Increased and highly stable levels of functional soluble interleukin-6 receptor in sera of patients with monoclonal gammopathy

Soluble human interleukin-6 receptor (sIL-6R) was measured in the serum of 30 healthy individuals, 32 individuals with monoclonal gammopathy of undetermined significance (MGUS), 20 patients with early multiple myeloma (MM) and 54 patients with overt MM. The serum activity recognized by an immunoradiometric assay was determined to be sIL-6R, because of its binding capacity to IL-6 and its molecular mass of 55 kDa. All sera of healthy individuals contained sIL-6R (mean value: 89 ng/ml, range 17-300 ng/ml). Serum sIL-6R levels were increased by 51% in patients with MGUS (mean value: 135 ng/ml, p<0.005), by 44% in patients with early myeloma (mean value: 128 ng/ml, p<0.001) and by 116 % in patients with overt MM (mean value: 193 ng/ml, p<0.001). In patients with MM, a complete lack of correlation (p>0.7) was found between serum sIL-6R levels and other previously recognized prognostic factors in this disease, particularly serum IL-6 levels and those factors related to tumor cell mass. The independence of serum sIL-6R levels on tumor cell mass was directly demonstrated by studying four patients with MM treated with autologous bone marrow transplantation for periods of between 320 and 760 days. These levels were found to be remarkably stable and constant, independent of whether patients relapsed or achieved complete remission. Finally, physiological concentrations of sIL-6R were found to increase by tenfold the sensitivity of human myeloma cell lines to IL-6. These observations suggest a high control of the sIL-6R level in vivo, and, possibly, an important functional role of this circulating protein in patients with monoclonal gammopathies.     

IL-6 and soluble IL-6 receptors (sIL-6R and sgp130) in human pleural effusions: massive IL-6 production independently of underlying diseases

IL-6, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130) levels were measured in sera and pleural effusions from 42 patients with metastatic carcinoma, non-Hodgkin's lymphoma, tuberculosis, cardiac failure and miscellaneous diseases. Pleural IL-6 levels measured by ELISA were very high in all patient groups (mean 34.8 ± 15.3 ng/ml) without significant difference according to diseases. IL-6 was shown to be biologically active in a proliferative assay. Serum IL-6 levels were low (0.049 ± 0.014 ng/ml) and did not correlate with pleural fluid levels. Pleural IL-6 levels correlated with the number of polymorphonuclear cells in pleural fluid (P< 0.03). Pleural sIL-6R levels (76 ± 8 ng/ml) were always lower than serum levels (196 ± 12 ng/ml; P< 0.0001) but correlated with them (P< 0.01). Pleural sIL-6R and albumin levels correlated (P< 0.01), suggesting a transudation of sIL-6R from the serum. Pleural sgp130 levels (10.9 ± 1.0 ng/ml) were lower than serum levels (24.6 ± 2.8 ng/ml; P< 0.002). After gel filtration of pleural fluid, the bulk of IL-6 (>90%) was recovered in a 15 000–30 000 fraction, corresponding to the expected mol. wt of free IL-6. These results suggest a production and a sequestration of IL-6 in the pleural cavity in all studied conditions.     

血清可溶性白细胞介素6受体的检测及其临床意义

以夹心ELISA方法检测30名正常对照者,22份可抽提核抗原(ENA)抗体阳性血清及49名Grave病患者血清sIL-6R水平.结果表明;本方法的灵敏度为80pg/ml,批内及批间误差分别为7.5%和9.6%.正常对照组、Grave病缓解组、Grave病未缓解组及ENA抗体阳性组的血活sIL-6R浓度分别为185.55±53.0ng/ml、191.65±62.0ng/ml、241.67±69.0ng/ml和264.86±108.53ng/ml.经统计学处理Grave氏病未缓解组和ENA抗体阳性组sIL-6R水平明显高于正常对照组对,Grave病缓解组与上常对照组血清sIL-6R浓度无差异提示slL-6R检测在ENA抗体产生中的作用和Grave病监测病情中的价值.     

Abnormal distribution of IL-6 receptor in aged MRL/lpr mice: elevated expression on B cells and absence on CD4+ cells.

A mAb against murine IL-6 receptor (IL-6R), KMH7, was obtained by immunization of hamster with recombinant soluble murine IL-6R. Flow cytometry analysis of IL-6R distribution on lymphocytes in BALB/c showed that IL-6R was expressed on peripheral lymph node (LN) T cells of either CD4+ or CD8+ phenotype, and Peyer's patch IgA+ B cells, but not on splenic B cells and thymocytes. A similar distribution was observed in 5 week old MRL/lpr and 16-week-old MRL/n mice. In contrast, in 16 week old MRL/lpr mice of both sexes, IL-6R was expressed on splenic IgM+ cells. Peripheral LN CD4+ T cells in 16 week old female MRL/lpr mice did not express IL-6R. Thymocytes in any population with a phenotype of CD4+ or CD8+, double negative, and double positive were not stained with KMH7 in both BALB/c and MRL/lpr mice. In both strains, IL-6R was induced in CD4+ or CD8+ thymocytes after 2 days of culture, suggesting that CD4+ thymocytes in MRL/lpr have a potential to express IL-6R. Our results suggest that overexpression of IL-6R on B cells and absence of IL-6R on peripheral CD4+ cells are concurrent with, or may contribute to, B cell hyperreactivity and T cell abnormality in this strain.     

Effect of cyclophosphamide on lymphokine production in MRL/lpr.Yaa mice

The Y chromosome (Yaa gene) from autoimmune BXSB mice has been shown to be responsible for the acceleration of autoimmune symptoms when transferred to MRL/lpr mice. We examined the pathological, serological and immunological characteristics of MRL/lpr.Yaa mice and the suppressive effect of cyclophosphamide (CP) on the mice. MRL/lpr.Yaa mice spontaneously developed a massive lymphadenopathy characterized by hypergammaglobulinemia, the presence of several autoantibodies, and autoimmune disease. In MRL/lpr.Yaa mice, IL-2, IL-4 and IL-5 production in concanavalin A (Con A)-stimulated splenocytes were about 10-fold lower than in BALB/c mice at 5 weeks of age.The concentrations of these lymphokines remained low until the mice were 16 weeks of age. The production of IFN- and IL-6 in 16 week old MRL/lpr.Yaa mice was about 4- and 2-fold lower, respectively, though these levels were similar in both strains at 8 weeks of age. It was found that this dysregulation of T cell function was almost identical to that in MRL/lpr mice. Administration of CP to MRL/lpr.Yaa mice ameliorated nephritis, and suppressed production of autoantibodies and the accumulation of abnormal T cells. CP also significantly elevated the production of lymphokines. These findings suggest that an abnormality of T cell function may contribute to the autoimmune pathogenesis of MRL/lpr.Yaa mice and that CP probably ameliorates autoimmune disease by improving the T cell functions.     

Injection of IL-12- and IL-18-encoding plasmids ameliorates the autoimmune pathology of MRL/Mp-Tnfrsf6lpr mice: synergistic effect on autoimmune symptoms

IL-12 and IL-18 are mediators involved in the onset and progression of the autoimmune disease developing in MRL/Mp-Tnfrsf6(lpr) (lpr) mice, which display symptoms similar to the human systemic lupus erythematosus (SLE). The pathology is characterized by progressive lymphadenopathy and auto-antibody-mediated multiple organ failure, e.g. glomerulonephritis, or pneumonitis and a concomitant increase in serum levels for IFNgamma and tumor necrosis factor-alpha (TNFalpha). In this study, we intramuscularly injected lpr mice with plasmids encoding IL-12 and IL-18, either alone or in combination, in order to affect the development of the autoimmune disease. Five biweekly injections of the combined plasmids starting at 4-5 weeks of age diminished serum levels of TNFalpha and reduced the ability of lymphocytes from treated mice to produce IFNgamma in vitro. Injection of both plasmids synergistically attenuated the development of autoimmune syndromes, lymphoproliferation in secondary lymphoid organs, proteinuria and kidney damage, and pneumonitis. We conclude that IL-12 and IL-18 synergistically affect the pathogenesis of the T(h)1-dependent autoimmune syndrome of lpr mice and that approaches that target both IL-12 and IL-18 may be a therapeutic option in the treatment of autoimmune SLE.     

High-level production of alternatively spliced soluble interleukin-6 receptor in serum of patients with adult T-cell leukaemia/HTLV-I-associated myelopathy.

We have previously shown, using human T-cell lymphocytotrophic virus-I (HTLV-I)-infected cell lines, that soluble interleukin-6 receptor (sIL-6R) is generated through an alternative splicing mechanism. In this study, we examined human sera for the presence of alternatively spliced soluble IL-6R (AS-sIL-6R). We produced a monoclonal antibody (mAb) recognizing the unique sequence of AS-sIL-6R peptide, generated by an altered reading frame. We also made recombinant AS-sIL-6R protein in Spodoptera frugiperda-9 (Sf-9) cells carrying baculovirus, which encoded altered sIL-6R or conventional IL-6R cDNA. mAbs specifically recognized AS-sIL-6R, but not conventional IL-6R, as demonstrated by Western blot analyses, fluorescence-activated cell sorter, immunofluorescence analyses and enzyme-linked immunosorbent assay (ELISA). We adapted an ELISA system and used it for detection of altered sIL-6R in sera from 23 healthy persons, 12 patients with adult T-cell leukaemia (ATL) and 13 patients with HTLV-I-associated myelopathy (HAM). Serum levels of AS-sIL-6R were 6.4 or 6.1 times greater in ATL (28.7+/-20.4 ng/ml, P<0.0001) and in HAM patients (27.5+/-12.1 ng/ml, P<0.0001) than in healthy individuals (4.5+/-2.1 ng/ml). High levels of AS-sIL-6R were also observed in plasma from rheumatoid arthritis patients and in persons with elevated levels of alanine aminotransferase (ALT), antinuclear antibody (ANA), or alpha-fetoprotein (AFP). However, in human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV) or hepatitis C virus (HCV)-infected individuals, AS-sIL-6R levels were not elevated. In this study, we confirmed that AS-sIL-6R is indeed present in human sera. These observations suggest that alternative splicing of IL-6R mRNA is of consequence in ATL, HAM and in some autoimmune diseases. The HTLV-I-infected T cells appeared to play an important role in AS-sIL-6R production.     

Interstitial pneumonitis in autoimmune MRL/lpr mice and its treatment with cyclosporin A

Age-associated changes of anti-double-stranded (ds) DNA antibodies, anti-single-stranded (ss) DNA antibodies, and serum immune complex concentrations were studied in MRL/lpr mice. All anti-ds DNA antibodies, anti-ss DNA antibodies, and immune complexes began to be detected in the sera of MRL/lpr mice aged 8 to 13 weeks and increased remarkably after 17 weeks of age. Almost no pathological findings were observed histologically in the lungs of MRL/lpr mice aged 8 weeks but interstitial pneumonitis became evident at 14 weeks of age. Peribronchial and perivascular lymphocyte infiltrations were seen in the lungs of 14-week-old MRL/lpr mice and became more severe at 21 weeks of age. Oral administration of cyclosporin A to 15-week-old MRL/lpr mice markedly prolonged their life span. The lungs of 44-week-old MRL/lpr mice given cyclosporin A showed few pathological findings except for minimal perivascular lymphocyte infiltration.     

Soluble interleukin-6 receptor (sIL-6R) in cerebrospinal fluid of patients with inflammatory and non inflammatory neurological diseases

IL-6 acts on target cells via the ligand-binding protein interleukin-6 receptor (IL-6R) and the affinity-converting and signal-transducing glycoprotein 130 (gp130). Soluble interleukin-6 receptor (sIL-6R) has an agonistic role because the soluble complex (IL-6/sIL-6R) can activate cells that do not express IL-6R and an antagonistic role as it enhances the inhibitory activity of sgp130. Soluble forms of both receptors, sIL-6R and sgp130, regulate the action of IL-6. sIL-6R was measured by a sensitive enzyme-linked immunosorbent assay in paired sera and cerebrospinal fluid (CSF) from 46 patients with inflammatory neurological diseases (IND), 45 patients with relapsing-remitting multiple sclerosis (RR-MS), 13 patients with primary progressive multiple sclerosis (PP-MS), 17 patients with other non inflammatory neurological diseases (NIND) and 13 mentally healthy individuals--healthy controls (HC). Patients with RR-MS had CSF sIL-6R levels comparable to those from patients with IND, but higher than patients with NIND and HC. A positive correlation between the CSF/serum albumin (QAlb) and CSF sIL-6R levels was observed in IND but not in RR-MS patients indicating that CSF sIL-6R levels in IND patients could be influenced by serum sIL-6R and blood brain barrier (BBB) permeability properties. RR-MS patients had higher values of [CSF/serum sIL-6R:CSF/serum albumin] (sIL-6R index) than IND patients suggesting that in multiple sclerosis (MS), the increase in CSF sIL-6R could be due to intrathecal synthesis of sIL-6R. The finding of increased CSF sIL-6R concentrations (>979 pg/ml) with sIL-6R index (>4.66), in correlation with positive oligoclonal bands in RR-MS patients, suggests that values of sIL-6R index > 4.66 indicate intrathecal increase of sIL-6R and might be used as an indicator of neuroimmunoregulatory and inflammatory processes in the central nervous system (CNS).     

A novel autoimmune pancreatitis model in MRL mice treated with polyinosinic:polycytidylic acid

In this study we established a new animal model for exploring the pathogenesis of autoimmune pancreatitis. We have found previously that MRL/Mp-+/+(MRL/+) mice develop pancreatitis spontaneously by an autoimmune mechanism but only when they are more than 34 weeks old. Because this disease might be a model of multi-factorial diseases controlled by genetic and environmental factors, beginning at 6 weeks old, we injected polyinosinic:polycytidylic acid (poly I:C) into MRL/+ mice and in addition, into MRL/Mp mice bearing the Fas deletion mutant gene, lpr (MRL/lpr). Poly I:C induced chronic severe pancreatitis in all the MRL/+ mice and to a lesser extent in the MRL/lpr mice by 18 weeks of age. There was no pancreatitis in control mice of both strains at the same age. Other than chronic pancreatitis, no severe autoimmune diseases were observed in MRL/+ mice. Immunohistochemical examinations revealed predominant infiltration of CD4+ T cells and Mac-2+ activated macrophages in the pancreatic lesions. Splenic expression of the mRNAs for TNF-alpha and IL-10, which is known to suppress the development of pancreatitis, were increased in both strains of mice. These findings suggest that an MRL strain of mice treated with poly I:C might be a good model for developing new approaches to the study of the pathogenesis of autoimmune pancreatitis.     

三氧化二砷对MRL/lpr狼疮鼠T-bet/GATA3信号通路的影响

目的:本文旨在探讨三氧化二砷(arsenic trioxide,ATO)对MRL/lpr狼疮鼠T-bet/GATA3信号通路的影响及其作用机制。方法:将20周龄MRL/lpr狼疮鼠和正常C57BL/6J小鼠随机分组,分别接受ATO(0.4mg·kg~(-1)·d~(-1))和同体积生理盐水(NS)治疗2个月,分离脾脏淋巴细胞,然后用实时荧光定量PCR法检测T-bet、GATA3、IFN-γ、IL-4的mRNA水平及T-bet/GATA3 mRNA的比值,Western blot法检测T-bet和GATA3的蛋白表达,ELISA法检测血清中IFN-γ和IL-4的浓度。结果:(1)MRL/lpr狼疮鼠NS组T-bet、IFN-γ的mRNA及蛋白表达、Tbet/GATA3 mRNA比值均高于C57BL/6J小鼠NS组(P0.05),而GATA3、IL-4的mRNA及其蛋白表达均低于C57BL/6J小鼠NS组(P0.05);(2)在MRL/lpr狼疮鼠中,与NS组相比,ATO组T-bet、IFN-γ的mRNA及蛋白表达、T-bet/GATA3 mRNA比值均下降(P0.05),而2组中GATA3、IL-4的mRNA及蛋白表达无明显差异;(3)在C57BL/6J小鼠中,NS组和ATO组之间以上指标均无显著性差异。结论:ATO可能通过影响MRL/lpr狼疮鼠Tbet/GATA3信号通路,降低T-bet表达,从而减少Th1型细胞因子IFN-γ的表达和分泌。     

Interleukin-1 Contributes to High Level IgG Production in the Murine MRL/Ipr Lupus Model

The autoimmune syndrome in MRL/lpr mice resembles human lupus, both in its serologic and immunopathologic characteristics. The contribution of IL-1 to high-level Ig production in the MRL/lpr model is poorly understood. We investigated the effect of treating B-cell-enriched, or, B plus T cell suspensions derived from either pre-disease or diseased lupus-prone MRL/lpr mice with IL-1ß or IL-1 receptor antagonist (IL-1Ra). Disparate patterns of IgG production by B cells and B plus T cells derived from diseased versus pre-diseased MRL/lpr mice was observed following treatment with IL-1ß. Remarkably, IL-1ß caused significant suppression in IgG production by B cells derived from diseased MRL/lpr mice as compared to B cells derived from pre-disease mice. In mix-and-match experiments with B plus T cells from pre-disease and diseased MRL/lpr mice, both T cell help and B cell hyperactivity, originating in diseased MRL/lpr mice were found to be important factors in high-level IgG production in diseased MRL/lpr mice. Furthermore, IL-1Ra treatment of B plus T cell co-cultures derived from diseased MRL/lpr mice was able to significantly suppress IgG production, whereas, IL-1Ra treatment of B plus T cell co-cultures derived from pre-disease MRL/lpr mice demonstrated virtually no suppression in IgG production. Collectively, these results indicate a potentially important but complex role for IL-1 in influencing high-level IgG production in MRL/lpr mice with established disease.     

High circulating levels of biologically inactive IL-6/SIL-6 receptor complexes in systemic juvenile idiopathic arthritis: evidence for serum factors interfering with the binding to gp130

We previously demonstrated that high levels of IL-6/sIL-6R complexes are present in sera of patients with systemic juvenile idiopathic arthritis (s-JIA) and that the amount of IL-6 estimated in the IL-6/sIL-6R complexes is markedly higher than that measured by the B9 assay. Here, we show that two additional bioassays, employing human myeloma XG-1 cells and human hepatoma Hep3B cells, detected serum IL-6 levels similar to those measured by the B9 assay and approximately 10-fold lower than the IL-6 levels estimated to be present in the IL-6/sIL-6R complex. Using an assay for the measurement of the amount of circulating IL-6 complexed with the sIL-6R and available for binding to gp130 (gp130 binding activity), we show that the IL-6/gp130 binding activity is similar to that detected by the bioassays and again significantly lower than that estimated to be present in the IL-6/sIL-6R complex. Addition of recombinant human IL-6 (rhIL-6) to sera of patients or controls results in a markedly lower increase in the gp130 binding activity in patients than in controls. Moreover, sera from s-JIA patients inhibited in a dose dependent manner the gp130 binding activity assay. These results show that sera from patients with s-JIA contain a factor, or factors, that inhibit(s) the binding of the IL-6/sIL-6R complex to gp130. This inhibitory activity does not appear to be due to soluble gp130, C-reactive protein or autoantibodies to IL-6.     

Abnormal IgG galactosylation in MRL-lpr/lpr mice: pathogenic role in the development of arthritis

MRL-lpr/lpr (MRL/lpr) mice spontaneously develop arthritis by an increase in the incidence of agalactosylated oligosaccharides in serum IgG, similar to rheumatoid arthritis patients. However, whether this association has a pathogenic significance is still unknown. In this study, we analyzed the oligosaccharide structure of serum IgG in various MRL mice with or without arthritis, to clarify the relationship between the oligosaccharide abnormality and the development of arthritis. The level of agalactosylation in serum IgG was comparable in both arthritis-free MRL/lpr and MRL-+/+ (MRL/+) mice at 6 weeks of age. In contrast, the incidence of IgG lacking galactose markedly increased in MRL/lpr mice at 6 months of age (the age at which arthritis occurred), compared with that from age-matched MRL/+ mice without arthritis. However, the proportion of agalactosylated IgG increased similarly in anti-CD4 monoclonal antibody-treated MRL/lpr mice at 6 months of age, despite the absence of the development of arthritis, because of depletion of CD4+ T cells. These results suggest that the abnormality in IgG galactosylation of MRL/lpr mice developed in an age-dependent manner, but it did so independently of CD4+ T cell-dependent B-cell activation and is not a consequence of the development of arthritis.     

Treatment effect of a traditional Chinese medicine,Ren-shen-yang-rong-tang (Japanese name: Ninjin-Youeito), on autoimmune MRL/MP-lpr/lpr mice

MRL/Mp-lpr/lpr(MRL/lpr) mice were treated with a traditional Chinese herbal medicine, Ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT) intraperitoneally (i.p.) every 3 days or per os (p.o.) 6 times/week from before the onset of autoimmune disease (6 weeks of age). Fifty percent survival time was found in placebo-controlled male and female mice of 28 and 22 weeks of age, respectively. NYT-treatment markedly prolonged the survival time of MRL/lpr mice. That is, 50% survival time was 43 weeks in the i.p.-treated male mice and 30 weeks of age in the p.o.-treated female mice. Further, NYT-treatment significantly reduced occurence of thymic atrophy and prevented the anomalous accumulation of B220⁺ T-cells in lymphnode and spleen, both of which are characteristic in MRL/lpr mice. Moreover, grades of proteinuria were significantly reduced in both the i.p.- and p.o.-treated groups compared with the control groups. Such clinical benefit and increased survival time were interestingly not associated with the decrease in the level of autoantibodies.     

Unusual acidic light chains in murine SLE serum.

The sera of autoimmune and other mouse strains were analysed by high resolution two dimensional gel electrophoresis and silver staining. The most striking finding was the presence of unusually acidic immunoglobulin light chains in sera from 4-5 month old MRL/Mp-lpr/lpr mice. Similar light chains were found in lesser amounts in NZB/NZW and BXSB sera, and traces were observed in MRL/Mp-+/+, NZB, and in normal sera. The intensity of the acidic light chain spots increased with age in MRL/Mp-lpr/lpr mice, coincident with the development of autoimmunity. These acidic light chains circulated as components of complete IgG molecules, as they were no longer demonstrable in serum which had been rendered free of IgG by absorption with Cowans strain staphylococci. Because both cryoglobulins and glomerular eluates from MRL/Mp-lpr/lpr mice contained acidic immunoglobulin light chains, these molecules may be involved in immune complex formation and resultant injury.