Yoshimasa Fujita

Anti-aminoacyl-tRNA synthetase antibodies in clinical course prediction of interstitial lung disease complicated with idiopathic inflammatory myopathies

In the treatment of polymyositis and dermatomyositis (PM/DM), the complication of interstitial lung disease (ILD) is an important prognostic factor. It has been reported that autoantibodies against aminoacyl-tRNA synthetases (ARS) are strongly associated with ILD. The aim of this study is to examine the correlation between anti-ARS and the clinical course of ILD. We investigated 41 cases of PM/DM with ILD. The response of ILD to corticosteroids (CS) was determined according to the change in respiratory symptoms, image findings, and pulmonary function between, before and 2 months after the treatment. Anti-ARS (anti-Jo-1, PL-7, PL-12, EJ, OJ and KS) antibodies were screened with the RNA immunoprecipitation assay. In the stratification into ILD-preceding, simultaneous and myopathy-preceding types, anti-ARS antibodies were significantly frequent in the ILD-preceding type (p < 0.05). In the stratification into anti-ARS-positive and negative groups, the response of ILD to CS was significantly better in the positive group (p < 0.05). However, recurrence of ILD was significantly more frequent in the positive group (p < 0.01), and 2 year prognoses of pulmonary function (%VC and %DLCO) were not different between the two groups. In conclusion, screening of anti-ARS may be useful to predict late-onset myopathy in ILD-preceding patients and to predict the clinical course of ILD in PM/DM patients.

Leptin inhibits stress-induced apoptosis of T lymphocytes

Leptin, which is secreted by adipocytes, the placenta and the stomach, not only controls appetite through leptin receptors in the hypothalamus but also regulates cell‐mediated immunity. In this study we have demonstrated that continuous injection of leptin prevents the reduction in lymphocyte numbers normally observed in fasted and steroid‐injected mice. Consistent with leptin‐induced protection, we observed up‐regulation of the bcl‐xL gene as a result of signal transduction via leptin receptors on lymphocytes. We suggest that leptin might contribute to the recovery of immune suppression in malnourished mice by inhibiting lymphocyte apoptosis.

Cutoff Values of Serum IgG4 and Histopathological IgG4+ Plasma Cells for Diagnosis of Patients with IgG4-Related Disease.

IgG4-related disease is a new disease classification established in Japan in the 21st century. Patients with IgG4-related disease display hyper-IgG4-gammaglobulinemia, massive infiltration of IgG4+ plasma cells into tissue, and good response to glucocorticoids. Since IgG4 overexpression is also observed in other disorders, it is necessary to diagnose IgG4-related disease carefully and correctly. We therefore sought to determine cutoff values for serum IgG4 and IgG4/IgG and for IgG4+/IgG+ plasma cells in tissue diagnostic of IgG4-related disease. Patients and Methods. We retrospectively analyzed serum IgG4 concentrations and IgG4/IgG ratio and IgG4+/IgG+ plasma cell ratio in tissues of 132 patients with IgG4-related disease and 48 patients with other disorders. Result. Serum IgG4 >135 u2009mg/dl demonstrated a sensitivity of 97.0% and a specificity of 79.6% in diagnosing IgG4-related disease, and serum IgG4/IgG ratios >8% had a sensitivity and specificity of 95.5% and 87.5%, respectively. IgG4+cell/IgG+ cell ratio in tissues >40% had a sensitivity and specificity of 94.4% and 85.7%, respectively. However, the number of IgG4+ cells was reduced in severely fibrotic parts of tissues. Conclusion. Although a recent unanimous consensus of all relevant researchers in Japan recently established the diagnostic criteria for IgG4-related disease, findings such as ours indicate that further discussion is needed.

Proposed diagnostic criteria, disease severity classification and treatment strategy for TAFRO syndrome, 2015 version

TAFRO syndrome is a systemic inflammatory disorder characterized by thrombocytopenia, anasarca including pleural effusion and ascites, fever, renal insufficiency, and organomegaly including hepatosplenomegaly and lymphadenopathy. Its onset may be acute or sub-acute, but its etiology is undetermined. Although several clinical and pathological characteristics of TAFRO syndrome resemble those of multicentric Castleman disease (MCD), other specific features can differentiate between them. Some TAFRO syndrome patients have been successfully treated with glucocorticoids and/or immunosuppressants, including cyclosporin A, tocilizumab and rituximab, whereas others are refractory to treatment, and eventually succumb to the disease. Early and reliable diagnoses and early treatments with appropriate agents are essential to enhancing patient survival. The present article reports the 2015 updated diagnostic criteria, disease severity classification and treatment strategy for TAFRO syndrome, as formulated by Japanese research teams. These criteria and classification have been applied and retrospectively validated on clinicopathologic data of 28 patients with this and similar conditions (e.g. MCD with serositis and thrombocytopenia).

Anti-U1 RNP antibodies in cerebrospinal fluid are associated with central neuropsychiatric manifestations in systemic lupus erythematosus and mixed connective tissue disease.

OBJECTIVEnTo determine the significance of anti-U1 RNP antibodies in the cerebrospinal fluid (CSF) of patients with systemic lupus erythematosus (SLE) or mixed connective tissue disease (MCTD) who have central neuropsychiatric SLE (NPSLE).nnnMETHODSnThe frequency of antinuclear antibodies including anti-U1 RNP antibodies in the sera and CSF of 24 patients with SLE and 4 patients with MCTD, all of whom had neuropsychiatric syndromes, was determined using an RNA immunoprecipitation assay and an enzyme-linked immunosorbent assay. The frequency of anti-U1 RNP antibodies in the CSF of patients with central NPSLE was examined, and the anti-U1 RNP index ([CSF anti-U1 RNP antibodies/serum anti-U1 RNP antibodies]/[CSF IgG/serum IgG]) was compared with CSF interleukin-6 (IL-6) levels and the albumin quotient (Qalb, an indicator of blood-brain barrier damage). CSF and serum antibodies against U1-70K, U1-A, and U1-C, including autoantigenic regions, were examined, and the U1-70K, U1-A, and U1-C indices as well as the anti-U1 RNP index were calculated.nnnRESULTSnCSF anti-U1 RNP antibodies with an increased anti-U1 RNP index showed 64.3% sensitivity and 92.9% specificity for central NPSLE. The anti-U1 RNP index did not correlate with CSF IL-6 levels or the Qalb. The anti-U1-70K index was higher than the anti-U1-A and anti-U1-C indices in the CSF of anti-U1 RNP antibody-positive patients with central NPSLE. The major autoantigenic region for CSF anti-U1-70K antibodies appeared to be localized in U1-70K amino acid 141-164 residue within the RNA-binding domain.nnnCONCLUSIONnThe frequency of anti-U1 RNP antibodies in the CSF and the anti-U1 RNP index are useful indicators of central NPSLE in anti-U1 RNP antibody-positive patients. The predominance of anti-U1-70K antibodies in CSF suggests intrathecal anti-U1 RNP antibody production.

Deficient leptin signaling ameliorates systemic lupus erythematosus lesions in MRL/Mp-Fas lpr mice.

Leptin is secreted by adipocytes, the placenta, and the stomach. It not only controls appetite through leptin receptors in the hypothalamus, it also regulates immunity. In the current study, we produced leptin-deficient MRL/Mp-Faslpr mice to investigate the potential role of leptin in autoimmunity. C57BL/6J-ob/ob mice were backcrossed with MRL/Mp-Faslpr mice, which develop human systemic lupus erythematosus (SLE)-like lesions. The effects of leptin deficiency on various SLE-like manifestations were investigated in MRL/Mp-Faslpr mice. The regulatory T cell population in the spleen was analyzed by flow cytometry, and the effects of leptin on regulatory T cells and Th17 cells were evaluated in vitro. Compared with leptin-producing MRL/Mp-Faslpr mice, leptin-deficient MRL/Mp-Faslpr mice showed less marked splenomegaly and a particularly low population of CD3+CD4−CD8−B220+ T cells (lpr cells). Their serum concentrations of Abs to dsDNA were lower, and renal histological changes at age 20 wk were ameliorated. Regulatory T cells were increased in the spleens of leptin-deficient MRL/Mp-Faslpr mice. Leptin suppressed regulatory T cells and enhanced Th17 cells in vitro. In conclusion, blockade of leptin signaling may be of therapeutic benefit in patients with SLE and other autoimmune diseases.

CD4+ T-cell dysfunctions through the impaired lipid rafts ameliorate concanavalin A-induced hepatitis in sphingomyelin synthase 1-knockout mice

Membrane microdomains consisting of sphingomyelin (SM) and cholesterol appear to be important for signal transduction in T-cell activation. The present study was designed to elucidate the role of membrane SM in vivo and in vitro using sphingomyelin synthase 1 (SMS1) knock out (SMS1(-/-)) mice and Concanavalin A (ConA)-induced hepatitis. After establishing SMS1(-/-) mice, we investigated CD4+ T-cell functions including proliferation, cytokine production and signal transduction in vivo. We also examined severity of hepatitis, cytokine production in serum and liver after ConA injection at a dose of 20 mg kg(-1). CD4+ T cells from SMS1(-/-) mice showed severe deficiency of membrane SM and several profound defects compared with wild-type controls as follows: (i) cellular proliferation and production of IL-2 and IFN-γ by co-cross-linking of CD3 and CD4; (ii) tyrosine phosphorylation of LAT and its association with ZAP-70; (iii) clustering and co-localization of TCR with lipid rafts. Consistent with these impaired CD4+ T-cell functions in vitro, SMS1(-/-) mice showed decreased serum levels of IL-6 and IFN-γ by ConA injection, which renders SMS1(-/-) mice less sensitive to ConA-induced hepatitis. These results indicated that the deficiency of membrane SM caused the CD4+ T-cell dysfunction through impaired lipid raft function contributed to protection of ConA-induced liver injury, suggesting that the membrane SM is critical for full T-cell activation both in vitro and in vivo.

Aseptic meningitis in mixed connective tissue disease: cytokine and anti-U1RNP antibodies in cerebrospinal fluids from two different cases.

In this paper, we report two patients with mixed connective tissue disease (MCTD) who developed aseptic meningitis. In both cases, the concentrations of IFN-γ and IL-6 in cerebrospinal fluid (CSF) were increased. In the first case, with non-steroidal anti-inflammatory drugs (NSAIDs)-induced meningitis, where anti-U1RNP antibodies (Abs) were not detected in CSF, NSAIDs induced both IFN-γ and IL-6 secretion from peripheral blood mononuclear cells in vitro. In the second case, with disease-associated meningitis, anti-U1RNP Abs were detected also in CSF. Of note, anti-U1RNP Abs appeared to be more concentrated in CSF than in serum and CSF-anti-U1RNP Ab titer was correlated with disease activity. We suggest that IFN-γ and IL-6 may be involved in both disease-associated and drug-induced aseptic meningitis, whereas CSF-anti-U1RNP Abs is detected only in a patient with MCTD-associated aseptic meningitis.

Upregulation of aquaporin expression in the salivary glands of heat-acclimated rats

It is known that aquaporin (AQP) 5 expression in the apical membrane of acinar cells in salivary glands is important for the secretion of saliva in rodents and humans. Although heat acclimation enhances saliva secretion in rodents, the molecular mechanism of how heat induces saliva secretion has not been determined. Here, we found that heat acclimation enhanced the expression of AQP5 and AQP1 in rat submandibular glands concomitant with the promotion of the HIF-1α pathway, leading to VEGF induction and CD31-positive angiogenesis. The apical membrane distribution of AQP5 in serous acinar cells enhanced after heat acclimation, while AQP1 expression was restricted to the endothelial cells in the submandibular glands. A network of AQPs may be involved in heat-acclimated regulation in saliva secretion. Because AQPs probably plays a crucial role in saliva secretion in humans, these findings may lead to a novel strategy for treating saliva hyposecretion.

Cellular heat acclimation regulates cell growth, cell morphology, mitogen-activated protein kinase activation, and expression of aquaporins in mouse fibroblast cells.

The heat shock response has been extensively studied by a number of investigators to understand the molecular mechanism underlying the cellular response to severe heat stress (higher than 42°C). But, body or tissue temperature increases by only a few degrees Celsius during physiological events. Therefore, the physiological cellular response to mild heat stress rather than severe heat stress is likely to be more important. Repeated exposure to hyperthermia for consecutive 5 days induces heat acclimation which is an adaptive physiological process in humans and animals. However, thus far, the effect of continuous exposure to heat stress on cells has not been fully evaluated. In this study, we investigated an adaptive physiological process that is induced in culture cells by continuous exposure to mild heat stress for 5 days. Exposure to heat activated p38-mitogen-activated protein kinase; inhibited cell growth without apoptosis; and increased the levels of HSPs and HSF-1 in mouse fibroblast cells. Interestingly, exposure to heat regulated the expression of aquaporins and induced morphological change. In a physiological sense, these results suggested that continuous exposure to mild heat stress for 5 days, in which heat acclimation is attained in humans and animals, might induce molecular adaptation to heat in cells.