Is treat-to-target really working in rheumatoid arthritis? a longitudinal analysis of a cohort of patients treated in daily practice (RA BIODAM)

OBJECTIVES

To investigate whether following a treat-to-target (T2T)-strategy in daily clinical practice leads to more patients with rheumatoid arthritis (RA) meeting the remission target.

METHODS

RA patients from 10 countries starting/changing conventional synthetic or biological disease-modifying anti-rheumatic drugs were assessed for disease activity every 3 months for 2 years (RA BIODAM (BIOmarkers of joint DAMage) cohort). Per visit was decided whether a patient was treated according to a T2T-strategy with 44-joint disease activity score (DAS44) remission (DAS44 <1.6) as the target. Sustained T2T was defined as T2T followed in ≥2 consecutive visits. The main outcome was the achievement of DAS44 remission at the subsequent 3-month visit. Other outcomes were remission according to 28-joint disease activity score-erythrocyte sedimentation rate (DAS28-ESR), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI) and American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) Boolean definitions. The association between T2T and remission was tested in generalised estimating equations models.

RESULTS

In total 4356 visits of 571 patients (mean (SD) age: 56 (13) years, 78% female) were included. Appropriate application of T2T was found in 59% of the visits. T2T (vs no T2T) did not yield a higher likelihood of DAS44 remission 3 months later (OR (95% CI): 1.03 (0.92 to 1.16)), but sustained T2T resulted in an increased likelihood of achieving DAS44 remission (OR: 1.19 (1.03 to 1.39)). Similar results were seen with DAS28-ESR remission. For more stringent definitions (CDAI, SDAI and ACR/EULAR Boolean remission), T2T was consistently positively associated with remission (OR range: 1.16 to 1.29), and sustained T2T had a more pronounced effect on remission (OR range: 1.49 to 1.52).

CONCLUSION

In daily clinical practice, the correct application of a T2T-strategy (especially sustained T2T) in patients with RA leads to higher rates of remission.

TNF receptor involvement in TNF-mediated activities against syngeneic malignant and normal mouse thymocytes

Receptor-dependent tumor necrosis factor (TNF)-mediated activities against mouse thymoma cells and normal thymocytes syngeneic for C57 mice were examined to determine the specific involvement of TNF receptors R1 and R2. Both receptors are expressed by EL4 thymoma cells and normal C57 thymocytes. TNF-mediated activities included (a) cytotoxicity, (b) induction of hyposensitivity to TNF-mediated lysis, (c) costimulatory stimulation of thymocyte proliferation, and (d) activation of NF-kB-like transcription factor. The ability of polyclonal antisera against TNF receptors to mimic the above TNF-mediated activities was determined. The results clearly showed that anti-TNF-R1 antibodies were cytotoxic against EL4 cells, induced hyposensitivity of S-EL4 to TNF lysis and activated the NF-kB-like transcription factor in EL 4 cells and syngeneic normal thymocytes. Antisera against TNF-R2 only mimicked TNF-mediated costimulation of thymocyte proliferation with IL2. No direct correlation was noted between TNF activation of NF-kB and TNF-mediated lysis.

Developmental T cell receptor gene rearrangements: relatedness of the alpha/beta and gamma/delta T cell precursor

To examine the relationships between T cell populations at various stages of development, T cell receptor (TcR) gene rearrangements were compared between the four murine populations of (a) early thymocytes, (b) early splenocytes, (c) adult thymocytes and (d) adult splenocytes. TcR alpha gene rearrangements were shown to progress from 5' to 3' regions of the J alpha locus and from 3' to 5' regions of the V alpha locus during the development of T cells in both the thymus and spleen. Thus, the gene rearrangement potentials of proximal genes varied with age, yielding a biased repertoire in the young vs. adult animal. As evidence that gamma/delta and alpha/beta gene rearrangements appeared concomitantly in individual precursors, it was found that: (a) multiple adult thymocytes bore alpha gene rearrangements on one chromosome and delta gene rearrangements on the homologous chromosome, and (b) V gamma 3-J gamma 1 rearrangements, prominent joins in the early gamma/delta T cell population, were also prominent in the early alpha/beta T cell subset. These data illustrate the non-random nature of the developmental TcR gene rearrangement and suggest that alpha/beta and gamma/delta T cell populations derive from related, if not identical, T cell precursor populations.

The effects of blockade of interleukin 2 receptors and interleukin 4 receptors on cytokine production

The understanding of the regulation of cytokine production and T-cell proliferation by other cytokines is far from complete. We have examined the supernatant concentration of different cytokines in cultured peripheral blood lymphocytes (PBL) incubated with monoclonal antibodies against the interleukin-2 receptor (IL-2R) or interleukin-4 receptor (IL-4R) complex in order to analyse the importance of these receptors in the production of other cytokines. The PBL cultures were stimulated with phytohaemagglutinin and phorbol myristate acetate. The addition of anti-Tac to PBL cultures resulted in increased free IL-2 due to blockade of IL-2R. MR6 (a monoclonal antibody against IL-4R) did not affect the supernatant concentration of IL-2 in cultured PBL. Blockade of IL-2R or IL-4R both resulted in increased IL-4 in supernatant. The increase in supernatant concentration of IL-4 in PBL cultured with MR6 was due to a direct interaction with the IL-4R complex but the increase in IL-4 with anti-Tac was due to the accumulation of free IL-4 as an effective blockade of IL-2R prevented the full expression of IL-4R. Neither anti-Tac nor MR6 affected the IL-6 production by activated PBL, suggesting the existence of an IL-2- and IL-4-independent pathway. Blockade of IL-2R or IL-4R both resulted in a reduction of interferon-gamma (IFN-gamma) production, indicating that both endogenously generated IL-2 and IL-4 are important mediators of IFN-gamma induction in PBL cultures stimulated with T-cell mitogens.

Tumour-associated upregulation of the IL-4 receptor complex

In a previous study we have shown that monoclonal antibody MR6, which we believe recognizes a component of the human IL-4 receptor complex, binds to a wide variety of epithelial tumours. We have now used this reagent to carry out more detailed analysis of tumours of the breast. Our immunohistochemical data indicate that approximately 30% of these tumours show elevated expression of the molecule to which MR6 binds. In addition, three samples of lymphoma were all MR6-positive. Normal breast tissue from the same patients was either negative or weakly positive. Immunoprecipitation and Western blotting analysis with MR6 show that the molecule expressed on tumour cells is indistinguishable from that on normal tissues. It has an apparent molecular weight of 200 kD, but is highly sensitive to proteolysis yielding a molecule of 145 kD. These data raise the possibility that upregulation of the IL-4 receptor complex may be involved in tumourigenesis. In addition, since only a third of tumours are MR6-positive, the antibody may have potential in differential diagnosis.

Functional evidence for a monoclonal antibody that binds to the human IL-4 receptor

The complex pleiotropic effects of the T-cell derived lymphokine interleukin-4 (IL-4) are becoming increasingly well documented; however, functional studies have been hampered by the lack of reagents directed against the receptor for this factor. In this report, we present data which suggest that the monoclonal antibody MR6 binds to the human interleukin-4 receptor (IL-4R). Addition of MR6 to cultures of T cells proliferating in response to IL-4 inhibited this response in a dose-dependent fashion, giving total inhibition at 10 micrograms/ml. Similarly, the IL-4-dependent production of specific antigen-induced IgE by B-cell populations was completely abrogated by MR6. Flow cytometric studies of the modulation of cell surface molecules after T-cell activation suggest that expression of the molecule detected by MR6 (p145-MR6) correlates inversely with that of the interleukin-2 receptor (IL-2R). These data, together with the previously determined molecular weight and tissue distribution of this molecule, strongly indicate that MR6 binds to the human IL-4R.

Development of anti-idiotypic antibodies against tumour antigens and autoantigens in ovarian cancer patients treated intraperitoneally with mouse monoclonal antibodies

Repeated intraperitoneal administration of therapeutic amounts of radiolabelled (iodine-131) murine monoclonal antibodies leads to the development of an immune response in the recipient, part of which is directed against the variable region (idiotype) of the administered antibody (anti-Id1 response). Human immunoglobulin purified from these patients inhibits binding of the original murine monoclonal antibody to its target tumour antigen and therefore represents an "internal image" of the tumour antigen. Furthermore, this study recorded the development of human antibodies that themselves bind to the tumour antigen, with a specificity identical or similar to that of the injected monoclonal antibody. These human antitumour antibodies are probably generated by way of the idiotypic network and confirm the existence of the idiotypic network. Accompanying this antitumour response the transient development of autoantibodies that react with connective tissue components of liver, kidney, spleen, and diaphragm was also observed.

Development of primary and secondary immune responses to mouse monoclonal antibodies used in the diagnosis and therapy of malignant neoplasms

Human anti-mouse immunoglobulin immune responses were studied in ten patients, eight with ovarian cancer and two with grade IV gliomas, diagnosed and treated with radiolabeled (123I, 131I) murine monoclonal antibodies. It was found that serum from these patients before treatment and from 18 control healthy individuals contained detectable antibodies to antigenic determinants on the Fc but not the F(ab')2 portion of mouse immunoglobulin. No change in this reactivity occurred after the initial (imaging) dose of monoclonal antibodies. However, repeated administration of mouse immunoglobulins for therapy resulted in an elevated immune response directed against determinants on both Fc and F(ab')2 regions of mouse immunoglobulin. This response contained increased levels of immunoglobulin M as well as immunoglobulin G and showed a marked prozone effect in our enzyme linked immunosorbent assay system. None of the immunized patients developed a detectable antiidiotypic response.