Lymphocyte Studies In Rheumatoid Arthritis Iii: A Comparative Study Of The Responses Of Peripheral Blood And Synovial Fluid Lymphocytes To Phytomitogens

Modulation of human T cell functions by surface sulphydryl groups: differential effects on IL-2 production and responsiveness

An impermeable thiol blocker has been used to investigate the role of sulphydryl (SH) groups in the production of and responsiveness to IL-2 by normal human T lymphocytes. Surface SH blockade of mononuclear cells prior to incubation with mitogen (phytohaemagglutinin, concanavalin A, CD3 MoAb) had no effect on production of IL-2 but markedly impaired cellular responsiveness to exogenous IL-2. Studies using MoAbs indicated that this effect was accompanied by decreased expression of both the CD25 and p75 subunits of the IL-2 receptor. Blocking surface SH groups did not affect binding of IL-2 to p75 on unstimulated mononuclear cells, but inhibited binding to high-affinity receptors on a T lymphoma cell line. The data are consistent with the hypothesis that sulphydryl groups on the IL-2 receptor are required for its function and may be involved in the interaction of the CD25 and p75 subunits leading to generation of the high-affinity binding site. The surface thiol identified on the IL-2 receptor may be a candidate for oxidation on cells from patients with chronic inflammatory diseases such as rheumatoid arthritis and thus contribute to the aberrant function of T cells in these patients.

Stimulation of rheumatoid synovial and blood T cells and lines by synovial fluid and interleukin-2: characterization of clones and recognition of a co-stimulatory effect

Rheumatoid arthritis (RA) is characterized by the presence of interleukin-2 (Il-2) receptor-positive T cells in the peripheral blood and synovial compartments. Utilizing the limiting dilution technique, the precursor frequencies of Il-2 responsive T cells were determined in peripheral blood and synovial sites from RA patients and in the blood of normal donors. The frequencies of Il-2 responsive T cells were significantly higher in RA patients (range from 1/180 to 1/7432) compared to normal donors (range from 1/400 to 1/8163). T-cell clones raised by the addition of Il-2 alone were predominantly of the CD4-positive phenotype. Peripheral blood T cells, synovial T-cell clones and lines derived from RA patients were co-stimulated with Il-2 and synovial fluid or supernatants from cultured synovial lining cells. This co-stimulation induced a strikingly enhanced proliferative T-cell response while synovial fluid alone was without effect. This stimulatory activity was found in the high molecular weight range (approximately 150 kDa) and could not be attributed to the action of immunoglobulins or known cytokines such as Il-2 or interleukin-1 (Il-1), suggesting the activity of a material that modulates the Il-2-dependent growth of T cells. The co-stimulatory capacity of synovial fluid with Il-2 may be relevant to the activated state, especially of synovial T cells.

Depressed T-cell reactivity to recall antigens in rheumatoid arthritis

Reactivity toward soluble recall antigens (Candida albicans, cytomegalovirus, herpes simplex, streptokinase-streptodornase, and influenza) was determined in cultures of peripheral blood mononuclear cells from 41 rheumatoid arthritis patients (with clinically active as well as inactive disease) and from 28 controls. In the group with clinically active rheumatoid arthritis we found an increased incidence of "anergy," defined as nonreactivity to three or more antigens. In an attempt to explain this decreased antigen reactivity, the latter was correlated with peripheral blood lymphocyte subsets, as defined by two-color immunofluorescence with a panel of eight monoclonal antibodies. We found a significantly lower number of memory T4 cells (CD4+CD45RA-) and a significantly higher number of the CD3-CD57+ (nonspecific suppressor) cells and of CD3-CD56+/CD16+ (natural killer) cells in anergic RA patients. In the total group of rheumatoid arthritis patients, the antigen reactivity correlated positively with the percentage of memory T4 cells. Antigen reactivity was negatively correlated with the percentage of CD3-CD57+ cells and of the CD3- natural killer cells in peripheral blood. Our data suggest that a decrease in memory T4 cells and an increase in nonspecific suppressor cells may contribute to the impaired cellular immune function in peripheral blood of rheumatoid arthritis patients.

Interleukin-2 inhibitor in rheumatoid arthritis synovial fluid does not inhibit mononuclear cell responses to mitogens

Synovial fluid (SF) from rheumatoid arthritis (RA) patients were tested for their ability to inhibit the proliferative responses of normal peripheral blood mononuclear cells (PBM) to mitogens and interleukin-2 (IL-2). SF significantly inhibited the responses to concanavalin A (CON A) and phytohaemagglutinin (PHA), but significantly enhanced the responses to IL-2. Similarly, SF mononuclear cells (SFM) were hyporesponsive to CON A and PHA compared with autologous PBM, but hyper-responsive to IL-2. It is concluded that an IL-2 inhibitor in RA SF is unlikely to be the cause of SFM hyporesponsiveness to mitogens.

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.

Inhibitor of interleukin-2 synthesis and response in rheumatoid synovial fluid

We studied the effects of a factor present in rheumatoid arthritis (RA) synovial fluid (SF) on interleukin-2 (IL-2)-dependent cell proliferation and on the production of IL-2 by mitogen-stimulated peripheral blood mononuclear cells. RA SF suppressed the responsiveness of a mouse T cell line (HT-2) to IL-2, indicating that it contained an inhibitor of the IL-2 response. When RA SF was fractionated by Sephadex G-200 gel filtration, the inhibitory activity was detected mainly in fractions with a molecular weight of approximately 150,000, but was also found in a 15-19-kd fraction. Removal of IgG from the 150-kd fraction, by means of an anti-IgG affinity column, did not reduce the activity of the fraction, nor was activity found in the eluted IgG. The inhibitory fractions reduced mouse thymocyte proliferative responses to IL-1 in the presence of phytohemagglutinin, and reduced the production of IL-2 by human peripheral blood mononuclear cells, but did not inhibit IL-1-induced human foreskin fibroblast proliferation; this suggests that the factor was not an IL-1 inhibitor. The inhibitory activity of the RA SF factor was blocked by an antibody against an inhibitor of IL-2 that was purified from a culture of the human monocytic leukemia cell line, THP-1. This finding also supports the conclusion that RA SF contains an IL-2 inhibitory factor. The observed inhibition of both IL-2 synthesis and IL-2 response suggests that the target of the inhibition was the T lymphocyte.

T cell subsets in the blast cell population in phytohemagglutinin-stimulated peripheral blood in vitro and in rheumatoid arthritis synovial fluid in vivo

The immunomodulatory T4/T8 ratio was studied in the total and activated lymphocyte populations by a method combining visualisation of 3H-thymidine incorporating blasts with autoradiography (AR) with simultaneous identification of the respective lymphocyte subsets using monoclonal antibodies in avidin-biotin-peroxidase complex (ABC) staining. In rheumatoid arthritis synovial fluid the activated T4/T8 ratio (calculated from T cells in the S phase of the cell cycle) was significantly different from the total T4/T8 ratio (calculated for all the T cells) (0.45 +/- 0.05 versus 0.69 +/- 0.05, P less than 0.01). Similarly, the activated and total T4/T8 ratios were also significantly different in the phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cell cultures at days 3 and 5.

A minority of patients with rheumatoid arthritis show a dominant rearrangement of T-cell receptor beta chain genes in synovial lymphocytes

The clonality of T lymphocytes isolated from the synovial fluid and peripheral blood of patients with rheumatoid arthritis was investigated by restriction enzyme fragment mapping of the rearrangements of the beta chain gene of the T-cell antigen receptor. Three patients showed a dominant rearrangement amongst their synovial fluid T cells which was not seen in their peripheral blood T-cell population, suggesting the presence of a predominating T-cell clone. However, most of the patients examined (8 out of 11) demonstrated polyclonal T-cell populations in both their synovial fluid and peripheral blood. Of four synovial fluid T-cell lines investigated, one showed evidence of a dominant T-cell clone.

Proliferative responses of mononuclear cells in Lyme disease. Reactivity to Borrelia burgdorferi antigens is greater in joint fluid than in blood

In 27 patients with early Lyme disease, the mean response of peripheral blood mononuclear cells (PBMC) to Lyme spirochetal Borrelia burgdorferi antigens (723 counts per minute) was similar to that of control subjects. During convalescence, 2-3 weeks later, the patients' mean response was significantly higher (2,075 cpm, P less than 0.008). Compared with those with early disease, the PBMC of 22 patients with Lyme arthritis reacted even more to B burgdorferi (2,923 cpm, P less than 0.0004), and, by far, the greatest response was in concomitantly obtained synovial fluid mononuclear cells (15,238 cpm, P less than 0.001). The PBMC of patients with early Lyme disease reacted slightly less to phytohemagglutinin and pokeweed mitogen than those of normal control subjects, but patients with arthritis had greater than normal mitogen responses. In contrast, mitogen reactivity among synovial fluid cells was markedly decreased and correlated inversely with the response to antigen. Thus, in patients with Lyme disease, the antigen-specific responses of mononuclear cells increase as the disease progresses, and in those with arthritis, the greatest reactivity to antigen is found in cells in the inflamed joint.

Lymphocyte activation in rheumatoid arthritis synovial fluid in vivo

Monoclonal antibodies were used in avidin-biotin-peroxidase complex staining for activation marker analysis of rheumatoid synovial fluid cells. Although Ia expression indicates T cell activation, cells displaying receptors for interleukin 2 (Tac)-and transferrin receptor (T9)- positive proliferating cells were relatively few. Similarly, activated terminal effector cells of suppressor/cytotoxic nature were scarce in rheumatoid synovial fluid, as suggested by a low expression of Tac and 4F2 markers. The in vivo situation in the rheumatoid arthritic (RA) joint does not seem to be due to the inability of synovial fluid lymphocytes to become activated, because mitogen stimulation in vitro, in spite of a low proliferative response, induced expression of all the activation markers studied. The relevance of the present observations to the down-regulation of the active, inflammatory-immune response in situ is speculative, but the data show that in spite of T-cell activation and Ia expression, activated terminal effector cells of suppressor/cytotoxic nature are few in the RA joint in vivo.

Specific cell-mediated responses to bacterial antigens and clinical correlations in reactive arthritis, Reiter's syndrome and ankylosing spondylitis

In 2 cases of ReA seen during the acute phase and shown serologically to be due to Y. enterocolitica 0:3, the LT test showed a marked response using as antigen a freeze dried preparation of the causative organism. The test result correlated with the activity of the disease when repeated during a flare in the 1st case, and during remission in both. Patients with ReA/RS in general showed a significantly higher response to the yersinia and klebsiella antigens tested when compared to AS, suggesting an overall difference in cell-mediated immunity to these enteric bacteria. AS cases reacted significantly less than controls to K. pneumoniae under suboptimal conditions. K. pneumoniae was shown to enhance the LT response to yersinia, possibly through an adjuvant effect. This was found with AS, ReA and in controls, though whether it is of relevance in the etiopathogenesis of AS or ReA/RS remains far from clear. Acute non-traumatic synovitis of the knee, occurring de novo, or in association with psoriasis, inflammatory bowel disease, or as part of RS, may be accompanied by evidence of heightened reactivity to streptococci both by blood and synovial fluid mononuclear cells. In 1 case with serological evidence of streptococcal infection and erythema nodosum, these changes were found to parallel disease activity. ReA can, it appears, follow recent streptococcal infection, and be associated with B27.

Immune reactivity in palindromic rheumatism: response to mitogens

Lymphocyte responsiveness to various mitogens was studied in patients with palindromic rheumatism. The results show an enhanced lymphocyte reactivity to T-dependent mitogens during the first few days after an acute attack of the disease.

Increased DNA and/or RNA content of synovial fluid cells in rheumatoid arthritis: a flow-cytometry study

Flow-cytometry studies of DNA and RNA content were carried out in acridine orange-stained synovial fluid lymphocytes from 11 patients presenting with classical or definite rheumatoid arthritis. Monoclonal antibodies were used to detect specific T cell surface antigens (OKT3, OKT4, OKT8) and antigens associated with lymphocyte activation (OKIa 1, OKT10). T3 positive cell percentages were comparable to those of normal blood, although T4/T8 ratios were decreased in 4 out of 5 cases, and HLA-DR positive cells increased. Six out of 11 patients showed percentages of dividing cells varying from 2.2 to 7.2% as compared with less than 1% in the other patients and in normal blood. Nondividing cells were characterised by an increase in their RNA content compared with normal blood. A greater increase of RNA content was observed in patients with lower percentages of dividing cells, suggesting a G1/S block. Changes in cellular DNA and/or RNA contents provide a valuable parameter of lymphocyte activation, not necessarily linked to the expression of differentiation antigens by activated cells.

Autologous mixed lymphocyte reactions in patients with rheumatoid arthritis and juvenile rheumatoid arthritis: both non-T cells and in-vivo-activated T cells can act as stimulator cells

The lymphocyte responses in autologous mixed lymphocyte reactions (AMLR) between irradiated non-T and T lymphocytes from the peripheral blood (PB) of rheumatoid arthritis (RA) and juvenile RA (JRA) patients were decreased compared with the AMLR responses of normal PB lymphocytes. Normal AMLR responses were seen in synovial tissue and the synovial fluid lymphocytes from RA and JRA patients. The lymphocyte responses were also decreased in AMLR between irradiated non-T cells from peripheral blood and T cells from synovial tissue (ST) in RA patients and between irradiated non-T from PB and synovial fluid (SF) T cells in JRA patients. However, when irradiated non-T cells from ST of RA patients or from SF of JRA patients were mixed with autologous PB T lymphocytes, increased lymphocyte responses were observed. SF T lymphocytes and ST T cells were also shown to stimulate autologous PB T lymphocytes.

Interleukin 1 activity in the synovial fluid of patients with rheumatoid arthritis

The synovial fluids (SF) of patients with rheumatoid arthritis (RA) were investigated for their effects on thymocytes of C3H/HeJ mice. Of the 20 SF tested, 17 (85%) showed an augmentation of the phytohaemagglutinin (PHA) induced thymocyte stimulation. Out of 16 SF of patients with osteoarthrosis, such an activity was detected in only one (6.25%). Further characterisation of the amplification factor revealed that (1) the SF of RA patients augmented both the PHA and the Concanavalin A response of the thymocytes (2) in the absence of mitogens, SF-treated thymocytes showed an increased uptake of 3H-thymidine, (3) the SF did not propagate the growth of an interleukin 2 dependent ovalbumin specific T cell clone, but (4) the SF were found to be required for optimal interleukin 2 release by spleen cells stimulated with suboptimal doses of lectin. Based on these biological effects the factor in the SF of RA patients is suggested to represent an interleukin 1 (IL-1). IL-1 produced in cultures by activated macrophages has been shown to stimulate T and B cell functions and to induce the production of collagenase and prostaglandins by cultured synovial cells. Both properties of IL-1 could be relevant in the pathogenesis of RA.

Indomethacin inhibits in vitro immunoglobulin production by human B-lymphocytes

Immunoglobulin production from human B-lymphocytes stimulated in vitro with pokeweed mitogen (PWM) was measured after 11 days of cell culture. IgM and IgG levels in culture supernatants were quantified using ELISA techniques. Addition of the prostaglandin cyclooxygenase inhibitor indomethacin (10(-7) M) to cell cultures concurrently with PWM, inhibited both IgM and IgG synthesis by 80-90% in the four individuals studied. Reduction of immunoglobulin production was apparently concentration-related over the range studied (10(-6)-10(-8) M) and was not associated with cytotoxicity. If this action of indomethacin results from inhibition of cyclooxygenase, then prostaglandins or other arachidonic acid products could be involved in the regulation of human B-lymphocyte immunoglobulin production.

Changes in immune function in patients with rheumatoid arthritis following treatment with sodium aurothiomalate

The mitogenic response of peripheral blood lymphocytes from 21 patients with rheumatoid arthritis to concanavalin-A (con--A), phytohaemagglutinin (PHA), and pokeweed mitogen (PWM) was significantly lower than in 30 normal subjects. After 15--24 weeks' treatment with sodium aurothiomalate (GST) the response to these mitogens rose to within the normal range. Improvement over pretreatment values was significant for con-A and PWM measured as area under the dose response curve but only for con--A if response at optimal mitogen concentration is the sole criterion. The improvement in PHA response was not significant with either method of measurement. There was an improvement in disease activity by 15--24 weeks as measured by a fall in serum C-reactive protein (CRP), IgM rheumatoid factor (RF), Clq binding activity (ClqBA), and Ritchie articular index. Con--A lymphocyte responsiveness was inversely related to serum CRP levels, but measurements of disease activity were otherwise unrelated to lymphocyte mitogen responsiveness. The observed improvement in peripheral blood lymphocyte responsiveness during gold treatment contrasts with the suppressive effect of gold in vitro. We suggest that the improvement in lymphocyte function is due to the lessening of rheumatoid disease activity during gold treatment, and that the low serum gold levels in our patients were insufficient to mask this effect. Sera from some of our patients were capable of suppressing the function of normal lymphocytes, and this was less apparent after treatment. The suppressive effect of sera correlated with ClqBA. Suppressive factors in serum, including possibly immune complexes, may be one factor leading to suppression of lymphocyte function during rheumatoid arthritis. Such an inverse relationship between humoral and cellular immune mechanisms might influence the clinical expression of rheumatoid arthritis.

Con A-induced suppressor cell activity and T-lymphocyte subpopulations in peripheral blood lymphocytes of patients with rheumatoid arthritis and juvenile rheumatoid arthritis

Suppressor cell activity was investigated in peripheral blood lymphocytes from twenty patients with rheumatoid arthritis (RA) and twenty patients with juvenile rheumatoid arthritis (JRA) using a concanavalin A/mixed lymphocyte culture assay. The mean suppression in the RA patients was slightly reduced compared with the suppressor cell activity in adult controls (25 +/- 5% suppression compared with 37 +/- 5%; P less than 0.05, Student's t test), whereas the JRA patients had normal suppressor cell activity (mean 46 +/- 5% versus 43 +/- 5% in healthy children matched for age and sex). The RA patients had normal proportions of T-cell subpopulations, 13.3% T gamma cells and 49.8% T mu cells, compared with 13.8% and 58.0% in controls. The JRA patients, however, had a significantly reduced mean percentage of T gamma cells, 6.6%, compared with 13.8% in healthy children (P less than 0.05, Mann-Whitney U-test). The mean percentage of T mu cells was 53.7%, versus 56.2% in the controls. The relation between suppressor cell activity and suppressor cells enumerated by membrane markers is discussed.

Improvement in peripheral blood lymphocyte response to concanavalin A and pokeweed mitogen during gold treatment of rheumatoid arthritis

Peripheral blood lymphocyte mitogen responsiveness was studied in 21 patients with rheumatoid arthritis being treated with sodium aurothiomalate. There was a significant increase in lymphocyte response to concanavalin A and pokeweed mitogen but not to phytohaemagglutinin. This observed increase in lymphocyte response contrasts with the suppressive effect of gold salts in vitro. We propose that this apparent contradiction may be explained by the relatively low serum gold levels measured in our patients, compared with expected levels in synovial membrane. Thus gold could suppress rheumatoid inflammation in the "target tissue" while having little suppressive action in the peripheral blood compartment, where a removal of suppressive influences due to active disease might then be seen as a net improvement in lymphocyte responsiveness.