IgA Rheumatoid Factor Research Articles

Quantification of cross-reactive idiotype-positive rheumatoid factor produced in autoimmune rheumatic diseases. An indicator of clonality and B cell proliferative mechanisms

The aetiology of sustained autoantibody production in human autoimmune diseases is unknown. Evidence for structural similarities and common clonal origin among autoantibodies have been demonstrated through the expression of cross-reactive idiotype (CRI). In the present study we use four monoclonal antibodies (MoAbs) with specificity for non-overlapping CRI on human rheumatoid factor (RF) autoantibodies to define the structural features of polyclonal RF characteristic of patients with autoimmune rheumatic diseases. The pattern of CRI expression in the serum of 12 patients with rheumatoid arthritis (RA), eight with systemic lupus erythematosus (SLE) and 20 with primary Sjögren's syndrome and 34 normal individuals were determined in parallel with the level of IgM RF, IgA RF and autoantibodies to the cellular antigens SS-A, SS-B, Sm, nRNP and dsDNA and cryoglobulins. The results demonstrate significant elevation in the level of IgM and IgA expressing VHI (G6 and G8) and VHIII (B6 and D12) associated CRI in the serum of patients with autoimmune rheumatic diseases compared with normal individuals. These increases paralleled, but did not equal the increase in the level of immunoglobulins and RF. However, when expressed as proportion of immunoglobulin, only the VHI-associated CRI were significantly elevated in patients compared with normal individuals. The proportion of IgM RF expressing the VHI-associated CRI was higher in patients with Sjögren's syndrome compared with SLE and RA. Furthermore, the proportion of IgA RF expressing the G6 CRI was higher than G6+ IgM RF. These findings imply that different mechanisms contribute to RF production in autoimmune diseases. It is suggested that polyconal B cell activation is likely to be a contributing mechanism. However, such polyclonal activation is unlikely to be random since a selective elevation in the level of specific autoantibodies and VHI-associated CRI is observed. Furthermore, the data demonstrate that a proportion of autoantibodies in autoimmune diseases are immunoglobulin germline gene encoded. This is more evident in some patients with primary Sjögren's syndrome, where RF is likely to be oligoclonal or monoclonal in individuals with lymphoproliferation.

Rheumatoid factors and glomerulonephritis

It is presently unknown whether rheumatoid factors have a pathogenic role in the development of various types of glomerulonephritis with immune deposits. Three isotypes of rheumatoid factors (RFs), which are autoantibodies to IgG, were measured using the solid-phase fluorescence immunoassay in sera from patients with diffuse proliferative lupus nephritis (DPLN), membranous lupus nephritis (MLN), IgA nephropathy (IgAN) and idiopathic membranous nephropathy (MN). RF activity of immunoglobulins deposited in the glomeruli from these patients was also studied by examining the binding of the FITC-conjugated human IgG and Fc portion of IgG to the glomeruli of renal biopsy specimens. IgG, IgA and IgM RFs were significantly increased in sera from patients with DPLN, and the increase was significantly lower in patients with MLN, IgAN and MN. Human IgG bound to immunoglobulin on the glomeruli only in DPLN, but not in MLN, IgAN or MN. The Fc portion of IgG was demonstrated to be involved in this reaction. It was suggested that RFs and IgG may play a major role in immune deposits on the glomeruli in DPLN and may be involved in the development of DPLN; however, this is not likely in MLN, IgAN or MN.

Antibody Clustering Helps Refine Lupus Prognosis

Our aim was to investigate a possible association between patterns of anti-dsDNA antibody isotypes (IgG, IgM, and IgA), rheumatoid factor (RF) isotypes (IgG, IgM, IgA), and IgG anti-C reactive protein (CRP) and systemic lupus erythematosus (SLE) disease activity (SLEDAI). Our study group included 98 patients, 86 women and 12 men, with a mean SLEDAI score of 7.9 +/- 4.1. We divided the patients into 4 groups by the serum anti-dsDNA antibody isotype intensity level. We found that patients in group 1 (IgG > IgM, 42 patients) had a statistically significantly higher SLEDAI score than group 2 (IgG < IgM, 13 patients) (10.57 +/- 4.62 versus 5.6 +/- 4, P = 0.0012), group 3 (IgG = IgM, 8 patients) (10.57 +/- 4.62 versus 6.2 +/- 1.98, P = 0.04), and group 4 (none, 35 patients) (10.57 +/- 4.62 versus 6 +/- 1.5, P = 0.0001). SLE patients with IgG RF or IgM RF isotype present had a significantly higher SLEDAI score compared with those without IgG RF or IgM RF (10.57 +/- 4.8 versus 7.6 +/- 4.1, P = 0.03, 10.6 +/- 5 versus 7.6 +/- 3.9, P = 0.046). The presence of IgA RF isotype was not associated with a higher SLEDAI score. IgG anti-CRP did not correlate differentially with SLEDAI scores. A combination of high-titer IgG anti-dsDNA with a positive RF of IgM isotype may serve as a marker for more active SLE.

Value of anti-mutated citrullinated vimentin antibodies in diagnosing rheumatoid arthritis

We assessed the diagnostic value of anti-mutated citrullinated vimentin antibodies (anti-MCV) and compared it with those of anti-cyclic citrullinated peptide antibodies (anti-CCP), IgA (ARF), IgM (MRF) and IgG (GRF) rheumatoid factors for rheumatoid arthritis (RA). Serum samples of 170 RA patients, with early and established RA, and 309 controls were tested for anti-MCV, anti-CCP, ARF, MRF and GRF using commercially available ELISA kits. Cut off of different tests was determined with ROC curves. The sensitivity and the specificity of anti-MCV were 74.1 and 79%, respectively. Sixty-five of 309 (21%) controls were anti-MCV positive. Sensitivity and specificity of anti-CCP were 72.4 and 96.1%, respectively. Only 12 of 309 (3.9%) controls were anti-CCP positive. Sensitivity of ARF, MRF and GRF were 64.1, 65.9 and 68.2%, respectively. Their specificity was 79.6, 74.4 and 68.9%, respectively. No significant association was observed between the antibodies tested and extrarticular manifestations. Anti-MCV shows comparable sensitivity but lower specificity than that of anti-CCP. They do not appear to be very useful in the diagnosis of RA.

Rheumatoid factors and anticyclic citrullinated peptide antibodies in pediatric rheumatology

Juvenile idiopathic arthritis (JIA) is a heterogenous childhood disease without reliable biomarkers for monitoring disease progression. Immunoglobulin (Ig) M rheumatoid factor (RF) is used to define a subset of JIA patients, but its significance in JIA is dependent on the method of measurement. In addition to IgM RF, IgA RF has been implicated in determining disease severity in JIA, including functional disability and joint damage. Anticyclic citrullinated peptide (anti-CCP) antibodies have been a valuable diagnostic tool in rheumatoid arthritis, with varied results in their significance in JIA patients. Recent studies have demonstrated the possible usefulness of isotypes of anti-CCP antibodies in monitoring JIA patients to determine disease outcome. Overall, RF isotypes and anti-CCP isotypic antibodies have demonstrated increasing importance in the evaluation of JIA patients to determine which patients may have more aggressive or severe disease and to aid in possible treatment plans to prevent joint damage and disability.

Prognostic factors of 10-year radiographic outcome in early rheumatoid arthritis: a prospective study

IntroductionThe objectives of this study were to determine the predictive factors of long-term radiographic outcome of rheumatoid arthritis (RA) and to describe the relationship between joint damage and disability over the course of the disease.MethodsA cohort of 191 patients with early RA referred from primary care physicians were prospectively followed for 10 years. To determine the predictive factors of radiographic outcome, univariate analysis of the relationship between baseline values and outcome measures was undertaken using a chi-squared or Fisher's exact test. Stepwise multiple logistic regression was also performed to select independent prognostic factors.ResultsFrom data available for 112 patients, univariate analysis revealed a total Sharp score at 10 years that was significantly correlated with erythrocyte sedimentation rate (ESR), presence and level of IgA rheumatoid factor, presence of an anti-citrullinated protein antibody (ACPA), serum level of matrix metalloproteinase-3 and radiographic score at baseline. Logistic regression identified the baseline erosion score to be the most important baseline parameter as an independent prognostic factor of total radiographic score at 10 years (odds ratio = 5.64; 95% confidence interval = 1.78 to 17.86). After excluding radiographic scores from the entry parameters, the presence of ACPA and ESR were also predictive of the final total Sharp score. The Health Assessment Questionnaire (HAQ) score was strongly correlated with disease activity parameters, such as disease activity score and pain, at baseline and at three, five and 10 years. No correlation was found between total radiographic Sharp score and HAQ score throughout the study.ConclusionsIn this prospective study, baseline radiographic score, ESR and ACPA were the best predictive factors of 10-year radiographic outcome in early RA. HAQ disability was associated with disease activity throughout the 10-year follow-up but not with joint damage. This discrepancy with previous reports may be due in part to the early start of therapy with disease-modifying anti-rheumatic drugs.

Do high levels of IgA rheumatoid factor indicate a poor response to treatment with TNF inhibitors in patients with RA?

Do high levels of IgA rheumatoid factor indicate a poor response to treatment with TNF inhibitors in patients with RA?

Predictive Value of Antibodies to Citrullinated Peptides and Rheumatoid Factors in Anti‐TNF‐α Treated Patients

This article will focus on the relationship between serum levels of anti-citrullinated peptide antibodies (anti-CCP) or rheumatoid factor (RF) and clinical response to TNF-alpha blockers in order to evaluate whether these antibodies may have a role as serological markers of response to therapy in rheumatoid arthritis (RA). The changes induced in anti-CCP levels after TNF blocking therapy still remain a controversial issue even though a marked reduction following conventional DMARDs has been reported in early disease. On the other hand, a drop in RF levels during treatment has been reported by many authors. Decreased IgM RF levels seem to parallel clinical response suggesting that this antibody can also be regarded as a marker of response to treatment. Pre-treatment RF positivity or negativity does not influence response to TNF-alpha blocking therapy while high pre-treatment levels of IgA RF seem to be associated with a poor response rate.

The ESPOIR cohort: A ten-year follow-up of early arthritis in France: Methodology and baseline characteristics of the 813 included patients

Objectives The French Society of Rheumatology initiated a large national multicenter, longitudinal and prospective cohort, the so-called “ESPOIR cohort study” in order to set up databases to allow various investigations on diagnosis, prognostic markers, epidemiology, pathogenesis and medico-economic factors in the field of early arthritis and rheumatoid arthritis. Methods Patients were recruited if they had undifferentiated arthritis or rheumatoid arthritis, of less than 6 months disease duration and if they were DMARD and steroids naïve. Patients have then to be followed every 6 months during the first 2 years then every year during at least 10 years. Clinical, biological, radiographic and medico-economic databases have been constituted to fit in the different objectives of the project and more than 20 scientific studies have already been accepted by the scientific committee. Results 813 patients were included (76.75% were female). The mean age was 48.07 ± 12.55 years. The mean delay from the onset of symptoms to referral to the rheumatologist was 74.8 ± 76.6 days. Baseline swollen and tender joint counts were 7.19 ± 5.37 and 8.43 ± 7.01; DAS28 score was 5.11 ± 1.31. CRP was abnormal in 38.9% of the patients; 44.2%, 45.8% and 38.8% had respectively IgM rheumatoid factor (RF), IgA RF and anti-CCP antibodies. HLA DRB1*01 or 04 genes were found in 56.7% of them. Finally, 22% of these patients had erosions on hand or feet at baseline.

Cytokines, autoantibodies and viral antibodies in premorbid and postdiagnostic sera from patients with rheumatoid arthritis: case–control study nested in a cohort of Norwegian blood donors

Objective:To assess the timing of changes in cytokines, cytokine-related markers, autoantibodies and viral antibodies in the pathogenesis of rheumatoid arthritis (RA).Methods:Case–control study nested in a prospective cohort of 31 330...

Meta-analysis: Diagnostic Accuracy of Anti–Cyclic Citrullinated Peptide Antibody and Rheumatoid Factor for Rheumatoid Arthritis

Rheumatoid factor (RF) and autoantibodies against cyclic citrullinated peptide (CCP) are markers that might help physicians diagnose rheumatoid arthritis. To determine whether anti-CCP antibody more accurately identifies patients with rheumatoid arthritis and better predicts radiographic progression than does RF. MEDLINE through September 2006 and reference lists of retrieved studies and review articles. Studies in any language that enrolled at least 10 participants and that examined the role of anti-CCP antibody and RF in the diagnosis or prognosis of known or suspected rheumatoid arthritis. Two authors independently evaluated studies for inclusion, rated methodological quality, and abstracted relevant data. The DerSimonian-Laird random-effects method was used to summarize sensitivities, specificities, and positive and negative likelihood ratios from 37 studies of anti-CCP antibody and 50 studies of RF. The pooled sensitivity, specificity, and positive and negative likelihood ratios for anti-CCP antibody were 67% (95% CI, 62% to 72%), 95% (CI, 94% to 97%), 12.46 (CI, 9.72 to 15.98), and 0.36 (CI, 0.31 to 0.42), respectively. For IgM RF, the values were 69% (CI, 65% to 73%), 85% (CI, 82% to 88%), 4.86 (CI, 3.95 to 5.97), and 0.38 (CI, 0.33 to 0.44). Likelihood ratios among IgM RF, IgG RF, and IgA RF seemed to be similar. Results from studies of patients with early rheumatoid arthritis were similar to those from all studies. Three of 4 studies found that risk for radiographic progression was greater with anti-CCP antibody positivity than with IgM RF positivity. Many studies had methodological limitations. Studies of RF were heterogeneous and had wide ranges of sensitivity and specificity. Anti-CCP antibodies are more specific than RF for diagnosing rheumatoid arthritis and may better predict erosivedisease.

Treatment of DMARD-Resistant Active Rheumatoid Arthritis Patients with Leflunomide: Central Taiwan Experience

Objective: To examine the efficacy and safety of leflunomide (LEF) for patients with active rheumatoid arthritis (RA) who have been resistant to conventional disease-modifying antirheumatic drugs (DMARDs) including methotrexate (MTX). Methods: In this open-label, 48-week study, 61 patients with RA who remained active (DAS28≧5.1) despite therapy with conventional DMARDs for at least 4 months were given LEF, 10mg/day. Patients were required to have been receiving a stable dosage of MTX 12.5mg/week for at least 8 weeks prior to study enrollment. Efficacy variables were morning stiffness, patient global assessment, physician assessment, number of swollen joints, number of tender joints, IgM rheumatoid factor (RF), IgA RF, Wintrobe erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and platelet count. Safety measures included monitoring of adverse events and laboratory values. Results: Sixty active RA patients completed one year of treatment. The mean DAS28 of patients before LEF were 6.3±0.9. Measurements after 4, 12, 24, and 48 weeks of LEF treatment all differed significantly from baseline, including tender joint count, swollen joint count, patient global assessment, physician global assessment, DAS28, and serology index of ESR, CRP, and RF. Changes between weeks 4 and 12, week 4 and 24, weeks 4 and 48 were also significant in variables described. The changes among week 12, 24 and 48 were of no significance. LEF efficacy showed a plateau of response after 12 months with treatment of LEF. However, improvement was sustained to the end point of the study. In these 61 patients, LEF treatment was generally well tolerated with the exception of elevation of liver enzyme. Most patients with abnormal liver function returned to normal range without discontinuation of LEF. Only one patient withdrew from the study for persistent elevation of liver enzymes. The most commonly mentioned adverse events of diarrhea, nausea, stomatitis, upper respiratory tract infection, and rash were found and most adverse events were rated as mild in severity. No additional side effect was observed in combination therapy of MTX with LEF. Conclusion: LEF has therapeutic potential in DMARD-resistant active RA patients. It is a logical alternative for patients who have an incomplete response to optimal effective DMARDs. Results indicate that combination therapy with LEF is a safe and effective treatment for DMARD-resistant RA, with clinical benefit sustained over one year of treatment without evidence of new or increased toxicity.

High anti-cyclic citrullinated peptide levels and an algorithm of four variables predict radiographic progression in patients with rheumatoid arthritis: results from a 10-year longitudinal study

Objectives:New effective therapies with particularly good effect on joint destruction have highlighted the need for reliable predictors of radiographic progression in rheumatoid arthritis (RA). Our objective was to assess the...

Predicting factors for severity of rheumatoid arthritis: a prospective multicenter cohort study of 172 patients over 3 years

Rheumatoid arthritis may take an unfavourable course leading to rapid functional decline in a certain percentage of patients. Early identification of these patients is desirable. The aim of this study was to evaluate clinical and laboratory parameters for their value in the prediction of bad outcome. A total of 172 patients with early arthritis were followed for 3 years. Higher initial values for erythrocyte sedimentation rate, IgG and IgM rheumatoid factor, serum concentration of cartilage oligomeric matrix protein, Health Assessment Questionnaire score, Larsen score of feet, disease activity score, and swollen and tender joint count predicted worse outcome. An association with the presence of IgA rheumatoid factor or anti-cyclic-citrullinated peptide could not be established. We conclude that prognosis in an individual with rheumatoid arthritis depends on many factors. The determination of independent prognostic factors for progression of rheumatoid arthritis is a valuable tool in early arthritis to select patients for more aggressive therapy.

Low serum level of COMP, a cartilage turnover marker, predicts rapid and high ACR70 response to adalimumab therapy in rheumatoid arthritis

The aim of this study was to evaluate serum biomarkers, used in clinical routine, to predict the American College of Rheumatology (ACR) response to long-term anti-TNF alpha treatment (adalimumab). Sera from 29 consecutive rheumatoid arthritis patients were analysed for anti-cyclic citrullinated peptide (anti-CCP), cartilage oligomeric matrix protein (COMP) and IgM and IgA RFs (class-specific rheumatoid factors) at the start of treatment with adalimumab and after 3, 6 and 12 months. The response to the therapy was evaluated by ACR 20, 50, 70 and by DAS 28 scores. The mean serum COMP level of the population did not change after treatment. However, patients with low serum COMP levels (<10 U/l) at baseline showed a significant (p<0.02) higher ACR70 response (>50%) within 3 months, and also at 6 months, than patients with higher COMP values (ACR70<20%). This was also reflected by significantly higher decrease in DAS score at 3 (p<0.02) and 6 months (p<0.01) treatments. The IgM RF titre decreased significantly (p=0.02) after the therapy, but the percentage of serum positivity for anti-CCP and IgA/IgM RF did not change. No significant correlation was shown between serum COMP levels and C-reactive protein/erythrocyte sedimentation rate during the follow-up. Neither were any correlations shown between ACR/DAS 28 scores and anti-CCP, Ig M/IgA RFs. Our data indicate that low (<10 U/l) serum COMP before starting anti-TNF alpha treatment predicts a rapid (within 3 months) and high ACR70 response compared to RA patients with higher COMP values. This might reflect different mechanisms in the cartilage process in the RA disease at that time of treatment with different therapeutic sensitivity to anti-TNF alpha treatment.

Absence of antibody to cyclic citrullinated peptide in sera of non-arthritic patients with chronic hepatitis B virus infection

The objective of this study was to investigate if antibody to cyclic citrullinated peptide (anti-CCP) is detected in sera of patients with chronic hepatitis B virus (HBV) infection. Serum anti-CCP and IgA, IgG, and IgM rheumatoid factor (RF) isotypes were measured by enzyme-linked immunosorbent assay on 176 non-arthritic patients with HBV infection. IgA RF, IgG RF, and IgM RF were detectable in 29.5, 21, and 18.8% of the tested sera, respectively, with a total seropositivity rate of 42.7%. Marginally elevated anti-CCP was detected in one patient (0.6%). By regression analysis, there was no statistically significant association between the serum levels of anti-CCP and serum IgA, IgG, or IgM RF (R (2) = 0.033, with respective p values of 0.224, 0.297, and 0.334). In conclusion, anti-CCP was rarely detected in non-arthritic patients with HBV infection in contrast to RF. Thus, testing for anti-CCP may be a useful tool for the diagnosis of rheumatoid arthritis in this population.

Is measurement of IgM and IgA rheumatoid factors (RF) in juvenile rheumatoid arthritis clinically useful?

The prevalence and clinical relevance of IgM and IgA RF detected by ELISA were studied in 91 patients with juvenile rheumatoid arthritis (JRA) and 45 healthy children. IgM and IgA RF were detected, respectively, in 33 and 44% of the patients, compared to 6.7 and 15.6% of the healthy children (p = 0.001 and 0.0006, respectively). The frequency of IgM RF was significantly higher in patients with polyarticular (52%) as compared to systemic onset JRA (21%; p = 0.04). Five out of ninety-one patients and none of the control group were IgM RF positive by the latex test. High levels of IgM RF were detected more frequently in patients with active disease (p = 0.01) and positive latex agglutination test (p < 0.001) and had a marginally significant association with severe radiological deformities (p = 0.05). The presence of IgA RF was associated with active disease in polyarticular onset JRA children (p = 0.04). In conclusion, high levels of IgM RF and the detection of IgA RF can be useful in assessing clinical activity in a subset of patients with JRA.

Analysis of human sera that are polyreactive in an addressable laser bead immunoassay

Background: Following the introduction of addressable laser bead immunoassays (ALBIA) into our clinical laboratory, it was noted that certain sera would exhibit reactivity to numerous antigens in the array. To further understand the nature of this reactivity, we analyzed the reactivity of sequential sera that were identified over a 1 year period. Methods: Sera that demonstrated reactivity to 6 or more of the 8 antigens in an ALBIA kit (QuantaPlex 8: chromatin, Sm, RNP, Scl-70, ribosomal P protein, SS-A/Ro, SS-B/La, Jo-1) were tested for autoantibodies by indirect immunofluorescence (IIF) on HEp-2 cell substrates, for IgG, IgM and IgA rheumatoid factor, chromatin and ribosomal P protein by ELISA and by LINE immunoassay (LIA) and immunoblotting (IB). Results: In one calendar year, 40/4096 (0.8%) sera analyzed in a routine clinical laboratory setting demonstrated reactivity to 6 or more antigens in the QuantaPlex 8 kits. There was no common IIF pattern that could be attributed to the polyreactive sera. There was no apparent correlation of polyreactivity with IIF titers, indeed, 4/40 (10%) sera had a negative ANA at the screening dilution of 1/160. When subjected to IB, LIA and ELISA, polyreactivity to three or more antigens was confirmed for 12/40 (30%) of sera while 8/40 (20%) had reactivity to 1–2 antigens and 20 (50%) did not react with any antigens in these assays. Overall agreement of positive or negative tests between the ALBIA and IB, LIA and ELISA was 75% for chromatin, 50% for SS-A, 27.5% for Sm, 25% for Rib-P, 22.5% for RNP, 20% for Scl-70, 15% for Jo-1 and 7.5% for SS-B. 17/40 (42.5%) had a positive IgM, IgG or IgA rheumatoid factor, and 12/40 (30%) had all three isotype rheumatoid factors. Conclusions: On average, the agreement between ALBIA and other assays in this study of polyreactive sera was 30%. Approximately, one-half of sera that demonstrate reactivity to multiple autoantigens in a commercial ALBIA were confirmed to have reactivity to at least one autoantigen in another diagnostic assay and 30% could be regarded as polyreactive. Other sera, some of which had rheumatoid factor, appeared to have high background binding without demonstrating specific binding to any of the cognate antigens.

Autoantibodies in rheumatoid arthritis: association with severity of disease in established RA

Autoantibodies in rheumatoid arthritis (RA) are useful both for diagnosis and prognosis. Antibodies directed against citrullinated antigens have recently been shown to predict development of RA as well as poor outcome in early arthritis. Data on their role in established RA is limited. We studied the association of various autoantibodies in RA with its severity. A total of one hundred and twenty nine-patients with established RA was enrolled and sera were collected and stored at -70 degrees C. Data regarding erosions, deformities, and extra-articular features were collected. IgM rheumatoid factor (RF) was measured using nephelometry and value above 20 U was considered positive. IgA RF was measured by enzyme-linked immunosorbent assay (ELISA) and value above the mean+/-2 SD of normal healthy control was taken as positive. Anti-keratin antibody (AKA) was detected by indirect immunofluorescence assay using rat esophagus as substrate. Anti-cyclic citrullinated peptide (CCP) antibodies were measured by commercial ELISA and a value above 5 U was considered as positive. The prevalence of various autoantibodies was: IgM RF 82.2%, anti-CCP antibodies 82.2%, AKA 51.9%, and anti IgA RF 45%. The concordance rate of anti-CCP antibodies with IgM RF was 83%, with AKA 68%, and with IgA RF 60.5%. All but one patient positive for AKA were positive for anti-CCP antibodies. The presence of IgM RF, AKA, and anti-CCP antibody was associated with joint erosions and deformities. None of the antibodies had any association with presence of extra-articular features. No association of IgA RF was seen with erosions, deformities, or extra-articular features. Among 23 seronegative RA patients, 11 were positive for anti-CCP antibodies and 6 were AKA positive. The presence of anti-CCP antibodies was associated with presence of deformities (p<0.05). Anti-CCP antibodies are present in majority of patients with established RA including seronegative patients. Both anti-CCP and AKA, in addition to conventional marker like IgM RF, are associated with severe erosive disease.

Circulating levels of B lymphocyte stimulator in patients with rheumatoid arthritis following rituximab treatment: Relationships with B cell depletion, circulating antibodies, and clinical relapse

To assess the effects of B lymphocyte depletion on serum B lymphocyte stimulator (BLyS; trademark of Human Genome Sciences, Rockville, MD) levels in patients with rheumatoid arthritis (RA), and to assess the relationship of serum BLyS levels with peripheral blood B cell depletion, levels of autoantibodies and antimicrobial antibodies, the return of peripheral blood B cells, and clinical relapse. Fifteen patients with active RA underwent rituximab-based B cell depletion therapy (BCDT). Disease activity was assessed clinically, peripheral blood CD19+ B cell counts were determined by flow cytometry, and serum levels of BLyS, IgM, IgA, and IgG rheumatoid factors (RFs), anti-cyclic citrullinated peptide, and antimicrobial antibodies were assessed using enzyme-linked immunosorbent assays. Peripheral blood B cell depletion was achieved in all 15 patients, and an American College of Rheumatology 20% response was achieved in 13 patients. Following clinical relapse, 7 patients underwent at least 1 additional cycle of BCDT. In every case, serum BLyS levels markedly rose post-BCDT and remained elevated for at least 1-2 months. Serum levels of RF, but not those of anti-tetanus toxoid or anti-pneumococcal polysaccharide antibodies, fell significantly. A decline in serum BLyS levels was associated with the reemergence of B cells in peripheral blood, which, in turn, antedated clinical relapse by variable periods of time. The patterns of B cell depletion, serum BLyS and antibody levels, and clinical relapse for each BCDT cycle were remarkably similar in re-treated patients. Rituximab-based BCDT leads to marked increases in serum BLyS levels. This may contribute significantly to the survival and/or regeneration of B cell populations capable of triggering clinical relapse.