T lymphocytes of rheumatoid arthritis patients show augmented reactivity to a fraction of mycobacteria cross-reactive with cartilage

Clonal heterogeneity of synovial fluid T lymphocytes from patients with rheumatoid arthritis

Although substantial evidence suggests that synovial T lymphocytes are critical in the pathogenesis of rheumatoid arthritis (RA), little is known regarding their antigenic specificities, antigen receptor gene rearrangements, and mechanisms of activation. To assess the extent of expansion of specific clones among RA synovial fluid T cells, Southern blot analyses of T-cell receptor (TCR) gene rearrangements were performed on 40 RA synovial fluid T-cell clones, as well as on both fresh and polyclonally activated T cells from RA synovial fluid, RA peripheral blood, and normal peripheral blood. Two of the clones had identical TCR rearrangement patterns, but the remainder were unique. The nonclonal RA T-cell samples showed the same pattern of TCR beta-chain rearrangement that was observed among normal peripheral blood T cells, indicating no dominant clonal T-cell population in these samples. It was noted that with sufficient exposure of autoradiograms of the Southern blots, discrete TCR gene rearrangements, representing in some cases common D beta J beta (D, diversity; J, joining) rearrangements, were evident in T cells from peripheral blood of normal individuals and patients with RA, as well as T cells from RA synovial fluid. Taken together, the findings indicate that only a minor degree of oligoclonality can be demonstrated among T lymphocytes from RA synovial fluid.

Dendritic cells in health and disease

Cells with a dendritic morphology that are rich in surface class II histocompatibility antigens (Ia antigens) but lacking in other lymphocytes or monocyte markers constitute a small (less than 1%) proportion of circulating mononuclear cells, but in inflammatory joint effusions they comprise up to 7% of the mononuclear population. Their role as accessory cells in normal autologous and allogenic mixed leukocyte reactions is reviewed and the possible contribution of dendritic cells to intra-articular immunologic processes is considered.

Clinical and laboratory studies of arthritis in leprosy

Arthritis associated with leprosy is underreported. In Egypt 66 patients from a leprosy colony were studied, 20 of whom had arthropathy. This was characterised by an inflammatory symmetrical peripheral polyarthritis. The wrist, metacarpal and proximal interphalangeal joints of the hands, the knees, and the metatarsophalangeal joints of the feet were affected with associated morning stiffness. The arthritis was erosive in 11 out of 20 patients, had no features of the arthritis associated with erythema nodosum leprosum reactions, but symptomatically responded to antileprosy treatment. This arthritis would seem to be a previously unrecognised feature of leprosy.

Isolation of CD4- CD8- mycobacteria-reactive T lymphocyte clones from rheumatoid arthritis synovial fluid

The majority of peripheral T cells express a heterodimeric, alpha/beta T-cell receptor, which recognizes specific antigenic peptides bound to self major histocompatibility complex (MHC) molecules, and either the CD4 or CD8 surface markers. An additional subset of T cells, whose physiological function is unknown, express a distinct CD3-associated receptor composed of gamma and delta chains. This subset includes cells lacking both CD4 and CD8 surface markers, which may be involved in autoimmunity. The recognition specificity of the gamma/delta receptors is not well characterized and has been defined in only one case to date, a murine cell line which shows MHC-linked specificity. In this report, we describe the isolation of CD4- CD8-, gamma/delta TCR bearing T cell clones from the synovial fluid of a rheumatoid arthritis patient. These T cell clones respond specifically to mycobacterial antigens without MHC restriction.

Primary structure of a human mitochondrial protein homologous to the bacterial and plant chaperonins and to the 65-kilodalton mycobacterial antigen

The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.

Arthritis associated with adjuvant mycobacterial treatment for carcinoma of the bladder

A patient who developed an inflammatory polyarthritis following intravesical administration of bacillus Calmette-Guérin (BCG) used in the treatment of bladder cancer is described. An inflammatory synovitis comprising predominantly T lymphocytes was demonstrated on synovial biopsy. The synovitis resolved spontaneously within 14 days in this 'human model' of adjuvant arthritis.

Elevated levels of the 90 kd heat shock protein in a proportion of SLE patients with active disease

The human 90 kd heat shock protein (hsp 90) is associated with the receptor for glucocorticoid hormones and is believed to play a role in the cellular response to corticosteroids. The levels of this protein in the peripheral blood lymphocytes of patients with systemic lupus erythematosus (SLE) have been investigated and compared with those observed in normal individuals and patients with rheumatoid arthritis. Fifteen percent of SLE patients were found to exhibit hsp 90 levels well in excess of those observed in the other groups. These patients all had active disease. The significance of these findings is discussed both in terms of the disease processes occurring in these patients and the efficacy of steroid therapy.

Raised serum IgG and IgA antibodies to mycobacterial antigens in rheumatoid arthritis

Autoantigens cross reactive with mycobacteria are implicated in the pathogenesis of adjuvant arthritis in the rat, and there are reports of changes in the immune response to mycobacteria in human rheumatoid arthritis (RA). We have therefore examined the IgM, IgG, and IgA antibody levels to crude mycobacterial antigens and to two recombinant mycobacterial heat shock/stress proteins (65 kD and 71 kD) in sera from patients with RA, systemic lupus erythematosus (SLE), and Crohn's disease, and from healthy controls. IgA binding to the crude mycobacterial antigens was significantly raised in RA sera, though IgG and IgM binding tended to be lower than in controls. Both IgA and IgG binding to the heat shock proteins were significantly raised in the RA sera. Smaller significant rises in both classes were seen in sera from patients with SLE, and in the IgA class only to the 65 kD protein in Crohn's disease. The rises in IgG and IgA antibodies to the 65 kD protein in RA were significantly higher than in the other diseases, however. It is interesting that this protein is the one responsible for adjuvant arthritis in the rat.

Persistence of collagen type II-specific T-cell clones in the synovial membrane of a patient with rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease characterized by T-cell infiltration of the synovium of joints. Analysis of the phenotype and antigen specificity of the infiltrating cells may thus provide insight into the pathogenesis of rheumatoid arthritis. T cells were cloned with interleukin 2, a procedure that selects for in vivo-activated cells. All clones had the CD4 CDW29 phenotype. Their antigen specificity was tested by using a panel of candidate joint autoantigens. Four of 17 reacted against autologous blood mononuclear cells. Two clones proliferated in response to collagen type II. After 21 months, another set of clones was derived from synovial tissue of the same joint. One of eight clones tested showed a strong proliferative response against collagen type II. The uncloned synovial T cells of a third operation from another joint also responded to collagen type II. The persistence of collagen type II-specific T cells in active rheumatoid joints over a period of 3 years suggests that collagen type II could be one of the autoantigens involved in perpetuating the inflammatory process in rheumatoid arthritis.

The recombinant 65-kD heat shock protein of Mycobacterium bovis Bacillus Calmette-Guerin/M. tuberculosis is a target molecule for CD4+ cytotoxic T lymphocytes that lyse human monocytes

Since little is known about Tc cells in the human immune response to intracellular parasites, we have studied the role of Tc cells in response to M. bovis Bacillus Calmette-Guerin (BCG). Donors whose PBMC responded to BCG, purified protein derivative (PPD), and the recombinant 65-kD heat shock protein (HSP) of BCG generated BCG/PPD-specific CD4+ effector T lymphocytes that lysed PPD as well as recombinant 65-kD-pulsed monocytes. Nonpulsed or irrelevant antigen-pulsed target cells were lysed to a much lower but still significant extent. PPD-stimulated effector lymphocytes of a recombinant 65-kD nonresponder lysed PPD but not recombinant 65-kD-pulsed monocytes. Recombinant 65-kD-educated effector lymphocytes lysed both recombinant 65-kD- and PPD-pulsed monocytes. In addition, these effector cells efficiently lysed nonpulsed target cells. These results demonstrate that in recombinant 65-kD responders, the recombinant 65-kD HSP of BCG is an immunodominant target as well as a triggering molecule for BCG/PPD-specific CD4+ cytotoxic T cells that lyse autologous monocytes. The implications of these findings with respect to the role of the 65-kD HSP in autoimmunity are discussed.

Contemporary issues: diseases with a food vector

Foodborne disease has become a contemporary issue. Several large, well-publicized outbreaks of foodborne disease have heightened public awareness that harmful microorganisms may be present in food and that chronic as well as acute disease may be caused by foodborne microbes. The field of food microbiology has likewise experienced a resurgence of interest. New tools, such as recombinant deoxyribonucleic acid technology and monoclonal antibody production, used to elucidate microbial virulence factors have facilitated identification of disease-causing microbes once thought to be harmless and demonstrated the complexity of individual virulence mechanisms previously considered to be well understood. Foodborne pathogens are also causing disease via some surprising food vectors, such as chopped, bottled garlic and sauteed onions. In addition to acute gastrointestinal disturbances, certain microorganisms may, through complex interactions with the human immune response, cause chronic diseases that affect several major organ systems. These microbes are serving as models in studies of molecular mimicry and genetic interrelatedness of procaryotes and eucaryotes. Other recently recognized attributes of foodborne microorganisms, such as the heat shock phenomenon and the possible nonculturability of some bacteria, may affect their ability to cause disease in humans. Because foodborne disease is a major cause of morbidity and mortality, the study of these diseases and their causative microorganisms presents a unique challenge to many professionals in the subdisciplines of microbiology, epidemiology, and clinical medicine.

Tuberculous rheumatism (Poncet's disease) in a child

A 2-year-old boy who had increasing difficulty walking and had large, warm, sterile knee and ankle effusions was found to have active vertebral tuberculosis and a large prevertebral abscess. Lymphocyte proliferation assays demonstrated increased purified protein derivative-induced reactivity of synovial fluid lymphocytes compared with peripheral blood lymphocytes. The arthritis responded rapidly to antituberculous and antiinflammatory drugs. This patient's disease represented an example of tuberculous rheumatism (Poncet's disease).

Autoreactive T cells in rheumatic disease. II. Function and specificity of an autoreactive T helper cell clone established from a HLA-B27+ reactive arthritis

T cell lines were established by limiting dilution of peripheral blood (PBL) and synovial fluid lymphocytes (SFL) of a patient with HLA-B27+ reactive arthritis. Among these cell lines, the CD4 phenotype was dominant. Functionally, the majority of these cell lines exhibited helper activity for the immunoglobulin production by autologous B cells and proliferated in response to autologous mononuclear cells. In most cases, this autoreactive response was associated with alloreactivity. Only one cell line, the autoreactive CD4+ T cell clone, UA-S2, which was derived from the synovial fluid, proliferated in a highly specific manner in response to a determinant associated with MHC class II products present on autologous mononuclear cells. The restriction element was shown to be associated with DR molecules by inhibition experiments with monoclonal antibodies. Within the patient's family, the capacity of mononuclear cells to stimulate a proliferative response of UA-S2 segregated together with the HLA haplotype A2 or 32, B27, Cw1, DRw11 which was contributed by the patient's mother. UA-S2 proved to be a functional helper T cell clone. In the absence of additional antigen or mitogen, it induced IgG and IgM synthesis of autologous and family members' B cells. This helper activity of UA-S2 showed the same MHC restriction as the proliferative response. Although the patient's father also typed DRw11, this haplotype was not recognized by UA-S2. It is suggested that this autoreactive T cell clone detects a microheterogeneity of the serologically defined DRw11 haplotype. Indeed, typing of the patient's family members with cellular reagents established a difference between the two DRw11 haplotypes.

Synovial fluid T cell reactivity against 65 kD heat shock protein of mycobacteria in early chronic arthritis

The in vitro proliferative response against a recombinant 65 kD Mycobacterium bovis protein that has 100% homology with the 65 kD protein of M tuberculosis was tested in synovial fluid and peripheral blood mononuclear cells from patients with rheumatoid arthritis (RA) and other types of chronic arthritis. An acetone precipitate (AP) of M tuberculosis, and a purified protein derivative (PPD) of M tuberculosis were also tested. Responsiveness of synovial fluid lymphocytes to the mycobacterial antigens was found both in patients with RA and in patients with other forms of chronic inflammatory arthritis, but not among controls. T cell reactivity against mycobacterial antigens was nearly always higher in synovial fluid than in peripheral blood in those patients who showed reactivity. A significant association was found between responsiveness of synovial T cells to the 65 kD protein and AP, but no relation between responsiveness to the 65 kD protein and PPD. Both the number of 65 kD protein responders and the mean proliferative response of synovial T cells to the 65 kD protein were inversely correlated with duration of joint inflammation. Thus, a 65 kD-protein-specific reactivity of synovial T cells, mainly present in an early stage of joint inflammation, may be responsible for triggering chronic arthritis.

Loss of functional suppression is linked to decreases in circulating suppressor inducer (CD4+ 2H4+) T cells in multiple sclerosis

A consistent immunological finding in patients with progressive multiple sclerosis is a loss of functional suppression. We have recently found decreases in suppressor inducer T cells in progressive multiple sclerosis as measured by two-color immunofluorescence using differentiation markers CD4 and 2H4. In the present study, we examined the relationship between functional suppression and circulating CD4+ 2H4+ T cells using a two-stage assay. (1) T cells were stimulated for 7 days with irradiated non-T cells (autologous mixed lymphocyte reaction [AMLR]) and harvested. It has previously been shown that suppressor T cells are generated during the course of the AMLR. (2) The AMLR-generated suppressor T cells were then incubated with mononuclear cells plus pokeweed mitogen, and immunoglobulin (Ig) synthesis was measured. There was less AMLR-induced suppression of IgG synthesis in patients with progressive multiple sclerosis as compared with normal subjects and patients with other neurological diseases. More importantly, there were significant correlations between decreases in circulating CD4+ 2H4+ cells and the AMLR (p = 0.009). Thus, the decreases in functional suppression and the decreases in the AMLR in multiple sclerosis appear tightly linked to CD4+ 2H4+ cells, and their measurement provides a means to monitor suppressor function phenotypically. Decreases in suppressor inducer T cells may in part explain immunoregulatory abnormalities observed in multiple sclerosis.

Abnormal helper-inducer/suppressor-inducer T-cell subset distribution and T-cell activation status are common to all types of chronic synovitis

We have previously shown that rheumatoid synovial T cells are virtually all helper-inducer (CD4+4B4+UCHL1+) rather than suppressor-inducer (CD4+2H4+) cells. CD8 cells were also largely 4B4+. In addition, the majority of T cells were HLA-DR+. To investigate whether these findings were specific for rheumatoid disease, we studied the prevalence of these markers in a variety of chronic inflammatory arthropathies such as ankylosing spondylitis, Reiter's syndrome, and psoriatic arthritis. Again, almost 90% of the T cells were 4B4+UCHL1+ and only 11% were 2H4+; 50% expressed the HLA DR antigen. Thus this phenotypic distribution represents a final common pathway of chronic synovitis and may help to explain the immunopathology of the lesion.

Abnormalities in CD4+ T-lymphocyte subsets in inflammatory rheumatic diseases

The monoclonal antibodies anti-2H4 and anti-4B4 identify the suppressor-inducer (CD4+2H4+) and helper-inducer (CD4+4B4+) subpopulations of CD4 (T4+) lymphocytes, respectively. The cell surface phenotype of peripheral blood lymphocytes and synovial fluid lymphocytes in patients with rheumatoid arthritis and other inflammatory joint diseases was analyzed by use of these and other well-characterized anti-T-cell monoclonal antibodies. In the synovial fluid of patients with rheumatoid arthritis, there was a markedly decreased percentage of T4+2H4+ suppressor-inducer cells (3.1 +/- 1 percent) and an increased percentage of T4+4B4+ helper-inducer cells (29.1 +/- 9 percent) as compared with the proportions found in the peripheral blood of normal individuals (T4+2H4+: 19.0 +/- 6 percent, T4+4B4+: 23.0 +/- 7 percent). Moreover, patients with other chronic and acute inflammatory joint diseases exhibited highly similar synovial T-cell findings to those of the patients with rheumatoid arthritis (T4+2H4+: 4.2 +/- 3 percent, T4+4B4+: 33.1 +/- 9 percent). In contrast, there were no significant differences between the normal control subjects and patients with rheumatoid arthritis in the percentage of T4+2H4+ cells in peripheral blood lymphocytes, nor were there significant differences between normal control subjects, patients with rheumatoid arthritis, and patients with other joint diseases (osteoarthritis, gout, B27+ spondyloarthropathy, and psoriatic arthritis) in the number of T4+4B4+ cells or in the T4/T8 ratio of peripheral blood lymphocytes. However, very low numbers of T4+2H4+ (suppressor-inducer) peripheral blood lymphocytes were seen in a subgroup of patients, including five of seven with Reiter's syndrome and several patients with systemic rheumatic disease syndromes. In addition, although the percentage of T4+2H4+ cells in peripheral blood lymphocytes of patients with osteoarthritis (13.7 +/- 7 percent) and gout (14.3 +/- 7 percent) was decreased compared with that of normal controls (19.0 +/- 6 percent) (osteoarthritis versus normal controls p less than 0.025), this difference appeared to reflect alterations due to age rather than disease. Consistent with the phenotypic changes observed, synovial T cells were also functionally defective, since autologous mixed lymphocyte reaction-activated T4 cells from the synovial fluid of patients with rheumatoid arthritis failed to exhibit suppressor-inducer activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Molecular mechanisms of autoimmunity

Autoimmune diseases result from a combination of genetic susceptibility factors and exogenous influences such as infection or chemical (including drug) exposure. Germline DNA variations in genetic type as well as defects in antigen recognition acquired during thymic education of developing T-lymphocytes both contribute to impaired self: nonself discrimination and set the stage for later development of such diseases as myasthenia gravis, polymyositis, or systemic lupus erythematosus. In addition, drugs such as D-penicillamine, hydralazine, procainamide, or quinidine induce T-cell or B-cell changes which precipitate auto-reactivity and cause drug-induced disease. Intervention in autoimmune diseases with prednisone, alkylating agents or the future use of more selective monoclonal antibody reagents may be life-saving in some of these disorders.

Autoantibodies from rheumatoid arthritis patients recognize antigens on the synoviocyte surface

We have found autoantibodies in the sera from rheumatoid arthritis (RA) patients which recognize two cell surface antigens of approximately 70 kDa and 28 kDa from synoviocyte extracts as detected by immunoprecipitation analysis. These polypeptides were immunoprecipitated from extracts containing mainly macrophage-like synoviocytes (type A) but not from extracts of homogeneous fibroblast-like synoviocytes (type B). These autoantigens are not selectively expressed by RA synoviocytes, since both RA and non-rheumatoid synovia were reactive for RA sera. From the panel of different RA sera tested, 64% immunoprecipitated the 70 kDa band, and 27% recognized the 28 kDa polypeptide. These differences in the specificity of the sera seemed to be related to the clinical state of the donor. The sera from patients suffering from other autoimmune diseases such as autoimmune thyroiditis and systemic lupus erythematosus (SLE) do not appear to be reactive for these specificities, but sera from patients with Sjögren's syndrome, psoriatic arthritis, and Crohn's disease showed a weak cross-reactivity with the 70 kDa polypeptide. This autoreactivity against synovial cells in RA supports the idea that these cells participate in the initial immune response of the disease.

Cloning of the mycobacterial epitope recognized by T lymphocytes in adjuvant arthritis

Adjuvant arthritis (AA) is a chronic disease inducible in rats by immunization with an antigen of Mycobacterium tuberculosis. After the isolation of arthritogenic T-cell lines and clones, it became possible to demonstrate that the critical M. tuberculosis antigen contained an epitope cross-reactive with a self-antigen in joint cartilage. Like AA rats, patients suffering from rheumatoid arthritis demonstrated specific T-lymphocyte reactivity to the M. tuberculosis fraction containing the cross-reactive epitope. To characterize the critical M. tuberculosis epitope we used AA T-cell clones to screen mycobacterial antigens expressed in Escherichia coli and genetically engineered truncated proteins and synthetic peptides. The AA T-cell clones recognized an epitope formed by the amino acids at positions 180-188 in the sequence of a Mycobacterium bovis BCG antigen. Administration of this antigen to rats induced resistance to subsequent attempts to produce AA.

Future trends in the treatment of rheumatoid arthritis in the light of current etiopathogenetic theories

The current treatment of rheumatoid arthritis is based on the use of synthetic chemical compounds, the mechanism and action of which have been more or less unknown. Usually this therapeutic effectiveness was discovered accidentally. Often the initial use of such compounds was motivated on the basis of generally diffuse ideas about the eventual pathogenesis of rheumatoid arthritis. The main site of action of most of these drugs has recently been elucidated. Depending on their multiple sites of action the polypharmacy frequency relied upon at present seems also to be theoretically motivated. Many new possibilities for treatment which have appeared recently have resulted from the amission of page limitation. These include various thymic (46), steroid and other hormones (67) and various vehicles or new modes of application, e.g. percutaneous, for directing the effects of drugs selectively to the target tissue, organ and cells. The use of specific T cell clones in therapy (68) has been only briefly dealt with in this article, and the development of operative techniques, endoprosthesis technology and orthopedic devices have not been dealth with at all. Chemical synovectomies with 165Dy-FHMA and other agents (69) will be developed further etc. This overview mainly deals with future trends in the treatment of rheumatoid arthritis based on advances made in the evaluation of the etiopathogenesis. Due to advances in basic sciences and medicine, the pathogenetic mechanisms effective in rheumatoid arthritis are better known today than ever before. The same progress in science has for the first time in history provided us with a potential means of producing bioactive mediators and reagents in sufficient amounts to enable their use also for therapeutic trials and treatment. In addition to the need to develop better methods of treatment for the patients crippled by this chronic disease, studies on the pathogenesis will also be of great benefit to our ideas about exactly what is involved in the complex process clinically known as rheumatoid arthritis.

Interactions between the immune system and connective tissue in arthritis. Possible significance of an affinity between IgG and native type II collagen

The synovial inflammation in rheumatoid arthritis (RA) resembles inflammatory reactions in other tissues concerning features such as increased expression of MHC class II antigens and infiltration of large amounts of activated T lymphocytes. The present communication is concerned with how to explain features such as local production of rheumatoid factors that distinguish the synovial inflammation in seropositive RA from other chronic inflammatory reactions; We show here that monomeric IgG and, to an even higher extent, aggregated IgG show a high binding capacity for native collagen type II. This finding is discussed in the light of previous findings that native collagen II structures are readily exposed to the environment in the cartilage of inflamed joints, and the evidence that T-cell reactivity to cartilage-derived molecules among them collagen II appears to be a common feature in seropositive RA. We suggest that an enhanced formation of IgG-collagen II complexes in RA joints, together with activation of T-cells to collagen II or collagen II-associated structures may constitute the basis for local rheumatoid factor production and to disease perpetuation in seropositive RA.

Interactions between the immune system and connective tissue in arthritis: aspects on T-cell activation

The synovial inflammation in rheumatoid arthritis can both serve as a model for the study of chronic inflammation in general and be analyzed with the goal to understand which features that distinguish RA from other chronic inflammatory diseases. In this paper we discuss both these problems with the emphasis on mechanisms of T cell activation and how activation of T cells against structures associated with the cartilage may contribute to the perpetuation of RA by means of triggering rheumatoid factor production. We also present some original data concerning phenotypes of in vivo activated synovial T cells, demonstrating high levels of HLA-DR expression, low levels of CD45+/Leu3a+ T "suppressor/inducer" cells and varying numbers of Leu 15+/Leu2a+ "suppressor" T cells. The observed phenotypic pattern is compatible with the occurrence of a normal but perpetuated immune response to a persistant antigen "X" in the arthritic joint.

T cell clones in rheumatoid arthritis (RA)

The development of T cell clones has greatly enhanced our knowledge of pathogenetic mechanisms in autoimmune diseases. Thus, it has been possible to induce experimental arthritis in susceptible animals by solely injecting arthritogenic T cell lines or clones. In contrast to many animal models, in rheumatoid arthritis the inciting antigen(s) have still not been identified. However, it has been possible to raise T cell clones from the inflammatory membrane by the addition of Interleukin-2 and/or mitogens. These clones are primarilig of the CD4+ (helper/inducer) phenotype. Molecular analyses on T cell receptor genes have not clearly shown a predominant rearrangement pattern in most studies indicating a polyclonal origin of RA synovial T cells. The availability of T cell clones will clearly help in the near future to probe for the inducing antigen(s) in inflammatory rheumatic diseases thus rendering a basis for new immunotherapeutic approaches.

Significance of cell-mediated and humoral immunity in the acute and chronic phase of antigen-induced arthritis in rabbits

In the course of antigen-induced arthritis of rabbit cell-mediated and humoral immune responses were repeatedly tested in order to prove their significance for the acute and chronic phase of inflammation. The arthritis was monitored during the progression of the inflammation by means of the joint swelling and at the end of experiments by histological evaluation of synovitis and cartilage degradation. Following the arthritis induction a strong increase of specific antibodies and of circulating immune complexes was evident. The correlations between antibody levels and joint swellings confirmed that the local formation of immune complexes is responsible for the initiation and perpetuation of arthritis. In the early phase after immunization the responsiveness of lymphocytes to antigenic and mitogenic stimulation was increased, in the late chronic phase of arthritis proliferative responses of lymphocytes to cartilage matrix components were revealed. No direct correlations could be demonstrated between any cell-mediated immune response and the severity of arthritis. The hyperreactivity of cell-mediated immunity is suggested to be responsible for the transition of the acute arthritis into the chronic stage. The deficiency of an effective suppression results in the activation of B-lymphocytes with increased production of antibodies, maintaining the inflammatory process for a long time. Under these conditions the release of cartilage matrix components during the acute joint reaction induces autoimmune responses against cartilage, which could contribute to the chronification of arthritis and to cartilage degradation.

Abnormal distribution of the helper-inducer and suppressor-inducer T-lymphocyte subsets in the rheumatoid joint

T lymphocytes can be divided into two main phenotypic populations, CD4 and CD8. These can be further subdivided into 2H4, 4B4, or UCHL1 subsets by appropriate monoclonal antibodies. We have investigated these subsets in the synovial fluid of patients with rheumatoid arthritis and have found (i) a virtual absence of CD4+ 2H4+ and the marked reduction of CD8+ 2H4+ T cells; (ii) a marked increase of CD4+ 4B4+ and CD8+ 4B4+ T cells; and (iii) a marked increase of CD4+ UCHL1+ and CD8+ UCHL1+ T cells compared with peripheral blood. Although the functions of the CD8 subsets are not known, the virtual absence of CD4+ 2H4+ suppressor-inducer T cells and the marked increase of CD4+ 4B4+ helper-inducer T cells and of CD4+ UCHL1+ memory T cells may help to explain the many known functional immunological properties of synovial T cells.

Therapeutic vaccination against adjuvant arthritis using autoimmune T cells treated with hydrostatic pressure

An ideal treatment for autoimmune diseases would be a nontoxic means of specifically neutralizing the autoreactive lymphocytes responsible for the disease. This goal has been realized in experimental autoimmunity models by immunizing rats or mice against their own autoimmune cells such that the animals generate an immune response specifically repressive to the disease-producing lymphocytes. This maneuver, termed lymphocyte vaccination, was demonstrated to be effective using some, but not all, autoimmune helper T-lymphocyte lines. We now report that T lymphocytes, otherwise incapable of triggering an immune response, can be transformed into effective immunogens by treating the cells in vitro with hydrostatic pressure. Clone A2b, as effector clone that recognized cartilage proteoglycan and caused adjuvant arthritis in Lewis rats, is such a cell. Untreated A2b could not trigger an immune response, but inoculating rats with pressure-treated A2b induced early remission of established adjuvant arthritis as well as resistance to subsequent disease. Specific resistance to arthritis was associated with anti-idiotypic T-cell reactivity to clone A2b and could be transferred from vaccinated rats to naive recipients using donor lymphoid cells. Aggregation of T-lymphocyte membrane components appeared to be important for an immune response because the effects of hydrostatic pressure could be reproduced by treatment of A2b with chemical cross-linkers or with agents disrupting the cytoskeleton. Populations of lymph node cells from antigen-primed rats, when treated with hydrostatic pressure, could also induce suppression of disease. Thus, effective vaccines can be developed without having to isolate the autoimmune T lymphocytes as lines or clones. These results demonstrate that effector T lymphocytes suitably treated may serve as agents for specifically controlling the immune system.

Histopathology of arthritis induced in rats by active immunization to mycobacterial antigens or by systemic transfer of T lymphocyte lines. A light and electron microscopic study of the articular surface using cationized ferritin

We analyzed the histopathologic findings of arthritis in 3 rat models: adjuvant arthritis induced by active immunization to Mycobacterium tuberculosis (MT) antigens, arthritis produced by passive transfer of an intrinsically arthritogenic line of anti-MT T lymphocytes, and bystander arthritis produced by intraarticular injection of a foreign antigen, ovalbumin, into rats with T lymphocyte line cells specific for the ovalbumin antigen. The histopathology of the tibiotarsal and knee joints was studied by light microscopy and the articular surface of the cartilage by electron microscopy after labeling with cationized ferritin. The lesions in the 3 models of arthritis were compared. In active adjuvant arthritis, inflammatory lesions and cartilage destruction were found as early as 9 days after immunization, and persisted for as long as 11 months. Similar, but somewhat milder, lesions were found in arthritis produced by transfer of anti-MT T lymphocytes. Inflammatory signs were present at 4 days, when there was no evidence of joint edema. Severe inflammatory lesions were found in arthritis induced by transfer of anti-ovalbumin T lymphocytes that was followed by ovalbumin injection into the knee. Pathologic changes were found to be similar in all 3 models. Thus, the changes could be attributed to the action of T lymphocytes, irrespective of whether the target antigen was intrinsic to the joint.

Silica exposure and rheumatoid arthritis: a follow up study of granite workers 1940-81

The incidence and prevalence of subjects awarded disability pensions and the prevalence of subjects receiving free medicines because of rheumatoid arthritis were studied in a Finnish cohort of 1026 granite workers hired between 1940 and 1971 and followed up until 31 December 1981. The incidence of awards of disability pensions because of rheumatoid arthritis during 1969-81, the prevalence of rheumatoid arthritis on 31 December 1981, and the prevalence of subjects receiving free medicines for rheumatoid arthritis at the end of 1981 were significantly higher among the granite workers than in the general male population of the same age. Retrospective analysis of the records of all patients with rheumatoid arthritis in the cohort showed a predominance of a severe, serologically positive and erosive form of rheumatoid arthritis, usually with an age at onset of 50 or over. The possible aetiological or pathophysiological role of granite dust in rheumatoid arthritis may be based on the effects of quartz on the immune system.

The 65kDa antigen of mycobacteria-a common bacterial protein?

The 65 kilodalton antigen of Mycobacterium tuberculosis and M. leprae is a well-characterized, strongly immunogenic protein eliciting antibody and T-cell responses in infected patients. Recent studies have disclosed regions of cross-reactivity between the 65kDa antigen and proteins in many other bacterial species. These include the product of the ams gene in E. coli which is involved in the processing of RNA. Here Douglas Young and his colleagues discuss these observations, the significance of the 65kDa antigen and its possible role in the pathogenesis of mycobacterial and other diseases.

Modes of action of second-line agents

The slow acting anti-rheumatic drugs (SARDS) are a chemically heterogeneous group. They produce a more profound effect on clinical and biochemical aspects of rheumatoid arthritis than do the aspirin-like non steroidals. The similarities in their clinical effects suggest that they have a common mode of action. Review of the known activity of SARDs on different cell types at various anatomical sites suggest that in fact different SARD drugs act in differing and sometimes conflicting ways. The site of action of SARDs within the body--whether at the level of synovial inflammation or of the systemic immune response--is largely undetermined. The effects produced by a single agent in vivo and in vitro are not always the same so a single mode of action, for example through possession of a thiol group, cannot explain the effects of all SARDs. Indeed a single agent such as aurothiomalate may show multiple effects and the same is now shown to be true for the newer agent sulphasalazine. A unifying hypothesis is put forward to explain the clinical similarities but different cellular effects. It is proposed that all SARDs act on some aspect of the central reaction in the ongoing immune response where antigen presentation to T helper cells results in interleukin 2 production and the generation of activated T cells. The precise site affected in this cell to cell/monokine reaction will vary between drugs, but the overall effect of blocking this will be similar for all drugs, both in short term clinical benefit and in the problem of disease flares after withdrawal of therapy.

Regulation of autoimmune disease physiological and therapeutic

An important question is how the immune system can control the behavior of autoimmune effector lymphocytes. My colleagues and I have investigated this question in four models. Three models of organ specific autoimmune diseases were studied using the specific autoimmune lines or clones of T lymphocytes functionally involved in the disease process. The fourth model was an anti-idiotypic network triggered spontaneously by autoantibodies. This article reviews the evidence indicating that healthy individuals can carry potentially virulent autoimmune T lymphocytes without symptoms. This carrier state of autoimmunity implies the existence of natural mechanisms of counter-autoimmunity. One natural element appears to be clones of suppressor-inducer T lymphocytes that arise in the course of the autoimmune response. We have discovered that autoimmune effector T lymphocytes can serve as inducers of their own suppression either artificially, by manipulating the T cell membrane, or naturally, by exposing the individual to very low concentrations of some effector T cell clones. Regarding the regulation of autoreactive B lymphocytes, we have observed that spontaneous generation of anti-idiotypic antibodies may have a particular bias for autoantibody idiotypes. Counter-autoimmunity appears to involve recognition of the self-reactive lymphocyte receptors resulting in the activation of suppressor cells. These suppressor cells can prevent disease or cause remission of established disease.