Dysbiosis Contributes to Arthritis Development via Activation of Autoreactive T Cells in the Intestine

OBJECTIVE

The intestinal microbiota is involved in the pathogenesis of arthritis. Altered microbiota composition has been demonstrated in patients with rheumatoid arthritis (RA). However, it remains unclear how dysbiosis contributes to the development of arthritis. The aim of this study was to investigate whether altered composition of human intestinal microbiota in RA patients contributes to the development of arthritis.

METHODS

We analyzed the fecal microbiota of patients with early RA and healthy controls, using 16S ribosomal RNA-based deep sequencing. We inoculated fecal samples from RA patients and healthy controls into germ-free arthritis-prone SKG mice and evaluated the immune responses. We also analyzed whether the lymphocytes of SKG mice harboring microbiota from RA patients react with the arthritis-related autoantigen 60S ribosomal protein L23a (RPL23A).

RESULTS

A subpopulation of patients with early RA harbored intestinal microbiota dominated by Prevotella copri; SKG mice harboring microbiota from RA patients had an increased number of intestinal Th17 cells and developed severe arthritis when treated with zymosan. Lymphocytes in regional lymph nodes and the colon, but not the spleen, of these mice showed enhanced interleukin-17 (IL-17) responses to RPL23A. Naive SKG mouse T cells cocultured with P copri-stimulated dendritic cells produced IL-17 in response to RPL23A and rapidly induced arthritis.

CONCLUSION

We demonstrated that dysbiosis increases sensitivity to arthritis via activation of autoreactive T cells in the intestine. Autoreactive SKG mouse T cells are activated by dysbiotic microbiota in the intestine, causing joint inflammation. Dysbiosis is an environmental factor that triggers arthritis development in genetically susceptible mice.

MELD and Child-Pugh Scores Are Related to Immune Status of Intrahepatic Natural Killer Cells in Liver Transplant Candidates

BACKGROUND

The role and phenotypic alterations of intrahepatic natural killer (NK) cells in liver disease were investigated. Although intrahepatic NK cells reportedly functionally deteriorate in the fibrotic liver, it remains unclear how the clinical severity of liver disease affects intrahepatic NK cells in patients with advanced liver failure.

METHODS

We analyzed the phenotypic properties of intrahepatic NK cells by using mononuclear cells extracted from ex vivo liver perfusate effluents from patients who underwent liver transplantation. The relationship between the clinical severity of liver disease and the phenotype of intrahepatic NK cells in these patients was also evaluated. To estimate the immunological responsiveness of intrahepatic NK cells, phenotypic enhancement after interleukin-2 stimulation was analyzed.

RESULTS

Intrahepatic NK cells from patients with advanced liver failure exhibited down-regulated monomodal expression of NKp46, a major activating molecule. Notably, the expression level of NKp46 decreased depending on the severity of liver disease, Model for End-Stage Liver Disease score, and Child-Pugh score rather than the etiology. After in vitro recombinant interleukin-2 stimulation, the enhancement of expression of cytotoxic molecules, NKp44, and tumor necrosis factor-related apoptosis-inducing ligand was significantly impaired in intrahepatic NK cells from patients with liver failure, concurrently with decreased expression of CD122 and interleukin-2 receptor beta.

CONCLUSIONS

Our results suggest that terminal deterioration of liver environments by chronic liver disease impairs the potential of local NK cells, depending on the severity of the deterioration. These influences of advanced liver failure on intrahepatic NK cells may be attributed to multicentric carcinogenesis in patients with liver failure.

Sporotrichal Tenosynovitis Diagnosed Helpfully by Musculoskeletal Ultrasonography

A 72-year-old man presented with persistent oligoarthritis and positive results for rheumatoid factor and was suspected of having rheumatoid arthritis (RA). However, the musculoskeletal ultrasonography (MSUS) findings were not consistent with those of typical RA. He had undergone surgery for carpal tunnel syndrome, which allowed both histopathological and microbiological examinations to be performed. A synovial tissue culture was positive for Sporothrix schenckii, and he was diagnosed with sporotrichal tenosynovitis. He received anti-fungal therapy, and the sporotrichal tenosynovitis resolved. This case suggests that MSUS is a useful modality, and sporotrichal tenosynovitis, though rare, should be considered in the differential diagnosis of RA.

Single-channel Recordings of TREK-1 K+ Channels in Periodontal Ligament Fibroblasts

The periodontal ligament (PDL) works as a suspensory ligament when external mechanical stress is placed on the teeth. PDL fibroblasts, the principal cells in the PDL, are responsible for many PDL functions. We hypothesized that mechanosensitive ion channels are present in human PDL fibroblasts, which are capable of responding to mechanical stress during normal function of the tissue. Using patch-clamp techniques, we detected mechanosensitive TREK-1 K+ channels (a member of the two-pore-domain K+ channel family), whose single-channel conductance was 104 pS in symmetrical K+-rich solutions. The open probability of the channel was low in the quiescent state, but it was strongly increased by the induction of membrane stretch. Arachidonic acid also enhanced the channel activity. RT-PCR and immunocytochemical observations showed the expression of TREK-1 K+ channels in PDL fibroblasts. The results suggest that the activation of TREK-1 K+ channels by masticatory stress contributes to the hyperpolarization of PDL fibroblasts.

Safety and efficacy of CT-P13 in Japanese patients with rheumatoid arthritis in an extension phase or after switching from infliximab

OBJECTIVES

This study aimed to evaluate the safety of CT-P13 in patients with rheumatoid arthritis (RA) during long-term treatment or after switching from innovator infliximab (IFX).

METHODS

Patients who completed 54 weeks of treatment in a phase I/II study (PI/II) received CT-P13 at an initial dose of 3 mg/kg at Week 62, with dose increases permitted up to 10 mg/kg. The primary endpoint was adverse event (AE) incidence.

RESULTS

Thirty-four of 38 patients in the maintenance group and 29 of 33 in the switch group reported at least one AE. Safety profiles in both groups were similar to those in PI/II. Eleven of 28 patients who were positive for anti-drug antibodies (ADA) at Week 62 discontinued the study before Week 110. Forty-one of 43 ADA-negative patients remained negative, and 10 of 28 ADA-positive patients became negative during the study. The mean DAS28 (ESR) at Week 134 was 3.166 in the maintenance group and 3.955 in the switch group.

CONCLUSIONS

CT-P13 was well tolerated in patients who maintained the treatment after 54 weeks and in patients who switched to CT-P13 after 54 weeks of IFX treatment. The study also demonstrated a stable clinical efficacy of CT-P13 in RA patients.

Hemophagocytic lymphohistiocytosis with leukoencephalopathy in a patient with dermatomyositis accompanied with peripheral T-cell lymphoma: a case report

Background

Hemophagocytic lymphohistiocytosis associated with autoimmune diseases is seen in patients with systemic juvenile idiopathic arthritis, adult-onset Still’s disease, and systemic lupus erythematosus, whereas it is rarely seen in patients with dermatomyositis. In addition, central nervous system involvement with dermatomyositis is rare. To the best of our knowledge, this is the first case of hemophagocytic lymphohistiocytosis complicated by leukoencephalopathy in a patient with dermatomyositis accompanied with peripheral T-cell lymphoma.

Case presentation

A 17-year-old Asian male adolescent with dermatomyositis and hemophagocytic lymphohistiocytosis that were controlled with corticosteroid therapy presented to our hospital with high fever and altered consciousness. Brain magnetic resonance imaging revealed multiple cerebral lesions. We diagnosed the central nervous system lesions as leukoencephalopathy secondary to dermatomyositis and hemophagocytic lymphohistiocytosis. Because corticosteroid and cyclophosphamide pulse therapy was ineffective, he was treated with a modified hemophagocytic lymphohistiocytosis-2004 protocol, which resulted in the disappearance of the lesions of his central nervous system.

Conclusions

Our findings suggest that the hemophagocytic lymphohistiocytosis-2004 protocol including etoposide should be initiated immediately in patients with hemophagocytic lymphohistiocytosis who respond poorly to treatment for the underlying disease. Moreover, irrespective of the underlying disease, patients with hemophagocytic lymphohistiocytosis with central nervous system lesions might require bone marrow transplantation.

Incidence and Predictors of Biological Antirheumatic Drug Discontinuation Attempts among Patients with Rheumatoid Arthritis in Remission: A CORRONA and NinJa Collaborative Cohort Study

Objective.

We conducted a longitudinal observational study of biological disease-modifying antirheumatic drugs (bDMARD) to describe the proportions of patients with rheumatoid arthritis in remission who discontinued these agents, and to assess the potential predictors of the decision to discontinue.

Methods.

We used data from the US COnsortium of Rheumatology Researchers Of North America (CORRONA) and the Japanese National Database of Rheumatic Diseases by iR-net in Japan (NinJa) registries, and ran parallel analyses. Patients treated with bDMARD who experienced remission (defined by the Clinical Disease Activity Index ≤ 2.8) were included. The outcome of interest was the occurrence of bDMARD discontinuation while in remission. The predictors of discontinuation were assessed in the Cox regression models. Frailty models were also used to examine the effects of individual physicians in the discontinuation decision.

Results.

The numbers of eligible patients who were initially in remission were 6263 in the CORRONA and 744 in the NinJa. Among these patients, 10.0% of patients in CORRONA and 11.8% of patients in NinJa discontinued bDMARD while in remission over 5 years, whereas many of the remaining patients lost remission before discontinuing bDMARD. Shorter disease duration was associated with higher rates of discontinuation in both cohorts. In CORRONA, methotrexate use and lower disease activity were also associated with discontinuation. In frailty models, physician random effects were significant in both cohorts.

Conclusion.

Among patients who initially experienced remission while receiving bDMARD, around 10% remained in remission and then discontinued bDMARD in both registries. Several factors were associated with more frequent discontinuation while in remission. Physician preference likely is also an important correlate of bDMARD discontinuation, indicating the need for standardization of practice.

Low rates of biologic-free clinical disease activity index remission maintenance after biologic disease-modifying anti-rheumatic drug discontinuation while in remission in a Japanese multicentre rheumatoid arthritis registry

OBJECTIVE

To examine in detail the outcomes of biologic DMARD (bDMARD) discontinuation while in remission occurring in daily clinical practice settings. We examined a multicentre longitudinal registry of RA patients.

METHODS

We utilized data from the NinJa multicenter registry in Japan. Patients who used bDMARDs and had one or more successive visits in remission (defined by the clinical disease activity index (CDAI) ≤2.8) before discontinuation were included. The outcome of failing bDMARD-free disease control was defined as a composite of the following: re-use of bDMARDs, intensification of non-biologic DMARDs or of oral glucocorticoids, or loss of CDAI remission.

RESULTS

Among 1037 patients who initially achieved remission on bDMARDs, 46 patients discontinued bDMARDs while remaining in remission. Of these 46 subjects, 41 (89.1%) were female, the median disease duration was 6.0 years and 31 (70.5%) had reported radiographical erosions. At the baseline, 27 (58.7%) used MTX and 19 (41.3%) used oral glucocorticoids. The bDMARD-free remission failure rate was estimated to be 67.4% at 1 year and 78.3% at 2 years. Loss of remission and reuse of bDMARDs were the more common reasons for failure. Lower CDAI within the remission range was associated with fewer failures.

CONCLUSION

We found a high rate of failing bDMARD-free CDAI remission, indicating difficulty of maintaining disease control, even in patients who were in remission. Modification of non-biologic treatment was observed in some of the patients who remained in remission. Considering the cost of bDMARDs, such strategies for maintaining disease control after bDMARD discontinuation may be an important option.

Semaphorin 4D Contributes to Rheumatoid Arthritis by Inducing Inflammatory Cytokine Production: Pathogenic and Therapeutic Implications

Objective

Semaphorin 4D (Sema4D)/CD100 has pleiotropic roles in immune activation, angiogenesis, bone metabolism, and neural development. We undertook this study to investigate the role of Sema4D in rheumatoid arthritis (RA).

Methods

Soluble Sema4D (sSema4D) levels in serum and synovial fluid were analyzed by enzyme‐linked immunosorbent assay. Cell surface expression and transcripts of Sema4D were analyzed in peripheral blood cells from RA patients, and immunohistochemical staining of Sema4D was performed in RA synovium. Generation of sSema4D was evaluated in an ADAMTS‐4–treated monocytic cell line (THP‐1 cells). The efficacy of anti‐Sema4D antibody was evaluated in mice with collagen‐induced arthritis (CIA).

Results

Levels of sSema4D were elevated in both serum and synovial fluid from RA patients, and disease activity markers were correlated with serum sSema4D levels. Sema4D‐expressing cells also accumulated in RA synovium. Cell surface levels of Sema4D on CD3+ and CD14+ cells from RA patients were reduced, although levels of Sema4D transcripts were unchanged. In addition, ADAMTS‐4 cleaved cell surface Sema4D to generate sSema4D in THP‐1 cells. Soluble Sema4D induced tumor necrosis factor α (TNFα) and interleukin‐6 (IL‐6) production from CD14+ monocytes. IL‐6 and TNFα induced ADAMTS‐4 expression in synovial cells. Treatment with an anti‐Sema4D antibody suppressed arthritis and reduced proinflammatory cytokine production in CIA.

Conclusion

A positive feedback loop involving sSema4D/IL‐6 and TNFα/ADAMTS‐4 may contribute to the pathogenesis of RA. The inhibition of arthritis by anti‐Sema4D antibody suggests that Sema4D represents a potential therapeutic target for RA.

Monocyte CD64 expression as a novel biomarker for the disease activity of systemic lupus erythematosus

Objective

Interferon alpha (IFN-α) is a key cytokine associated with systemic lupus erythematosus (SLE). IFN-α induces the expression of CD64 on monocytes (mCD64). Although enhanced mCD64 expression has been reported in patients with SLE, it has never been assessed quantitatively. The aim of this study was to investigate whether or not mCD64 expression correlates with SLE disease activity.

Methods

The mCD64 expression levels were assessed quantitatively in 40 patients with active or inactive SLE by using flow cytometry. The mCD64 expression levels were subsequently compared with the SLE disease activity index (SLEDAI) and levels of existing SLE activity biomarkers, such as anti-DNA antibody, complements, and so on.

Results

The mCD64 expression was significantly higher in active disease than in inactive disease SLE (median molecules/cell, interquartile range: 34,648, 8174–24,932 and 20,865, 6357–21,503, respectively; p < 0.001). The levels of mCD64 expression strongly correlated with SLEDAI ( r = 0.68, p < 0.001).

Conclusion

The mCD64 expression is a simple and useful biomarker for evaluating disease activity in patients with SLE.

Clinical efficacy of simultaneous splenectomy in liver transplant recipients with hepatitis C virus

BACKGROUND

Interferon (IFN) therapy is a well-established antiviral treatment for hepatitis C virus (HCV) - infected patients. However, susceptibility to thrombocytopenia is a major obstacle in its initiation or continuation, particularly in patients with HCV who underwent liver transplantation (LT). We previously showed that the coexistence of splenomegaly and thrombocytopenia could result in persistent thrombocytopenia after LT. Here we retrospectively evaluated the validity of this criterion for simultaneous splenectomy in recipients with HCV.

PATIENTS AND METHODS

Subjects included 36 recipients with HCV who received LT between January 2006 and February 2012 at Hiroshima University. We analyzed the spleen volume, body surface area, platelet (PLT) count, and rate of completion or continuation with IFN therapy in these recipients.

RESULT

Of these recipients, 30 did not require simultaneous splenectomy according to the criterion, and 24 actually did not receive simultaneous splenectomy. In this group, 21 (87.5%) started IFN therapy. Fifteen (71.4%) of these recipients completed or continued IFN therapy, whereas 13 (61.9%) achieved either a sustained virological response (SVR) or an end-of-treatment response. The PLT count increased to >100,000/mm(3) 1 month after LT in 16 (66.7%) recipients from this group.

CONCLUSION

Our criterion detected the PLT count outcome after LT in recipients with HCV and achieved a better SVR result after IFN therapy.

Infection-immunity liaison: pathogen-driven autoimmune-mimicry (PDAIM)

Autoimmunity causes pathological conditions resulting in autoimmune diseases (ADs). Although autoimmunity is a mystery, immunological dogma suggests that autoreactive cell reactivation (ACR) breaks self-tolerance and induces autoimmunity. Thus, ACR is a royal pathway for ADs. Cumulative evidence implicates environmental factors as secondary triggers of ADs in the genetically susceptible hosts. Infection is the most likely trigger. Although several mechanisms have been proposed to explain how infectious agents trigger ADs, ACR is assumed to be an essential pathway. Here, by showing some exemplary ADs, we propose two novel pathways, "molecular modification pathway" and "hyper-immune-inflammatory response pathway", which induce AD-like conditions directly by infectious agents without ACR. These AD-like conditions are actually not true "ADs" according to the current definition. Therefore, we define them as "pathogen-driven autoimmune-mimicry (PDAIM)". Confirming PDAIM will open perspectives in developing novel fundamental and non-immunosuppressive therapies for ADs. The idea should also provide novel insights into both the mechanisms of autoimmunity and the pathogenesis of ADs.

Drug free REmission/low disease activity after cessation of tocilizumab (Actemra) Monotherapy (DREAM) study

OBJECTIVES

To investigate the duration of remission and low disease activity (LDA) after cessation of tocilizumab (TCZ) treatment in rheumatoid arthritis patients who showed remission or LDA as assessed by DAS28 in response to preceding TCZ monotherapy, and to explore the factors contributing to prolonged efficacy duration.

METHODS

Disease activity was monitored for 56 weeks. The rate of continued efficacy was estimated by Kaplan-Meier curves.

RESULTS

A total of 187 patients were eligible. At baseline of this study, median disease duration was 7.8 years, preceding TCZ treatment period was 4.0 years and DAS28 was 1.5. The rate of continued LDA at 52 weeks was 13.4 % according to the Kaplan-Meier estimate. 19 patients (10 %) were completely drug-free and 17 patients (9.1 %) fulfilled DAS28 remission at 52 weeks. Multivariate Cox regression analysis identified low serum IL-6 and normalisation of MMP-3 levels at cessation of TCZ as independent predictive markers for longer duration of LDA. In patients with low serum IL-6 (<12.9 pg/mL) and normal MMP-3 levels, the rate of continued LDA reached 38.0 % at 52 weeks.

CONCLUSIONS

TCZ monotherapy may induce biologics-free remission or LDA without concomitant use of synthetic DMARDs. Serum levels of IL-6 and MMP-3 are useful markers for identifying patients who could discontinue TCZ without acute disease flare.