Rheumatoid arthritis: how well do the theories fit the evidence?

Enhanced Anti-Inflammatory Effect of the Combination of Lactiplantibacillus plantarum LS/07 with Methotrexate Compared to Their Monotherapies Studied in Experimental Arthritis

The gut microbiome (GM) of rheumatic arthritis (RA) patients is often altered in composition and function. Moreover, methotrexate (MTX), one of the most frequently used disease-modifying antirheumatic drugs, is known to negatively affect GM composition. The modulation of immune system activity is one of the therapeutic benefits of probiotics. The aim of the current investigation was to determine the impact of MTX therapy combined with one of the Lactobacillus strains, Lactoplantibacillus plantarum LS/07 (LB), on adjuvant arthritis (AA) in rats. Methods focused on biometric and inflammatory parameters in AA, particularly on plasmatic levels of IL-17A, MMP-9, and MCP-1, and the activities of gamma-glutamyl transferase in the spleen and joints were applied. Enhancing the effect of MTX, LB positively influenced all biometric and inflammatory parameters. The findings of the present study may be of help in proposing novel therapeutic strategies for RA patients.

Efficacy of Probiotics in Rheumatoid Arthritis and Spondyloarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: We aimed to provide a systematic review and meta-analysis of randomized controlled trials assessing the effect of probiotics supplementation on symptoms and disease activity in patients with chronic inflammatory rheumatic diseases (rheumatoid arthritis (RA), spondylarthritis (SpA), or psoriatic arthritis). Methods: A systematic literature review and meta-analysis from RA and SpA randomized controlled trials were conducted searching for articles in MEDLINE/PubMed and abstracts from recent international rheumatology meetings. The control group was a placebo or another dietary intervention. The risk of bias of the selected studies was evaluated using the Cochrane Collaboration tool and the Jadad scale. Results: The initial search yielded 173 articles. Of these, 13 studies were included in the qualitative synthesis, 8 concerning a total of 344 RA patients and 2 concerning a total of 197 SpA patients. Three meta-analyses were also analyzed. Probiotic strains and quantities used were different among trials (5 studies using Lactobacillus sp., 1 trial Bacillus coagulans and the others a mix of different probiotic strains). Time to assess response ranged from 8 weeks to one year. Two studies associated probiotic supplementation with a dietary intervention. Meta-analysis showed a statistically significant decrease of C-reactive protein (CRP) concentration (mean difference (MD)) −3.04 (95% CI −4.47, −1.62) mg/L, p < 0.001; I² = 20%, n patients = 209) with probiotics in RA. However, after excluding high-risk-of-bias trials of meta-analysis, there was no difference between probiotics and placebo on DAS28 (standard MD −0.54; 95% CI −1.94 to 0.85, p = 0.45, I² 93%, n patients = 143). The two studies on SpA patients showed no efficacy of probiotics. Conclusions: Probiotic supplementation might decrease RA activity with a moderate decrease effect on CRP, but lack of evidence and studies’ heterogeneity do not allow us to propose them to patients with inflammatory arthritis to control their disease. Further RCTs are required in the future to determinate the efficacy of probiotics and the optimal administration design.

Probiotics in Autoimmune and Inflammatory Disorders

Probiotics have been used to ameliorate gastrointestinal symptoms since ancient times. Over the past 40 years, probiotics have been shown to impact the immune system, both in vivo and in vitro. This interaction is linked to gut microbes, their polysaccharide antigens, and key metabolites produced by these bacteria. At least four metabolic pathways have been implicated in mechanistic studies of probiotics, based on mechanistic studies in animal models. Microbial⁻immune system crosstalk has been linked to: short-chain fatty acid production and signaling, tryptophan metabolism and the activation of aryl hydrocarbon receptors, nucleoside signaling in the gut, and activation of the intestinal histamine-2 receptor. Several randomized controlled trials have now shown that microbial modification by probiotics may improve gastrointestinal symptoms and multiorgan inflammation in rheumatoid arthritis, ulcerative colitis, and multiple sclerosis. Future work will need to carefully assess safety issues, selection of optimal strains and combinations, and attempts to prolong the duration of colonization of beneficial microbes.

Managing Rheumatoid Arthritis with Dietary Interventions

Self-help by means of dietary interventions can help in management of various disorders including rheumatoid arthritis (RA), a debilitating autoimmune disease. Dietary interventions necessitate a widespread appeal for both patients as well as clinicians due to factors including affordability, accessibility, and presence of scientific evidences that demonstrate substantial benefits in reducing disease symptoms such as pain, joint stiffness, swelling, tenderness and associated disability with disease progression. However, there is still an uncertainty among the community about the therapeutic benefits of dietary manipulations for RA. In the present review, we provide an account of different diets and their possible molecular mechanism of actions inducing observed therapeutic benefits for remission and management of RA. We further indicate food that can be a potential aggravating factor for the disease or may help in symptomatic relief. We thereafter summarize and thereby discuss various diets and food which help in reducing levels of inflammatory cytokines in RA patients that may play an effective role in management of RA following proper patient awareness. We thus would like to promote diet management as a tool that can both supplement and complement present treatment strategies for a better patient health and recovery.

The therapeutic effect of probiotics on rheumatoid arthritis: a systematic review and meta-analysis of randomized control trials

Rheumatoid arthritis is an autoimmune disease in which probiotics appears to have an immune modulating action along with decreased inflammatory process. Therefore, we aim to investigate the efficacy of probiotics as an adjuvant therapy for rheumatoid arthritis. A comprehensive literature search was performed using nine databases including PubMed and Web of Science. Interesting data was extracted and meta-analyzed. We assessed the risk of bias using Cochrane Collaboration's tool. The protocol was registered in PROSPERO (CRD 42016036769). We found nine studies involving 361 patients who met our eligibility criteria. Our meta-analysis indicated that pro-inflammatory cytokine IL-6 was significantly lower in the probiotics compared with the placebo group (standardized mean difference = - 0.708; 95% confidence interval (CI) - 1.370 to 0.047, P = 0.036). However, there was no difference between probiotics and placebo in disease activity score (mean difference 0.023; 95% CI - 0.584 to 0.631, P = 0.940). Probiotics lowered pro-inflammatory cytokines IL-6 in RA; however, its clinical effect is still unclear. Hence, many high-quality randomized controlled trials (RCTs) are still needed to prove this effect.

Altered gut microbiota in RA: implications for treatment

Rheumatoid arthritis (RA) is an autoimmune disease with progressive joint disorder. The complex interplay of genetic and environmental influences is important for the development of the disease. A growing body of evidence has shed light on the association of dysbiosis of gut microbiota with RA. Certain gut microbial strains have been shown to inhibit or attenuate immune responses in RA experimental models, suggesting that specific species among intestinal commensal bacteria may play either a pathogenic or a protective role in the development of RA. Oral intake of probiotics/prebiotics can therefore represent a therapeutic approach for RA treatment. However, the relevant scientific work has only just begun, and the available data in this field remain limited. Fortunately, utilization of new sequencing technologies allows expanded research on the association of intestinal bacterial flora and human diseases to be attempted. In this review, we summarize the role of gut microbiota in RA progression and address how specific bacterial strains regulate the immune response in disease process. Probiotics/prebiotics in the treatment of RA is also discussed.

Genetic and environmental risk factors for rheumatoid arthritis

Multiple genetic and environmental factors have been associated with an increased risk for rheumatoid arthritis (RA). Of these, the strongest associations have been seen with female sex, a family history of RA, the genetic factor the "shared epitope," and exposure to tobacco smoke. There is also renewed interest in mucosal inflammation and microbial factors as contributors to the development of RA. However, the identification of a "preclinical" period of RA that can be defined as local or systemic autoimmunity as measured by autoantibodies and other biomarkers prior to the development of clinically apparent synovitis suggests that the risk factors for RA are acting long prior to first clinical evidence of IA. As such, a major challenge to the field will be to investigate the full spectrum of the development of RA, from initiation and propagation of autoimmunity during preclinical RA and transition to clinically apparent synovitis and classifiable RA, to determine which genetic and environmental factors are important at each stage of disease development. Understanding the exact role and timing of action of risk factors for RA is especially important given the advent of prevention trials in RA, and the hope that a full understanding of genetic and environmental factors in RA could lead to effective preventive interventions.

Probiotic bacteria: a viable adjuvant therapy for relieving symptoms of rheumatoid arthritis

The burgeoning use of probiotics has proliferated during the past two decades. However, the effect of probiotic administration for either the prevention or treatment of rheumatoid arthritis (RA) has been investigated in a limited number of studies. Randomized controlled clinical trials have provided evidences that specific probiotics supplementation exhibit anti-inflammatory effects, help to increase daily activities and alleviate symptoms in patients with RA. Therefore, using probiotic bacteria as an adjuvant therapy may be considered as a promising treatment option for RA. This review summarizes the available data about the therapeutic and preventive effect of probiotics in RA, together with probiotic supplement as a possible therapy in clinical treatment.

Effects of Lactobacillus casei supplementation on disease activity and inflammatory cytokines in rheumatoid arthritis patients: a randomized double-blind clinical trial

AIM

The present study aimed at investigating the effects of Lactobacillus casei 01 supplementation on symptoms and inflammatory biomarkers of rheumatoid arthritis (RA) in women.

METHOD

In this randomized double-blind clinical trial, female patients with established RA for more than 1 year, 20-80 years of age and body mass index (BMI) lower than 40, who followed stable medication for 3 months prior to the supplementation, were randomly allocated to receive either one capsule containing 10(8) colony forming units (CFU) of L. casei 01, or a placebo for 8 weeks; allocation was stratified by BMI and menopausal status. Disease activity score-28 (DAS28) was calculated, European League Against Rheumatism (EULAR) response was evaluated and the cytokines, interleukin (IL)-1β, IL-6, IL-10, IL-12 and tumor necrosis factor (TNF)-α were measured.

RESULTS

Thirty patients were recruited in each group; 22 and 24 patients were analyzed in the probiotic and placebo groups, respectively. L. casei 01 supplementation decreased serum high-sensitivity C-reactive protein (hs-CRP) levels, tender and swollen joint counts, global health (GH) score and DAS28 (P < 0.05). More patients in the L. casei 01 group had moderate response to the treatment, based on the EULAR criteria, at the end of the study (P < 0.01). At the end of the study, a significant difference was observed between the two groups for IL-10, IL-12 and TNF-α changes through the study course (P < 0.05), in favor of the probiotic group. No adverse effects were reported for the intervention.

CONCLUSION

Probiotic supplementation may be an appropriate adjunct therapy for RA patients and help alleviate symptoms and improve inflammatory cytokines.

Probiotic supplementation improves inflammatory status in patients with rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease in which the gut microbiota is altered. Probiotics are microorganisms that can normalize gut microbiota; thus, they may help to alleviate RA symptoms. The objective of the present clinical trial was to assess the effects of probiotic supplementation on disease activity and inflammatory cytokines in patients with RA.

METHODS

Forty-six patients with RA were assigned into two groups in this randomized, double-blind, placebo-controlled clinical trial. The patients in the probiotic group received a daily capsule that contained a minimum of 10(8) colony-forming units of Lactobacillus casei 01 for 8 wk. The placebo group took capsules filled with maltodextrin for the same time period. Questionnaires, anthropometric measurements, and fasting blood samples were collected, and the participants were assessed by a rheumatologist at baseline and at the end of the trial.

RESULTS

Disease activity score was significantly decreased by the intervention, and there was a significant difference between the two groups at the end of the study (P < 0.01). Three of the assessed serum proinflammatory cytokines (tumor necrosis factor-α, interleukin-6, and interleukin-12) significantly decreased in the probiotic group (P < 0.05); however, serum levels of interleukin-1 β were not significantly affected by the probiotic (P = 0.22). The serum level of regulatory cytokine (interleukin-10) was increased by the supplementation (P < 0.05). The proportion of interleukin-10 to interleukin-12 was significantly increased in the probiotic group as well.

CONCLUSIONS

L. casei 01 supplementation improved the disease activity and inflammatory status of patients with RA. Further studies are warranted to confirm these results, and such confirmation may lead to the introduction of probiotics as adjunctive therapy for this population.

Oncogenic inflammation and autoimmune disease

Many models exist to explain the induction and perpetuation of autoimmune diseases. Despite their validation in a variety of animal models, the basis for autoimmune disease in humans remains unknown. Here, we propose that an important aspect of autoimmune disease is the active participation of the target organ due to endogenously produced co-stimulatory factors that cause prolonged antigen presentation and lymphocyte activation. Evidence suggests that a major source of such endogenous signaling comes from newly transformed cells within the target organ that produce pro-inflammatory factors.

Inverse correlation between the incidences of autoimmune disease and infection predicted by a model of T cell mediated tolerance

The contribution of pathogenic infections to the etiology of autoimmune diseases remains one of the outstanding problems in immunology. According to the classical concept of antigen mimicry, a direct correlation between the incidence of autoimmunity and infections would be expected. This view is supported by a few examples of autoimmune disorders, which are documented as being caused by infection with particular pathogens. In contrast, there are several experimental animal models where infection appears to prevent the onset of autoimmunity. Moreover, some epidemiological studies suggest an inverse correlation between the incidence of autoimmunity and infections in human populations. Here we propose a solution to this puzzle based on a theoretical model of tolerance driven by regulatory T cells. The concepts here developed delineate the conditions predicting an inverse correlation between the incidence of autoimmunity and exposition to common infections, and those in which antigen mimicry and inflammation of target organs have a role in the etiology of specific autoimmune disorders.

The B lymphocyte in rheumatoid arthritis: recirculation of B lymphocytes between different joints and blood

In order to search for further evidence for a pathogenetic role of recirculating, antigen-driven B cell clones in rheumatoid arthritis (RA) rearranged VH genes were analysed for clonal relationship and somatic mutations from synovial tissue and peripheral blood of a patient with RA undergoing synovectomy of several finger joints. DNA was prepared from the synovial tissue of two finger joints and blood. PCR for the different VH families was performed with one specific oligonucleotide for each VH family and a mixture of JH-specific oligonucleotides. The PCR products were separated on a high resolution acrylamide gel differentiating one base pair difference of length. Transfer of the products onto a nylon membrane and hybridization with an oligonucleotide specific for the FR3 region revealed a polyclonal representation of rearranged VH1, VH3, VH4 and VH5 genes. The VH6 family, which is encoded by a single germline gene, was represented by few distinct bands, with some bands of identical height for both joints and blood. DNA from these bands of interest was eluted, reamplified by PCR, cloned and sequenced. Sequence analysis of 27 independent bacterial colonies allowed distribution of the different VH genes to seven B cell clones (A-G). Members of clone A were found in both joints and blood, clones B and C in one joint and blood, clone D in both joints, and clones E, F and G only in one joint. The VH regions were somatically mutated with characteristic patterns for the different clones. In conclusion, our findings confirm the systemic character of RA, because they show that not only expansion and affinity maturation of B cells occur in synovial membranes but antigen-specific B cells recirculate between different joints and blood.

The pituitary-adrenal axis in idiopathic retinal vasculitis

AIMS

To determine whether patients with idiopathic retinal vasculitis have altered production of cortisol and dehydroepiandrosterone sulphate (DHEA-S), and whether differences in these variables occur between those who are sensitive (SS) and resistant (SR) to steroids.

METHODS

20 patients with retinal vasculitis (off treatment) and 10 control subjects were prospectively recruited. Morning cortisol and DHEA-S levels were measured, and cortisol secretion rates and short synacthen tests (SST) carried out in patients before treatment, when on prednisolone 20 mg/day, and in controls.

RESULTS

There were no differences in any variables between patients and controls. For retinal vasculitis patients pretreatment, the SST was lower in SR patients (p=0.02). More of the SR patients had ischaemic retinal vasculitis ( p<0.001).

CONCLUSIONS

Cortisol and DHEA-S are not involved in the pathogenesis of retinal vasculitis. SR in retinal vasculitis may be associated with a defective hypothalamic-pituitary-adrenal axis.

High IgE in rheumatoid arthritis (RA) patients is complexed with anti-IgE autoantibodies

This study presents data on more than 300 RA and allergic patients analysed for their serum levels of anti-immunoglobulin isotype autoantibodies and IgE. We observed high levels of IgE in sera of RA and allergic patients. Interestingly, we measured significantly higher specific IgE levels against Alternaria but not against nine other allergens in the RA compared with the allergic group. As expected, anti-IgG autoantibodies (rheumatoid factors (RF)) of different isotypes were detected in sera from RA patients only. However, we found increased titres of complexed anti-IgE autoantibodies in all RF+ groups and in the allergic group. These findings may explain why despite elevated IgE levels a decreased prevalence of allergic diseases in RA patients has been observed.

Reduction of disease causative T-cells in experimental autoimmune disease models by a new antirheumatic drug, TAK-603

We investigated the mode of action of a new quinoline derivative, TAK-603 (ethyl 4-(3,4-dimethoxyphenyl)-6,7-dimethoxy-2-(1,2,4-triazol-1-ylmeth yl) quinoline-3-carboxylate), in adjuvant arthritis (AA), a model of rheumatoid arthritis. AA rat splenocytes transferred the arthritis to normal syngeneic rats upon inoculation, but the cells from AA rats treated with TAK-603 (6.25 mg/kg/day) caused only mild arthritis with significantly less foot pad swelling and a lower arthritis score. An effect of TAK-603 in the induction phase of AA was suggested. TAK-603 had little effect on CD4+ and CD8+ T-cell populations in the AA rat splenocytes. We therefore estimated the frequency of T-cells which are reactive to the so-called disease causative antigen using a limiting dilution assay (LDA). The ratio of T-cells responsive to PPD, which increased in AA rat splenocytes with the severity of the arthritis, was reduced in AA rats treated with TAK-603. Furthermore, the ratio of MBP (myelin basic protein)-reactive T-cells, which were generated in experimental allergic encephalomyelitis (EAE) rats, were also reduced by TAK-603 administration. These data suggest that TAK-603 acts on the immune system and reduces the number of cells reactive to the relevant antigen.

The B cell repertoire of patients with rheumatoid arthritis. II. Increased frequencies of IgG+ and IgA+ B cells specific for mycobacterial heat-shock protein 60 or human type II collagen in synovial fluid and tissue

OBJECTIVE

A qualitative and quantitative analysis of the functional, antigen-specific B cell receptor repertoire of patients with rheumatoid arthritis (RA) in synovial and peripheral compartments.

METHODS

B cells were activated to grow and differentiate at high efficiency in vitro under limiting-dilution conditions. Isotype and specificity of the secreted Ig were tested by enzyme-linked immunosorbent assay.

RESULTS

In contrast to peripheral B cells, most synovial B cells had already switched to IgG/IgA in vivo. The frequencies of B cells specifically recognizing foreign antigens were decreased within the synovial population, whereas the frequencies of B cells specific for type II collagen, mycobacterial heat-shock protein 60 (hsp60), or IgG Fc fragments were significantly increased, revealing a negative correlation in terms of frequencies.

CONCLUSION

B cells specific for human type II collagen, hsp60, and IgG Fc fragments are produced and/or expanded locally within the affected joints of RA patients. Thus, the specific immune system is definitely involved in the local inflammatory and destructive processes.

Possible mechanisms of chronic leprosy-related arthritis

Microbial agents induce arthritis through mechanisms such as direct infiltration of tissue and by inducing autoimmune phenomena. The mechanisms involved in this last type of arthritis have been investigated. In experimental models of adjuvant and reactive arthritis, the involvement of T cells in some cases mycobacteria in the development of arthritis have been confirmed. Cross-reactivity between the 65 kD mycobacterial protein and cartilage proteoglycans has been postulated as a possible mechanism. In this study, chronic peripheral arthritis was observed in patients with Hansen's disease, in patients with resolved Hansen's and in those with paucibacillary forms. This arthritis was not related to reactional states (erythema nodosum leprosum and reversal reaction), in contrast to several reports in the literature. The mechanisms by which microbes could induce chronic arthritis are discussed herein.

Pristane-induced arthritis is CD4+ T-cell dependent

The development of arthritis induced in mice by intraperitoneal injection of the non-antigenic mineral oil pristane (2,6,10,14-tetramethylpentadecane) was shown to depend on the presence of CD4+ T cells. Initial experiments assessed the influx of lymphoid cells into the peritoneal cavity of CBA/Igb mice after pristane injection. Both CD4+ and CD8+ cell numbers were maximal around 50 days. Other experiments confirmed our original observation that irradiated pristane-treated mice failed to develop arthritis unless they were reconstituted with spleen cells from normal donors. This finding has been extended by showing that the population of transferred splenic lymphoid cells must contain CD4+ T cells, while CD8+ T cells and B cells were not required for reconstitution. Conventionally housed and hsp 65-immunized animals are known to harbour T cells reactive with hsp 65. In addition, hsp 65-immunized mice are resistant to the development of pristane-induced arthritis (PIA). Thus, additional experiments assessed the population of splenic T cells activated and proliferating against mycobacterial 65,000 MW heat shock protein (hsp 65). In cultures of purified splenic T cells derived from both conventional and hsp 65-immunized mice, removal of CD4+ T cells significantly reduced the proliferative response to hsp 65, while removal of CD8+ T cells often enhanced the response. These proliferative responses were also shown to be major histocompatibility complex (MHC) class II restricted. The present findings demonstrate that PIA is CD4+ T-cell mediated, and immunodominant environmental antigens such as hsp 65 activate this population of lymphocytes. The CD4+ hsp 65-reactive population may be pathogenic or protective in PIA, depending upon the route of sensitization.

Comparison of rheumatoid factors of rheumatoid arthritis patients, of individuals with mycobacterial infections and of normal controls: evidence for maturation in the absence of an autoimmune response

We analyzed the rheumatoid factors (RF) produced by Epstein-Barr virus-transformed monoclonal B cells established from four patients with rheumatoid arthritis (RA), three individuals with a history of Mycobacterium tuberculosis (TB) and four normal controls (NI). Fifty-eight RF were analyzed for specific activity (international units-RF/microgram) for the Fc part of IgG and their interaction with tetanus toxoid (TT) and DNA (polyspecificity). Furthermore, we sequenced the V-D-J heavy chain region of 16 (9TB-/7RA-) RF. Significant differences were observed between the NI-RF and the TB- and RA-RF. While the RF repertoire of normal individuals comprised of low-avidity RF of which the majority (15/17) were polyspecific, more than half of the TB- and RA-RF were monoreactive. Furthermore, the monospecific TB- and RA-RF were of significantly higher avidity than the NI-RF (RA > TB > > NI). With respect to polyspecificity specificity, the RF in the three groups were comparable: the interaction with DNA, TT as well as with Fc was inhibited either by an increase of the ionic strength to 0.3-0.5 M NaCl or by addition of the polyanion dextran sulfate, indicating that the antibodies interacted with similar anionic epitopes shared by the three antigens. Analysis of the V-D-J heavy chain regions showed significant differences between the respective RF. The salt-sensitive binding was highly correlated with the presence of arginine in the complementarity-determining region 3 (CDR3). Furthermore, whereas the polyspecific RF consisted predominantly of germ-line encoded antibodies, the genes of the monospecific RA/TB-RF were somatically mutated (RA > TB). It is therefore likely that maturation of RF can be initiated by chronic infections and that monospecific, somatically mutated RF are not a unique characteristic of autoimmune diseases.

Immunomodulating and articular protecting activities of a new anti-rheumatic drug, TAK-603

We investigated the pharmacological activities of a newly synthesized anti-rheumatic drug, TAK-603. (1) In vivo: In adjuvant arthritic (AA) rats, TAK-603 inhibited the hind paw swelling and the body weight loss. The minimum effective dose was 3.13 mg/kg/day (p.o.). Histological and radiographic studies showed that TAK-603 suppressed the development of synovial lesions and joint and bone destruction. TAK-603 was also effective in AA rats when administered for the first 7 days after the adjuvant injection. It suppressed type IV allergy (25 mg/kg/day, p.o.) but had no effect on type III allergy. It had little effect in acute inflammation, analgesic and antipyretic models. These data suggest that TAK-603 acts on the immune system, especially on cellular immunity. (2) In vitro: TAK-603 suppressed the mitogen-induced proliferation of mouse lymphocytes and the ConA-induced IFN-gamma and IL-2 production by rat lymphocytes at 10(-7) to 10(-5) M. It also significantly inhibited the IL-1 induced extracellular matrix reduction in rabbit chondrocytes. It had no effects on prostaglandin E2 (PGE2) production in rat peritoneal cells. These data show that TAK-603 has the ability to suppress the immune system and protect cartilage from destruction. TAK-603 is expected to be a promising drug for rheumatoid arthritis.

The B lymphocyte in rheumatoid arthritis: analysis of rearranged V kappa genes from B cells infiltrating the synovial membrane

The participation of the humoral immune system in rheumatoid arthritis (RA) is characterized by the production of rheumatoid factors (RF). RF are autoantibodies against the Fc part of IgG which are encoded by diverse germ-line genes. Most of the RF-encoding genes are unmutated, but in RA, a substantial quantity is encoded by somatically mutated genes. In addition, the synovial membranes (SM) of the diseased joints of RA patients are infiltrated by B lymphocytes which form germinal center-like aggregates. To analyze the local immune response, B cell foci from two RA SM were isolated by micromanipulation. From DNA of these foci, the rearranged kappa light chain variable region (V kappa) genes were amplified by polymerase chain reaction (PCR), cloned and sequenced. The amplification of different V kappa-J kappa combinations of different foci suggested oligoclonal expansion of B lymphocytes, which was confirmed by sequence analysis: each PCR product contained members of a single B cell clone. The sequence analysis of 29 different clones revealed rearrangements of diverse V kappa genes. Both frequent representatives of the V kappa 3 and the V kappa 1 family, as well as rarely used genes such as the L10 and B2 genes of the V kappa 2 and V kappa 5 families were found. Of the eleven potentially functional gene rearrangements, eight were significantly mutated, indicating their derivation from antigen-selected B cells. Intraclonal diversity in one of these clones may suggest ongoing mutation in the diseased synovial membrane of patients with RA.

Immunopathogenesis and immunotherapy in rheumatoid arthritis: an area in transition

In years to come, new therapeutic modalities for the treatment of chronic arthritis will be launched for general clinical use. These therapies, until today only used in clinical studies, are based on knowledge obtained from animal models of chronic arthritis. This knowledge not only ushers therapeutic use in humans: in many settings, the animal studies have proven to be irreplacable tools to get insights into the pathogenesis of chronic arthritis. Rheumatoid arthritis (RA) shows a strong linkage of susceptibility to a certain epitope common to some HLA-DR beta chains; this immunogenetic linkage is the strongest evidence for specific, T-cell dependent immunity in the pathogenesis of the disease. Despite intense efforts, no unequivocal proofs of T-cell specificity or oligoclonality have been found in RA. Therapeutic efforts directed against T-cells or T-cell functions have also at the best showed partial effects. As compared to the local production of T-cell cytokines in the joint, monokine production is abundant. Therapies aimed at neutralizing the effects of the cartilage-devastating monokine TNF-a have showed remarkable results in small clinical trials. The possibility of increasing the presence of the regulatory cytokines IL-4, IL-10 and TGF-beta has also been explored, but only in animal studies. Immunology has also shed light on the mode of action of the commonly used 'disease modifying' drugs, and combinations of such drugs have shown increased potentials in recent clinical studies. The possibility of combining traditional anti-arthritic drugs with recent immunological tools seem promising for the future. This review discusses recent advances in the understanding of pathogenesis and delineate new therapeutic approaches for chronic arthritis from the point of view of the immunologically oriented clinician.

Synovial fibroblasts as accessory cells for staphylococcal enterotoxin-mediated T-cell activation

Rheumatoid arthritis (RA) is thought to be the result of T-cell-mediated autoimmune phenomena. So far, a critical autoantigen has not been identified. Recently, superantigens have been implied in the pathogenesis of RA. In the present study it was tested whether major histocompatibility complex (MHC) class II-positive synovial fibroblast cells (SFC) function as superantigen-presenting cells. SFC were stimulated with interferon-gamma (IFN-gamma) to express class II antigens; then they were cultivated in the presence of T cells with or without staphylococcal enterotoxins (SE). T-cell activation was measured as proliferation and interleukin-2 (IL-2) production. Depending on the dose and type of SE, activation of T-cell clones and also of peripheral T cells was seen. T-cell activation was inhibited by antibodies to MHC class II antigens and also by antibodies to intracellular adhesion molecule type-1 (ICAM-1). The data suggest that class II-positive SFC have the capacity to serve as accessory cells for superantigen-mediated T-cell activation. Thus SFC may participate in the propagation of a T-cell dependent immune response.

Expression of a human fetal anti-DNA antibody idiotype BEG-2 beta in the families of patients with rheumatoid arthritis

BEG-2 is a monoclonal antibody produced by the human-human hybridoma technique from a 12 weeks old human fetus. A polyclonal antiserum was raised in an (NZW x Half-lop hybrid) rabbit against BEG-2 and the anti-BEG-2 anti-idiotype was purified and characterised. Using this rabbit reagent the expression of the BEG-2 beta idiotype was analysed in 12 patients with active rheumatoid arthritis and their close family members (n = 54). Twenty five sera from healthy controls were analysed to establish a normal range. Ten of 12 patients (83%) with rheumatoid arthritis expressed the BEG-2 idiotype as well as 11 of 54 healthy unaffected relatives (20%).

PPD and hsp65 induced monoarthritis initiates spontaneous recurrent flares in Lewis rats

OBJECTIVES

To investigate the time course of a monoarthritis induced with the purified protein derivative of tuberculin (PPD) or a recombinant 65 kDa heat shock protein (rhsp65) in two different strains of sensitised rats.

METHODS

Wistar and Lewis rats, sensitised with heat killed Mycobacterium tuberculosis in oil, were challenged intraarticularly with PPD or rhsp65 and monitored for six weeks. Inflammation was assessed by joint swelling, histology, and radiographic studies.

RESULTS

Sensitised Lewis rats injected with PPD or rhsp65 showed a chronic response with recurrent spontaneous flares, while Wistar rats showed one inflammatory episode.

CONCLUSIONS

The Wistar strain response to PPD resembles a transient reactive arthritis, while the response of the Lewis strain mimics the relapsing nature of rheumatoid synovitis, providing an interesting model to determine dominant immunopathogenic mechanisms.

Granzyme-positive cytotoxic cells are specifically increased in early rheumatoid synovial tissue

OBJECTIVE

To define the expression and the phenotype of granzyme (Gran) A and B positive cytotoxic cells in synovial tissue (ST) from patients with rheumatoid arthritis (RA) with respect to disease duration and activity.

METHODS

Using antibodies against GranA and GranB, which serve as markers of activated natural killer (NK) cells and cytotoxic T lymphocytes, ST sections from 10 patients with early RA, 10 patients with longstanding RA, and 10 patients with osteoarthritis were examined. The phenotype of Gran+ cells was determined with double-labeling techniques.

RESULTS

Gran+ cells, the majority of which were NK cells, were found in ST from patients in all groups. Several of these cells did not express the surface markers CD16, CD56, and CD57. The highest ST expression of GranB was found in patients with early RA. In RA patients, there was a positive correlation of GranB expression with serum levels of acute-phase reactants, but not with histologic scores for inflammation.

CONCLUSION

Gran+ cells are mainly NK cells, a substantial proportion of which do not express conventional NK cell surface markers. GranB expression is specifically increased in the synovial tissues of patients with RA of short duration.

Promiscuous and specific binding of HIV peptides to HLA-DR1 and DR103. Impact on T-cell repertoire of nonimmunized individuals

The binding of immunogenic peptides to DR molecules is influenced by residues that point into the peptide-binding groove. The T-cell response toward a peptide complexed to an MHC molecule depends on the presence of a sufficient number of T cells reactive with peptide-MHC complex on the surface of APCs. From 96 overlapping HIV peptides, we have selected 11 that show a significant binding to either DR1, DR103, or both. These two DR molecules are identical except for three amino acids at positions 67, 70, and 71 on the beta chain. Peptide-specific T-cell lines and clones were generated with cells from nonimmunized donors homozygous for DR1 or DR103 by using either individual peptides or peptide pools for the in vitro priming. Three of the peptides induced T-cell-specific proliferative response in both individuals, and these peptides were not among those with highest affinity. Most of the peptides induced strong responses against autologous APCs. This might reflect cross-reactivity between HIV and self-peptides. Definition of peptides that both show promiscuous binding to DR and elicit a strong T-cell response is important for design of efficient synthetic vaccines.

Human rheumatoid factors with restrictive specificity for rabbit immunoglobulin G: auto- and multi-reactivity, diverse VH gene segment usage and preferential usage of V lambda IIIb

To determine the molecular and functional properties of human rheumatoid factors (RF), we established stable hybridomas and Epstein-Barr virus-transformed B cell lines from the synovial fluid or peripheral blood of three patients with rheumatoid arthritis and one patient with systemic lupus erythematosus. 17 cell lines were obtained that produced high-titer immunoglobulin M (IgM) RF that reacted exclusively with rabbit but not human IgG or IgG of other mammalian species. Certain anti-rabbit IgG RF also had specificity for other mammalian antigens (Ag), including cytoskeletal proteins and intracellular proteins found in HeLa cells, as well as for Ag present in an extract prepared from the cell wall of group A streptococci. 13 of the 17 RF contained lambda-type light (L) chains, of which 12 were classified serologically as members of the lambda-L chain variable region (V lambda) subgroup, designated V lambda III. The heavy chain V region (VH) and V lambda sequences of nine of these IgM lambda RF were determined at the cDNA level. Five VH genes in three VH families were used by these antibodies (Ab), including VH1 (dp21/1-4b and dp10 [51p1]/hv1051), VH3 (dp38/3-15 and dp77/13-21), and VH4 (dp70/4-4b). The deduced V gene-encoded amino acid sequences of the lambda chains of these IgM lambda RF confirmed their serological classification as lambda III, and they were further classified as members of the relatively uncommon V lambda III subgroup, designated V lambda IIIb. Based on cDNA analyses, nine were the product of three different V lambda III b germline genes. Two such genes, designated hsiggll150 and hsiggll295, were cloned and sequenced from genomic DNA. Unique combinations of these VH and V lambda III b genes could be related to distinctive patterns of reactivity among the IgM lambda RF. Although the VH and V lambda regions of these Abs were expressed primarily as germline-encoded sequences, four of nine multireactive Abs had extensive V region mutation, indicative of an Ag-driven process. The finding that lambda IIIb L chains are preferentially found among anti-rabbit IgG RF, and that some of these Ab have specificity for other protein, cellular, and bacterial Ag, provides new insight into the pathogenesis of RA and related diseases.

Cellular immune mechanisms in rheumatoid arthritis and other inflammatory arthritides

Advances in molecular genetics, cellular immunology and microbiology have offered promise in unravelling the aetiopathogenesis of inflammatory arthritides such as rheumatoid arthritis and reactive arthritis. Such insights are challenging the orthodox view that these diseases are primarily autoimmune in nature, and should lead to exciting and novel therapeutic approaches.