The role of T cells in rheumatoid arthritis

Clinical effectiveness and safety of additional administration of tacrolimus in rheumatoid arthritis patients with an inadequate response to abatacept: A retrospective cohort study

OBJECTIVE

Abatacept (ABT) demonstrates good clinical efficacy and retention in rheumatoid arthritis (RA) patients. However, no rescue treatment option against inadequate response to ABT exists. Since tacrolimus (TAC) and ABT suppress T lymphocytes via different mechanisms and a combination of these agents could potentially be effective, this study aimed to examine the efficacy and safety of add-on TAC therapy in RA patients with inadequate response to ABT.

METHODS

Of 550 patients treated with ABT and registered in a Japanese multicenter registry, 25 consecutive patients who underwent add-on TAC therapy and were followed for longer than 24 weeks were included in this study.

RESULTS

Mean patient age was 67.0 years, disease duration was 16.2 years, and duration of ABT treatment was 1.2 years at the initiation of add-on TAC therapy. Mean TAC dose was 1.2 mg/d at baseline and 1.6 mg/d at week 24. Mean Disease Activity Score of 28 joints - erythrocyte sedimentation rate was significantly improved at week 24 (3.35) relative to baseline (4.97). The proportion of patients who achieved low disease activity or remission was 40.0%, and the European League Against Rheumatism moderate or good response was 72.0%. ABT retention rate was 92.0% at week 24, as calculated by Kaplan-Meier analysis. Only one patient discontinued add-on TAC therapy due to an adverse event (itching sensation).

CONCLUSION

This is the first report describing the efficacy and safety profile of add-on TAC therapy with a focus on RA patients with inadequate response to ABT. Our findings suggest that add-on TAC therapy is a worthwhile complementary treatment option in daily clinical practice.

How Rheumatoid Arthritis Can Result from Provocation of the Immune System by Microorganisms and Viruses

The pathogenesis of rheumatoid arthritis (RA), similar to development of a majority of inflammatory and autoimmune disorders, is largely due to an inappropriate or inadequate immune response to environmental challenges. Among these challenges, infectious agents are the undisputed leaders. Since the 1870s, an impressive list of microorganisms suspected of provoking RA has formed, and the list is still growing. Although a definite causative link between a specific infectious agent and the disease has not been established, several arguments support such a possibility. First, in the absence of a defined pathogen, the spectrum of triggering agents may include polymicrobial communities or the cumulative effect of several bacterial/viral factors. Second, the range of infectious episodes (i.e., clinical manifestations caused by pathogens) may vary in the process of RA development from preclinical to late-stage disease. Third, infectious agents might not trigger RA in all cases, but trigger it in a certain subset of the cases, or the disease onset may arise from an unfortunate combination of infections along with, for example, psychological stress and/or chronic joint tissue microtrauma. Fourth, genetic differences may have a role in the disease onset. In this review, two aspects of the problem of “microorganisms and RA” are debated. First, is there an acquired immune deficiency and, in turn, susceptibility to infections in RA patients due to the too frequent and too lengthy infections, which at last break the tolerance of self antigens? Or, second, is there a congenital deficiency in tolerance and inflammation control, which may occur even with ordinary infection frequency and duration?

Lactobacillus casei suppresses experimental arthritis by down-regulating T helper 1 effector functions

Although the beneficial effects of probiotics on wide variety of diseases have been shown, little is known about how probiotics modulate the immune system. In this study we elucidated the underlying mechanisms how Lactobacillus casei (L. casei) protects against rheumatoid arthritis (RA) progression by investigating the effector functions of CD4(+) T cells. Oral administration of L. casei suppressed collagen-induced arthritis (CIA) and reduced paw swelling, lymphocyte infiltration and destruction of cartilage tissue. L. casei administration reduced type II collagen (CII)-reactive proinflammatory molecules (IL-1beta, IL-2, IL-6, IL-12, IL-17, IFN-gamma, TNF-alpha and Cox-2) by CD4(+) T cells. L. casei administration also reduced translocation of NF-kappaB into nucleus and CII-reactive Th1-type IgG isotypes IgG2a and IgG2b, while up-regulating immunoregulatory IL-10 levels. Our results suggest that oral administration of L. casei suppresses the type II collagen-reactive effector function of Th1-type cellular and humoral immune responses in arthritic inflammation.

Outcome of intensive immunosuppression and autologous stem cell transplantation in patients with severe rheumatoid arthritis is associated with the composition of synovial T cell infiltration

OBJECTIVE

To determine clinical and immunological correlates of high dose chemotherapy (HDC) + autologous stem cell transplantation (ASCT) in patients with severe rheumatoid arthritis (RA), refractory to conventional treatment.

METHODS

Serial samples of peripheral blood and synovial tissue were obtained from seven patients with RA treated with HDC and autologous peripheral blood grafts enriched for CD34+ cells. Disease activity was assessed with the Disease Activity Score (DAS), serum concentrations of C reactive protein (CRP), and human immunoglobulin (HIg) scans, and the extent of immunoablation was determined by immunophenotyping of peripheral blood mononuclear cells, and immunohistochemistry and double immunofluorescence of synovium.

RESULTS

Clinical responders (n = 5) had a larger number of cells at baseline expressing CD3, CD4, CD27, CD45RA, CD45RB, and CD45RO in synovium (p < 0.05), higher activity on HIg scans (p = 0.08), and a trend towards higher concentrations of CRP in serum than non-responders (n = 2). Subsequent remissions and relapses in responders paralleled reduction and re-expression, respectively, of T cell markers. A relatively increased expression of CD45RB and CD45RO on synovial CD3+ T cells was seen after HDC + ASCT. No correlations were found between DAS and changes in B cells or macrophage infiltration or synoviocytes.

CONCLUSIONS

HDC + ASCT results in profound but incomplete immunoablation of both the memory and naïve T cell compartment, which is associated with longlasting clinical responses in most patients. The findings provide strong circumstantial evidence for a role of T cells in established RA, and demonstrate a role for the synovium in post-transplantation T cell reconstitution.

Synovial fluid neutrophils transcribe and express class II major histocompatibility complex molecules in rheumatoid arthritis

OBJECTIVE

To investigate a potential interaction between neutrophils and T cells in rheumatoid arthritis (RA), by defining the optimal conditions for induction of class II major histocompatibility complex (MHC) expression on peripheral blood neutrophils in vitro and investigating the capacity for neutrophils to express class II MHC molecules in RA.

METHODS

Surface expression of class II MHC and costimulatory molecules by peripheral blood and synovial fluid (SF) neutrophils obtained from healthy controls and patients with RA was measured by flow cytometry and fluorescence microscopy. Intracellular class II MHC protein and messenger RNA (mRNA) were detected by Western blotting and Northern blotting, respectively.

RESULTS

Freshly isolated peripheral blood neutrophils from controls did not express surface class II MHC; expression was induced by culture with appropriate cytokines. Freshly isolated peripheral blood neutrophils from patients with RA expressed mRNA, but there was no surface expression of class II MHC. Freshly isolated SF neutrophils from patients with RA contained high levels of class II MHC mRNA, did not express surface class II MHC, but did have large intracellular amounts of this protein as detected by Western blotting. After culture for 20 hours in vitro, SF neutrophils from RA patients expressed large amounts of surface class II MHC but very low levels of costimulatory molecules CD80 and CD86. Fluorescence microscopy localized surface class II MHC to discrete areas on the neutrophil. Class II MHC-expressing neutrophils stimulated T cell proliferation.

CONCLUSION

Peripheral blood neutrophils from patients with RA but not healthy controls express class II MHC mRNA. SF neutrophils in RA synthesize and express large amounts of class II MHC but not costimulatory molecules. This might underlie a novel interaction with T cells that is important in terms of disease pathology.

Efficacy of tacrolimus in rheumatoid arthritis patients who have been treated unsuccessfully with methotrexate: a six-month, double-blind, randomized, dose-ranging study

OBJECTIVE

To assess the efficacy, safety, and optimal dose of tacrolimus monotherapy in patients with rheumatoid arthritis (RA).

METHODS

This phase II, randomized, double-blind, placebo-controlled monotherapy study was set in 12 community sites and 9 university-based sites. Two hundred sixty-eight patients with RA who were resistant to or intolerant of methotrexate (mean dose 15.2 mg/week) and had active disease for at least 6 months (mean tender joint count 28.2, mean erythrocyte sedimentation rate 46.5 mm/hour) were randomized to receive treatment after discontinuation of methotrexate. Those who received at least 1 dose of tacrolimus were analyzed; 141 completed the study. Stable dosages of nonsteroidal antiinflammatory drugs and low-dose prednisone were allowed during treatment. All patients were given 1, 3, or 5 mg of tacrolimus or placebo once daily for 24 weeks. The American College of Rheumatology definition of 20% improvement (ACR20) and the tender and swollen joint counts at the end of treatment were the primary outcomes.

RESULTS

ACR20 response rates demonstrated a clear dose response. The ACR20 response was observed in 15.5% of patients receiving placebo (95% confidence interval [95% CI] 7.1-23.9%), 29% of the 1 mg tacrolimus group (95% CI 18.3-39.7%) (P < 0.058); 34.4% of the 3 mg group (95% CI 22.7-46.0%) (P < 0.013), and 50% of the 5 mg group (95% CI 37.8-62.3%) (P < or = 0.001). The tender joint count improved statistically significantly in all tacrolimus groups. The swollen joint count, physical function, and patient-assessed pain improved statistically significantly in the 3 mg and 5 mg groups. The incidence of creatinine elevation > or =40% above baseline levels increased in a dose-dependent manner. Dropout rates were high (41-59%) and were more common for inefficacy in the placebo patients (71.4%), whereas they were more common for toxicity in the high-dose tacrolimus groups (31-33%). Discontinuation for creatinine elevation occurred in the 3 mg (3.1%) and 5 mg (10.9%) tacrolimus groups.

CONCLUSION

Tacrolimus improved disease activity in methotrexate-resistant or -intolerant patients with RA. A dose response was observed when efficacy and toxicity were assessed at different doses. The optimal dose of tacrolimus appears to be >1 mg but < or=3 mg daily.

T-cell receptor repertoire in human germinal centres

A search for an antigen-driven expansion of T lymphocytes in the inflamed joints in rheumatoid arthritis (RA) patients have been going on for decades. We here analyzed the human germinal centre T-cell receptor (TCR) Vbeta gene usage with polymerase chain reaction (PCR) combined with sequence analysis, to address the question of clonality in tonsils and synovial tissue from RA patients. Our data show a large degree of TCR heterogeneity in both these histological structures. Furthermore, clonally related T cells were found within different closely located germinal centres indicating either an active T-cell migration between germinal centres (GC) or that a T-cell clone may seed more than one GC.

A revival of the B cell paradigm for rheumatoid arthritis pathogenesis?

Dominant paradigms for the understanding of rheumatoid arthritis (RA) pathogenesis have changed over the years. A predominant role of B lymphocytes, and perhaps of the rheumatoid factor they produced, was initially invoked. In more recent years, recognition of antigens in the joint by T cells sparking an inflammatory cascade has been a more favored interpretation. Here, we re-examine some of the arguments that underpin this proposed role of joint T cells, in light of recent results from transgenic mice in which a self-reactive T-cell receptor provokes disease, but from outside the joint and indirectly via B lymphocytes and immunoglobulins.