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Featured researches published by Kenji Oku.


Rheumatology | 2008

Clinical features of haemophagocytic syndrome in patients with systemic autoimmune diseases: analysis of 30 cases.

Shinji Fukaya; Shinsuke Yasuda; Toko Hashimoto; Kenji Oku; Hiroshi Kataoka; Tetsuya Horita; Tatsuya Atsumi; Takao Koike

OBJECTIVES Haemophagocytic syndrome (HPS) is known as a relatively rare complication in autoimmune diseases. Here we analysed the clinical features of HPS in patients with systemic autoimmune diseases. METHODS One thousand and fourteen patients with systemic autoimmune diseases admitted to Hokkaido University Hospital from 1997 to 2007 were recruited [350 SLE, 136 RA, 98 polymyositis/dermatomyositis (PM/DM), 88 SSc, 91 vasculitis syndrome, 37 primary SS, 26 adult onset Stills disease (AOSD) and 188 other diseases]. Clinical features and treatment outcomes were retrospectively analysed. RESULTS Thirty cases (3.0%) fulfilled HPS criteria (progressive cytopenia in two or more lineages and haemophagocytosis in reticuloendothelial systems). Underlying diseases were SLE (18), RA (2), PM/DM (2), SSc (2), vasculitis (1), SS (2) and AOSD (3). Nineteen patients were diagnosed as having autoimmune-associated HPS, eight infection-associated, one drug-induced and one developed HPS after haematopoietic stem cell transplantation. For the treatment of HPS, high-dose corticosteroid monotherapy was given in 26 cases, being effective in 12 (46%). Ten out of 15 patients with corticosteroid-resistant autoimmune-associated HPS were treated with CsA, cyclophosphamide or tacrolimus, leading to the remission in 80%. The overall mortality rate was 20%. Multivariate analysis showed that the presence of infections and CRP level >50 mg/l on HPS related with poor prognosis. CONCLUSIONS The prevalence of HPS among in-hospital patients with systemic autoimmunity is not ignorable. Administration of immunosuppressants was effective in cases with autoimmune-associated HPS, whereas prognosis was poor in infection-associated HPS.


Arthritis & Rheumatism | 2012

Efficacy of the antiphospholipid score for the diagnosis of antiphospholipid syndrome and its predictive value for thrombotic events.

Kotaro Otomo; Tatsuya Atsumi; Olga Amengual; Yuichiro Fujieda; Masaru Kato; Kenji Oku; Tetsuya Horita; Shinsuke Yasuda; Takao Koike

OBJECTIVE To define the antiphospholipid score (aPL-S) by testing multiple antiphospholipid antibodies (aPL) and to evaluate its efficacy for the diagnosis of antiphospholipid syndrome (APS) and predictive value for thrombosis. METHODS This study comprised 2 independent sets of patients with autoimmune diseases. In the first set of patients (n = 233), the aPL profiles were analyzed. Five clotting assays for testing lupus anticoagulant and 6 enzyme-linked immunosorbent assays (IgG/IgM anticardiolipin antibodies, IgG/IgM anti-β(2)-glycoprotein I, and IgG/IgM phosphatidylserine-dependent antiprothrombin antibodies) were included. The association of the aPL-S with a history of thrombosis/pregnancy morbidity was assessed. In the second set of patients (n = 411), the predictive value of the aPL-S for thrombosis was evaluated retrospectively. Two hundred ninety-six of these patients were followed up for >2 years. The relationship between the aPL-S and the risk of developing thrombosis was analyzed. RESULTS In the first set of patients, the aPL-S was higher in those with thrombosis/pregnancy morbidity than in those without manifestations of APS (P < 0.00001). For the aPL-S, the area under the receiver operating characteristic curve value was 0.752. In the second set of patients, new thromboses developed in 32 patients. The odds ratio (OR) for thrombosis in patients with an aPL-S of ≥30 was 5.27 (95% confidence interval [95% CI] 2.32-11.95, P < 0.0001). By multivariate analysis, an aPL-S of ≥30 appeared to be an independent risk factor for thrombosis (hazard ratio 3.144 [95% CI 1.383-7.150], P = 0.006). CONCLUSION The aPL-S is a useful quantitative index for diagnosing APS and may be a predictive marker for thrombosis in autoimmune diseases.


Annals of the Rheumatic Diseases | 2009

Complement activation in patients with primary antiphospholipid syndrome

Kenji Oku; Tatsuya Atsumi; Miyuki Bohgaki; Olga Amengual; Hiroshi Kataoka; Tetsuya Horita; Shinsuke Yasuda; Takao Koike

Objective: To investigate the significance of complement activation in patients with primary antiphospholipid syndrome (APS). Methods: Thirty-six patients with primary APS, 42 control patients with non-systemic lupus erythematosus (SLE) connective tissue diseases, and 36 healthy volunteers were analysed retrospectively. Serum complement levels (C3, C4, CH50) and anaphylatoxins (C3a, C4a, C5a) were examined in all subjects, and serum complement regulatory factors (factor H and factor I) were measured in patients with primary APS. Plasma anticoagulant activity was determined in a mixing test using the activated partial thromboplastin time. Results: Serum complement levels were significantly lower in patients with primary APS than in patients with non-SLE connective tissue diseases (mean (SD) C3: 81.07 (17.86) vs 109.80 (22.76) mg/dl, p<0.001; C4: 13.04 (8.49) vs 21.70 (6.96) mg/dl, p<0.001; CH50: 31.32 (8.76) vs 41.40 (7.70) U/ml, p<0.001) or healthy volunteers. Only two healthy subjects with low serum C4 levels showed hypocomplementaemia, whereas most patients with primary APS showed raised serum C3a and C4a. No subjects showed raised C5a. Patients with primary APS with low serum C3 or C4 had significantly higher levels of C3a or C4a than healthy controls. No patients had low serum complement regulatory factors. Among patients with primary APS, hypocomplementaemia was significantly more common in those with high anticoagulant activity than in those with low or normal activity. Conclusion: Hypocomplementaemia is common in patients with primary APS, reflecting complement activation and consumption, and was correlated with anticoagulant activity, suggesting that antiphospholipid antibodies may activate monocytes and macrophages via anaphylatoxins produced in complement activation.


Rheumatology | 2015

The efficacy of tacrolimus in patients with interstitial lung diseases complicated with polymyositis or dermatomyositis

Takashi Kurita; Shinsuke Yasuda; Koji Oba; Toshio Odani; Michihito Kono; Kotaro Otomo; Yuichiro Fujieda; Kenji Oku; Toshiyuki Bohgaki; Olga Amengual; Tetsuya Horita; Tatsuya Atsumi

OBJECTIVE Interstitial lung diseases (ILDs) complicated with PM or DM are frequently aggressive and refractory to treatment. Recently some reports have suggested the potential benefit of tacrolimus for severe ILD complicated with PM/DM. However, little evidence has yet shown the efficacy of tacrolimus in these settings. The aim of this study was to evaluate the efficacy of tacrolimus as a treatment for PM-/DM-related ILD. METHODS This retrospective study comprised 49 previously untreated patients diagnosed as PM-/DM-related ILD admitted to Hokkaido University Hospital from January 2000 to July 2013. These patients were treated with tacrolimus plus conventional therapy or only with conventional therapy (prednisolone, i.v. CYC and/or ciclosporin). The primary endpoint was defined as the time to relapse or death of respiratory cause or a serious adverse event. The secondary endpoint was defined as the time from the initiation of immunosuppressive treatment to relapse or death of respiratory cause. Endpoints were compared by adjusted Cox regression model by using inverse probability of treatment weighting in order to reduce the impact of these selection biases and potential confounding factors. RESULTS After adjustment, the tacrolimus group (n = 25) had significantly longer event-free survival as compared with the conventional therapy group (n = 24). The weighted hazard ratio (HR) was 0.32 (95% CI 0.14, 0.75, P = 0.008). In addition, the tacrolimus group had significantly longer disease-free survival as compared with the conventional therapy group. The weighted HR was 0.25 (95% CI 0.10, 0.66, P = 0.005). CONCLUSION The addition of tacrolimus to conventional therapy significantly improved the prognosis of patients with PM-/DM-related ILD.


European Journal of Clinical Investigation | 2012

Pathophysiology of thrombosis and pregnancy morbidity in the antiphospholipid syndrome.

Kenji Oku; Olga Amengual; Tatsuya Atsumi

Eur J Clin Invest 2012; 42 (10): 1126–1135


Seminars in Thrombosis and Hemostasis | 2008

Antiprothrombin Antibody Testing: Detection and Clinical Utility

Kenji Oku; Tatsuya Atsumi; Olga Amengual; Takao Koike

Anticardiolipin antibody (aCL), anti-beta2 glycoprotein I antibodies, and lupus anticoagulant (LA) are the only laboratory tests considered within the revised criteria for the classification of the antiphospholipid syndrome (APS). Recently, antibodies against phosphatidylserine-prothrombin complex (aPS/PT) have been detected, and these antibodies, rather than antibodies against prothrombin alone, are closely associated with APS and LA. The sensitivity and specificity of aPS/PT for the diagnosis of APS were assessed in a population of patients with a variety of autoimmune disorders. aCL and aPS/PT have similar diagnostic value for APS, therefore aPS/PT should be further explored, not only for research purposes but also as a candidate for one of the laboratory criteria for the classification of the APS.


Lupus | 2012

Predominant prevalence of arterial thrombosis in Japanese patients with antiphospholipid syndrome

Yuichiro Fujieda; Tatsuya Atsumi; Olga Amengual; Toshio Odani; Kotaro Otomo; Masaru Kato; Kenji Oku; Yujiro Kon; Tetsuya Horita; Shinsuke Yasuda; Takao Koike

Objective: To study the clinical and immunological manifestations of antiphospholipid syndrome (APS) in the Japanese population by a single-centre registration. Methods: In this retrospective cohort study, 141 consecutive patients with APS, fulfilling the Sydney revised Sapporo criteria for definite APS, who visited our autoimmune clinic from 1988 to 2010, were recruited and followed up. All the patients were interviewed and underwent a general physical examination by qualified rheumatologists on the day of blood sampling. Results: The population comprised 119 woman and 22 men with a mean age at diagnosis of 44 years (range 9–79 years). Seventy patients (49.6%) had primary APS, and 71 (50.4%) had systemic lupus erythematosus. The prevalence of thrombosis was 85.8 per cent, arterial thrombosis was found in 93 patients (66.0%) and venous thrombosis was found in 46 patients (32.6%). The most common thrombosis was cerebral infarction [86/141 (61.0%)] followed by deep vein thrombosis [33/141 (23.4%)]. Among 70 pregnant women, 45 (64.3%) had obstetric complications. Lupus anticoagulant was detected in 116 patients (82.3%), anticardiolipin antibodies in 83 (58.9%), anti-β2 glycoprotein I antibodies in 73 (51.8%) and phosphatidylserine-dependent antiprothrombin antibodies in 98 (69.5%). Conclusion: High prevalence of arterial thrombosis was noted in Japanese patients with APS. The profile of heterogeneous and complex clinical manifestations was substantiated in Japanese patients with APS.


Lupus | 2011

The short-term role of corticosteroid therapy for pulmonary arterial hypertension associated with connective tissue diseases: report of five cases and a literature review.

Mototsugu Kato; Hiroshi Kataoka; Toshio Odani; Yuichiro Fujieda; Kotaro Otomo; Kenji Oku; Tetsuya Horita; Shinsuke Yasuda; Tatsuya Atsumi; Hiroshi Ohira; Ichizo Tsujino; Masaharu Nishimura; Takao Koike

Pulmonary arterial hypertension (PAH) is a life-threatening complication in connective tissue diseases (CTD). It remains controversial whether immunosuppressive therapy is useful for PAH associated with CTD (PAH-CTD). The Dana Point algorithm does not refer such treatments in patients with PAH-CTD due to the lack of evidence. However, some case reports have shown the potential efficacy of immunosuppression for PAH-CTD. Here we report five cases of PAH-CTD treated with corticosteroids and discuss the current management of PAH-CTD with immunosuppressive agents. Our cases consisted of three active systemic lupus erythematosus (SLE), a quiescent SLE and an active polymyositis. WHO functional classes at baseline were class III in three cases and class II in two. Median follow-up period was 44 (28–92) weeks. PAH was diagnosed by right heart catheterization in all cases (median pulmonary arterial pressure was 45 (29–49) mmHg). All patients received 1 mg/kg of prednisolone (PSL) for 2–4 weeks, followed by appropriate dose reduction. Methylprednisolone pulse therapy was performed in patients resistant to the high dosage of PSL. Four patients received vasodilators in combination. The therapy as above improved WHO functional class 4 weeks after the initiation of PSL in all the patients. Two patients required dose increase or additional administration of vasodilators due to the dose reduction of PSL. Corticosteroid therapy may be effective for PAH-CTD at least in the short term, even in low general activity of CTD or moderate PAH. Our experience suggests that corticosteroid therapy, by itself or in conjunction with standard vasodilators, is effective for PAH-CTD patients.


Lupus | 2015

An independent validation of the Global Anti-Phospholipid Syndrome Score in a Japanese cohort of patients with autoimmune diseases

Kenji Oku; Olga Amengual; Toshiyuki Bohgaki; Tetsuya Horita; Shinsuke Yasuda; Tatsuya Atsumi

Sir, We previously proposed a quantitative score defined as ‘antiphospholipid score (aPL-S)’, in which, by testing multiple antiphospholipid antibodies (aPL), thrombotic risk may be evaluated in antiphospholipid syndrome (APS) patients. This score is validated in our cohort, as well as cohorts in other institution, as a useful quantitative index for diagnosing APS and predicting thrombosis in autoimmune diseases. Recently, Sciascia et al. broadened this idea by taking into account the aPL profile with conventional cardiovascular risks, and developed and validated the ‘Global Anti-Phospholipid Syndrome Score’ (GAPSS) as a marker of APS manifestations. In order to validate the GAPSS independently, we applied it to a cohort of 282 consecutive patients who attended the Hokkaido University Hospital rheumatology clinic from January 2002 to December 2003. There were 41 APS (17 primary APS) patients, 88 systemic lupus erythematosus (SLE) without APS, 50 rheumatoid arthritis, 16 Sjogren’s syndrome, 21 systemic sclerosis, 10 polymyositis/dermatomyositis and 56 other autoimmune diseases. Overall, thrombosis and/or pregnancy loss (APS manifestations) were observed in 43 patients (38 arterial thrombosis, 24 venous thrombosis and 11 pregnancy loss). Higher values of GAPSS were observed in patients who had experienced one or more of the APS manifestations compared with the patients without APS manifestations (Figure 1). When clinical subgroups were analyzed, patients with a history of arterial and/or venous thrombosis showed higher GAPSS compared with patients without APS manifestations. Patients with a history of pregnancy morbidity failed to show a significant difference in GAPSS compared with patients without APS manifestations (Figure 1). The smaller number of patients with history of pregnancy loss in our cohort was likely to be a primary factor in the insignificance of GAPSS in evaluating risks of pregnancy loss. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and area under the curve (AUC) of the receiver operating characteristic (ROC) curve at various levels of GAPSS cut-off are shown in Table 1. In our cohort, maximum AUC of ROC curve was at the cut-off level of GAPSS 6, lower than the cut-off level of GAPSS 10 in the original cohort in the UK. The reason for differences in adequate cut-off levels of ROC curve in GAPSS between two cohorts may be attributed to their different characteristic backgrounds. Our cohort consists of patients with various autoimmune diseases, while the original UK cohort comprised patients with APS and/or SLE. In our cohort, non-APS patients who scored GAPSS> 10 were all SLE patients (6/282). The high GAPSS in SLE patients was mainly due to the high incidence of ‘aPL carriers’. The adequate cut-off value of GAPSS may differ among patients with and without SLE. We demonstrated that aPL profile with conventional cardiovascular risks can be successfully quantified by GAPSS in an independent cohort of patients with autoimmune diseases. GAPSS correlated with a history of APS manifestations, particularly with thrombosis, suggesting that it is a suitable quantitative marker for APS. However, one should consider the appropriate cut-off to be adapted to different kinds of cohorts by reviewing their basic characteristics.


Lupus | 2015

Primary prophylaxis to prevent obstetric complications in asymptomatic women with antiphospholipid antibodies: a systematic review.

Olga Amengual; D. Fujita; Erika Ota; L Carmona; Kenji Oku; Mayumi Sugiura-Ogasawara; Atsuko Murashima; Tatsuya Atsumi

Objective Obstetric complications are common in patients with antiphospholipid syndrome. However, the impact of antiphosholipid antibodies (aPL) in the pregnancy outcomes of asymptomatic aPL carriers is uncertain. The aim of this systematic review is to assess whether primary prophylaxis is beneficial to prevent obstetric complications during pregnancy in asymptomatic women positive for aPL who have no history of recurrent pregnancy loss or intrauterine fetal death. Methods Studies evaluating the effect of prophylactic treatment versus no treatment in asymptomatic pregnant aPL carriers were identified in an electronic database search. Design, population and outcome homogeneity of studies was assessed and meta-analysis was performed. The pooled Mantel–Haenszel relative risk of specific pregnancy outcomes was obtained using random effects models. Heterogeneity was measured with the I2 statistic. All analyses were conducted using Review Manager 5.3. Results Data from five studies involving 154 pregnancies were included and three studies were meta-analysed. The risk ratio and 95% confidence interval (CI) of live birth rates, preterm birth, low birth weight and overall pregnancy complications in treated and untreated pregnancies were 1.14 (0.18–7.31); 1.71 (0.32–8.98); 0.98 (0.07–13.54) and 2.15 (0.63–7.33),respectively. Results from the meta-analysis revealed that prophylactic treatment with aspirin is not superior to placebo to prevent pregnancy complications in asymptomatic aPL carriers. Conclusion This systematic review did not find evidence of the superiority of prophylactic treatment with aspirin compared to placebo or usual care to prevent unfavourable obstetric outcomes in otherwise healthy women with aPL during the first pregnancy.

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