Yuko Ota

Anti-MDA5 antibody, ferritin and IL-18 are useful for the evaluation of response to treatment in interstitial lung disease with anti-MDA5 antibody-positive dermatomyositis

OBJECTIVE The aim of this study was to investigate the precise clinical characteristics and to analyse the association between the anti-MDA5 antibody (anti-MDA5ab) titre and disease status in patients with anti-MDA5ab-positive DM. METHODS Twenty-seven patients who presented with DM and were positive for the anti-MDA5ab were enrolled. The association between the clinical manifestations and the clinical parameters, including the anti-MDA5ab, was analysed. RESULTS The complication of rapidly progressive interstitial lung disease (RP-ILD) occurred in 20 (74%) patients. The frequencies of fatal outcome, relapse and malignancy were 33, 4 and 4%, respectively. Remarkably, a fatal outcome occurred within the first 6 months. Compared with six non-RP-ILD patients, elderly age at onset, severely involved pulmonary function and high levels of serum ferritin were present in 20 RP-ILD patients with anti-MDA5ab. Alveolar-arterial oxygen difference (AaDO(2)) ≥32 mmHg and ferritin ≥828 ng/ml at admission were poor prognostic factors in RP-ILD patients with anti-MDA5ab-positive DM. The median value of the anti-MDA5ab titre on admission was higher in patients who later died than in those who survived. The efficacy of treatment was indicated by the anti-MDA5ab, ferritin and IL-18 concentrations. The decline index of the anti-MDA5ab titre after treatment was lower in the subset of patients who died than in the subset of patients who lived. Sustained high levels of anti-MDA5ab, ferritin and IL-18 were present in the patients who died. CONCLUSION Anti-MDA5ab titre and ferritin and IL-18 concentrations are useful for the evaluation of the response to treatment and the status of ILD in patients with anti-MAD5ab-positive DM.

Increased ferritin predicts development and severity of acute interstitial lung disease as a complication of dermatomyositis

OBJECTIVES Acute/subacute interstitial pneumonia (A/SIP) is an intractable and fatal complication of DM. Since a useful indicator predicting the complication of A/SIP has not been found, the aim of this study was to determine whether serum ferritin is a potential predictive indicator of the occurrence of A/SIP in 64 patients with DM. METHODS Of the total patients enrolled, 19 had A/SIP, 24 had chronic interstitial pneumonia and 21 were without interstitial lung disease (ILD). Clinical manifestations and laboratory data were obtained from medical records on admission. RESULTS Serum ferritin levels were extremely high in patients with DM with A/SIP. It was significantly higher in DM with A/SIP than that in DM without A/SIP (median 790 vs 186 ng/ml; P < 0.0001). The cumulative survival rate for 6 months was 62.7% in patients with DM with A/SIP. Moreover, the cumulative survival rate was significantly (P = 0.016) lower in the group with ferritin levels > or =1500 ng/ml than the rate in the group with ferritin levels <1500 ng/ml. CONCLUSIONS Serum ferritin can be useful as a predictor of the occurrence of A/SIP and correlates with the prognosis of A/SIP in DM. The intensive treatment using combination therapy with various immunosuppressant agents should be chosen for patients with ILD with DM showing hyperferritinaemia, especially levels >1500 ng/ml.

Clinical manifestations of neurological involvement in primary Sjögren’s syndrome.

The aim of this study was to evaluate neurological manifestations of primary Sjögren’s syndrome (pSS) and investigate the etiology and pathogenesis of peripheral and central nervous complications in pSS. Thirty-two patients with pSS were enrolled in the present study, 20 of whom had neurological involvement plus sicca symptoms. The clinical features were evaluated by neurological examinations including nerve conduction study, magnetic resonance imaging, cerebrospinal fluid, and electroencephalogram. The frequency of fever was significantly higher (P = 0.006) in pSS with neurological involvement than in pSS without neurological involvement. There was no statistical significance in other factors between the two groups. Peripheral nervous system (PNS), central nervous system (CNS), and both PNS and CNS involvements were revealed in 14, 3, and 3 patients, respectively. Optic neuritis and trigeminal neuralgia were revealed frequently in cranial neuropathy. Anti-aquaporin 4 antibody was detected in one patient with optic neuritis. Of the nine patients with polyneuropathy, eight patients presented pure sensory neuropathy including small fiber neuropathy (SFN). pSS with SFN appeared to have no clinically abnormal features, including muscle weakness and decreasing deep tendon reflex. Skin biopsy revealed epidermal nerve fiber degenerated in one pSS patient with pure sensory neuropathy who was diagnosed as having SFN. Our observations suggest that a number of mechanisms can be attributed to neurological involvements in pSS rather than just the mechanisms previously described (i.e., vasculitis and ganglioneuronitis). Presumably, specific autoantibodies may directly induce injury of the nervous system.

Clinical Manifestations of Adult‐Onset Still's Disease Presenting With Erosive Arthritis: Association With Low Levels of Ferritin and Interleukin‐18

Adult‐onset Stills disease (AOSD) is a clinical entity with a heterogeneous etiology. We have encountered patients with AOSD who had severe polyarthritis and who fulfilled the classification criteria for rheumatoid arthritis (RA); however, most patients with AOSD typically exhibit mild arthritis. In this study, we proposed 2 clinical subsets of AOSD and investigated the clinically significant characteristics of the 2 subtypes.

PLD4 as a novel susceptibility gene for systemic sclerosis in a Japanese population

OBJECTIVE Systemic sclerosis (SSc) is an autoimmune disease for which multiple susceptibility genes have been reported. Genome-wide association studies have shown that large numbers of susceptibility genes are shared among autoimmune diseases. Recently, our group identified 9 novel susceptibility genes associated with rheumatoid arthritis (RA) in a Japanese population. The aim of this study was to elucidate whether the 18 genes that displayed associations or suggestive associations for RA in our previous study are associated with SSc in Japanese. METHODS We performed an association study that included 415 patients with SSc and 16,891 control subjects, followed by a replication study that included 315 patients and 21,054 control subjects. The 18 markers reported to display association with RA were analyzed for their associations with SSc in the first study, and 5 markers were further analyzed in the replication study. The inverse variance method was used to evaluate the associations of these markers with SSc in a combined study. RESULTS In the phospholipase D4 gene (PLD4), rs2841277 displayed a significant association with SSc in Japanese patients (P = 0.00017). We observed that rs2841280 in exon 2 of PLD4 was in strong linkage disequilibrium with rs2841277 and introduced an amino acid alteration. We also observed associations between SSc and rs6932056 in TNFAIP3 and rs2280381 in IRF8 (P = 0.0000095 and P = 0.0030, respectively), both of which displayed associations with SSc in a European population. CONCLUSION We determined that PLD4 is a novel susceptibility gene for SSc in Japanese, thus confirming the involvement of PLD4 in autoimmunity. Associations between SSc and TNFAIP3 or IRF8 were also detected in our Japanese population. SSc and RA appear to share relatively large proportions of their genetic backgrounds.

Association study of a polymorphism of the CTGF gene and susceptibility to systemic sclerosis in the Japanese population

Objectives: To validate the association of a single nucleotide polymorphism (SNP) of the connective tissue growth factor gene (CTGF) with susceptibility to systemic sclerosis (SSc) in the Japanese population. Methods: 395 Japanese patients with SSc, 115 patients with rheumatoid arthritis and 269 healthy Japanese volunteers were enrolled in the study. An SNP (rs6918698) at –945 bp from the start codon in the promoter region of the CTGF gene was determined by allelic discrimination with the use of a specific TaqMan probe. Results: The G allele showed a significantly higher frequency in patients with SSc than in controls (p<0.001; odds ratio 1.5; 95% confidence interval 1.2 to 1.9). In particular, the clinical subsets of SSc showed a more significant association between the G allele and diffuse cutaneous SSc (p<0.001) and the presence of interstitial lung disease (p<0.001), the presence of anti-topoisomerase I antibody (p<0.001) and anti-U1RNP antibody (p = 0.010). Association analyses using the genotype of the SNP yielded results similar to those of analyses using the allele. Conclusions: This study confirms the association between an SNP in the CTGF gene and susceptibility to SSc, especially in the presence of diffuse cutaneous SSc, interstitial lung disease and anti-topoisomerase I antibody. The results strongly suggest that this SNP may be a powerful indicator of severe skin and lung involvement in patients with SSc.

Brief Report: Association of HLA–DRB1*0101/*0405 with susceptibility to anti–melanoma differentiation–associated gene 5 antibody–positive dermatomyositis in the Japanese population

OBJECTIVE The complication of interstitial lung disease (ILD) in polymyositis/dermatomyositis (PM/DM) is associated with anti-aminoacyl-transfer RNA synthetase (anti-aaRS) antibody or anti-melanoma differentiation-associated gene 5 (anti-MDA-5) antibody positivity. Anti-MDA-5 antibody is associated with clinically amyopathic DM and fatal outcome due to rapidly progressive ILD in Asian populations. The association between genetic factors and anti-MDA-5 antibody-positive DM is unclear. This study was undertaken to investigate the HLA-DRB1 genotype in patients with anti-MDA-5 antibody-positive DM. METHODS We examined genetic differences among 17 patients with anti-MDA-5 antibody-positive DM, 33 patients with anti-aaRS antibody-positive PM/DM, 33 patients with PM/DM without anti-aaRS antibody or ILD, and 265 healthy controls. RESULTS The frequencies of HLA-DRB1*0101 and DRB1*0405 were 29% and 71%, respectively, in patients with anti-MDA-5 antibody-positive DM, which were higher than the frequencies in healthy controls (10% and 25%, respectively). Among the 17 patients with anti-MDA-5 antibody-positive DM, 16 (94%) harbored either the DRB1*0101 or DRB1*0405 allele. The combined frequency of the DRB1*0101 allele and the DRB1*0405 allele was significantly higher in patients with anti-MDA-5 antibody-positive DM than in patients with PM/DM without anti-aaRS antibody or ILD, with an odds ratio (OR) of 42.7 (95% confidence interval [95% CI] 4.9-370.2) (P = 1.1 × 10(-5)), or in patients with anti-aaRS antibody-positive PM/DM (OR 13.3 [95% CI 1.6-112.6], P = 4.5 × 10(-3)). CONCLUSION Our findings indicate that HLA-DRB1*0101/*0405 is associated with susceptibility to anti-MDA-5 antibody-positive DM in the Japanese population.

Interleukin-18 is a key mediator in dermatomyositis: potential contribution to development of interstitial lung disease

OBJECTIVE To determine whether IL-18 is involved in the inflammation of DM and PM. METHODS Thirty-three patients with DM were enrolled in this study, including 25 with interstitial lung disease (ILD). In addition, 16 patients with PM were enrolled, including 6 with ILD. All patients were admitted to our hospital as a result of their condition requiring treatment, and clinical laboratory data including serum IL-18 were recorded on admission. RESULTS Serum IL-18 was significantly (P < 0.0001) higher in both DM and PM patients than in healthy controls (n = 30). Serum ferritin and IL-18 were significantly (P = 0.003 and 0.0044, respectively) higher in DM than in PM patients. Additionally, ferritin and IL-18 were significantly (P = 0.023 and 0.034, respectively) higher in DM patients with ILD than in DM patients without ILD. Significant positive correlations were found between creatine kinase (CK) and ferritin (r(s) = 0.39, P = 0.024); CK and IL-18 (r(s) = 0.48, P = 0.005); and IL-18 and ferritin (r(s) = 0.54, P = 0.0012) in the DM group as a whole. These findings were different for the DM plus ILD subgroup: significant positive correlations were found between CK and ferritin (r(s) = 0.40, P = 0.047); CK and IL-18 (r(s) = 0.63, P = 0.0008); and IL-18 and ferritin (r(s) = 0.41, P = 0.042). CONCLUSION Serum IL-18 was strikingly elevated in patients with DM and was associated particularly with disease activity and ILD complication in DM.

Ghrelin attenuates collagen production in lesional fibroblasts from patients with systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease characterized by thickening of the skin and tissue fibrosis of the internal organs. Ghrelin is primarily described as a gut hormone, and many studies currently indicate that ghrelin has protective effects in different organs, including the heart, pancreas, lung and liver, resulting from its anti-fibrotic properties. We found decreased levels of ghrelin in the plasma from patients with SSc compared with those from healthy controls. In skin fibroblast cultures, recombinant ghrelin diminished the production of collagen type I. In addition, the mRNA levels of COL1A2 and TGFB genes were significantly decreased by the stimulation of ghrelin. We showed that ghrelin may exert anti-fibrotic effects in the skin fibroblasts from patients with SSc. Because the plasma levels of ghrelin are low in SSc, the administration of ghrelin could be a new strategy for the treatment of SSc.

Sildenafil attenuates the fibrotic phenotype of skin fibroblasts in patients with systemic sclerosis

Systemic sclerosis (SSc) is a multi-organ fibrotic disease that affects the skin and various internal organs. Therapeutic strategies for tissue fibrosis have not been established; however, aberrantly activated fibroblasts in affected lesions are key targets for modulating fibrosis. Recently, increased intracellular cyclic GMP (cGMP) levels were demonstrated to improve fibrosis levels in various diseases. The purpose of this study was to assess the anti-fibrotic properties of cGMP in cultured fibroblasts from patients with SSc. The phosphodiesterase (PDE) 5 inhibitor sildenafil increased the intracellular cGMP levels in skin fibroblasts in a dose-dependent manner. Sildenafil treatment also significantly decreased the expression of several pro-fibrotic factors that were upregulated by TGF-β1 treatment in SSc skin fibroblasts. These inhibitory effects occurred via non-canonical TGF-β signaling. Our findings revealed that sildenafil might be a novel strategy to treat tissue fibrosis and vasculopathy in SSc.