Detection of anti-Proteus antibodies in sera of patients with rheumatoid arthritis

This study was carried out to determine increased level of antibodies to certain bacteria in rheumatoid arthritis (RA) patients. Fifty RA patients and 25 each of those suffering from osteoarthritis (OA) and healthy controls were tested for antibodies to somatic ('O) and flagellar ('H') antigens of Proteus mirabilis, Escherichia coli, and for antibodies to 'O' antigen of Klebsiella pneumoniae by standard tube agglutination method. Anti-Proteus antibodies against 'O' and 'H' antigens could be demonstrated in 70% and 64% RA cases respectively, and were statistically significant. Antibodies could be demonstrated against E. coli 'O' and 'H' antigens in 86% and 92% RA cases respectively, and were statistically significant. Against K. pneumoniae 'O' antigen, no antibody could be demonstrated in any of RA and OA cases, and healthy controls. Of the 50 RA patients, 30 had raised CRP levels. Antibodies against P. mirabilis and E. coli antigens appeared to be independent from CRP. Thus a specific elevation in the immune response to P. mirabilis and E. coli has been demonstrated in patients with RA from India.     

Correlative studies of rheumatoid factors and anti-viral antibodies in patients with rheumatoid arthritis.

An analysis of the relationship between the immune response to ubiquitous herpes family viruses, namely Epstein-Barr virus (EBV), cytomegalovirus (CMV), and varicella-zoster virus (VZV) and the presence of rheumatoid factors (RF), which are autoantibodies characteristic of patients with rheumatoid arthritis (RA), was conducted. Antibody profiles (RF, anti-viral antibodies) were monitored in the serum of the RA patients, and in normal individuals. No patient was found to have circulating RF in the absence of anti-viral antibodies. When the patients and normal controls were subdivided according to the presence of serum RF, it was found that when RF were present, the frequency of anti-CMV antibodies, but not anti-EBV or anti-VZV antibodies, was significantly higher (P = 0.02) when compared with RF-negative individuals. The titres of anti-CMV but not anti-VZV antibodies were found to increase in the RA patients with disease duration. To see if these viruses could stimulate RF production in vitro, peripheral blood mononuclear cells (PBMC) isolated from the patients and normal controls were stimulated with viral antigens. PBMC from normal controls, but not from RA patients, appeared to be responsive to viral antigen stimulation and produced RF. These data suggest that the immune response to CMV, to a greater extent than to EBV or VZV, correlates with the presence of RF.     

Anti-idiotypic antibodies to rubella virus

Summary Polyclonal and monoclonal anti-idiotypic (Ab2) and monoclonal anti-anti-idiotypic antibodies were generated against rubella virus-specific neurtralizing and/or hemagglutination inhibiting monoclonal antibodies. None of the characterized Ab2's recognized the putative rubella virus receptor.This work was supported in part by a grant from The National Multiple Sclerosis Society.     

Anti-collagen antibodies in sera from rheumatoid arthritis patients.

Anti-cartilage antibodies, demonstrable by immunofluorescence, were found in 3.3% of rheumatoid arthritis patients. In most of these patients antibodies to type II collagen were detected. In specificity studies on these anti-collagen antibodies, they appeared to be type specific, showing no reaction with collagen types I and III. Denatured type II collagen reacted much less well than native type II, but isolated peptides from different regions of the collagen molecule were differentiated by individual sera. Removal of the glycoside side chains from native type II collagen had no effect on its antigenicity. The findings suggest that these patients produce highly specific antibodies which react with the triple helix of type II collagen.     

Anti-idiotypic antibodies in patients with different clinical forms of paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Latin America. Patients with PCM show a wide spectrum of clinical and pathological manifestations depending on both host and pathogen factors. Two clinical forms of the disease are recognized: the acute or juvenile form and the chronic or adult form. The major antigenic component of the parasite is a glycoprotein of 43 kDa (gp43). All patient sera present antibodies against gp43 (anti-gp43) and, as demonstrated before by our group, spontaneous anti-idiotypic (anti-Id) antibodies (Ab2) can be detected in patient sera with high titers of anti-gp43. Since it has been postulated that anti-Id antibodies may have a modulating function, we decided to purify and characterize anti-Id antibodies in this system. The possible correlation of Ab2 titers with different clinical forms of disease was also verified. Results showed that purified human anti-Id antibodies (human Ab2) recognized specifically the idiotype of some murine monoclonal anti-gp43 (17c and 3e) but not others (40.d7, 27a, and 8a). Spontaneous anti-Id antibodies were found in all clinical forms of disease. The majority of patients (88%, n = 8) with the acute form of PCM had high titers of Ab2. However, among patients with the multifocal chronic form of the disease, only 29% (n = 14) had high titers of Ab2; 70% (n = 10) of patients with the unifocal chronic form had low titers of Ab2. A correlation between Ab2 titers and anti-gp43 titers was observed before and during antimycotic treatment. Our results suggest that titers of anti-Id antibodies correlate with the severity of PCM in humans.     

Anti-endothelial cell antibodies in patients with rheumatoid arthritis complicated by vasculitis.

IgG antibodies reactive with human umbilical vein endothelial cells were found in 19 out of 28 patients with rheumatoid vasculitis (RV), in four out of 24 patients with rheumatoid arthritis (RA), in seven out of 10 patients with systemic lupus erythematosus (SLE), but not in healthy donors. In four patients with RV who were followed longitudinally, regression of vasculitic episodes coincided with decreasing titres of anti-endothelial antibodies (AEA). Binding activity to endothelial cells was observed in intact IgG and F(ab')2 fragments of IgG. AEA activity was unrelated to antibodies against nuclear, blood group or major histocompatibility complex antigens and did not involve immune complexes. AEA activity was not specific for endothelial cells since the AEA-positive sera and the IgG fractions prepared from these sera also reacted with fibroblasts. Adsorption of positive sera and corresponding IgG fractions with endothelial cells decreased the IgG binding reactivity on both fibroblasts and endothelial cells. These findings show that RV patients have IgG-AEA, and suggest that these antibodies may play a role in the pathogenesis of the disease.     

"Anti-idiotypic" antibodies to HLA in transiently sensitized DST patients

To test the hypothesis whether "anti-idiotypic" antibodies (Ab2) were involved in the loss of sensitization following donor-specific blood transfusions (DST), we investigated nine potential kidney graft recipients who became transiently sensitized after DST. Inhibiting "anti-idiotypic" activity of post-DST sera was determined using a complement-dependent cytotoxicity inhibition assay. The follow-up after DST ranged from 9 to 66 months. The nine patients developed 12 different anti-HLA antibodies (Ab1). Inhibiting post-DST serum activity was found in relation to four of them, while enhancement of cell killing caused by post-DST sera was observed in relation to six anti-HLA antibodies. In two patients presenting with more than one anti-HLA antibody inhibition was found with only one of the antibodies, indicating that the blocking of Ab1 was specific for the respective antibody. Enhancement was associated with a significantly prolonged sensitization of the patients. On the average, 5.7 +/- 5.0 months were necessary before "anti-idiotypic" activity was developed after the loss of sensitization, whereas enhancement was found immediately thereafter. Testing by flow cytometry indicated that enhancing sera still contained subthreshold levels of Ab1. Our results indicate that DST can induce the development of "anti-idiotypic" antibodies following a short period of sensitization. This finding provides further evidence that anti-idiotypic antibodies might be relevant factors in the eventual disappearance of sensitization to HLA antigens.     

Relationship between anti-CCP antibodies and oxidant and anti-oxidant activity in patients with rheumatoid arthritis

Objective/Aim: A new group of autoantibodies in Rheumatoid Arthritis (RA), the anti-cyclic citrullinated peptide (anti-CCP) antibodies directed to citrulline-containing proteins, which are of value for the severity of RA. Up to date, the relationship between anti-CCP antibodies and oxidant, anti-oxidant activity in patients with RA has not been elucidated in the previous studies. In this study we aimed to investigate the effect of anti-CCP antibodies in the circulation on whole blood, serum and synovial fluid oxidant and anti-oxidant activity in patients with RA. Materials and Methods: RA patients with anti-CCP (+) (n=25) and anti-CCP (-) (n=24) were recruited into the study. All patients had a positive rheumatoid factor (RF). The patients who were under treatment with only non-steroidal antiinflammatory drugs (NSAID) at the study time included in the study. Catalase (CAT), Glutathione peroxidase (GSHPx), Myeloperoxidase (MPO) activities and the levels of Malondialdehyde (MDA) were measured in whole blood, serum and synovial fluid in both groups. Results: There were no significant differences in terms of the mean whole blood and serum antioxidative activity (CAT, GSHpx) and the mean blood and serum MDA and MPO values (oxidative activity), between the patients with anti-CCP(+) and those with anti-CCP(-). There was increased synovial oxidant activity (MDA and MPO levels) (p<0.05) in anti-CCP(+) RA patients with or without ESR negativity when compared with anti-CCP(-) RA patients. There was positive correlation between anti-CCP antibody levels and synovial MDA and MPO levels (r=0.435, p<0.05, r=0.563, p<0.05 respectively) in anti-CCP (+) group. Conclusions: In conclusion, anti-CCP antibody positivity seems to be associated with increased synovial fluid oxidant activity (increased MDA and MPO levels) in patients with RA. These conclusions need to be validated in a larger controlled study population.     

Antiphospholipid antibodies as a possible risk factor for atherosclerosis in patients with rheumatoid arthritis

Atherosclerosis shares many similarities with inflammatory and autoimmune diseases, among them rheumatoid arthritis (RA). Anticardiolipin antibodies (aCL) and antibodies against beta2-glycoprotein I (anti-beta2GPI) have been detected in sera of RA patients in several studies. We demonstrated aCL and anti-beta2GPI in a selected group of 70 patients with RA (premenopausal women, non-diabetic, non-hypertensive) and compared them with age- and sex-matched controls. There was a significant higher internal carotid artery intima-media thickness and number of plaques in RA patients compared to controls. aCL of IgG and IgM classes were present in 15.7% of RA patients as compared to 5% in the control group. Thirty percent of RA patients had anti-beta2GPI of IgG, IgM and IgA classes compared to 7.5% in controls. Major differences were seen in IgG and IgA classes. Our results support the idea that aCL and anti-beta2GPI represent an important risk factor for atherosclerosis in RA patients. Elevated levels of phosphatidylserine-dependent antiprothrombin antibodies did not contribute significantly to the general prevalence of antiphospholipid antibodies.     

检测抗聚丝蛋白抗体在类风湿关节炎诊断中的意义

目的探讨抗聚丝蛋白抗体(AFA)对类风湿关节炎(RA)诊断的价值,并比较与RA的其他早期诊断指标的相关性。方法从人表皮细胞中提取并部分纯化聚丝蛋白(filaggrin)抗原,用于免疫印迹检测(Western blot)103例RA血清标本和140例对照血清,包括系统性红斑狼疮(SLE)、干燥综合征(SS)、骨性关节炎(OA)95份及正常人45份。APF和AKA用间接免疫荧光法检测。结果103例RA病人的AFA阳性率、特异性分别为35.9%,93.7%,显著高于疾病对照组和正常人(P<0.001)。在AFA阳性的37例中,AKA也阳性的为26例,重叠率为70.3%;APF亦阳性的为31例,重叠率为83.8%,AFA与AKA、APF之间存在相关性。结论AFA对RA具有很高的特异性。AFA的检测可用于RA的临床诊断。AFA与APF及AKA有相关性,但不能完全取代它们的检测。     

Pathogenic role of antibodies to citrullinated proteins in rheumatoid arthritis

In the last 10 years, the discovery that antibodies to citrullinated proteins are highly specific for rheumatoid arthritis has led to a model of pathogenesis that ties together the genetic and environmental risk factors for susceptibility and severity of disease. The authors propose that the chronic inflammation is driven by two phases of an immune response. The first phase is the priming of autoimmunity, which may occur many years before the onset of disease and is caused by environmental factors, such as smoking and infectious agents, in the context of disease susceptibility alleles. This may occur in sites outside the joint, such as the respiratory tract. The second phase is the induction of arthritis, which is associated with the generation of citrullinated proteins within the joint, which is then perpetuated as the erosive disease by a local chronic immune response. The identity of candidate synovial citrullinated antigen(s), whether fibrin, vimentin, α-enolase, collagen type II or others yet to be described, may be the key to the pathogenesis of the destructive disease characteristic of rheumatoid arthritis. There is emerging evidence that citrullination may already be modified by established therapy in rheumatoid arthritis, but more specific inhibitors of deimination may provide new agents for future treatments.     

Anti-neutrophil cytoplasm antibodies in rheumatoid arthritis.

Anti-neutrophil cytoplasm antibodies (ANCA) occur occasionally in rheumatoid arthritis (RA), but their incidence and clinical significance have been unclear. In this study we have investigated 58 patients with RA. In 22 patients the disease was inactive and the remaining 36 with active disease were further subdivided into those without clinical evidence of vasculitis (26), those with cutaneous vasculitis (8) and those with systemic vasculitis (2). ANCA were demonstrated by indirect immunofluorescence in 10 of the 58 patients (17%). While both perinuclear (pANCA) and cytoplasmic (cANCA) staining were detected, pANCA were more common (70%). Neutrophil-specific anti-nuclear antibodies (ANNA) were demonstrated in a further eight sera (14%) and ANA were detected on Hep-2 cells in 30 of the 58 sera (52%). ELISAs for the detection of anti-myeloperoxidase and anti-elastase antibodies were then established. Five sera with pANCA and five that contained ANNA were negative for both anti-myeloperoxidase and anti-elastase antibodies, suggesting other as yet unidentified cytoplasmic antigens as the target molecules. However, anti-myeloperoxidase or anti-elastase antibodies were found in four sera that had homogeneous or speckled ANA on both Hep-2 cells and neutrophils. One serum contained both antibodies. The presence of ANCA detected by indirect immunofluorescence or of anti-myeloperoxidase or anti-elastase antibodies in these patients with RA was not associated with disease activity nor with the demonstration of cutaneous vasculitis or renal disease (P NS). A possible association with systemic vasculitis remains to be confirmed. There is an incomplete correlation between indirect immunofluorescence patterns and antibody specificity in ELISA systems.     

Anti-type II collagen antibodies in rheumatoid arthritis

Antibodies to native chick and bovine Type II collagen were measured by radio immunoassay, in 83 rheumatoid arthritis (RA) patients and 14 normal controls. Anti-chick Type II collagen and anti-bovine Type II collagen antibodies were found in 48% and 43% of RA patients, respectively. A strong correlation of antibodies to chick and antibodies to bovine collagen was described, suggesting cross-reactivity between different collagen species. There was an association between the presence of anti-native Type II collagen antibody and the expression of HLA-DR2. It is suggested that the production of anti-collagen antibody may be under genetic control in RA, but not associated with the major genetic marker of disease susceptibility, HLA-DR4.     

Anti-idiotypic antibodies induce neutralizing antibodies to bovine herpesvirus 1.

A neutralizing murine monoclonal antibody (mAb) of the IgG2a isotype (MM-113), specific for bovine herpesvirus 1 (BHV-1) glycoprotein gIV, was used to develop anti-idiotypic antibodies (anti-Id) in a calf. The bovine anti-Id were isolated from the serum of the immunized calf by affinity chromatography on an MM-113-Sepharose column, followed by repeated adsorption on a murine IgG2a column. The anti-Id thus obtained specifically reacted with MM-113, but not with isotype-matched controls. They also inhibited the binding of MM-113 to BHV-1 in a concentration-dependent manner. Mice immunized with the anti-Id produced neutralizing antibodies to BHV-1. The anti-Id bound to cells permissive to BHV-1 in a cell-binding radioimmunoassay (RIA).     

Microvascular abnormalities in patients with rheumatoid arthritis

Microvascular involvement represents one of the first apparent steps in many autoimmune diseases such as rheumatoid arthritis (RA). Early in the disease, peripheral microangiopathy may be easily recognized and studied by videocapillaroscopy. The aim of this study has been to observe the differences in labial microcirculation between healthy patients and patients suffering from RA. A total of 30 healthy patients and 30 patients suffering from RA were examined. The patients with conditions known to compromise microcirculation, such as diabetes, hypertension, or some pharmacological treatments were not included in the study. All the patients were non-smokers. Labial capillaroscopy was used to investigate the characteristics of microcirculation. Visibility, course, tortuosity, as well as the possible presence of microhemorrhages, the average caliber of the capillary loops and the number of visible capillary loops per square millimeter were evaluated for each patient. The investigation was simple, non-invasive, and repeatable for each patient. In patients suffering from RA, it was possible to observe a reduced caliber of capillaries, as well as greater elongated capillaries, in comparison to controls. This study shows that capillary alterations in patients suffering from RA occur in labial mucosa microcirculation; such evidence could be extremely important in the diagnosis of suspected RA.