Akinari Mizokami

FK506 augments activation-induced programmed cell death of T lymphocytes in vivo.

FK506 is an immunosuppressive drug that inhibits T cell receptor-mediated signal transduction. This drug can induce immunological tolerance in allograft recipients. In this study, we investigated the in vivo effects of FK506 on T cell receptor-mediated apoptosis induction. Injection of anti-CD3 antibody (Ab) in mice resulted in the elimination of CD4+ CD8+ thymocytes by DNA fragmentation. FK506 treatment significantly augmented thymic apoptosis induced by in vivo anti-CD3 Ab administration. Increased thymic apoptosis resulted in the disappearance of CD4+ CD8+ thymocytes after anti-CD3 Ab/FK506 treatment. DNA fragmentation triggered by FK506 was induced exclusively in antigen-stimulated T cells, since enhanced DNA fragmentation induced by in vivo staphylococcal enterotoxin B (SEB) injection was confirmed in SEB-reactive V beta 8+ thymocytes but not in SEB-nonreactive V beta 6+ thymocytes. In addition to thymocytes, mature peripheral T cells also die by activation-induced programmed cell death. A similar effect of FK506 on activation-induced programmed cell death was observed in SEB-activated peripheral spleen T cells. In contrast, cyclosporin A treatment did not enhance activation-induced programmed cell death of thymocytes and peripheral T cells. Apoptosis is required for the generation and maintenance of self-tolerance in the immune system. Our findings suggest that FK506-triggered apoptosis after elimination of antigen-activated T cells may represent a potential mechanism of the immunological tolerance achieved by FK506 treatment.

Increased levels of serum IgM antibody to staphylococcal enterotoxin B in patients with rheumatoid arthritis.

OBJECTIVE--To investigate the role of superantigen in rheumatoid arthritis (RA) by assaying the serum levels of staphylococcal enterotoxin B (SEB) antibodies. METHODS--Serum IgG and IgM SEB antibodies were measured using an enzyme linked immunosorbent assay (ELISA), and confirmed by Western blot analysis. The T cell receptor V beta (TCR V beta) repertoire was analysed using the reverse transcriptase polymerase chain reaction. RESULTS--RA patients had increased levels of serum IgM SEB antibody compared with normal subjects, patients with systemic lupus erythematosus, Sjögrens syndrome, and Behçets disease. The titres of rheumatoid factor (RF) showed no correlation with the levels of IgM SEB antibodies, and the levels of SEB antibodies were not inhibited by the addition of human immunoglobulin, or after absorption of RF. RA patients whose disease duration was less than 10 years had greater levels of serum IgM SEB antibodies than those with disease duration more than 10 years. The levels of IgM and IgG SEB antibodies in synovial fluid from RA patients were correlated with those in their sera. Western blot analysis detected IgM and IgG SEB antibodies as a band of approximately 30 kDa molecular size. The percentage of TCR V beta 2, V beta 5.2, and V beta 12 in phytohaemagglutinin stimulated peripheral T cells correlated significantly with the levels of serum IgM SEB antibody in RA patients. CONCLUSION--These results suggest that SEB, one of the superantigens, may have a critical role in the pathogenesis of RA.

Synovial cells are potent antigen‐presenting cells for superantigen, staphylococcal enterotoxin B (SEB)

There is ample evidence suggesting that superantigens may act as a triggering factor in the pathogenesis of rheumatoid arthritis (RA). We investigated whether superantigen could activate T cells in the presence of synovial cells. T cells were cultured with SEB in the presence of interferongamma (IFN‐γ)‐treated synovial cells. T cell proliferation and activation were assessed by 3H‐thymidine incorporation and IL‐2 production. The expression of HLA class II antigens and adhesion molecules on synovial ceils was detected by flow cytometer. In the presence of IFN‐γ‐treated synovial cells, T cells proliferated vigorously and produced IL‐2 in response to SEB. A low SEB‐induced T cell response was noticed in the presence of untreated synovial cells. Allogeneic as well as autologous IFN‐γ‐treated synovial cells markedly enhanced SEB‐induced T cell proliferation. IFN‐γ‐treated synovial cells had increased expression of HLA class II antigens and intercellular adhesion molecule‐1 (ICAM‐1) adhesion molecules. MoAbs towards these antigens markedly inhibited the SEB‐induced T cell response. These results indicate that activated synovial cells are potent antigen‐presenting cells for SEB to T cells, and that superantigens may play a critical role in the pathogenesis of RA through activated synovial cells.

A case of cytophagic histiocytic panniculitis: Successful treatment of recurrent attacks with steroid pulse therapy and oral cyclosporin A

SummaryWe report a 35-year-old man, who had been diagnosed with Weber-Christian disease, presented with acute onset of high fever, malaise, jaundice and hepatosplenomegaly with subcutaneous nodules. Laboratory tests showed elevated serum ferritin and liver enzymes, especially lactate dehydrogenase (LDH), with pancytopenia and coagulation abnormalities. Peripheral blood and bone marrow examinations showed erythro-, leuko- and thrombo-phagocytic histiocytes and macrophages. The patient developed the same clinical features seven years ago. Based on diagnosis of cytophagic histiocytic panniculitis, the patient was treated with steroid pulse therapy and oral cyclosporin A. The combination therapy caused a marked improvement in the clinical condition.

Up-regulation of human T lymphotropic virus type 1 (HTLV-1) tax/rex mRNA in infected lung tissues

HTLV‐1 has been implicated in certain pulmonary diseases. We previously demonstrated that expression of HTLV‐1 tax/rex mRNA, encoding the transcriptional transactivator Tax, was closely associated with infiltration of activated T lymphocytes into lung tissue. To explore mechanisms of tax/rex expression in the lung, tax/rex mRNA expression and proviral DNA load were compared between peripheral blood mononuclear cells (PBMC) and bronchoalveolar lavage cells (BALC) from four patients with HTLV‐1‐associated myelopathy (HAM/TSP) and 13 carriers with various pulmonary symptoms. Semiquantitative detection of tax/rex mRNA strongly suggested that the lung was a preferential site for its expression. Proviral DNA loads in non‐HAM/TSP carriers were variable but correlated well between PBMC and BALC in each individual, and revealed no relationship with tax/rex mRNA expression. In contrast, both cell groups from four HAM/TSP patients expressed detectable tax/rex mRNA accompanied by high proviral DNA load. The ratio of tax/rex mRNA expression to proviral DNA load was higher in BALC than in PBMC in three of four carriers and in three of four HAM/TSP patients, suggesting up‐regulation of tax/rex mRNA in infected lung tissue. To analyse differences in distribution of HTLV‐1 quasispecies between the two tissues, phylogenetic analysis was performed for sequence sets of the proviral tax open reading frame (ORF: 1059 bp) derived from PBMC and BALC of two infected individuals. Sequences derived from the two tissues distributed similarly to branches of phylogenetic trees, and there was no evidence of selective distribution of certain quasispecies in the lung. Our results suggest the presence of tissue‐specific conditions that activate viral expression in infected cells in the lung. Constitutive exposure of this tissue to foreign antigens leading to up‐regulation of basal viral promoter activity is likely to be one such mechanism.

Comparative molecular analysis of HTLV-I proviral DNA in HTLV-I infected members of a family with a discordant HTLV-I-associated myelopathy in monozygotic twins

In order to elucidate the underlying mechanisms of a discordant case with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in monozygotic twins, we investigated HTLV-I tax sequences of 10 - 18 polymerase chain reaction-based clones each derived from peripheral blood mononuclear cells of the twins as well as their infected mother and an elder brother who also suffered from HAM/TSP. Sequence comparison revealed that three of the infected individuals including a twin with HAM/TSP shared the consensus tax sequence identical to the reference, ATK-1, but that of another healthy twin was different at five nucleotide positions including three nonsynonymous changes from ATK-1. This finding strongly suggested that different HTLV-I strains infected the monozygotic twins and the difference in infected proviral sequences determined the discordant clinical outcomes. Transfection and subsequent reporter assays failed to show a significant difference in transactivation activity on HTLV-I LTR and NF-kappaB elements between the products of the two sequences. Two HAM/TSP patients (a twin and elder brother) among three members infected with the ATK-1 type virus shared a paternal HLA allele which was absent in the healthy individual (mother). Genetic analysis of sequence variation in the tax sequences of the discordant twins showed that the Dn/Ds ratio was high in the healthy twin but low in the twin with HAM/TSP, implying the presence of more intense selection forces in the carrier. Our findings strongly suggested that a particular combination of HTLV-I strains with an HLA genotype would be a risk for HAM/TSP.

Increased prevalence of MEFV exon 10 variants in Japanese patients with adult-onset Still's disease.

Autoinflammatory diseases include a large spectrum of monogenic diseases, e.g. familial Mediterranean fever (FMF), as well as complex genetic trait diseases, e.g. adult‐onset Stills disease (AOSD). In populations where FMF is common, an increased MEFV mutation rate is found in patients with rheumatic diseases. The aim of this study was to examine MEFV mutations in Japanese patients with AOSD. Genomic DNA was isolated from 49 AOSD patients and 105 healthy controls, and exons 1, 2, 3 and 10 of the MEFV gene genotyped by direct sequencing. MEFV mutation frequencies in AOSD patients were compared with controls. We found no significant difference in overall allele frequencies of MEFV variants between AOSD patients and controls. However, MEFV exon 10 variants (M694I and G632S) were significantly higher in AOSD patients than controls (6·1 versus 0%). In addition, there was no significant difference between MEFV variant carriers and non‐carriers with clinical manifestations, but the monocyclic clinical course of the AOSD disease phenotype was observed less frequently in patients without MEFV variants. AOSD patients had significantly higher frequencies of MEFV exon 10 mutations, suggesting that low‐frequency variants of MEFV gene may be one of the susceptibility factors of AOSD.

Clinical significance of anti-citrullinated peptide antibody in Japanese patients with established rheumatoid arthritis.

First Department of Internal Medicine, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki University School of Health Science, Gotokai Hospital, Nagasaki North Hospital, Nagasaki Citizen Hospital, Labour Welfare Corporation Nagasaki Rosai Hospital, The Japanese Red Cross Nagasaki Atomic Bomb Hospital, Department of Public Health, Graduate School of Biomedical Sciences, Department of Radiology and Radiation Research, Graduate School of Biomedical Sciences, Kurume University School of Medicine, Medical Centre, The First Department of Internal Medicine, Kurume University School of Medicine, National Ureshino Hospital, Sasebo Central Hospital, and Isahaya General Hospital, Japan

Comparative risk of hospitalized infection between biological agents in rheumatoid arthritis patients: A multicenter retrospective cohort study in Japan

Objective Knowing the risk of hospitalized infection associated with individual biological agents is an important factor in selecting the best treatment option for patients with rheumatoid arthritis (RA). This study examined the comparative risk of hospitalized infection between biological agents in a routine care setting. Methods We used data for all RA patients who had first begun biological therapy at rheumatology divisions of participating community hospitals in Japan between January 2009 and December 2014. New treatment episodes with etanercept, infliximab, adalimumab, abatacept, or tocilizumab were included. Patients were allowed to contribute multiple treatment episodes with different biological agents. Incidence rates (IRs) of hospitalized infection during the first year of follow-up were examined. Cox regression analysis was used to calculate hazard ratios (HRs) for overall hospitalized infection and for pulmonary hospitalized infection, adjusting for possible confounders. Results A total of 1596 new treatment episodes were identified. The incidence of overall hospitalized infection during the first year was 86 with 1239 person-years (PYs), yielding a crude IR of 6.9 per 100 PYs (95% confidence interval [CI], 5.6–8.6). After correction for confounders, no significant difference in risk of hospitalized infection was observed between treatment groups: adjusted HRs (95% CI) were 1.54 (0.78–3.04) for infliximab, 1.72 (0.88–3.34) for adalimumab, 1.11 (0.55–2.21) for abatacept, and 1.02 (0.55–1.87) for tocilizumab compared with etanercept. Patient-specific factors such as age, RA functional class, body mass index (BMI), prednisolone use, and chronic lung disease contributed more to the risk of hospitalized infection than specific biological agents. The incidence of pulmonary hospitalized infection was 50 and a crude IR of 4.0 per 100 PYs (95% CI, 3.1–5.3). After adjustment for confounders, adalimumab had a significantly higher HR for pulmonary hospitalized infection compared with tocilizumab: an adjusted HR (95% CI) was 4.43 (1.72–11.37) for adalimumab. BMI, prednisolone use, diabetes mellitus, and chronic lung disease were also significant factors associated with the risk of pulmonary hospitalized infection. Conclusions The magnitude of the risk of overall hospitalized infection was not determined by the type of biological agents, and patient-specific risk factors had more impact on the risk of hospitalized infection. For pulmonary hospitalized infections, the use of adalimumab was significantly associated with a greater risk of this complication than tocilizumab use.

Ultrasound-detected bone erosion is a relapse risk factor after discontinuation of biologic disease-modifying antirheumatic drugs in patients with rheumatoid arthritis whose ultrasound power Doppler synovitis activity and clinical disease activity are well controlled

BackgroundIn the present study, we explored the risk factors for relapse after discontinuation of biologic disease-modifying antirheumatic drug (bDMARD) therapy in patients with rheumatoid arthritis (RA) whose ultrasound power Doppler (PD) synovitis activity and clinical disease activity were well controlled.MethodsIn this observational study in clinical practice, the inclusion criteria were based on ultrasound disease activity and clinical disease activity, set as low or remission (Disease Activity Score in 28 joints based on erythrocyte sedimentation rate <3.2). Ultrasound was performed in 22 joints of bilateral hands at discontinuation for evaluating synovitis severity and presence of bone erosion. Patients with a maximum PD score ≤1 in each joint were enrolled. Forty patients with RA were consecutively recruited (November 2010–March 2015) and discontinued bDMARD therapy. Variables at the initiation and discontinuation of bDMARD therapy that were predictive of relapse during the 12 months after discontinuation were assessed.ResultsThe median patient age was 54.5 years, and the median disease duration was 3.5 years. Nineteen (47.5%) patients relapsed during the 12 months after the discontinuation of bDMARD therapy. Logistic regression analysis revealed that only the presence of bone erosion detected by ultrasound at discontinuation was predictive of relapse (OR 8.35, 95% CI 1.78–53.2, p = 0.006). No clinical characteristics or serologic biomarkers were significantly different between the relapse and nonrelapse patients. The ultrasound synovitis scores did not differ significantly between the groups.ConclusionsOur findings are the first evidence that ultrasound bone erosion may be a relapse risk factor after the discontinuation of bDMARD therapy in patients with RA whose PD synovitis activity and clinical disease activity are well controlled.