Correlation of disease activity and drug therapy with the autologous mixed lymphocyte reaction in rheumatoid arthritis

Increment of CD8S6F1 cells in synovial fluid from patients with rheumatoid arthritis

OBJECTIVE

To investigate the role of CD8 cell subsets in the pathogenesis of rheumatoid arthritis (RA) and the phenotypes of T cells adherent or non-adherent to the target cells (endothelial cells and synovial cells) pre-treated with IL-1 beta.

METHODS

The expression of S6F1 on CD8 cells and that of an activation marker on CD8 cells and CD8 cell subsets was evaluated in specimens of peripheral blood and synovial fluid obtained from 15 patients with RA and 10 with osteoarthritis (OA) using a two- or three-colour immunofluorescence method for analysis.

RESULTS

The percentage of CD8S6F1 cells among CD8 cells in synovial fluid was significantly greater than that of peripheral blood. Synovial fluid from RA patients had a greater percentage of CD8S6F1 cells compared with either peripheral blood of matched patients or synovial fluid of OA patients. The percentage of CD8HLA-DR cells in synovial fluid was markedly greater than that in paired samples of peripheral blood in patients with RA. In the CD8S6F1 cells from both groups of patients, synovial fluid showed an increased percentage of HLA-DR cells compared with peripheral blood. Similar results were observed in CD8 cells lacking S6F1 expression (CD8S6F1-) from both groups of patients. There was no significant difference in the percentage of HLA-DR cells between CD8S6F1 and CD8S6F1- cell populations in peripheral blood. In contrast with peripheral blood, in synovial fluid of RA patients the percentage of HLA-DR cells in the CD8S6F1 cell population was markedly greater than that in the CD8S6F1- population. However, the percentage of HLA-DR cells in both cell populations was similar in synovial fluid of OA patients. In both the endothelial and the synovial cell adhesion assays, the percentage of CD8S6F1 among CD8 cells and the mean fluorescence intensity of S6F1 antigen on CD8S6F1 cells were significantly greater in the adherent T cell population than that in the non-adherent T cell population.

CONCLUSION

These results suggest that increased expression of S6F1 antigen and the increased percentage of HLA-DR cells on CD8 cells in synovial fluid may be responsible for the migration of these cells into inflamed synovial tissues, and for cellular interactions between these cells and synovial cells or the extracellular matrix.

T cell interactions in active rheumatoid arthritis: insights from the human autologous mixed lymphocyte reaction as a model of T cell activation cascade

The autologous mixed lymphocyte reaction (AMLR) represents the activation, proliferation and differentiation of T cells in response to signals from autologous non-T cells. Using monoclonal anti-Leu8 antibody to isolate subpopulations of human CD4+ and CD8+ T cells, we have investigated the role of these subpopulations in the T cell activation cascade during the course of AMLR. In normal subjects, CD4+Leu8+ cells are necessary for the initiation of the AMLR response, and sequentially lead to activation and proliferation of both CD4+Leu8- cells and CD8+Leu8+ cells. The activated CD8+Leu8+ cells, in turn, induce CD8+Leu8- cells to generate proliferation of the latter cells. Soluble mediators could be involved in the T cell activation cascade induced by the AMLR. Patients with active rheumatoid arthritis have a profound defect in the AMLR. Further analysis indicates that rheumatoid arthritis CD8+ T cells are markedly defective as responding cells in the AMLR. The impaired AMLR response by CD8+ cells cannot be reconstituted with AMLR-derived supernatants from normal T cells. The data suggest that the defective CD8+ T cell function may contribute to the pathogenesis of the disease.

D-penicillamine

D-Pen represents an effective treatment for a proportion of patients with RA and PSS. Its status in the treatment of juvenile RA is uncertain. The best results will be obtained by a skillful, careful physician maintaining careful surveillance for toxicity. Neither the mode of action nor the mechanisms of toxicity are well understood in RA. Consequently, safer and more effective analogues of D-pen have not been produced.

In vivo regulation of the murine syngeneic mixed lymphocyte reaction

Previous work from this laboratory has suggested that a CD8+ T suppressor (Ts) cell network regulated the murine syngeneic mixed lymphocyte reaction (SMLR). We have attempted to disrupt this network by the inoculation of anti-CD8 monoclonal antibodies (mAb) in vivo. Intraperitoneal inoculation of three mAbs resulted in a marked increase in the proliferation of CD4+, self-Ia-reactive splenic T cells in vitro to syngeneic, but not to allogeneic, spleen cells. Suppression was not limited to a specific mouse strain as the enhanced SMLR was reproducible following anti-CD8 treatment of three strains of mice. In vivo depletion of CD8+ T cells was not a prerequisite for enhancement of the SMLR as several mAb to CD8 augmented the SMLR independent of their capacity to cause CD8 T cell depletion. Moreover, enhancement of the SMLR could be mimicked in vitro by inclusion of anti-CD8 mAb in in vitro cultures of responder T cells and irradiated Ia+ syngeneic stimulators. Since the in vitro SMLR was enhanced following mAb treatment, it was expected that the in vivo SMLR would also be increased. However, no evidence of increased in vivo autoreactivity could be detected following in vivo treatment with anti-CD8 mAb, indicating that other mechanisms in addition to CD8+ regulatory T cells acted to regulate the in vivo activity of autoreactive T cells.

Impaired autologous mixed lymphocyte reaction (AMLR) reactivity of peripheral blood T cell subsets in rheumatoid arthritis

We examined AMLR reactivity of unseparated T cells and CD4+ and CD8+ T cell subsets in peripheral blood from 11 rheumatoid arthritis (RA) patients and 10 healthy controls. T cell subsets were isolated by negative selection using complement mediated cytotoxicity. AMLR reactivity of six patients (designated RA-L was reduced below the range of the controls' responses. Five patients (designated RA-N) exhibited normal AMLR reactivity. We observed impaired AMLR reactivity of CD4+ T cells from RA-L relative to RA-N and healthy controls (P < 0.05). CD4+ T cell reactivity of RA-L was reconstituted to normal with pharmacological doses of recombinant interleukin-2 (IL-2) (100 U/ml). In contrast, CD8+ T cells from RA-L in the presence of 100 U/ml IL-2 exhibited markedly impaired AMLR reactivity relative to RA-N and healthy controls (P < 0.05). Dose-response studies revealed partial reconstitution of CD4 T cells with physiological concentrations of IL-2 (10 U/ml). To examine the possibility that in vivo pre-activation of T cells in RA accounted for the findings, T cells or subsets were cultured alone for 7 days in the presence of 100 U/ml IL-2. A trend toward enhanced reactivity of CD4+ and CD8+ T cells in L-RA relative to N-RA and healthy controls was observed, but the differences were not statistically significant. There was no correlation between reactivity of T cells alone in the presence of IL-2 and AMLR reactivity. The results suggest the possibility that abnormal AMLR reactivity of CD4+ and CD8+ T cell subsets in RA may arise as a consequence of different pathophysiological mechanisms.

Analysis of the responding and stimulating cells in the AMLR of patients with rheumatoid arthritis using limiting dilution

Plastic adherent and non-adherent mononuclear cells derived from synovial fluid were found to stimulate peripheral blood mononuclear cells of patients with rheumatoid arthritis (RA) in an autologous mixed lymphocyte reaction (AMLR). Stimulation produced by adherent cells was consistently greater than that produced by non-adherent mononuclear cells. CD11 enriched cells were not significant stimulators in the AMLR, however their presence was required for a significant reaction to occur. Limiting dilution studies revealed that the most plausible model involved two or more cells of the same type in each of the stimulator and responder populations for the AMLR to occur.

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)

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.

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.

Second-line drug treatment in rheumatoid arthritis associated with depressed autologous mixed lymphocyte reaction

The AMLR (autologous mixed lymphocyte reaction) was performed in 24 control subjects, 41 patients with rheumatoid arthritis (RA), 19 patients with ankylosing spondylitis (AS), and 7 patients with psoriatic arthritis (PSA). It was found to be depressed in 21 of the RA subjects and this was linked to medication with sodium aurothiomalate or D-penicillamine. Addition of ultrapure interleukin 1 (IL-1), indomethacin, or catalase did not cause any improvement in the AMLR but some improvement was noted in those RA patients with subnormal AMLR when pure, recombinant interleukin 2 (IL-2) was added to the cultures. Since autoreactive T-cells are generated during the AMLR which are capable of providing help for immunoglobulin production, it is proposed that the defective AMLR seen after second-line drug treatment may be the mechanism whereby rheumatoid factor (RF) production is down-regulated during such treatment.

T lymphocyte lines from arthritic synovial fluid: establishment and function

T lymphocyte lines have been established, with the addition of interleukin-2 (IL-2), from the synovial fluid (SF) of patients with arthritis. Characterisation of seven of these SF-derived T cell lines showed them to be T3+, T11+, and to contain a significant proportion of T8+ cells (mean 41%). The proportion of T4+ cells varied among the lines, with a mean T4+/T8+ ratio of 0.6. A significant autologous mixed lymphocyte reaction (AMLR) was observed only in one of four T cell lines assayed. Two of four lines assayed showed natural killer (NK) cell-like activity, while one line displayed a significant suppressor activity, suggesting that the T cell population in SF contained NK-like cells or suppressor cells, or both, either of which may be selected in the establishment of SF-derived T cell lines.