Takahiro Okazaki

Regulation of antigen-specific CTL and Th1 cell activation through 5-Hydroxytryptamine 2A receptor.

Serotonin (5-Hydroxytryptamine, 5-HT) is one of the most extensively studied neurotransmitters in the central nervous system. Also expressed in peripheral tissues, 5-HT participates in vasoconstriction and in aggregation of platelets through 5-HT(2A) receptor (5-HT2AR). However, there have been few studies regarding the interaction between 5-HT and 5-HT2AR in the immune system. In the current study, we analyzed the role of 5-HT and its 5-HT2AR in the activation of antigen-specific Th1 and cytotoxic T lymphocytes (CTL) in mice. RT-PCR and western blotting analyses confirmed the expression of 5-HT2AR in both CD4 and CD8 T cells. Both antigen-specific and anti-CD3 stimulation of IL-2 and IFN-γ production from these cells were inhibited by a selective 5-HT2AR inhibitor, sarpogrelate hydrochloride. Concanavalin A (ConA) activation of CD4(+) and CD8(+) T cells, which were purified from mouse spleen following depletion of endogenous 5-HT, was enhanced by a selective 5-HT2AR agonist, (R)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Such DOI-induced T cell activation was nullified by sarpogrelate. Moreover, an ELISPOT study showed that sarpogrelate also reduced antigen-specific induction of both CTL and Th1 cells in vivo following immunization of mice with cognate antigens. These data suggest that antigen-specific Th1 and CTL cells might be regulated by 5-HT signaling through 5-HT2AR on their surfaces and that 5-HT2AR inhibitor might have an immunosuppressive effect in vivo.

Immunosuppressive effect of angiotensin receptor blocker on stimulation of mice CTLs by angiotensin II

While angiotensin II, which is produced by the renin-angiotensin-aldosterone system, is considered to be the major regulator molecule that controls both the blood pressure and fluid system, there is an increasing body of evidence that this bioactive peptide and its receptor might also contribute to the immune system. However, there are few details known about the direct effect that angiotensin type I receptors (AT1R) have on the cytotoxic T cell (CTL). To clarify the relationship between angiotensin II and its CTL receptor, we used murine splenic and antigen-specific CTLs. Murine CTLs constantly expressed AT1R, with the activation of the AT1R expression strengthened by both anti-CD3 Ab and the use of an antigen-specific methodology. Moreover, the production of IFN-gamma and TNF-alpha through CTL stimulation can be inhibited by the selective AT1R inhibitor, Losartan. In particular, the TNF-alpha production from activated CTL that had been magnified by angiotensin II, was nullified by the AT1R inhibitor. However, a cytotoxic assay indicated it did not have any effect on the cognate interaction of the CTLs. In addition, the antigen-specific CTL induction by immunization with the CTL antigenic peptide was reduced by angiotensin II type 1 receptor blocker (ARB) in vivo. These findings suggest that ARBs might have the ability to suppress excessive antigen-specific activation and induction of CTLs promoted by angiotensin II.

Clinical subsets associated with different anti-aminoacyl transfer RNA synthetase antibodies and their association with coexisting anti-Ro52

Abstract Objective: To characterize clinical features of polymyositis/dermatomyositis (PM/DM) patients with different anti-aminoacyl transfer RNA synthetase (ARS) antibodies and their association with anti-Ro52. Methods: Autoantibodies in sera from 97 Japanese patients (36 PM, 56 DM, and 5 clinically amyopathic DM), who satisfied Bohan and Peter or modified Sontheimers criteria, were characterized by immunoprecipitation and enzyme-linked immunosorbent assay. Clinical information was from medical records. Features associated with different anti-ARS and anti-Ro52 antibodies were analyzed. Results: The prevalence of anti-ARS was similar to other studies (Jo-1, 22%; EJ, 4%; OJ, 1%; PL-12, 1%), except for a high prevalence of anti-PL-7 (12%), which allowed us to characterize patients carrying this specificity. Serum creatine kinase >3000 IU/l was less common in anti-PL-7-positive patients (57%) than anti-Jo-1-positive patients (18%) (p = 0.0328) and was not found in anti-EJ-positive individuals. Interstitial lung disease was common in anti-ARS-positive patients (97%) (p < 0.0001 vs. 48% in anti-ARS-negative). Anti-Ro52 antibodies were frequently detected with anti-ARS (59%) (57% in anti-Jo-1, 67% in anti-PL-7) (vs. 21% in anti-ARS-negative, p < 0.0002). Anti-Ro52 was associated with overlap syndrome (26%) (vs. 7% in anti-Ro52-negative, p = 0.0119). Conclusions: Patients with different anti-ARS in combination with anti-Ro52 appear to be associated with distinctive clinical subsets.

Advantage of higher-avidity CTL specific for Tax against human T-lymphotropic virus-1 infected cells and tumors.

Strong CTL response can be observed and associated with the control of proviral load in human T-lymphotropic virus type 1 (HTLV-1) infection. However, there are few details with regard to how HTLV-1 specific CTLs work against HTLV-1 infected cells and adult T-cell leukemia cells (ATLs). In this study, using Tax-specific CTL lines with high- and low-functional avidity developed from HLA-A2-transgenic mice, we showed that higher avidity CTLs specific for Tax expressing larger numbers of TCRs and better binding strength to the antigen-HLA-A2 complex are much more efficient at eliminating HTLV-1 infected cells and, in particular, ATL tumor cells with the ability of recognizing a latent level of Tax product detected only with a real-time PCR. These findings suggest that such higher avidity CTLs specific for Tax in HTLV-1 could be responsible for preventing the development of HTLV-1 infection by detecting trace amount of antigens.

Combined disease with pulmonary arterial hypertension and pulmonary venous hypertension revealed after treatment of heart failure with preserved ejection fraction in a case with primary Sjögren syndrome

A 49-year-old woman with primary Sjögren syndrome initially developed pulmonary venous hypertension (PVH) due to heart failure with preserved ejection fraction. Endomyocardial biopsy specimens showed mild myocardial fibrosis. Pulmonary arterial hypertension (PAH) was revealed after the treatment with diuretics. During the treatment for PAH using upfront combination with pulmonary vasodilators and immunosuppressants, the patient developed combined disease with PAH and PVH. A careful hemodynamic assessment is necessary in such cases.

T cells upon activation promote endothelin 1 production in monocytes via IFN-γ and TNF-α

Endothelin 1 (ET-1), mainly produced from vascular endothelial cells, induces vasoconstriction in physiological conditions. The endothelin receptor antagonist is among the most effective agents for pulmonary hypertension. However, little is known about the production source of ET-1 in inflammation and immunity. Here, we studied whether T cell-mediated ET-1 production system exists and operates independent of the production system in vascular endothelial cells. ET-1 production was readily detectable in the culture supernatant of human PBMCs and murine spleen cells stimulated with anti-CD3 antibody. Immunocytostaining showed that ET-1-producing cells emerged only in PBMCs stimulated with anti-CD3 antibody. Using the Transwell system, both murine and human monocytes sorted with magnetic beads in the inner chamber produced ET-1 when T cells were activated with antigen or anti-CD3 antibody in the outer chamber. This ET-1 production was inhibited by anti-IFN-γ and/or TNF-α antibody. Furthermore, monocytes purified from ETflox/flox;Tie2-Cre( + ) mice, which conditionally lack ET-1 in hematopoietic stem cells and vascular endothelial cells, did not produce ET-1 even when stimulated by antigen-specific T cell activation. This study demonstrates the existence of an immune-mediated ET-1 production induced by T cells upon activation through IFN-γ and TNF-α.

Vasculitis syndrome—diagnosis and therapy

In patients with connective tissue disease, vascular injury induced by primary or secondary vasculitis syndromes can lead to organ dysfunction due to the loss of nutrient supply from the blood. Such vasculitis syndromes can be refractory to treatment and fatal. The nomenclature and the definition of vasculitis syndromes have recently been revised, and clinical practice guidelines for diseases associated with vasculitis syndrome are evolving. The present review provides an overview of vasculitis syndromes from the viewpoint of diagnosis and treatment.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) in a patient with microscopic polyangiitis following low-dose intravenous cyclophosphamide: a possible pathogenic link with disease activity

Abstract Syndrome of inappropriate antidiuretic hormone secretion (SIADH) induced by cyclophosphamide (CY) in rheumatology has been rarely described. Most reported cases developed SIADH at the first administration of high-dose CY. We report the case of a 76-year-old female with microscopic polyangiitis (MPA) who developed SIADH during the seventh course of low-dose intravenous cyclophosphamide (IVCY). Our report suggested that SIADH may be developed at any course of IVCY treatment and a process other than CY toxicity may be involved. An exacerbation of interstitial lung disease (ILD) and overexpression of inflammatory cytokines may have contributed to the development of SIADH in this case. Since the active phase of MPA might be a risk factor for SIADH, MPA patients should be evaluated for subclinical SIADH.

Rhabdomyolysis in a Patient with Polyarteritis Nodosa

Polyarteritis nodosa (PAN) is a medium vessel vasculitis affecting systemic organs. Muscle involvement of PAN usually lacks elevation of creatinine kinase (CK). We herein report a case of PAN with rhabdomyolysis. A 71-year-old man was hospitalized because of muscle weakness of the lower limbs that persisted for 1 month. On a physical examination, rapidly progressive lower proximal muscle weakness and bilateral drop foot were observed. His blood test showed an elevation in the C-reactive protein (19.5 mg/dL) and CK (13,435 IU/L) levels and negativity for anti-neutrophilic cytoplasmic antibody. Computed tomographic angiography showed stenosis of the left renal artery. Electromyogram indicated mono-neuritis multiplex pattern, and enhanced magnetic resonance imaging demonstrated discretely granular hyperintensities on T2 and slow tau inversion recovery in his femoral muscles. A femoral muscle-biopsy specimen showed fibrinoid necrosis of medium-sized vessels and disruption of the elastic lamina of the vessel wall in fascia. Furthermore, muscle necrosis was localized depending on the arterial distribution, suggesting ischemic changes in the muscles. Given these findings, he was diagnosed with PAN with rhabdomyolysis and treated with methyl-prednisolone pulse therapy followed by oral prednisolone at 50 mg/day. He was additionally treated with monthly intravenous cyclophosphamide at 500 mg. Sustained remission has been obtained for two months since the treatment. Although rhabdomyolysis rarely manifests with PAN, it should be included in a differential diagnosis of febrile patients presenting with acute myalgia and weakness with CK elevation.

SAT0259 High plasma concentration of mycophenolate acid in early phase of induction therapy predicts good renal outcome in lupus nephritis class iii or iv

Background Mychophenolate mofetil (MMF) is recommended as initial induction treatment for most cases of lupus nephritis (LN) class III-IV. Although the association between area under the concentration-versus-time curve (AUC) of myochophenolate acid (MPA) and therapeutic efficacy has been well shown in renal transplantation, it has been poorly investigated in LN. Furthermore, MMF interacts with multiple factors and its concentration may be decreased by high prednisolone (PSL) dose, low serum albumin level and low creatinine clearance. Since these factors dramatically change in induction phase of LN, the plasma concentration of MPA may also change by fixed dose of MMF administration. Here, we measured AUC0–12 of MPA at different phases of induction treatment, early and middle, and prospectively investigated which concentration predicted future renal response in LN class III-IV. Objectives To investigate the relationship between the plasma concentration of MPA in early or middle phase of induction therapy and future renal response. Methods We prospectively enrolled patients with biopsy proven LN class III or IV who hospitalized from Apr to Oct 2016. As induction therapy, PSL was started at dose of 1mg/kg/day and tapered to 10mg/day by 12 weeks. Fixed dose of MMF at 2,000mg/day was continuously introduced. We measured 2 points of MPA plasma concentration depending on the phase of induction therapy, at early (week 2) and middle (week 12). We evaluated the association between these concentration and complete renal response (CR) rate at week 12. Results Six patients were enrolled. AUC0–12 between the early and the middle phase was not correlated (R2=0.17, p=0.7), but that of the early phase tended to be lower (47.4±25.6 vs 58.9±19.1 mgh/L). All the patients with high AUC0–12 (over 40mgh/L) at the early phase achieved CR at week 12 (Figure 1). But we could not find any association between AUC0–12 at middle phase and CR rate at week 12.Figure 1 Conclusions High AUC0–12 of MPA at the early phase of induction therapy might predict good renal response. Disclosure of Interest None declared