Kazuhiro Kurasawa

Increased interleukin-17 production in patients with systemic sclerosis.

OBJECTIVE To determine the role of a novel T cell-derived cytokine, interleukin-17 (IL-17), which activates fibroblasts and endothelial cells, in the pathogenesis of systemic sclerosis (SSc). METHODS We examined IL-17 production by lymphocytes from the peripheral blood (PBL) and from fibrotic lesions of the skin and lungs of SSc patients by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. We also studied the effect of IL-17 on the proliferation of fibroblasts and on the production of cytokines and the expression of adhesion molecules on endothelial cells in vitro. RESULTS IL-17 messenger RNA was expressed in unstimulated PBL and lymphocytes from the skin and lungs of SSc patients, but not in similar samples from patients with systemic lupus erythematosus (SLE) or polymyositis/dermatomyositis or from healthy donors. IL-17 levels were also increased in the serum of SSc patients, but not in that of SLE patients or healthy donors. IL-17 overproduction was significantly related to the early stage of SSc, but not to other clinical features of SSc. Moreover, IL-17 enhanced the proliferation of fibroblasts and induced the expression of adhesion molecules and IL-1 production in endothelial cells in vitro. CONCLUSION IL-17 is overproduced by T cells from the peripheral blood and fibrotic lesions of the skin and lungs in SSc patients. These results suggest that IL-17 overproduction plays an important role in the pathogenesis of SSc, especially in the early stages of the disease, by inducing the proliferation of fibroblasts and the production of IL-1 and the expression of adhesion molecules on endothelial cells.

Effect of FK-506, a novel immunosuppressive drug on murine systemic lupus erythematosus

A novel immunosuppressive compound extracted from the fermentation broth of Streptomyces tsukubaensis belongs to the macrolide family. We gave this drug (FK-506) to MRL/lpr and NZB X NZW F1 (B/W F1) mice, an animal model of human systemic lupus erythematosus (SLE), to investigate its effect on the course of the disease. This drug showed potential to prolong the lifespan, to reduce proteinuria, and to prevent the progression of nephropathy. Appreciable differences in the levels of anti-dsDNA antibodies between treated and control animals were nil.

Involvement of JAK2, but not PI 3‐kinase/Akt and MAP kinase pathways, in anti‐apoptotic signals of GM‐CSF in human eosinophils

Granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) transmits anti‐apoptotic signals in eosinophils and is involved in tissue eosinophilia at the site of allergic inflammation. We determined whether phosphatidylinositol 3‐kinase (PI 3‐kinase) and mitogen‐activated protein kinase (MAP kinase) are involved in anti‐apoptotic signals of GM‐CSF in eosinophils. GM‐CSF phosphorylated Akt, a downstream component of PI 3‐kinase, and MAP kinases (ERK1 and ERK2) at 10 min after stimulation in eosinophils. GM‐CSF prevented eosinophil apoptosis and sustained its survival during the 5‐day culture. However, neither two PI‐3 kinase inhibitors, wortmannin and LY294002, nor MEK inhibitor PD98059 inhibited GM‐CSF‐induced survival of eosinophils, although wortmannin and PD98059 inhibited GM‐CSF‐induced Akt phosphorylation and MAP kinase activation in eosinophils, respectively. In contrast, JAK2 inhibitor AG‐490 inhibited both GM‐CSF‐induced JAK2 phosphorylation and cell survival in eosinophils. These results indicate that activation of JAK2, but not activation of PI 3‐kinase/Akt and MAP kinase pathways, is critical for anti‐apoptotic signals of GM‐CSF in human eosinophils. Our findings suggest that manipulation of JAK2 activation would be useful for the treatment of allergic disorders. J. Leukoc. Biol. 65: 700–706; 1999.

Activation of pulmonary T cells in corticosteroid‐resistant and ‐sensitive interstitial pneumonitis in dermatomyositis/polymyositis

To study the activation states and cytokine profiles of pulmonary T cells in corticosteroid‐resistant and corticosteroid‐sensitive interstitial pneumonitis (IP) in dermatomyositis (DM)/polymyositis (PM), we examined the activation markers and cytokine profiles of T cells in bronchoalveolar lavage fluids (BALF) from patients with IP in DM/PM before prednisolone therapy and then compared the activation states of T cells according to the therapeutic response of IP to prednisolone therapy. CD25+ CD4+ T cells in BALF were significantly increased in both corticosteroid‐resistant and corticosteroid‐sensitive IP in DM/PM as compared with those in controls without IP. Furthermore, CD25+ CD4+ T cells in BALF were significantly more increased in corticosteroid‐resistant IP than those in cortico teroid‐ sensitive IP. Moreover, CD25+ CD8+ T cells in BALF were significantly increased only in corticosteroid‐resistant IP, but not in corticosteroid‐sensitive IP or controls without IP. IFN‐γ mRNA was detected in BALF T cells in corticosteroid‐resistant and corticosteroid‐sensitive IP but not in controls without IP, whereas IL‐4 mRNA was virtually undetected in BALF T cells in both the IP groups. However, there were no significant differences in CD4/CD8 ratio of BALF T cells, HLA‐DR+ BALF T cells or CD25+ and HLA‐DR+ peripheral blood T cells between the two IP groups. These results indicate that activated Th1‐type pulmonary T cells play an important role in the development of corticosteroid‐ resistant IP in DM/PM and that the increase in CD25+ CD8+ T cells in BALF is a useful indicator for corticosteroid‐resistant IP in DM/PM and hence may be an indicator for early use of cyclosporin.

Platelet-activating factor activates mitogen-activated protein kinases through the activation of phosphatidylinositol 3-kinase and tyrosine kinase in human eosinophils.

We determined whether platelet‐activating factor (PAF) activates mitogen‐activated protein (MAP) kinases in human eosinophils, and if so, which signaling pathways are utilized for the MAP kinase activation. PAF activated 42‐and 44‐kDa MAP kinases (ERK1/ERK2) in eosinophils, which became maximal at 1 min after stimulation. The PAF receptor antagonist E6123 and pertussis toxin inhibited the PAF‐induced MAP kinase activation in eosinophils. The phosphatidylinositol 3‐kinase (PI 3‐kinase) inhibitor wortmannin, tyrosine kinase inhibitors herbimycin A and genistein, and an intracellular Ca2+ chelator BAPTA/AM inhibited PAF‐induced MAP kinase activation in eosinophils, whereas protein kinase C inhibitors staurosporine and calphostin C had no effect. Furthermore, wortmannin as well as herbimycin A and genistein, but not BAPTA/AM, prevented PAF‐induced tyrosine phosphorylation of Shc adapter protein in eosinophils. Finally, the specific MEK inhibitor PD98059 inhibited PAF‐induced chemotaxis in eosinophils. Taken together, these results indicate that PAF activates MAP kinases in eosinophils through the activation of PI 3‐kinase and a tyrosine kinase and the increase in intracellular Ca2+ and that PAF‐induced MAP kinase activation mediates chemotaxis in eosinophils. J. Leukoc. Biol. 67: 117–126; 2000.

T-Lymphocyte–Receptor Repertoire of Infiltrating T Lymphocytes Into NOD Mouse Pancreas

This study analyzed T-lymphocyte–receptor Vβ genes of infiltrating lymphocytes into the pancreases of 12-to 16-wk-old NOD mice with severe insulitis and 5-wk-old mice with mild insulitis by the quantitative polymerase chain reaction method. The Vβ transcripts on infiltrating T lymphocytes into pancreases with severe insulitis in older NOD mice were diverse. In contrast, the Vβ11 gene transcript was predominantly expressed on T lymphocytes in the pancreas in younger NOD mice with mild insulitis, suggesting the possible role of Vβ11+ T lymphocytes in triggering insulitis in this species.

Detection of Inflammatory Lesions by F-18 Fluorodeoxyglucose Positron Emission Tomography in Patients with Polymyositis and Dermatomyositis

Objective. To evaluate the usefulness of F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in the management of patients with inflammatory myopathy. We examined whether FDG-PET scanning detects myositis or extramuscular lesions in patients with polymyositis (PM) and dermatomyositis (DM). Methods. FDG-PET imaging was performed in 24 patients with active inflammatory myopathy (PM, 11; DM, 13). The images were read by radiologists in a blinded manner. FDG uptake into muscles was judged positive when the intensity of muscles was higher than or equal to that of the liver. As controls, FDG imaging findings of patients with a lung mass and without muscle diseases were used. To investigate associations between FDG-PET findings and clinical/laboratory findings, the patients’ medical records were reviewed retrospectively. Results. Increased FDG uptake in muscles was found in 8 of 24 (33%) patients. In 67 of 69 (97%) controls without muscle diseases, no muscle FDG uptake was detected. The sensitivity of FDG-PET to detect myositis was lower than that of electromyogram (EMG), magnetic resonance imaging, and muscle biopsy. There were no significant differences in clinical manifestations between patients with and without increased FDG uptake in muscles, although patients with FDG muscle uptake had a tendency to have extended myositis with endomysial cell infiltration. FDG-PET detected neoplasms in patients with associated malignancy. FDG uptake in lungs was found in 7 of 18 patients with interstitial lung disease. Conclusion. FDG-PET imaging has limited usefulness for the evaluation of myositis in patients with PM/DM because of its low sensitivity, although it might be useful for detection of malignancy in these patients.

CD4-CD8- T cells bearing invariant Vα24JαQ TCR α-chain are decreased in patients with atopic diseases

Atopic disorders are caused by disregulated activation of T helper 2 (Th2) cells that produce IL‐4 and IL‐5. Because the presence of IL‐4 potently augments the differentiation of naive T cells into Th2 cells, it is important to seek the cell population which provides IL‐4 for naive T cells. Recently, a unique subpopulation of T cells, natural killer (NK) T cells, has been shown to produce a large amount of IL‐4 upon activation, suggesting their regulatory role in initiation of Th2 cell differentiation. To determine whether NK T cells play a regulatory role in human Th2 cell‐mediated atopic diseases, we analysed the frequency of invariant Vα24JαQ CD4−CD8− double‐negative (DN) T cells, human NK T cells, in patients with atopic asthma and atopic dermatitis. We also studied cytokine production from Vα24+ Vβ11+ DN T cells, which comprise most of Vα24JαQ DN T cells. We found that the invariant Vα24JαQ DN T cells were greatly diminished in patients with asthma and atopic dermatitis. On the other hand, there was no significant difference in Vα24+ CD4+ T cells possessing invariant Vα24JαQ TCR between healthy subjects and atopic patients. We also found that Vα24+ Vβ11+ DN T cells from healthy subjects predominantly produced interferon‐gamma (IFN‐γ) but not IL‐4 upon activation. These results suggest that NK T cells may not be essential for human atopic disease and that the disappearance of NK T cells, most of which produce IFN‐γ, may be involved in the pathogenesis of atopic diseases.

Anti-TIF1-γ antibody and cancer-associated myositis A clinicohistopathologic study

Objective:We aimed to analyze the clinical and histopathologic features of cancer-associated myositis (CAM) in relation to anti–transcriptional intermediary factor 1 &ggr; antibody (anti-TIF1-&ggr;-Ab), a marker of cancer association. Methods:We retrospectively studied 349 patients with idiopathic inflammatory myopathies (IIMs), including 284 patients with pretreatment biopsy samples available. For the classification of IIMs, the European Neuromuscular Center criteria were applied. Patients with CAM with (anti-TIF1-&ggr;-Ab[+] CAM) and without anti-TIF1-&ggr;-Ab (anti-TIF1-&ggr;-Ab[−] CAM) were compared with patients with IIM without cancers within and beyond 3 years of myositis diagnosis. Results:Cancer was detected in 75 patients, of whom 36 (48%) were positive for anti-TIF1-&ggr;-Ab. In anti-TIF1-&ggr;-Ab(+) patients with CAM, cancers were detected within 1 year of myositis diagnosis in 35 (97%) and before 1 year of myositis diagnosis in 1. All the anti-TIF1-&ggr;-Ab(+) patients with CAM satisfied the dermatomyositis (DM) criteria, including 2 possible DM sine dermatitis cases, and were characterized histologically by the presence of perifascicular atrophy, vacuolated fibers (VFs), and dense C5b-9 deposits on capillaries (dC5b-9). In contrast, 39 anti-TIF1-&ggr;-Ab(−) patients with CAM were classified into various subgroups, and characterized by a higher frequency of necrotizing autoimmune myopathy (NAM). Notably, all 7 patients with CAM classified into the NAM subgroup were anti-TIF1-&ggr;-Ab(−) and exhibited no dC5b-9 or VFs. Conclusions:CAM includes clinicohistopathologically heterogeneous disease entities. Among CAM entities, anti-TIF1-&ggr;-Ab(+) CAM has characteristically shown a close temporal association with cancer detection and the histopathologic findings of dC5b-9 and VFs, and CAM with NAM is a subset of anti-TIF1-&ggr;-Ab(−) CAM.

Short-term administration of anti-L3T4 MoAb prevents diabetes in NOD mice.

We treated 2‐week‐old and 8‐week‐old non‐obese diabetic (NOD) mice with 1 mg of anti‐L3T4 MoAb weekly for 4 weeks. This short‐term treatment of anti‐L3T4 MoAb prevented the development of overt diabetes in NOD mice, in both groups, even after cessation of the therapy. However, there were overt mononuclear cell infiltrations in the majority of islets, and no appreciable differences in the degree of insulitis between treated and control mice. There were also no significant differences in the percentage of L3T4+ T cells expressing Vβ5, Vβ8 and Vβ11 antigens between the treated and the control group. In contrast, most of male NOD mice injected with 200 mg/kg of cyclophosphamide did not become diabetic when the spleen cells from the MoAb‐treated female NOD mice were transferred to these animals 48 h before the cyclophosphamide injection. Thus, the tolerance induced by the short‐term administration of anti‐L3T4 MoAb to NOD mice may not be due to clonal deletion, but rather to newly generated suppressor cells in the animals.