Anti-keratin antibodies in rheumatoid arthritis.

A naturally occurring antibody that reacts with the keratinised tissue of animal oesophagus was found in the serum of 75 out of 129 patients (58%) with classical or definite rheumatoid arthritis (RA) but not in sera from 105 healthy people. Detection of the antibody, which is unrelated to rheumatoid factor, is more specific for RA than the reaction in the sheep-cell agglutination test but less sensitive.     

Anti-idiotypic antibodies in a patient with monoclonal rheumatoid factor after pneumococcal bacteremia

A 51-yr-old Japanese female patient with monoclonal IgM gammopathy with rheumatoid factor activity was admitted because of pneumococcal bacteremia. About 2 wk after admission, her rheumatoid factor activity became undetectable by RAHA test and radioimmunoassay, subsequent to the initial marked elevation. The suppressive capacity of the patient's IgG fraction on the rheumatoid activity of her monoclonal IgM on January 11 was determined. The IgG fraction obtained on February 22 blocked the binding of the rheumatoid factor to rabbit IgG. The suppressive activity in the IgG fraction of February 22 was shown to be localized within the F(ab')2 fragment. Furthermore, the specificity of the suppressive serum factor was shown by the inability to block the binding of SRBC coupled with diazotized phosphorylcholine to anti-pneumococcal antibody. Thus, the marked reduction of rheumatoid factor activity was considered to result from anti-idiotypic antibody transiently appearing in her serum after pneumococcal bacteremia.     

Circulating Antinuclear Antibody and Rheumatoid Factor in Coal Pneumoconiosis

Circulating antinuclear antibody and rheumatoid factor have been measured in 109 coal miners with pneumoconiosis whose chest radiograph showed a range of abnormalities varying from simple pneumoconiosis of mild degree to advanced progressive massive fibrosis.At a screening dilution of 1/10 the overall incidence of antinuclear antibody was 17%. In almost half of the positive cases the titre was 1/40 or greater.The prevalence of antinuclear antibody was lowest in those with simple pneumoconiosis (9%) and highest in those with category C progressive massive fibrosis (27%). A similar but less striking trend was seen with rheumatoid factor, ranging from 6% in simple pneumoconiosis to 18% in category C progressive massive fibrosis. The trend of increasing frequency of autoantibodies with advancing radiographic category was most marked when the frequencies of antinuclear antibody and rheumatoid factor were combined. These autoantibodies were found in 13% of the miners with simple pneumoconiosis and 45% of those with category C progressive massive fibrosis (P for the trend=0·01).     

Competition between antigen and anti-idiotypes for rheumatoid factors

Many idiotypic determinants on antibody molecules are thought to be located at the antigen binding site, and therefore the interaction between idiotype (Id) and anti-idiotype (anti-Id) is expected to be inhibited by the antigen. We describe two IgG and one IgM rheumatoid factors whose interactions with their respective anti-Id could only be partially inhibited by very large amounts of antigen, i.e., normal IgG. The anti-Id, however, readily inhibited the binding of their respective rheumatoid factors to IgG. The differences in interaction energies resulted in failure of antigen to readily block the Id-anti-Id interaction, and did not mean that the Id was not at the antigen combining site. The association constants for the Id-anti-Id interactions varied from 1.3 to 14.8 X 10(7) M-1, whereas the strength of the rheumatoid factor antigen bond is on the order of 10(5) M-1 for interaction with monomeric IgG. In addition, the anti-Id were able to remove rheumatoid factors that were bound to solid phase IgG, indicating that anti-Id have the potential for disrupting the immune complexes formed by antigen and antibody.     

Analysis of immune complexes in rheumatoid arthritis for Epstein-Barr virus antigens reveals cross-reactivity of viral capsid antigen and human IgG

We recently defined the immunochemical characteristics of immune complexes (IC) isolated from synovial fluid (SF) of patients with rheumatoid arthritis with the use of Western blot analysis. In the present study, we probe for exogenous antigens in the IC by examining the specificity of antisera raised against the IC. Anti-IC antisera demonstrated strong reactivity against the viral capsid antigen (VCA) of Epstein Barr virus (EBV), which was not explained by preimmune reactivity, polyclonal B cell activation, or Fc-mediated binding in the immunofluorescence or ELISA systems used to measure antibody titers. However, comparable anti-VCA reactivity was detected in antisera raised against non-rheumatoid SF. This phenomenon was not due to antigen since monoclonal anti-VCA antibody probing the IC by Western blot detected only IgG, nor to idiotype/anti-idiotype interaction since normal IgG absorbed out the anti-VCA reactivity. A monoclonal anti-VCA antibody competitively inhibited the binding of anti-IgG to IgG, and Fc fragment of IgG competitively inhibited the monoclonal antibody binding to VCA. No relationship between IgG anti-VCA antibody and IgG rheumatoid factor could be demonstrated. These data demonstrate an unexpected cross-reactivity of Fc fragment of IgG and VCA of EBV through the analysis of SF IC.     

Rheumatoid Arthritis,Rheumatoid Factor,and Tests for Australia or Hepatitis-associated Antigen

False-positive results in tests for hepatitis-associated antigen using latex agglutination techniques may be due to rheumatoid factor in the serum. Possibly the use of IgM antibody in preparing the latex particles might diminish the occurrence of such reactions. No evidence was found for a relation between rheumatoid arthritis and a significant incidence of hepatitis-associated antigen detectable by countercurrent immunoelectro-osmophoresis.     

IgG antinuclear antibodies with cross-reactive rheumatoid factor activity

To investigate whether IgG antinuclear antibodies have cross-reactive rheumatoid factor activity, monoclonal IgG antibodies to DNA and Sm from autoimmune MRL-lpr/lpr mice were assayed by ELISA for binding to IgG antigens. Of the nine anti-DNA and anti-Sm monoclonals tested, six showed significant binding to affinity-purified rabbit IgG (RIgG) and human IgG (HIgG). To confirm that cross-reactivities were due to a single antibody, immunoabsorption of a representative polyspecific monoclonal termed C11 (anti-DNA, anti-Sm) on either Sepharose-DNA or Sepharose-RIgG resulted in marked loss of activity to the three antigens DNA, Sm and RIgG compared with immunoabsorption on Sepharose-bovine serum albumin. The monomolecular nature of the cross-reacting antibody was also suggested by inhibition analysis of C11; DNA inhibited C11 binding to RIgG 64%, whereas Sm inhibited binding to RIgG 33%. Aggregated RIgG and HIgG, however, did not inhibit binding of C11 to DNA, Sm, or solid-phase RIgG, probably reflecting the low affinity of this antibody for fluid phase Ig. Together, these findings suggest that antinuclear autoantibodies of the IgG, as well as the IgM, class have polyspecific IgG binding activity and suggest that IgG antinuclear antibodies may emerge from rheumatoid factor responses.     

Clinical trial outcome of anti-tumour necrosis factor alpha therapy in rheumatic arthritis

Rheumatoid arthritis is a common debilitating disease. Chronic joint inflammation leads to irreversible joint damage. Disability is a common sequel, therefore it is a major healthcare burden. Treatment by convention disease modifying anti-rheumatic drugs improves symptoms and signs but does not improve long-term prognosis. Tumour necrosis factor alpha is a powerful pro-inflammatory cytokine. Blocking this cytokine by either monoclonal antibody or soluble receptor reduces inflammation, improves symptoms and significantly reduces joint damage. Tumour necrosis factor alpha antagonists are major breakthroughs in the treatment of rheumatoid arthritis. In the UK, they are approved for the treatment of rheumatoid arthritis in patients with active disease who have failed at least two disease modifying anti-rheumatic drugs.     

Elevated autoantibody content in rheumatoid arthritis synovia with lymphoid aggregates and the effect of rituximab

Introduction  

The purpose of this study was to quantitatively evaluate the contribution of synovial lymphoid aggregates to autoantibody (rheumatoid factor [RF] and anti-cyclic citrullinated peptide [anti-CCP]) and total immunoglobulin (IgG and IgM) production in rheumatoid arthritis (RA) patients and the effect thereon of the B-cell-depleting antibody, rituximab, in the ARISE (Assessment of Rituximab's Immunomodulatory Synovial Effects) trial.     

Enzyme immunoassay of HBeAg employing beta-D-galactosidase

An enzyme-linked immunosorbent assay (ELISA) system for hepatitis B e antigen (HBeAg) was developed employing beta-D-galactosidase conjugated with antibody to HBeAg (anti-HBe) and using m-maleimidobenzoyl-N-hydroxysuccinimide ester as the coupling reagent. The experimental conditions for quantitative assay of HBeAg were determined. The presence of rheumatoid factor in test sera did not affect the results. This assay system is more sensitive than the micro-Ouchterlony method and as sensitive as radioimmunoassay. The use of beta-D-galactosidase for ELISA in the field of virology is recommended.     

Antiglobulin factor in sera from patients with liver disease.

(1) An antiglobulin factor, non-neutralizable by human gamma-globulin, was demonstrated in sera of two patients with liver disease. (2) By absorption and elution techniques, two fractions were differentiated in a serum: one is reactive to rabbit antibody and the other seems cross-reactive to rabbit and human antibodies. (3) In double immunodiffusion test, the antiglobulin factor formed a precipitation band with heat-aggregated human IgG as did rheumatoid arthritis serum. (4) While the antiglobulin activity to rabbit antibody was demonstrated in both the IgM and IgG fractions, the reactivity to human antibody was localized in the IgM fraction. (5) From its selective reactivity to individual anti-D sera (sensitizers), at least a part of the specificity of the antiglobulin factor must be related to anti-Gm (1), and consequently can be regarded as auto-reactive.     

Modulation of human rheumatoid factor-specific lymphocyte responses with a cross-reactive anti-idiotype bearing the internal image of antigen

Rabbit anti-idiotypic antibodies to human rheumatoid factor (RF) autoantibodies were isolated by affinity chromatography on rabbit anti-human IgG Fc Sepharose 4B. The anti-idiotypic antibodies bore the "internal image" of the antigen, human IgG. They reacted specifically with multiple human monoclonal and polyclonal IgM-RF, independent of any particular light or heavy chain amino acid sequence. The anti-idiotypes did not react with IgM or IgG proteins lacking RF activity. The present experiments determined the potential of the "internal image" antibodies to modulate in vitro lymphocyte functions. The addition of anti-idiotypic antibody to peripheral blood mononuclear cell cultures from patients with rheumatoid arthritis elicited lymphocyte proliferation, but not RF synthesis. The antibody did not induce the proliferation of lymphocytes from a normal individual. Moreover, the anti-idiotype specifically suppressed IgM-RF secretory responses when preincubated with B cells before co-culture with autologous pokeweed mitogen-activated T cells. The data show that the anti-idiotypic antibodies with the "internal image" of antigen are capable of interacting with B cell receptors in an antigen-restricted manner, and possess specific immunomodulatory properties.     

Association study of single nucleotide polymorphisms in pre-miRNA and rheumatoid arthritis in a Han Chinese population

The aim of this study was to perform an association study between two single nucleotide polymorphisms (SNPs) rs2910164 G>C and rs3746444 T>C in pre-miRNA (hsa-mir-146a and hsa-mir-499) and rheumatoid arthritis (RA) in the Han Chinese population. 208 Han Chinese patients with RA and 240 healthy controls were recruited in this study. The SNPs was genotyped by polymerase chain reaction-restriction fragment length polymorphism. Anti-cyclic citrullinated peptide (anti-CCP) antibody was measured by enzyme linked immunosorbent assay and rheumatoid factor (RF) was measured by rate nephelometry. The genotype frequencies between cases and controls were compared by χ(2) analysis. No significant association between the SNPs (rs2910164 and rs3746444) and RA was observed (P = 0.631 and 0.775, respectively), and the SNPs did not show any association with the RF-positive (P = 0.631 and 0.775, respectively). However, there was a significant difference on the level of anti-CCP antibody between different genotypes in rs3746444 (P = 0.007). The heterozygote CT had significantly higher level of anti-CCP antibody compared with homozygote CC and TT (P = 0.054 and 0.003, respectively). We first investigated the association between the SNPs (rs2910164 G>C and rs3746444 T>C) in the pre-miRNA (hsa-mir-146a and hsa-mir-499) and RA in a Han Chinese population. We did not find a significant association between the SNPs and the susceptibility to RA, while the SNP rs3746444 may affect anti-CCP antibody production.     

Antibody Fc engineering for enhanced neonatal Fc receptor binding and prolonged circulation half-life

ABSTRACT

The neonatal Fc receptor (FcRn) promotes antibody recycling through rescue from normal lysosomal degradation. The binding interaction is pH-dependent with high affinity at low pH, but not under physiological pH conditions. Here, we combined rational design and saturation mutagenesis to generate novel antibody variants with prolonged half-life and acceptable development profiles. First, a panel of saturation point mutations was created at 11 key FcRn-interacting sites on the Fc region of an antibody. Multiple variants with slower FcRn dissociation kinetics than the wildtype (WT) antibody at pH 6.0 were successfully identified. The mutations were further combined and characterized for pH-dependent FcRn binding properties, thermal stability and the FcγRIIIa and rheumatoid factor binding. The most promising variants, YD (M252Y/T256D), DQ (T256D/T307Q) and DW (T256D/T307W), exhibited significantly improved binding to FcRn at pH 6.0 and retained similar binding properties as WT at pH 7.4. The pharmacokinetics in human FcRn transgenic mice and cynomolgus monkeys demonstrated that these properties translated to significantly prolonged plasma elimination half-life compared to the WT control. The novel variants exhibited thermal stability and binding to FcγRIIIa in the range comparable to clinically validated YTE and LS variants, and showed no enhanced binding to rheumatoid factor compared to the WT control. These engineered Fc mutants are promising new variants that are widely applicable to therapeutic antibodies, to extend their circulation half-life with obvious benefits of increased efficacy, and reduced dose and administration frequency.     

Denosumab

Denosumab is an anti-receptor activator of nuclear factor (NF)-kappaB (RANK) ligand human monoclonal antibody studied as a treatment for postmenopausal osteoporosis (PMO) and bone destruction due to rheumatoid arthritis (RA) or metastatic cancers. As of February 2009, the candidate was undergoing US Food and Drug Administration review, and might be approved by October 2009. Late phase clinical trials demonstrated that denosumab possesses a similar safety profile to bisphosphonates and that it can be either equally or more effective than bisphosphonates at preventing bone loss due to PMO, RA or cancer treatment and metastases.Key Words: monoclonal antibody, RANKL, bone loss, osteoporosis, breast cancer, rheumatoid arthritis     

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.     

抗RA33抗体、RF、CRP、ANA与ENA联合检测在类风湿性关节炎患者诊断、治疗及预后中的作用

目的：探讨血清抗RA33抗体、RF、CRP联合检测在类风湿性关节炎患者诊断、治疗及预后中的作用。方法：采用ELISA法对35例类风湿性关节炎患者和30例健康对照者进行抗RA33抗体的检测,间接免疫荧光法检测ANA、免疫印迹法检测ENA,免疫比浊法进行类风湿因子（RF）及CRP的检测。结果：类风湿性关节炎患者组RF水平为：[（104．51±153．88）KIU／L]与健康对照组[（10．89±2．78）KIU／L]比较,差异非常显著（p〈0．01）;类风湿性关节炎组CRP[（11．60±23．24）mg／L]与健康对照组[（2．57±2．18）mg／L]比较,差异显著（p〈0．05）;类风湿性关节炎组抗RA33抗体水平：[（17．81±35．11）U／mL]与健康对照组[（8．10±8．40）U／mL]比较,差异非常显著（p〈0．01）。RF、抗RA33抗体、CRP及ANA诊断类风湿性关节炎的灵敏度分别为：80．00％,34．29％,42．86％,62．86％;RF、抗RA33抗体、CRP及ANA诊断类风湿性关节炎的特异性分别为：93.33％,93.33％,90．00％,96．67％;ENA的检出率均较低。结论：类风湿性关节炎患者抗RA33抗体检出的灵敏度低,但特异性强。对类风湿性关节炎患者进行抗RA33抗体、ANA、RF、CRP、ENA联合检测,对于疾病的进展、病因分析、指导治疗和改善预后均具有重要意义。     

Determination of the rheumatoid factor in gouty patients

The authors have examined the incidence of the rheumatoid factor in the serum of a group of 100 patients, 95 males and 5 females, suffering from gout, of whom only 6 suffered from chronic gout. The rheumatoid factor in the serum was measured by RA-test (1:40) and by Waaler-Rose test (1:32). The rheumatoid factor was not present in the examined subjects and so we can state that such serum parameter does not represent, for its negativity, a laboratory index of any evidence in the gout and it doesn't represent a reason for diagnostic doubts with other forms with the rheumatoid factor in the serum.     

Neutralization of vascular endothelial growth factor prevents collagen-induced arthritis and ameliorates established disease in mice

Vascular endothelial growth factor (VEGF) is implicated in the pathogenesis of inflammatory joint diseases, including rheumatoid arthritis (RA). To determine the importance of this cytokine in vivo, the effect of administering VEGF-neutralizing antibodies to mice with collagen-induced arthritis (CIA), which has many immunological and pathological similarities to human RA, has been investigated. Either saline, normal rabbit immunoglobulin or anti-human VEGF121 rabbit polyclonal antibody was administered to mice subcutaneously either before the onset of arthritis or after the establishment of clinical disease. Anti-VEGF antibody administered prior to disease onset significantly delayed the development of arthritis and decreased clinical score and paw thickness as well as histological severity. On the other hand, the frequency of occurrence of disease compared to either the control group administered saline or normal rabbit immunoglobulin was not altered. Anti-VEGF antibody also significantly ameliorated clinical and histological parameters even when administered after disease onset. These results indicate a possible therapeutical potential for anti-VEGF treatment in human arthritis.     

Use of total lymphoid irradiation (TLI) in studies of the T cell-dependence of autoantibody production in rheumatoid arthritis

The effect of total lymphoid irradiation (TLI) on T cell-dependent and -independent humoral immune responses was studied in patients with intractable rheumatoid arthritis (RA). The serum levels of several autoantibodies and of antibodies to diphtheria (DT) and tetanus (TT) toxoids and to pneumococcal polysaccharide (PPS; 12 antigenic types) were studied before and after TLI. In addition, the patients were given a booster injection of DT and TT and a single injection of pneumococcal vaccine after radiotherapy. Antibody levels to DT and TT decreased about twofold after TLI and did not rise significantly (p greater than 0.05) after a booster injection. However, there was no reduction in antibody levels to PPS after TLI, and a significant rise in titers was observed after a single vaccination (p less than 0.01). The serum levels of rheumatoid factor (RF), anti-nuclear antibody (ANA), and granulocyte associated IgG rose slightly after TLI. Thus, the autoantibodies and antibodies to polysaccharides appear to be relatively independent of helper T cell function, which is markedly reduced after TLI. On the other hand, antibodies to protein antigens such as DT and TT appear to be more closely dependent upon T helper function in man, as has been reported in rodents. The findings suggest that T cell-independent autoantibody responses alone do not maintain the joint disease activity in RA, because improvement in joint disease after TLI has been reported.