our results demonstrated that PBLs from SLE patients displayed lower levels of lck mRNA and p56lck protein as compared to healthy donors. The apoptosis of fresh or cultured PBLs was enhanced in SLE patients, especially in anti-DNA negative group. The expression of p56lck was inverse correlated with apoptosis of fresh and cultured SLE PBLs, especially in anti-DNA negative patients. Double staining FACS analysis showed that p56lck expression was lower in apoptotic than in non-apoptotic PBLs. p56lck specific activity was directly correlated to apoptosis in SLE PBLs. While the low expression of p56lck may be the result of lower degree of synthesis, the increased specific activity could directly correlated to the extent of apoptosis in SLE PBLs. Based on our observations, we assume that the p56lck dysregulation could play a role in SLE pathogenesis.

Immunopathogenesis of vasculitis

Vasculitis is defined by the presence of leukocytes in the vessel wall with reactive damage to mural structures, leading to tissue ischemia and necrosis. The immunopathologic events that initiate the process of vascular inflammation and blood vessel damage are unclear. Damage of vascular endothelial cells and the recruitment and accumulation of the inflammatory infiltrate are determined by the endothelial cell and the bystanders, including the expression of adhesion molecules, the secretion of peptides and hormones, and the specific interaction with inflammatory cells. In addition to the endothelial cells, which provide costimulatory function, other cellular components and nonendothelial structures of the vessel wall are involved in controlling the inflammatory process, serve as antigen-presenting cells, and contribute with inflammatory mediators.

Mitochondrial hyperpolarization and ATP depletion in patients with systemic lupus erythematosus

OBJECTIVE

Peripheral blood lymphocytes (PBLs) from systemic lupus erythematosus (SLE) patients exhibit increased spontaneous and diminished activation-induced apoptosis. We tested the hypothesis that key biochemical checkpoints, the mitochondrial transmembrane potential (deltapsim) and production of reactive oxygen intermediates (ROIs), mediate the imbalance of apoptosis in SLE.

METHODS

We assessed the deltapsim with potentiometric dyes, measured ROI production with oxidation-sensitive fluorochromes, and monitored cell death by annexin V and propidium iodide staining of lymphocytes, using flow cytometry. Intracellular glutathione levels were measured by high-performance liquid chromatography, while ATP and ADP levels were assessed by the luciferin-luciferase assay.

RESULTS

Both deltapsim and ROI production were elevated in the 25 SLE patients compared with the 25 healthy subjects and the 10 rheumatoid arthritis patients. Intracellular glutathione contents were diminished, suggesting increased utilization of reducing equivalents in SLE. H2O2, a precursor of ROIs, increased deltapsim and caused apoptosis in normal PBLs. In contrast, H2O2-induced apoptosis and deltapsim elevation were diminished, particularly in T cells, and the rate of necrotic cell death was increased in patients with SLE. The intracellular ATP content and the ATP:ADP ratio were reduced and correlated with the deltapsim elevation in lupus. CD3:CD28 costimulation led to transient elevation of the deltapsim, followed by ATP depletion, and sensitization of normal PBLs to H2O2-induced necrosis. Depletion of ATP by oligomycin, an inhibitor of F0F1-ATPase, had similar effects.

CONCLUSION

T cell activation and apoptosis are mediated by deltapsim elevation and increased ROI production. Mitochondrial hyperpolarization and the resultant ATP depletion sensitize T cells for necrosis, which may significantly contribute to inflammation in patients with SLE.

Cancer of the uterine cervix may be significantly associated with a gene polymorphism coding for increased IL-10 production

The purpose of our prospective, case-controlled study was to investigate the hypothesis that women who are genetically programmed to produce high or medium levels of IL-10 were more likely to develop cancer of the uterine cervix than individuals genetically predisposed to low IL-10 production. The population was recruited from patients attending gynecological clinics at 2 hospitals in Harare, Zimbabwe. Laboratory tests were performed in the Departments of Immunology, Chemical Pathology and Medical Microbiology, Medical School, University of Zimbabwe, and simultaneously at the Department of Biological Sciences, University of Manchester, United Kingdom. Included in our study were 77 women with histologically proven cancer of the uterine cervix and 69 age- and parity-matched healthy women. All of the patients and healthy controls were from the Shona ethnic group that inhabits northern Zimbabwe. DNA was purified from cervical cytobrush samples obtained from women with cervical cancer. Control DNA was extracted from urine or peripheral blood samples from the healthy women. The Qiagen DNA extraction kit was used. Detection of allele A and/or G at -1082 in the promoter region of the IL-10 gene was carried out using the ARMS-PCR technique. Polymorphism in the amplified products was detected by gel electrophoresis in the presence of ethidium bromide and were bands visualized under UV light. The data comprise 77 women who developed invasive cervical cancer and 69 healthy women matched for age and parity. Patients with cancer were significantly (p = 0.001) more likely to be predisposed to produce higher (A/G) levels of IL-10. The genotype encoding for high (G/G) production of IL-10 was only observed in one cancer patient. The prevalence of low producers of IL-10 in the cancer group was significantly lower than in the healthy women. There were no high producers amongst the healthy women. These data suggest that the genetically acquired ability to produce higher levels of IL-10 may be a significant factor in the development of cervical cancer.

Lymphopenia in occupational pulmonary silicosis with or without autoimmune disease

An increased prevalence of autoimmune diseases such as rheumatoid arthritis has been demonstrated in silica-exposed patients. The aim of this study was to determine the peripheral blood lymphocyte phenotype in a population of silicotic workers employed in the slate mines of the district. Silicosis was assessed in 58 patients according to the International Labor Office's criteria. Clinical and biological data including flow cytometric evaluation of the lymphocyte subsets were compared with those from 41 healthy volunteers. The silicotic patients had a higher prevalence of autoimmune diseases (6/58 versus 0/41: P < 0.05) and of elevated antinuclear antibody titres compared to the control group. A very significant decrease of total lymphocyte count (P < 0.001) involving B, T and Natural Killer cells was found in silicotic patients as compared with matched healthy volunteers. A significant increase in the percentage of activated T cells (12.3%) was observed in the silicotic group as compared to 6.5% in the control group (P = 5 x 10(-5)). Our results show that in silicotic patients, the absolute number of circulating lymphocytes is diminished with an increased proportion of activated T cells. Whether these findings could predispose to the development of autoimmune disorders is discussed.

Interleukin-10 and apoptotic death of circulating lymphocytes in surgical/anesthesia trauma

OBJECTIVE

To examine the relationship between circulating interleukin-10 (IL-10) and the occurrence of lymphocyte apoptosis after surgical/anesthesia trauma.

METHODS

Data were collected prospectively on 18 adult patients undergoing elective major surgery. Blood sampling for assessment of lymphocyte apoptosis and IL-10 levels was performed on the day before surgery (t(0)) and at 24 and 96 hours after operation (t(1) and t(2), respectively). After lymphocyte isolation, quantification of apoptosis was made by staining apoptotic cells with 7-amino-actinomycin D. Plasma IL-10 concentrations were measured using enzyme-linked immunosorbent assay.

RESULTS

A significantly increased frequency of apoptotic CD4(+) and CD8(+) cells (p < 0.05) was observed at t1 measurement (8.10% +/- 0.58% and 12.21% +/- 1.47% for CD4(+) and CD8(+), respectively) compared with preoperative values (1.53% +/- 0.38% and 1.32% +/- 0.45% for CD4(+) and CD8(+), respectively). Plasma IL-10 levels showed a significant elevation at both t(1) and t(2) times, peaking at t(1). At t(1), IL-10 levels were correlated with the frequency of CD4(+) and CD8(+) apoptotic lymphocytes (r = 0.78, p = 0.0005 for IL-10 vs. apoptotic CD4(+); r = 0.71, p = 0.003 for IL-10 vs. apoptotic CD8(+)).

CONCLUSION

Surgical trauma is associated with a significant but transient increase in lymphocyte commitment to apoptosis and IL-10 production. The exact relationship linking the overproduction of IL-10 with lymphocyte apoptosis after a surgical operation is still elusive and requires further investigation.

The effect of interleukin-10 and of interleukin-12 on the in vitro production of anti-double-stranded DNA antibodies from patients with systemic lupus erythematosus

IL-10 and IL-12 are cytokines which are important in regulating immune responses. Plasma levels of IL-10 and autoantibodies against double-stranded DNA (dsDNA) often mirror disease activity in patients with SLE. IL-12 secretion from SLE patients' blood mononuclear cells also correlates with disease activity, but has an inverse relationship. The aim of this study was to measure the effect of IL-10 and of IL-12 on the production of IgG autoantibodies from patients with SLE, both cross-sectionally and longitudinally. Peripheral blood mononuclear cells (PBMC) were cultured with IL-10 (at 20 ng/ml or 2 ng/ml) or IL-12 (at 2 ng/ml or 0.2 ng/ml) or without cytokine and the supernatanants tested for the production of double-stranded DNA antibodies (dsDNA abs), single-stranded DNA antibodies (ssDNA abs) and total IgG antibodies (IgG abs) by ELISA. The BILAG disease activity index was recorded at each patient visit (a global score of six or more is regarded as active disease). In general, treatment with IL-10 caused PBMCs from patients with inactive disease to increase their antissDNA and dsDNA ab production (by upto 354% and 186%, respectively) while patients with active disease decreased their antibody production (by upto 91% and 97%, respectively). Overall there was a correlation between disease activity and change in antissDNA and dsDNA ab production (r = - 0.51; P = 0.03 and r = - 0.48; P = 0.042, respectively). Treatment with IL-12 at 0.2 ng/ml inhibited antissDNA and dsDNA antibody production, having the greatest effect on patients with active disease (decreasing antissDNA and dsDNA antibody production by upto 75% and 73%, respectively). This resulted in a significant correlation between disease activity and change in antissDNA antibody production (r = - 0.76; P = 0.03), but significance was not reached with antidsDNA antibody production (P = 0.06). Together these data suggest that the effect of these cytokines on antibody production by SLE PBMCs involves several factors; one of which is disease activity.

New approaches to treatment in systemic vasculitis: biological therapies

Although the effectiveness of biological agents in systemic vasculitis is unproven, their introduction heralds a new era of vasculitis treatment. These agents offer the promise of targeted immunotherapies; the possibility of greater efficacy (and fewer side-effects) than conventional vasculitis treatments; and the potential to provide novel insights into the pathophysiology of these diseases-insights that may be gained only by using these agents in humans. Challenges to the investigation of these therapies in the systemic vasculitides exist, but important basic and clinical investigations are already in progress. We review the major issues facing the investigation of biological agents in vasculitis; examine the rationale for believing that biological strategies in vasculitis will be efficacious; identify several candidate targets for biological approaches; and discuss the results to date of early studies. The potential biological targets discussed include cytokines such as tumour necrosis factor; interleukins-1, -6, and -12; interferon-gamma; the co-stimulatory molecules B7-1 and B7-2; and others.

Transgenic expression of IL-10 in T cells facilitates development of experimental myasthenia gravis

Ab to the acetylcholine receptor (AChR) cause experimental myasthenia gravis (EMG). Th1 cytokines facilitate EMG, whereas Th2 cytokines might be protective. IL-10 inhibits Th1 responses but facilitates B cell proliferation and Ig production. We examined the role of IL-10 in EMG by using wild-type (WT) C57BL/6 mice and transgenic (TG) C57BL/6 mice that express IL-10 under control of the IL-2 promoter. We immunized the mice with doses of AChR that cause EMG in WT mice or with low doses ineffective at causing EMG in WT mice. After low-dose AChR immunization, WT mice did not develop EMG and had very little anti-AChR serum Ab, which were mainly IgG1, whereas TG mice developed EMG and had higher levels of anti-AChR serum Ab, which were mainly IgG2, in addition to IgG1. At the higher doses, TG mice developed EMG earlier and more frequently than WT mice and had more serum anti-AChR Ab. Both strains had similar relative serum concentrations of anti-AChR IgG subclasses and IgG and complement at the muscle synapses. CD8(+)-depleted splenocytes from all AChR-immunized mice proliferated in the presence of AChR and recognized a similar epitope repertoire. CD8(+)-depleted splenocytes from AChR-immunized TG mice stimulated in vitro with AChR secreted significantly more IL-10, but less of the prototypic Th1 cytokine IFN-gamma, than those from WT mice. They secreted comparable amounts of IL-4 and slightly but not significantly reduced amounts of IL-2. This suggests that TG mice had reduced activation of anti-Torpedo AChR Th1 cells, but increased anti-AChR Ab synthesis, that likely resulted from IL-10-mediated stimulation of anti-AChR B cells. Thus, EMG development is not strictly dependent on Th1 cell activity.

IL-10 mediation of activation-induced TH1 cell apoptosis and lymphoid dysfunction in polymicrobial sepsis

Recent studies suggest that increased activation-induced lymphocyte apoptosis (AICD) is detected in mouse splenocytes during polymicrobial sepsis which may contribute to lymphocyte immune dysfunction [i.e., decreased interleukin (IL-)2 and interferon-gamma (IFN-gamma) production] leading to the associated morbidity seen in those animals. Thus, we wanted to examine the hypothesis that immune suppressive agents, such as IL-4, IL-10 or prostaglandin E2(PGE2), known to be elevated in septic animals, also contribute to this increase in AICD. Here we demonstrate that the inclusion of monoclonal antibody (mAb) to IL-10, but not anti-IL-4 or ibuprofen (IBU), blunted this sepsis induced increase in splenocyte AICD. Additionally, septic mice deficient in the IL-10 gene product (-/-) showed neither an increase in AICD nor a loss of IL-2/IFN-gamma release capacity. Interestingly, mAb to IL-10 did not altered the extent of AICD in a Th2-cell line, but exogenous IL-10 did potentiate Th1-like cell line AICD. This was consistent with the finding that the increased AICD seen in septic mouse splenocytes was restricted largely to the CD4+ cells producing IL-2 (Th1-cells) and that mAb to IL-10 treatment suppressed this change. Furthermore, IL-10 appears to mediate its AICD effect by upregulation of the Fas receptor and Fas receptor signaling protein components, but not by altered expression of Bcl/Bax/Bad family members, in septic mouse splenocytes. To the extent that these processes contribute in a pathological fashion to the animal's capacity to survive sepsis we have previously observed that in vivo post-treatment of mice with mAb IL-10 markedly attenuated septic mortality. Collectively, these data indicate that in the septic mouse the Th2 cytokine IL-10 not only serves to actively induce Th1 lymphocyte immune dysfunction but also plays a role in their apoptotic depletion. These processes in turn appear to contribute to the animal's inability to ward off lethal septic challenge.

Soluble CD95 concentrations are increased in patients with severe systemic lupus erythematosus, but not in their first degree relatives

OBJECTIVE

Plasma concentrations of soluble CD95 (sCD95) are raised in patients with systemic lupus erythematosus (SLE) before clinical relapses become manifest. Increased sCD95 concentrations may therefore be a familial characteristic that is associated with susceptibility to severe disease. To test this, sCD95 concentrations were measured in healthy first degree relatives of patients with severe and non-severe SLE.

METHODS

Seventy seven first degree relatives of 26 patients with severe, and 72 relatives of 25 patients with non-severe lupus were studied. Controls were 42 first degree relatives of 17 patients with chronic cutaneous lupus erythematosus (CCLE) and 63 partners of the patients with their first degree relatives. Severe lupus was defined as both multi-organ disease and cyclophosphamide treatment, non-severe lupus as neither. Organ damage was assessed with the SLICC-ACR index, disease activity with SLEDAI.

RESULTS

Soluble CD95 concentrations in relatives of patients with severe SLE were similar to those in relatives of patients with non-severe SLE, relatives of patients with CCLE, and controls (median (interquartile range) sCD95 concentration 0.59 (0.52-0.66) v 0.57 (0.50-0.63), 0.56 (0.51-0.71), and 0.55 (0.49-0.61) ng/ml, p=0.25, p=0.94, and p=0.17, respectively). Increased concentrations of sCD95, however, were found in patients with severe SLE compared with those in patients with non-severe SLE, patients with CCLE, and control relatives (0.77 (0.70-0.97) v 0.60 (0.54-0.67), 0.57 (0.54-0.71), and 0.57 (0.52-0.63) ng/ml, respectively, p<0.001). Concentrations of sCD95 were significantly correlated with damage index scores (rs=0.47, p<0.01). Basic and clinical characteristics of patients with SLE, including SLEDAI scores, could not explain these observations.

CONCLUSION

Soluble CD95 concentrations are associated with severity of the disease and not with susceptibility for severe SLE.

Impaired translational response and increased protein kinase PKR expression in T cells from lupus patients

Activation of peripheral blood T cells results in a rapid and substantial rise in translation rates and proliferation, but proliferation in response to mitogen stimulation is impaired in systemic lupus erythematosus (SLE). We have investigated translation rates and initiation factor activities in T cells from SLE patients in response to activating signals. Activation by PMA plus ionomycin strongly increased protein synthesis in control T cells but not in T cells from SLE patients. The rate of protein synthesis is known to be strongly dependent on the activity of two eukaryotic translation initiation factors, eIF4E and eIF2alpha. We show that following stimulation, eIF4E expression and phosphorylation increased equivalently in control and SLE T cells. Expression of eIF4E interacting proteins - eIF4G, an inducer, and 4E-BP1 and 4E-BP2, two specific repressors of eIF4E function - and the phosphorylation level of 4E-BP1, were all identical in control and SLE T cells. In contrast, the protein kinase PKR, which is responsible for the phosphorylation and consequent inhibition of eIF2alpha activity, was specifically overexpressed in activated SLE T cells, correlating with an increase in eIF2alpha phosphorylation. Therefore, high expression of PKR and subsequent eIF2alpha phosphorylation is likely responsible, at least in part, for impaired translational and proliferative responses to mitogens in T cells from SLE patients.

Expression of fas (CD95) ligand is correlated with IL-10 and granulocyte colony-stimulating factor expression in oral and oropharyngeal squamous cell carcinoma

The Fas/Fas ligand (FasL) pathway has been shown to be an important cellular pathway mediating apoptosis. In this study we investigated the expression of Fas and FasL and the rate of spontaneous apoptosis in 58 oral and oropharyngeal squamous cell carcinoma (SCC) by using immunohistochemical techniques. There was no correlation between Fas or FasL expression and clinicopathological factors. The expression of Fas in the tumor did not affect spontaneous apoptosis of the tumor cells. However, FasL expression was associated with IL-10 and granulocyte colony-stimulating factor expression in oral and oropharyngeal SCC. These results suggested that the Fas/FasL system is connected with the expression of various factors including cytokines in tumor cells.

Cytokine regulation of apoptosis and Bcl-2 expression in lymphocytes of patients with systemic lupus erythematosus

Both faulty regulation of apoptosis and the inappropriate expression of several interleukins have been considered important defects of lymphocytes in the human autoimmune disease systemic lupus erythematosus (SLE). We therefore tested the in vitro effect of recombinant interleukin (IL-)-2, 4, 7, and 15 on peripheral blood mononuclear cells from patients with SLE and from healthy volunteers. Intracellular Bcl-2 and Bax expression was measured by fluorocytometry and the rate of apoptosis was determined by the TUNEL technique and propidium iodide staining. IL-2, IL-4, IL-7 and IL-15 led to a significant increase in Bcl-2 and a reduction in cell death rates, which was even more pronounced in SLE. Bax levels remained unchanged. Interestingly, the high ex vivo Bcl-2 content of lymphocytes from some SLE patients was maintained after growth factor withdrawal. Anti-apoptotic cytokine signaling may significantly influence the deregulation of cell death in SLE lymphocytes.