Subclass distribution of IgG antibodies to the rat oesophagus stratum corneum (so-called anti-keratin antibodies) in rheumatoid arthritis.

Serum IgG, labelling the stratum corneum of the rat oesophagus epithelium, so-called anti-keratin antibodies (AKA) constitute the most specific marker for the diagnosis of rheumatoid arthritis. In this study, we investigated 31 IgG AKA-positive rheumatoid sera and 21 control sera from patients with non-rheumatoid inflammatory rheumatic diseases. The serum level of IgG1,2,3 and 4 was determined by radial immunodiffusion and the subclass distribution of IgG AKA by a three-step semi-quantitative immunofluorescence assay using standard monoclonal antibodies specific for each of the four human IgG subclasses. In the rheumatoid sera, the serum level of IgG1 was found to be significantly increased and the level of IgG2 significantly decreased with regard to the control sera, while the levels of IgG3 and 4 as well as total IgG were in the normal range. IgG1,2,3, and 4 AKA were detected in 27 (87%), 6 (19%), 4 (13%) and 11 (35%) of the 31 rheumatoid sera, respectively, and were found to be independent of the clinical and biological indices of the disease. In spite of inter-individual heterogeneity, two predominant profiles were distinguished: IgG1 (alone) and IgG(1 + 4), which together represented 18 sera (58%). The large predominance of IgG1 AKA and the quasi-absence of IgG2 AKA suggest that the recognized antigen may be partly comprised of protein. Moreover, the high frequency of occurrence of IgG4 AKA might result from chronic exposure to the eliciting antigen, which could be a genuine autoantigen since we demonstrated that it is also present in the stratum corneum of human epidermis.     

抗鼠食管角质层抗体的检测及其临床意义

对81例类风湿关节炎（RA）,166例其他风湿病患者和56例正常人进行了抗鼠食管角质层抗体（AKA）检测,以角质层线性、板层状荧光沉着,滴度≥1:80为阳性判断标准,结果:AKA在正常人和其他风湿病患者的阳性率分别为 0％（0/56）和 0.6％（1/166）,而在 RA的阳性率为 19.8％（16/81）;早期 RA的 AKA检出率为28.6％（6/21）;AKA阳性RA的 RF阳性率和平均滴度明显高于AKA阴性者（93.7％对36.9％,1:80对1:32）。提示AKA有助于RA早期诊断,且可能为预后不良的指标之一。     

Antikeratin antibodies in synovial fluid in rheumatoid arthritis

Serum and synovial fluid of 20 patients with classical or definite rheumatoid arthritis (RA) were tested for antikeratin antibodies (AKA) by indirect immunofluorescence using rat esophagus as antigen. AKA were found in 80% of the RA patients, in serum as well as in synovial fluid. None of the 54 serum control patients were AKA positive in serum. None of the 17 synovial fluid control patients were AKA positive in synovial fluid. F(ab)'2 fragments prepared from AKA positive RA serum retained antibody activity. AKA belonged to the IgG class of immunoglobulins. Corrected for the lower IgG content in synovial fluid, AKA constituted a higher percentage of the IgG in synovial fluid than in serum. This could imply a possibility of local production of AKA in the joint.     

IgG rheumatoid factors and anti-nuclear antibodies in rheumatoid vasculitis.

We studied the distribution and characteristics of circulating rheumatoid factors (RF) and anti-nuclear antibodies (ANA) in 30 rheumatoid arthritis (RA) patients who had polyarthritis alone (group I), 28 RA patients with polyarthritis and extra-articular disease (group II), 28 RA patients with systemic vasculitis (group III) and 60 healthy matched controls. IgG RF occurred more frequently and in higher serum titres in group III (100%) than RA patients in group I (40%), or in group II (18%) or in normal controls (5.8%). The serum titre of IgM RF was higher in vasculitis patients than in other RA patients. ANA were found in 74% of all RA patients and although the frequency did not differ in the three patient groups, the serum titre was significantly higher in the vasculitis group. Antibodies to extractable nuclear antigen were found only in group III (18.7%). Antibodies to histones were also more prevalent in group III than in the other RA groups. The serological abnormalities in rheumatoid vasculitis differed quantitatively as well as qualitatively from other RA patients.     

Failure to demonstrate any interaction between polyclonal rheumatoid factors and IgG antinuclear antibodies or other IgG autoantibodies.

The autoantibody profile results from 750 randomly selected patients with rheumatoid factor (RF) and/or antinuclear antibody (ANA) positive tests were retrospectively analysed in order to discover if there was any evidence to show that the presence of polyclonal rheumatoid factors affects the incidence and titre of IgG-ANA in these patients. The incidence of IgG-ANA in the RF-positive group (34.4%) was significantly greater than that found in the RF-negative groups (19.6%) (P < 0.001), and there was no significant difference between the mean IgG-ANA titres of the two groups (P = 0.987). The possibility that the presence of IgM-RF in serum might be responsible for the inhibition of IgG-ANA was examined by treating the sera of selected patients who were RF-positive but IgG-ANA-negative with the dissociating agent D-penicillamine (DP). After treatment, IgG-ANA could not be detected in any of the sera. Similar studies were carried out to ascertain if there was a masking effect by RF on two other IgG autoantibodies, anti-keratin antibody (AKA) and gastric parietal cell antibody (GPCA). There was no evidence from these studies that the presence of RF affects the incidence of either AKA or GPCA. We conclude from these results that the presence of RF is not a significant factor controlling the incidence of either IgG-ANA or other IgG autoantibodies and that the routine treatment of RF-containing serum with a dissociating agent before testing for autoantibodies would be unnecessary.     

Comparison and relevance of rheumatoid factors, antikeratin antibodies and anti-cyclic citrullinated peptides antibodies in rheumatoid arthritis

OBJECTIVES: to evaluate specificity and sensibility of the rheumatoid factors (RF), the anti-cyclic citrullinated peptide antibodies (CCP) and the anti-keratin antibodies (AKA) according to the rheumatoid arthritis (RA) diagnosis; pathology other than RA with at least one of these marker positive; the significance of the flocculent fluorescence of the antibodies AKA by indirect immunofluorescence (IIF). METHOD: two hundred forty height patients were studied: 121 RA, 89 inflammatory rheumatisms, 23 non inflammatory rheumatisms, and 15 non rheumatic affections. The RF was investigated by nephelometry, the anti-CCP by immunofluorometry and the AKA by IIF on rat oesophagus. RESULTS: specificity and sensibility were respectively in a retrospective manner: 68% and 83% for the RF, 95% and 76% for the anti- CCP, 83% and 40% for the AKA during RA with evolution of less than one year. The rates of agreements were: RF versus CCP: 81%, RF versus AKA: 57%, CCP versus AKA: 73%. Twelve patients with pathologies different from RA have positive anti-CCP or AKA. Thirty three of the patients with anti-CCP level superior to 130 U/mL have flocculent AKA versus only 5% when the anti-CCP are lower than 130 U/mL. CONCLUSION: the RF and the anti-CCP are complementary in RA. Autoimmune and neoplasic pathologies are sometimes responsible for the positivity of the anti-CCP and the AKA. The flocculent aspect of AKA in IIF may be associated with raised concentrations of anti-CCP.     

RF、AKA和抗CCP抗体联检对类风湿关节炎诊断的临床价值

目的:探讨类风湿因子(Rheum atoid factor,RF)、抗角质蛋白抗体(antikeratin antibody,AKA)及抗环瓜氨酸肽(anti-cyc lic c itru llinated peptide,CCP)抗体对类风湿关节炎(rheum atoid arthritis,RA)的临床意义和早期应用价值。方法:对40例类风湿关节炎患者、30例系统性红斑狼疮和30名正常健康体检者进行RF、AKA、抗CCP抗体检测,应用速率散射比浊法测定RF,间接免疫荧光法检测AKA,ELISA法测定抗CCP抗体。结果:40例RA患者血清中,RF灵敏度和特异性分别为70.0%、90.0%,AKA灵敏度和特异性分别为35.0%、96.7%,抗CCP抗体灵敏度和特异性分别为85.0%、93.3%,联检RF、AKA及抗CCP抗体灵敏度和特异性分别为97.07%、99.8%。结论:RF、AKA和抗CCP抗体可作为诊断RA比较特异的血清学指标,三项指标联检可在一定程度上弥补RF对RA的诊断不足,提高RA的阳性诊断率,且有助于疾病的预后判断。     

联检多项指标对类风湿关节炎诊断的临床价值

目的:探讨类风湿因子(Rheum atoid factor,RF)、抗角质蛋白抗体(AKA)、C-反应蛋白(C-reactiveprote in,CRP)和血沉(erythrocyte sed im entation rate,ESR)联检对类风湿关节炎(rheum atoid arthritis,RA)的临床诊断价值。方法:对35例类风湿关节炎患者、30例系统性红斑狼疮和30名正常健康体检者的RF、AKA、CRP及ESR检测,应用速率散射比浊法测定RF和CRP;间接免疫荧光法检测AKA;应用魏氏法测定ESR值。结果:35例RA患者血清中,RF灵敏度和特异性分别为71.4%、91.7%,AKA灵敏度和特异性分别为34.3%、96.7%,CRP灵敏度和特异性分别为91.4%、25%,ESR灵敏度和特异性分别为88.6%、83.3%。联检RF和AKA的灵敏度和特异性分别为81.2%、99.7%,联检RF、AKA、CRP及ESR的灵敏度和特异性分别为99.98%、99.97%。结论:RF、AKA、CRP及ESR可作为RA诊断的血清学指标,且四者联检有助于提高RA诊断的灵敏度及特异性。     

Humoral responses in human organ transplantation

The plasmas of fifteen patients undergoing organ transplantation were serially tested for a variety of humoral antibodies. The antibodies studied were those which usually reflect covert immunologic events, i.e. the antiglobulins (rheumatoid factors and serum agglutinators), heterophile antibodies and typical and atypical isoantibodies.

Although the isoantibodies and the heterophile antibodies were not significantly stimulated by organ transplantation, the administration of ALG (horse antilymphocyte globulin) invariably led to the presence of antihorse globulin antibodies. Three patients were Rh negative and received organs from Rh-positive donors. However, only one of the patients responded with anti-Rh antibodies, but these antibodies exceeded in titre the anti-Rh antibodies usually observed following intentional immunization of normal volunteers.

The most startling observation was the significant increase in titres of the serum agglutinators in eight of the patients. These observations suggest that the antigen–antibody complexes associated with chronic rejection may stimulate the production of the serum agglutinators.

     

Unsuspected strongyloidiasis in hospitalised elderly patients with and without eosinophilia

The prevalence and associated factors of chronic uncomplicated strongyloidiasis were estimated among 200 consecutive elderly patients (aged >or= 60 years) admitted to a general hospital in northern Italy. One-hundred patients had a peripheral eosinophil concentration >or= 500 cells/microL (group A), and 100 were age- and gender-matched controls (group B). Measurements included serum IgG anti-Strongyloides antibody titre by an indirect immunofluorescence assay, combined with faecal culture for Strongyloides stercoralis. Anti-Strongyloides antibodies were detected in 28 patients (at high titre in 11 patients). Seropositivity was significantly more common among group A than among group B patients (OR 4.85). Strong seropositivity for anti-Strongyloides antibodies was associated with farm work (p < 0.001), but not with other patient characteristics or with signs and symptoms of strongyloidiasis. In conclusion, strongyloidiasis was relatively common among elderly in-patients; eosinophilia and a history of farm work were the most useful indications for this diagnosis.     

Antiviral antibodies in rheumatoid synovial fluid and cryoprecipitates

Distribution of viral antibodies was examined by the indirect fluorescent antibody technique in specimens from rheumatoid arthritis and from systemic lupus erythematosus patients. Titres in sera from rheumatoid arthritis patients were usually equal to, or greater than, those in joint fluids. Viral antibodies were found in whole cryoprecipitates from joint fluids and in the IgG fractions of the cryoprecipitates. Anti-herpes simplex antibodies were most frequently found in cryoprecipitates and were at highest titre in sera and joint fluids. Anti-respiratory syncytial virus antibodies were next in frequency and in titre. No evidence was presented to support the concept of localized viral antibody synthesis in joints of rheumatoid arthritis patients. Serum antibody titres in systemic lupus erythematosus patients were similar to those in rheumatoid arthritis patients; however, viral antibodies were not found in the serum cryoprecipitates of systemic lupus erythematosus patients.     

Natural IgG to epidermal cytokeratins vs IgG to the stratum corneum of the rat oesophagus epithelium, so-called 'antikeratin antibodies', in rheumatoid arthritis and other rheumatic diseases.

In order to study the relationships between the circulating IgG autoantibodies to epidermal cytokeratins (AECK), which were described in normal human sera as well as in sera from patients with various diseases, and the so-called 'antikeratin' IgG antibodies ('AKA'), which are highly specific for rheumatoid arthritis (RA), we simultaneously investigated AECK by a specific ELISA using cytokeratins from human stratum corneum (SC) and 'AKA' by semiquantitative indirect immunofluorescence assay on rat oesophagus epithelium, in a large series of 595 rheumatic sera including 229 RA. AECK were found to be present in all the 595 sera, with large inter-individual variations in titre. Whatever the titre chosen as threshold, the autoantibodies (auto-Ab) were never found to be specific for any rheumatic disease. Moreover, in RA, they were found to vary independently of IgM rheumatoid factor (IgM-RF), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), while they were found to vary in parallel with the total serum IgG concentration. In contrast, although 568 of the 595 rheumatic sera contained antibodies that labelled the rat oesophagus SC, the highest titre-like values were obtained with RA sera. At a convenient threshold, 95 (41.5%) of the 229 RA were detected while only three false positives (0.08%) remained among the 366 non-RA sera. Moreover, in RA, 'AKA' were found to be related to IgM-RF, ESR and CRP, while their titre was found to be independent of the total serum IgG concentration. Lastly, no statistical correlation was found between the antibodies, either in the whole sample of 595 sera or in any diagnostic group. In conclusion, the simultaneous investigation of AECK and 'AKA' showed that they differ from each other in all the aspects explored. AECK belong to the widely explored family of natural auto-Ab against cytoskeleton components and do not constitute a diagnostic marker while, on the other hand, 'AKA' confirmed their high diagnostic specificity for RA. It can also be asserted that, in spite of their name, 'AKA' do not recognize human epidermal cytokeratins, at least in the denatured form they present in ELISA. Therefore, they recognize either conformational epitope(s) appearing on cytokeratins during the late stages of the cornification process, or epitope(s) borne by rat cytokeratins but absent on human cytokeratins, or lastly a non-cytokeratin SC antigen.     

类风湿因子及相关自身抗体对类风湿关节炎的诊断价值

目的探讨类风湿因子（RF）、抗环瓜氨酸肽抗体（抗CCP）及抗角蛋白抗体（AKA）联合检测对类风湿关节炎（RA）的临床诊断价值。方法对80例RA和65例非RA的其他自身免疫病患者检测RF、RF-IgM、抗CCP及AKA 4种指标。结果自身免疫性疾病女性发病较高,以RA组为甚;RA组的RF、RF-IgM、抗CCP及AKA高于其他自身免疫性疾病组;单指标检测RA诊断的敏感性为RF〉RF-IgM〉AKA〉抗CCP,特异性为RF-IgM〉抗CCP〉RF〉AKA。阳性预测值为抗CCP〉RF〉RF-IgM、AKA,阴性预测值为RF〉RF-IgM〉AKA〉抗CCP;以并联或串联方式联合检测均以RF、RF-IgM及抗CCP三联及RF、RF-IgM、抗CCP及AKA四联检测为佳,并联检测的敏感性分别为93%及97%,串联检测的特异性分别为98%及99%。结论 RF、RF-IgM、抗CCP及AKA 4种指标联合检测可提高对RA诊断的敏感性和特异性,对RA的早期诊断有较高价值。     

The Presence of Anti-Protein A Antibodies in Patients with Rheumatoid Arthritis

Sixteen patients with rheumatoid arthritis (RA) were examined for the presence of anti-protein A antibodies. The F(ab')2 preparations from five RA patients showed significant binding to IgG-free protein A on ELISA. The protein A binding was further examined by immunoblotting. The F(ab')2 preparations of high protein A-binding protein gave a specific reaction with IgG-free protein A on nitrocellulose paper. This demonstrates the presence of anti-protein A antibodies in patients with RA. Those RA patients with anti-protein A antibodies had more active disease as judged by the Lansbury's activity index. The level of serum rheumatoid factor (RAHA) was significantly higher in patients with anti-protein A antibodies than in those without anti-protein A antibodies.     

Low and high molecular weight cytomegalovirus-specific immunoglobulin M antibody in renal transplant patients with cytomegalovirus infections

Sera from 27 renal transplant patients with primary and recurrent CMV infections and which were known to contain CMV-specific IgM antibodies were investigated by indirect immunofluorescence for the presence of virus-specific high molecular weight IgM (19S IgM) and low molecular weight IgM (7S IgM). After sucrose gradient fractionation of the sera, 19S IgM was found in all 27 patients, whereas 7S IgM was present in 11 out of 19 (56%) patients with primary CMV infection and in 1 out of 8 (12%) patients with recurrent CMV infection. The presence of 7S IgM was unrelated to the titre of the virus-specific IgM in whole serum. The presence of IgM rheumatoid factor was monitored by a sensitive fluorescence assay using measles virus antigen/antibody complexes. The absorption of the serum fractions with heat-aggregated gamma globulin failed to remove the specific IgM staining indicating that it was not due to IgM rheumatoid factor. On the other hand adsorption with protein A/sepharose removed the specific IgM staining from the 7S IgM fractions but not from the 19S IgM fractions. This suggests that specific 19S and 7S IgM antibodies may belong to different subclasses of IgM.     

类风湿关节炎四种自身抗体的检测及意义

为评估类风湿因子(rheumatoid factor,RF)、抗环瓜氨酸肽(cyclic citrullinated pepdide,CCP)抗体、抗Sa抗体和抗角蛋白抗体(anti-keratin antibody,AKA)自身抗体对类风湿关节炎(rheumatoid arthritis,RA)诊断的意义,采用速率散...     

第二代抗环瓜氨酸肽抗体的检测在类风湿关节炎诊断中的意义

目的探讨抗环瓜氮酸肽（CCP）抗体的检测在类风湿关节炎（RA）诊断中的价值。方法ELISA法分别检测108例RA、89例非RA（其它风湿病患者）和78例健康体检者的抗CCP抗体；用间接免疫荧光法和速率散射比浊法检测抗角蛋白抗体（AKA）和类风湿因子（RF），分析CCP抗体的水平及与AKA、RF的相关性。结果抗CCP抗体的阳性率在RA中为87．4％（94／108），在非RA中为8．99％（8／89），正常人为0％（0／78）。3种抗体对RA诊断的敏感性和特异性分别为CCP87．4％、91．01％，AKA58．33％，82．24％，RF81．36％、75．35％。CCP抗体与AKA在RA患者血清中的阳性率之间差异非常显著，与RF差异不显著。3种方法的检测结果间存在相关性。结论用ELISA法检测血清中CCP抗体简便、结果可靠，对RA诊断具有高度的敏感性和特异性。     

The association of autoimmune diseases and anti-IgA antibodies in patients with selective IgA deficiency.

The prevalence of antibodies to immunoglobulin A (IgA) was studied in eighty-three subjects with selective IgA deficiency (SIgAD), thirty-three normal individuals, thirty-two children with juvenile rheumatoid arthritis (JRA) and normal or elevated IgA, seventeen children with systemic lupus erythematosus (SLE) and normal or elevated IgA, and thirteen patients with hypogammaglobulinaemia. Anti-IgA antibodies were detected by haemagglutination of human erythrocytes coated with one of two IgA myelomas by the chromic chloride technique. Antibodies to IgA were not found in significant titre in individuals with normal or elevated IgA or in those with hypogammaglobulinaemia. In IgA deficient patients, elevated titres were found in 25--30% of those who were healthy or who had non-rheumatic diseases, 50% of those with rheumatoid arthritis, 77% of those with JRA and 100% of those with SLE. Patients with rheumatic diseases and SIgAD may therefore be particularly at risk of developing anti-IgA-mediated reactions to blood products.     

Eosinophil involvement in rheumatoid arthritis as reflected by elevated serum levels of eosinophil cationic protein.

Circulating levels of eosinophil cationic protein (ECP), an eosinophil specific granule protein, and numbers of peripheral eosinophils were determined in 42 patients with rheumatoid arthritis. At the time of the investigation the patients were without drug treatment. They had normal blood counts of eosinophils but on average a five-fold increase of the serum ECP values compared with healthy subjects. The intracellular content of ECP in eosinophils isolated from 14 patients was normal. High serum levels of ECP were particularly observed in patients with a disease of rather short duration but with a more aggressive course. Other factors associated with high ECP values were blood eosinophil counts in the upper normal range, high rheumatoid factor titre and increased inflammatory activity as defined by elevated serum haptoglobin and blood platelet counts. No relation was found between serum ECP and circulating immune complexes or serum total IgE. Synovial fluids obtained from 14 patients with rheumatoid arthritis contained very high concentration of ECP; on average nine times higher than those in the circulation of the patients. During corticosteroid but not NSAID therapy serum ECP decreased on average about 50% compared with pre-treatment values. Although eosinophils are not a notable feature of the synovial membrane infiltrate or cellular joint exudate, data obtained indirectly indicates their participation in the inflammatory reaction in RA.     

Rheumatoid factor as a cause of positive reactions in tests for Epstein–Barr virus-specific IgM antibodies

Sera from twenty-eight patients with rheumatoid arthritis (RA) were titrated in indirect immunofluorescence tests for Epstein–Barr virus (EBV) specific antibodies. All had IgG antibodies to viral capsid antigen (VCA), 64% at titres [unk] 320, and 71% reacted also in tests for VCA-specific IgM antibodies at titres ranging from 20 to 640. The reactions observed in the IgM test were not due to VCA-specific IgM antibodies, however, but rather to rheumatoid factor (RF) usually an IgM antibody to the Fc regions of IgG. The titres recorded in the anti-VCA IgM test correlated significantly with the RF titres and both reactivities were abolished by adsorption onto IgG coated latex particles. In addition, they clearly depended upon the height of the IgG antibody titre to VCA, indicating that the more VCA-specific IgG molecules are present the more likely it is that RF will combine with them in sufficient quantity before or after their attachment to VCA-positive test cells so as to become detectable by the fluorescent antibodies to human IgM. Results comparable in every aspect were obtained with those sera from patients with Hodgkin's disease, nasopharyngeal or cervical carcinomas which reacted in the anti-VCA IgM test. Sera from patients with infectious mononucleosis may also contain RF, but in such cases its removal by adsorption onto IgG-coated latex particles did not generally reduce the VCA-specific IgM antibody titre. Removal of RF from any of the sera studied did not affect the titres of VCA-specific IgG and, where applicable, IgA or heterophil antibody titres. These results re-emphasize the pitfall created by RF noted previously in tests for virus-specific IgM antibodies.