Identification of autoantibodies associated with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of antinuclear antibodies. We performed serological analysis of cDNA expression library (SEREX) to identify autoantibodies associated with SLE. The screening of three different cDNA expression libraries with pooled sera of patients with SLE yielded 11 independent clones that reacted with pooled sera of patients with SLE. In this screening, autoantibodies to poly(ADP-ribose) polymerase (PARP), U1snRNP, and galectin-3 were prevalent in the sera of patients with SLE (26/68, 25/68, 12/63, respectively). The frequency of autoantibody to PARP was significantly higher in SLE than that of healthy donors (0/76) (38.2% vs 0%, p<0.00001). The autoantibody to PARP was infrequently detected in the serum of patients with RA (1/50). However, autoantibody to PARP was not found in the sera of patients with other rheumatic diseases including Sjogren's syndrome (0/19), systemic sclerosis (0/18), and polymyositis/myositis (0/37). The frequency of autoantibody to human galectin-3 (12/63) was significantly higher in SLE than that of healthy donors (0/56) (19% vs 0%, p=0.0006). Autoantibody to galectin-3 was not found in the sera of patients with rheumatoid arthritis (0/50), Sjogren's syndrome (0/18), and systemic sclerosis (0/19). Interestingly, autoantibody to galectin-3 was also prevalent in the sera of patients with polymyositis/dermatomyositis (16/37, 43.2%). Further functional characterization of these autoantibodies would be necessary to determine their value as diagnostic markers or to define clinical subsets of patients with SLE. Statistical analysis revealed that the presence of autoantibody to PARP was inversely related with pleurisy, and the presence of autoantibody to galectin-3 related with renal disease.     

Identification of citrullinated eukaryotic translation initiation factor 4G1 as novel autoantigen in rheumatoid arthritis

Antibodies against citrullinated proteins are highly specific for rheumatoid arthritis. We previously reported that functional variants of the gene encoding peptidylarginine deiminase type 4 were closely associated with RA. The purpose of this study was to investigate the citrullinated autoantigens recognized by serum samples from patients with RA. The human chondrocyte cDNA expression library was citrullinated by PADI4 and was immunoscreened with anti-modified citrulline antibodies and sera from patients with rheumatoid arthritis. One immunoreactive cDNA clone containing a 2480-base pair insert was isolated and sequence analysis revealed that the cDNA included a part of the eukaryotic translation initiation factor 4G1. Immunoreactivity against a recombinant citrullinated eIF4G1 fragment was observed with high specificity in 50.0% of RA patients. The levels of antibodies against citrullinated eIF4G1 were correlated with those of anti-CCP antibodies. Citrullinated eIF4G1 was identified as a candidate citrullinated autoantigen in RA patients. Citrullination of eIF4G1 may thus be involved in the pathogenesis of RA.     

Identification of a 48 kDa form of unconventional myosin 1c in blood serum of patients with autoimmune diseases

We searched for protein markers present in blood serum of multiple sclerosis (MS), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients in comparison to healthy human individuals. We used precipitation/extraction methods and MALDI TOF/TOF mass spectrometry, and identified a protein with Mr ~46 kDa as a fragment of human unconventional myosin IC isoform b (Myo1C). Western blotting with specific anti-human Myo1C antibodies confirmed the identity. Screening of blood serum samples from different autoimmune patients for the presence of Myo1c revealed its high level in MS and RA patients, relatively low level in SLE patients, and undetected in healthy donors. These data are suggesting that the level of p46 Myo1C in blood serum is a potential marker for testing of autoimmune diseases.     

Elevated levels of serum antibodies against alpha-1, 6-glucan in patients with systemic lupus erythematosus or rheumatoid arthritis

This study was undertaken to investigate whether levels of anti-alpha-1, 6-glucan antibodies in human sera correlate with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Serum samples were collected from patients with SLE (n = 30), RA (n = 30) and healthy adult volunteers. IgG, IgA and IgM levels against alpha-1, 6-glucan were measured using enzyme linked immunosorbent assays. Anti-alpha-1, 6-glucan IgG prevalence was raised in patients with active SLE (73.3%) and RA (60%) compared with healthy controls (13.3%). Strong correlation between anti-alpha-1,6-glucan-IgG levels and anti-perinuclear factor (r = 0.642; p<0.05) in RA patients or anti-nuclear antibodies (r = 0.675; p<0.05) in SLE patients was observed. No significant differences in anti-alpha-1,6-glucan-IgA or-IgM levels were noted between different groups. We conclude that anti-alpha-1,6-glucan-IgG levels were significantly elevated in patients with SLE or RA and positively correlated with disease activity.     

Accelerated Fas-mediated apoptosis of monocytes and maturing macrophages from patients with systemic lupus erythematosus: relevance to in vitro impairment of interaction with iC3b-opsonized apoptotic cells.

Impaired handling of apoptotic cells has been suggested as an important factor in the development of systemic lupus erythematosus (SLE), and a role for complement in the removal of apoptotic cells was shown recently. We studied the in vitro function of macrophages from 40 patients with SLE and their matched controls in the removal of heterologous apoptotic cells opsonized by iC3b. Interaction index of apoptotic cells opsonized by iC3b was significantly lower in patients with SLE and averaged 71% +/- 37 of that of healthy individuals (p < 0.002) and 69% +/- 35 of patients with rheumatoid arthritis (p < 0.007). SLE patients had increased apoptosis of both freshly isolated monocytes (p < 0.001) and maturing macrophages (p < 0.04) that led to decreased density of monocyte-derived macrophages. Apoptosis was inhibited by adding soluble Fas receptor indicating Fas-mediated apoptosis. As demonstrated in both healthy controls and patients with SLE, decreased macrophage density by itself caused significant decreased uptake of apoptotic cells by the remaining macrophages. Maintaining normal density in SLE patients either by an increased initial density or by using soluble Fas restored the interaction capacity of the individual macrophages in the majority of patients. We concluded that impaired in vitro interaction of iC3b-opsonized apoptotic cells with macrophages from patients with SLE was mainly associated with Fas-dependent accelerated apoptosis of the monocytes/macrophages. Accelerated apoptosis of phagocytes may represent a novel in vitro mechanism of impairment of interaction with apoptotic cells that, apart from reducing the number of professional phagocytes, alters the function of the remaining macrophages.     

Immune response to nucleic acid antigens and native DNA by human peripheral blood lymphocytes in vitro

The immunogenicity of DNA fragments (either oligonucleotide (oligo) or total DNA digest) covalently linked to keyhole limpet hemocyanin (oligo-KLH or DNA-KLH) was tested with peripheral blood lymphocytes (PBL) from 63 systemic lupus erythematosus patients (SLE) in vitro. PBL from 10 normal individuals and 11 rheumatoid arthritis (RA) patients served as controls. Antibodies to three nucleic acid antigens (oligo, denatured DNA (d-DNA), and native DNA (n-DNA] were assayed in supernatants of cultured lymphoid cells by a sensitive solid-phase radioimmunoassay. More than 50% of SLE and RA patient lymphoid cells formed spontaneous antibodies to one or several nucleic acid antigens. In contrast, only two normals did. After in vitro challenge with oligo-KLH or DNA-KLH, cultured lymphocytes of more than 50% of SLE patients formed antibodies to one or several nucleic acid antigens. Similar results were obtained in PBL from RA patients. In SLE patients, the response to both antigens was either monospecific or polyspecific, but DNA-KLH appeared to raise a greater proportion of antibody to n-DNA than oligo-KLH. A greater proportion of patients with active disease responded in vitro compared with those with inactive disease. A mixture of oligo together with KLH was not immunogenic in vitro. Oligo-KLH or DNA-KLH did not raise antibody to an irrelevant antigen, ovalbumin. Of particular interest, PBL from seven of 10 normal subjects formed antibody to n-DNA after challenge in vitro with oligo-KLH. The data support the view that DNA fragments could be an important immunogen in SLE. Furthermore, this study provides an in vitro model to test the tolerogenicity of similar fragments of DNA linked to self carrier molecules such as gamma-globulin.     

Increased concentrations of antibody against heat shock protein in patients with myeloperoxidase anti-neutrophil cytoplasmic autoantibody positive microscopic polyangiitis

To determine serum antibody against human and bacterial heat shock protein (HSP) 60/70 in myeloperoxidase (MPO)-specific anti-neutrophil cytoplasmic autoantibody (ANCA) positive microscopic polyangiitis (MPA), 58 patients with MPO-ANCA positive MPA, 48 with RA (rheumatoid arthritis) and 40 with SLE (systemic lupus erythematosus) were studied. Serum antibodies against HSP (human HSP 70, human HSP 60, Mycobacterium HSP 70, and Escherichia coli HSP 60) were measured by sandwich ELISA. The frequency of anti-human HSP 60/70 antibody positive patients was significantly greater in MPO-ANCA positive MPA than SLE and healthy controls. Anti-human HSP 60/70 antibody titers in patients with MPO-ANCA positive MPA were significantly higher than those of healthy controls; anti-bacterial HSP 60/70 antibody titers were also higher. There was a significant correlation between titers of anti-human HSP 70 antibody and anti-Mycobacterium HSP 70 antibody. A correlation was also found between titers of anti-human HSP 70 antibody and anti-human HSP 60 antibody. Anti-human and bacterial HSP 60/70 antibody titers changed in parallel with disease activity in patients with antibody positive MPA. The anti-HSP antibody titer was also increased in patients with RA and SLE. These results suggest that an immunological background via anti-HSP 60/70 antibodies might be associated with pathogenesis in MPO-ANCA positive MPA.     

重组腺相关病毒2型/人肿瘤坏死因子受体:Fc(rAAV2/hTNFR:Fc)的构建和生物学活性研究

为研究腺相关病毒2型载体应用于类风湿性关节炎进行基因治疗的可行性,首先构建携带人肿瘤坏死因子Ⅱ型受体胞外区和人免疫球蛋白IgG1Fc段融合基因的重组2型腺相关病毒(rAAV2／hTNFR：Fc),并对其生物学活性进行研究。以RT—PCR分别从U937和人淋巴细胞总RNA中扩增人肿瘤坏死因子Ⅱ型受体胞外区和人免疫球蛋白IgG1Fc段基因,并以重叠延伸PCR的方法将二者融合后克隆入pSNAV1载体质粒进行重组病毒生产,在进行重组病毒理化分析后,以TNFa细胞毒中和试验来研究该重组病毒的生物学活性。结果显示：所构建的重组病毒rAAV2／hTNFR：Fc基因结构与预期一致;病毒在体外感染BHK-21细胞后,含TNFR：Fc融合蛋白的表达上清可以有效中和人、大鼠、小鼠TNFα对L929的细胞毒性。所研究构建的重组腺相关病毒可以用来作为阻断TNFα的手段,进行类风湿性关节炎的基因治疗研究。     

Nature of double-stranded DNA binding activity in seropositive rheumatoid arthritis: formation of low avidity DNA/rheumatoid factor/IgG/low density lipoprotein complexes

Sera from majority of patients with seropositive rheumatoid arthritis, which generally lacked detectable anti-double stranded DNA in Farr, Crithidia luciliae, and microcomplement fixation assays, exhibited high levels of dsDNA binding in the presence of 3.5% polyethylene glycol when using intrinsically labeled 3H-PM2 DNA as antigen. Except for SLE, such increased dsDNA binding was absent in normal and a variety of other disease sera, including those from patients with seronegative rheumatoid arthritis. In contrast to the situation in SLE, in which dsDNA binding is mediated by specific anti-DNA antibody, the increased dsDNA binding activity in seropositive rheumatoid arthritis was shown to be dependent upon complex low avidity interactions involving DNA, IgG, IgM rheumatoid factor, and low density lipoproteins. Analysis of the composition of the polyethylene glycol serum precipitates by 2-dimensional gel diffusion, immunoelectrophoresis, and sodium dodecyl sulfate polyacrylamide gel electrophoresis failed to reveal the presence of additional DNA-binding proteins unique to seropositive rheumatoid arthritis. The only feature distinguishing high DNA binding sera from those with low DNA binding activity was an increased amount of polyethylene glycol-insoluble IgG in the former, presumably reflecting IgG/IgG and/or IgG/IgM complexes. The significance of these unusual DNA/low density lipoprotein/IgG/rheumatoid factor complexes with respect to the diagnostic specificity and pathophysiology of the DNA/anti-DNA system is discussed.     

DNA-specific antiidiotypic antibodies in the sera of patients with autoimmune diseases.

Blood sera of patients with autoimmune diseases scleroderma (Scl), systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA) have been shown to yield a specific immune response to topoisomerase I, the product of expression of a cDNA fragment cloned into lambda gt11 and monoclonal antibodies (MAB) to the enzyme. The 'topoisomerase test' is not absolutely specific for Scl. The stable positive response of autoimmune sera to anti-topoisomerase monoclonal antibodies has a specific character and is associated with the interaction of the Fab fragment of MAB with the IgG fraction of autoimmune serum. The response observed indicates the induction of anti-idiotypic antibodies against topoisomerase. The anti-idiotype, isolated by HPLC and affinity chromatography demonstrated the following functional activities: (i) the immunological reaction against DNA; (ii) high-affinity DNA-binding with topoisomerase-specific consensus; (iii) ability to compete with the native enzyme for binding with DNA and MAB to topoisomerase; (iv) immunological reaction against MAB to topoisomerase.     

In vivo evidence of regulation by pituitary-adrenal axis of urinary epinephrine excretion in men

The effect of the pituitary-adrenal axis on epinephrine synthesis in the human adrenal medulla was examined by the estimation of the 24-h urinary epinephrine level after treatment with glucocorticoids in four patients with systemic lupus erythematodes (SLE), one patient with rheumatoid arthritis (RA) and one patient with adrenal pheochromocytoma. 24-h urinary catecholamines (CAs) were measured by HPLC before and after glucocorticoid treatment, dexamethasone or prednisolone was orally given for more than seven days to patients with SLE, RA or isolated ACTH deficiency and five days to a patient with adrenal pheochromocytoma. In patients with isolated ACTH deficiency, the 24-h urinary epinephrine level was significantly lower than the normal range. In patients with SLE or RA, the 24-h urinary epinephrine level was normal and it was significantly suppressed by therapeutic doses of prednisolone 30-40 mg/day. In a patient with adrenal pheochromocytoma, 24-h urinary epinephrine was extremely high and it was significantly increased after dexamethasone 0.5 mg/day. These results suggest that epinephrine synthesis in the human adrenal medulla may be dependent on the pituitary-adrenal axis. But the increase in epinephrine synthesis due to dexamethasone in a patient with pheochromocytoma may reflect the direct effect via the feeding artery to the tumor, as previously shown in an in vitro culture system.     

Identification of the gene variations in human CD22

 CD22, a member of the immunoglobulin superfamily, is a B-cell transmembrane glycoprotein that acts as an accessory-signaling component of the B-cell antigen receptor (BCR). Recent evidence indicating the role of CD22 as a negative regulator of BCR signal transduction prompted us to test the possibility that genetic variations of human CD22 may be associated with autoimmune diseases. In this study, variation screening of the entire CD22 coding region was performed, and possible association with rheumatic diseases was tested, using the genomic DNA from 207 healthy Japanese individuals, 68 patients with systemic lupus erythematosus (SLE), and 119 patients with rheumatoid arthritis (RA). Through the variation screening, seven non-synonymous and four synonymous substitutions were identified. In addition, single base substitutions were found in two introns flanking exon-intron junctions. Among these variations, Q152E substitution within the second extracellular domain was observed with a marginally higher frequency in the patients with SLE (3/68, 4.4%) than that in healthy individuals (1/207, 0.5%) (P=0.048. SLE vs healthy individuals), although this difference was no longer significant after correction for the number of comparisons (Pc=0.62). No significant association was observed between any of the variations and RA. These findings indicate that a number of genetic variants are present in CD22, and suggest that CD22 could be considered a candidate for the susceptibility genes to autoimmune diseases. Received: 14 July 1998 / Revised: 7 September 1998     

Semaphorin 3A is a marker for disease activity and a potential immunoregulator in systemic lupus erythematosus

Introduction

Semaphorin 3A (sema3A) and neuropilin-1 (NP-1) play a regulatory role in immune responses and have a demonstrated effect on the course of collagen induced arthritis. This study was undertaken to evaluate the role of sema3A and NP-1 in the pathogenesis of systemic lupus erythematosus (SLE) and the specific effect of sema3A on the auto-reactive properties of B cells in SLE patients.

Methods

Thirty two SLE and 24 rheumatoid arthritis (RA) patients were assessed and compared with 40 normal individuals. Sema3A serum levels were measured and correlated with SLE disease activity. The in vitro effect of sema3A in reducing Toll-like receptor 9 (TLR-9) expression in B cells of SLE patients was evaluated.

Results

Sema3A serum levels in SLE patients were found to be significantly lower than in RA patients (55.04 ± 16.30 ng/ml versus 65.54 ± 14.82 ng/ml, P = 0.018) and lower yet than in normal individuals (55.04 ± 16.30 ng/ml versus 74.41 ± 17.60 ng/ml, P < 0.0001). Altered serum sema3A levels were found to be in inverse correlation with SLE disease activity, mainly with renal damage. The expression of both sema3A and NP-1 on B cells from SLE patients was significantly different in comparison with normal healthy individuals. Finally, when sema3A was co-cultured with cytosine-phosphodiester-guanine oligodeoxynucleotides (CpG-ODN)-stimulated B cells of SLE patients, their TLR-9 expression was significantly reduced, by almost 50% (P = 0.001).

Conclusions

This is the first study in which a reduced serum level of sema3A was found in association with SLE disease activity. It also raises the possibility that sema3A may have a regulatory function in SLE.     

心脏发育候选基因AHNAKβ的克隆和表达研究

心脏发育过程是一个错综复杂的过程,由一系列的基因参与完成.虽然目前已经鉴定出很多与心脏发育相关的基因,但是仍有很多心脏发育相关基因有待鉴定.作者从小鼠心脏cDNA文库中分离并鉴定了一个心脏发育候选基因AHNAKβ.AHNAKβ位于11q12.2,长1 064 bp,由6个外显子和5个内含子组成,其中开放阅读框(ORF)长450 bp (258~710 nt),编码含有149个氨基酸,蛋白质大小约为16.0 kD.我们构建了原核细胞表达载体,在大肠杆菌中表达并纯化了GST- AHNAKβ融合蛋白,然后制备了该蛋白的兔免疫血清.利用该抗体进行了小鼠成体组织Western blot以分析该基因的蛋白表达模式.研究结果表明AHNAKβ在小鼠成体子宫、小肠等多种组织表达,在心脏中表达较高,提示它可能在心脏组织中具有某种重要作用.     

A diallelic RFLP of the CD3-epsilon chain of the clonotypic T-lymphocyte receptor is not associated with certain autoimmune diseases

Summary A diallelic restriction fragment length polymorphism of the CD3-epsilon () gene, which encodes for an invariant component of the human T-lymphocyte receptor, is observed when using genomic DNA TaqI digests probed with a CD3- chain cDNA probe. This combination shows two alleles of 9.1 kb and 8.4 kb with a frequency of 0.66 and 0.34, respectively, in the Spanish population. None of these alleles is associated with susceptibility to juvenile rheumatoid arthritis (JRA) or insulin-dependent diabetes mellitus (IDDM).     

Early restoration of immune and vascular phenotypes in systemic lupus erythematosus and rheumatoid arthritis patients after B cell depletion

This translational multi‐centre study explored early changes in serologic variables following B lymphocyte depletion by rituximab (RTX) treatment in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients and investigated in vitro effects on the activity of other immune cells and the vascular endothelium. Eighty‐five SLE patients, seventy‐five RA patients and ninety healthy donors were enrolled. Two additional cohorts of selected SLE and RA patients were treated with RTX for 3 months. Changes in circulating levels of inflammatory mediators, oxidative stress markers and NETosis‐derived bioproducts were evaluated. Serum miRNomes were identified by next‐generation sequencing, and RTX‐induced changes were delineated. Mechanistic in vitro studies were performed to assess activity profiles. Altered inflammatory, oxidative and NETosis‐derived biomolecules were found in SLE and RA patients, closely interconnected and associated to specific miRNA profiles. RTX treatment reduced SLE and RA patients' disease activity, linked to a prominent alteration in those biomolecules and the reversal of altered regulating miRNAs. In vitro studies showed inhibition of NETosis and decline of pro‐inflammatory profiles of leucocytes and human umbilical vein endothelial cells (HUVECs) after B cell depletion. This study provides evidence supporting an early RTX‐induced re‐setting of the pro‐inflammatory status in SLE and RA, involving a re‐establishment of the homeostatic equilibrium in immune system and the vascular wall.     

Presence of antibodies against cyclic citrullinated peptides in patients with 'rhupus': a cross-sectional study

'Rhupus' is a rare condition sharing features of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). If rhupus is a distinctive entity, an overlap between RA and SLE or a subset of SLE is currently debated. This study was performed to explore the prevalence of antibodies against cyclic citrullinated peptides (anti-CCP antibodies) in rhupus. Patients meeting American College of Rheumatology criteria for RA, SLE, or both were included. Clinical and radiographic features were recorded and sera were searched for anti-CCP antibodies, rheumatoid factor, antinuclear antibodies, anti-extractable nuclear antigens, and antibodies against double-stranded DNA (anti-dsDNA antibodies). Seven patients for each group were included. Clinical and serological features for RA or SLE were similar between rhupus and RA patients, and between rhupus and SLE patients, respectively. Values for anti-CCP antibodies obtained were significantly (p < 0.05) higher in RA (6/7) and rhupus (4/7) than in SLE patients (0/7) and healthy subjects (0/7). Our data support the possibility that rhupus is an overlap between RA and SLE, because highly specific autoantibodies for RA (anti-CCP) and for SLE (anti-dsDNA and anti-Sm) are detected in coexistence.