Beneficial use of serum ferritin and heme oxygenase-1 as biomarkers in adult-onset Still's disease: A multicenter retrospective study.

BACKGROUND: Heme oxygenase (HO)-1 is a heme-degrading enzyme highly expressed in monocyte/macrophage, serum levels of which may be promising biomarker for adult-onset Still's disease (AOSD). We here report data on the use of serum ferritin and HO-1 levels in AOSD. METHODS: Under the Hypercytokinemia Study Group collaboration, we collected sera from a total of 145 AOSD patients. Three independent experts judged whether the patients were definite AOSD depending on the clinical information. These 91 'definite AOSD' patients were further divided into active, remission, and relapse groups. Forty-six cases of systemic vasculitis, sepsis, etc. were included as disease controls. Serum ferritin and HO-1 levels were measured using ELISA. Associations between clinical symptoms, serum ferritin, and HO-1 were explored. Multivariate regression analysis was performed to identify independent variables associated with definite AOSD diagnosis. RESULTS: Serum ferritin and HO-1 levels were significantly higher in active and relapsed AOSD cases compared to disease controls, and were reduced by the treatment. Although a significant correlation was found between serum ferritin and HO-1 levels, a discrepancy was found in some cases such as iron-deficiency anemia. Receiver operating characteristic analysis identified optimal levels of serum ferritin (>819 ng/ml; sensitivity 76.1% and specificity 73.8%), and serum HO-1 (>30.2 ng/ml; sensitivity 84.8% and specificity 83.3%) that differentiated AOSD from controls. Interestingly, 88.9% of patients with AOSD who relapsed exceeded the cut-off value of serum HO-1 > 30.2 ng/ml, but only 50.0% exceeded serum ferritin >819 ng/ml (p = .013), suggesting that serum HO-1 levels may be a convenient indicator of AOSD disease status. Multivariate analysis identified neutrophilia, RF/ANA negativity, sore throat, and elevated serum HO-1 as independent variables associated with AOSD diagnosis. CONCLUSION: We confirmed that serum ferritin and HO-1 serve as highly specific and sensitive biomarkers for AOSD. A future prospective study with large sample size is necessary to determine whether these biomarkers could be included in Yamaguchi's Criteria.

Erythematosus plaques with macrophage infiltration as an initial manifestation of macrophage activation syndrome in a patient with systemic lupus erythematosus.

The diagnosis of macrophage activation syndrome (MAS) in patients with systemic lupus erythematosus (SLE) may be challenging as it can mimic the clinical features of the underlying disease or be confused with an infectious complication. In this report, a Japanese woman in her forties had diverse clinical features of MAS at initial presentation of SLE, where erythematosus plaques with histiocytic infiltrates focally surrounding degenerated collagen might be the earliest indicator of MAS.

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-ß1 treatment in SSc skin fibroblasts. These inhibitory effects occurred via non-canonical TGF-ß signaling. Our findings revealed that sildenafil might be a novel strategy to treat tissue fibrosis and vasculopathy in SSc.

Cytokine profiles in polymyositis and dermatomyositis complicated by rapidly progressive or chronic interstitial lung disease.

OBJECTIVE: PM and DM are often complicated by interstitial lung disease (ILD). In this study we aimed to evaluate various serum cytokines in patients with PM/DM with ILD so as to clarify the differences in pathophysiology between anti-melanoma differentiation-associated gene 5 antibody-associated ILD (anti-MDA5-ILD) and anti-aminoacyl tRNA synthetase antibody-associated ILD (anti-ARS-ILD). METHODS: We evaluated the serum cytokine profiles of 38 patients with PM/DM and compared the cytokine profiles of the non-ILD and ILD subsets as well as the anti-MDA5-ILD and anti-ARS-ILD subsets. RESULTS: The myositis intention-to-treat activity index score, which indicates whole disease activity, significantly correlated with serum IL-6, IL-8, TNF-α and IP-10. These cytokine levels were significantly higher in the ILD subset than the non-ILD subset and were lower in the ILD subset following treatment. By multivariate analysis, TNF-α was the most significant cytokine [P = 0.0006, odds ratio (OR) 1.4, CI 1.1, 2.2] associated with PM/DM with ILD. IL-8 levels were significantly higher in anti-MDA5-ILD than in anti-ARS-ILD, although IL-6, TNF-α and IP-10 levels were high in both subsets. IL-8 was the most significant cytokine (P = 0.0006, OR 1.5, CI 1.1, 3.0) associated with anti-MDA5-ILD by multivariate analysis. Moreover, the ratio of IL-4 to IFN-γ was lower in anti-MDA5-ILD than in anti-ARS-ILD. CONCLUSION: IL-6, IL-8, TNF-α and IP-10 are associated with global disease activity in PM/DM. These cytokine levels were high, especially in the ILD subset. Serum IL-8 levels and the balance between IL-4 and IFN-γ may contribute to the differences in pathophysiology between anti-ARS-ILD and anti-MDA5-ILD.

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.

Urinary free light chain is a potential biomarker for ISN/RPS class III/IV lupus nephritis.

OBJECTIVES: To evaluate the use of urinary free light chains (FLCs) as a biomarker for proliferative LN and the potential association between the intensity of plasma cell infiltration of the kidney and urinary FLC levels in LN. METHODS: Forty-three SLE patients were consecutively enrolled in the study. These patients were divided into an International Society of Nephrology and Renal Pathology Society (ISN/RPS) class III/IV LN subset (n = 18) and an ISN/RPS class I/II/V (class non-III/IV) LN subset (n = 25). The expression of κ-LCs, λ-LCs, CD19 and CD138 in kidney specimens was also evaluated with immunohistochemical staining. To measure FLC levels before and after treatment, an additional six patients with class III/IV LN were consecutively enrolled. RESULTS: Urinary FLCs were significantly higher in the class III/IV LN subset than in the class non-III/IV LN subset. Urinary λ-FLC levels were significantly correlated with the urinary protein-creatinine ratio in the class III/IV LN subset (rs = 0.67, P < 0.01). Moreover, the LC-secreting CD19(-)/CD138(+) cell counts in the kidney specimens were higher in the class III/IV LN subset than in the class non-III/IV LN subset. Total urinary FLC levels were correlated with the numbers of CD138(+) cells in the kidney (r = 0.71, P = 0.03). Following treatment, urinary λ-FLCs could not be detected in any of the patients. CONCLUSION: The intensity of plasma cell infiltration of the kidney is associated with urinary FLC levels. Urinary FLCs are potentially useful biomarkers in ISN/RPS class III/IV LN or proliferative LN.

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.

Semiquantitative measurement of aquaporin-4 antibodies as a possible surrogate marker of neuromyelitis optica spectrum disorders with systemic autoimmune diseases.

OBJECTIVES: To assess the association between serum aquaporin-4 (AQP4) autoantibodies and neuromyelitis optica spectrum disorders (NMOSDs) associated with systemic autoimmune diseases. METHODS: We retrospectively studied 626 hospitalized patients with systemic lupus erythematosus (SLE) or Sjögren's syndrome (SS). We collected serum samples from those patients with suspected NMOSDs (i.e., myelitis or optic neuritis) at the time of onset and thereafter. AQP4 antibodies were measured by a cell-based indirect immunofluorescence assay using AQP4-transfected HEK-293 cells in a semi-quantitative manner. RESULTS: Sera from 6 patients with suspected NMOSDs and SLE (n = 3) or SS (n = 3) were evaluated. Among these, 2 patients' sera samples, i.e., 1 with SLE and 1 with SS, were positive for AQP4 antibodies. There was an inverse relationship between disease amelioration and antibody titer in one NMOSD patient, whereas the antibody titer remained high in the other NMOSD patient, whose clinical manifestations of NMOSDs did not improve despite intensive immunosuppressive treatments. CONCLUSIONS: These results indicate that serum AQP4 antibodies are present in some SLE/SS patients with myelitis/optic neuritis and might be associated with clinical outcomes. The semi-quantitative measurement of the AQP4 antibody might be a possible surrogate marker in patients with NMOSDs associated with systemic autoimmune diseases.

Interleukin-18 promoter polymorphisms in Japanese patients with rheumatoid arthritis: protective effect of the T allele and T/T genotype at rs360722.

Rheumatoid arthritis (RA) is a chronic inflammatory disease with a strong genetic contribution to its pathogenesis. Among numerous candidate genes, cytokine gene polymorphisms have been implicated. Interleukin-18 (IL-18) induces production of tumor necrosis factor-α and promotes T helper (Th)1-type immune responses. This study investigates the association between IL-18 promoter polymorphisms and RA susceptibility. A total of 2471 Japanese case-control samples (1493 RA patients and 978 healthy controls) were examined. Three haplotype tag single-nucleotide polymorphisms, rs1946518A/C, rs360718T/G, and rs360722T/C, spanning from the 5'UTR to intron 1 were genotyped using allelic discrimination with the use of specific TaqMan probes, and three haplotypes (A-T-T, C-T-C, and A-G-C) were determined. Among these polymorphisms, the frequency of the T allele at rs360722, which tags the A-T-T haplotype, was significantly lower in the RA patient group compared with the normal subjects [0.46 versus 0.49, P = 0.0061, Fisher's exact probability test, odds ratio (OR) = 0.85, 95% confidence interval (CI) = 0.75-0.95]. Having the T/T genotype further increased the significance (0.20 versus 0.27, P = 0.0006, OR = 0.72, 95% CI = 0.58-0.86). Therefore, presence of the T allele and T/T genotype at rs360722 reduces the susceptibility of Japanese people to RA.

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.

Clinical manifestations of Adult-onset Still's disease presenting with erosive arthritis: Association with low levels of ferritin and Interleukin-18.

Objective: Adult-onset Still's disease (AOSD) is a clinical entity with 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 two clinical subsets of AOSD and investigated the clinically significant characteristics of the two subtypes. Methods: We retrospectively analyzed 71 consecutive patients with AOSD. We reviewed the medical records of all patients who were followed up for more than 2 years. We classified all the patients with AOSD into the following 2 subsets: an RA subtype for patients who met the criteria for RA according to the American College of Rheumatology and a non-RA subtype for patients who did not meet the criteria for RA. Results: Our results indicated that the non-RA subtype was accompanied by severe inflammatory complications, including pleuritis and hemophagocytic syndrome. In addition, the serum ferritin and serum IL-18 levels were significantly higher in patients with the non-RA subtype than in those with the RA subtype. Interestingly, only 1 patient with the RA subtype had anti-CCP antibodies, and 1 non-RA subtype patient had rheumatoid factor. These findings distinguish these patients from patients with true RA. Conclusions: There were two subsets of patients with AOSD in the examined population. Patients with high levels of IL-18 or ferritin presented with severe systemic inflammatory disorders (the non-RA subtype), and patients with low levels of IL-18 or ferritin developed severe arthritis (RA subtype).

Clinical utility of computed tomographic scanning for the evaluation of lupus profundus in two patients with systemic lupus erythematosus.

Lupus profundus is a rare lupus-specific skin lesion with skin biopsies exhibiting lobular lymphocytic infiltration and destruction of subcutaneous fat tissue. In this report, a CT scan was effective in demonstrating both the presence and the extent of inflammation of lupus profundus in two patients with systemic lupus erythematosus (SLE). Case 1 was a 30-year-old woman developing erythema with subcutaneous induration on the upper arms during the quiescent phase of SLE. A skin biopsy confirmed a diagnosis of lupus profundus. A CT scan of the right upper arm demonstrated a high density area (HDA) of the subcutis under the erythema: a finding consistent with lupus profundus. Case 2 was a 28-year-old woman recently diagnosed with SLE. She also developed a skin ulcer on the right hip. A CT scan of the hip revealed an HDA and lipoatrophy of the subcutis around the ulcer: these findings were compatible with lupus profundus. Treatment with high-dose prednisolone improved the illness in the both cases. A CT scan is a useful and convenient imaging modality for confirming the diagnosis of lupus profundus.

Therapeutic efficacy of intravenous cyclophosphamide concomitant with moderate- to high-dose prednisolone in two patients with fasciitis panniculitis syndrome.

Fasciitis panniculitis syndrome (FPS) has been proposed as a new category of 'fasciitis' and includes the well-established eosinophilic fasciitis (EF). Unlike EF, FPS exhibits inconsistent eosinophilia and/or eosinophilic infiltration of the lesions. Principal histological FPS findings include dermal thickening, inflammation and thickening of the subcutaneous fat tissue, fibrous thickening of the fascia and inflammation of the adjacent muscle. FPS is commonly resistant to corticosteroids, and cimetidine is effective in approximately 80% of FPS patients. A new therapy for FPS is required for cases refractory to treatment or intolerant to cimetidine because of adverse drug reaction. In this report, two FPS patients were resistant to corticosteroids. Both received intravenous cyclophosphamide (IVCY) concomitant with moderate- to high-dose prednisolone (PSL), and this effectively treated the induration of the FPS lesions. Patient 1 was a 50-year-old woman who had been diagnosed with fasciitis following en bloc muscle biopsy of the thigh. She had been treated with high-dose PSL for 6 years, but the fasciitis was refractory. Induration of the neck, thorax and thighs resulted in impaired neck rotation, restrictive respiratory failure and impaired walking. A diagnosis of FPS was made by re-assessing the en bloc muscle biopsy. Although PSL (40 mg/day) for 18 days was ineffective, the addition of IVCY (400 mg) dramatically improved the disease manifestations. Patient 2 was a 68-year-old man who was diagnosed with fasciitis based on en bloc muscle biopsy of the left foot. He had been treated with PSL for 16 years, but the fasciitis was refractory. He exhibited lower limb induration and a refractory skin ulcer of the left foot. A diagnosis of FPS was made by re-assessing the en bloc muscle biopsy. Although PSL (40 mg/day) for 2 weeks was ineffective, the addition of IVCY (450 mg) improved both the lower limb induration and the skin ulcer. FPS may cause both entrapment vasculopathy of subcutis and perivasculitis of the subcutaneous fat tissue such that the skin ulcer might be closely related with the ischemic mechanism triggered by FPS. According to the clinical courses of our cases, IVCY combined with moderate- to high-dose PSL may be a new therapeutic choice for corticosteroid-resistant FPS patients.

Characteristics of patients with early systemic sclerosis and severe gastrointestinal tract involvement.

OBJECTIVE: To clarify the clinical features of patients with systemic sclerosis (SSc) who developed severe gastrointestinal tract (GIT) involvement in the early stage of the disease. METHODS: Three hundred two consecutive Japanese patients with SSc were investigated: Group 1 comprised 14 patients with severe GIT involvement (malabsorption syndrome and/or pseudo-obstruction) within 2 years of onset of SSc; group 2 consisted of all patients without severe GIT involvement (n = 288); and group 3 consisted of 117 patients without severe GIT involvement within 2 years of onset of SSc. Autoantibodies were evaluated using double immunodiffusion, ELISA, and immunoprecipitation. RESULTS: We found significant differences in clinical features among the 3 groups. Diffuse cutaneous type, erosive esophagitis, and myositis were more common in group 1 than in group 2 (p = 0.007, 0.003, and 0.003, respectively) or group 3 (p = 0.04, 0.002, and 0.01, respectively), whereas interstitial lung disease (ILD) was more frequent in group 2 (p = 0.005) and group 3 (p = 0.02) versus group 1. Antinuclear antibodies showed a nucleolar pattern significantly more frequently in group 1. Myositis-related autoantibodies, including anti-U1RNP, anti-U3RNP, anti-Ku, and anti-signal recognition particle antibodies, were observed in 57% of group 1. CONCLUSION: Our findings strongly suggest the existence of a subgroup of SSc patients with severe GIT involvement in the early stage. Among the Japanese individuals, these patients never developed severe ILD, even though they were classified as having diffuse cutaneous SSc.

Diagnostic reliability of cerebral spinal fluid tests for acute confusional state (delirium) in patients with systemic lupus erythematosus: interleukin 6 (IL-6), IL-8, interferon-alpha, IgG index, and Q-albumin.

OBJECTIVE: Acute confusional state (ACS) is an uncommon but severe central nervous system (CNS) syndrome in systemic lupus erythematosus (SLE) defined by clinical manifestations. To develop useful and reliable diagnostic tools for ACS, we evaluated the association of cerebral spinal fluid (CSF) tests with ACS and their predictive values for the diagnosis of ACS in SLE. METHODS: We performed a prospective study using a cohort of 59 patients with SLE and compared those with and without ACS. Associations between ACS and each CSF test [interleukin 6 (IL-6), IL-8, interferon-alpha, IgG index, and Q-albumin] were statistically evaluated. Each patient underwent all CSF evaluations. RESULTS: ACS was diagnosed in 10 patients (ACS group), SLE-related CNS syndromes except ACS in 13, and no CNS syndromes in 36 (non-CNS group). CSF IL-6 levels in the ACS group were significantly higher than those in the non-CNS group (p < 0.05). A positive IgG index (p = 0.028) was significantly associated with ACS. No other test showed a significant association with ACS. The positive and negative predictive values for the diagnosis of ACS in SLE were 80% and 85% for elevated CSF IL-6 levels (> or = 31.8 pg/ml), and 75% and 83% for the IgG index, respectively. CONCLUSION: No single CSF test had sufficient predictive value to diagnose ACS in SLE, although CSF IL-6 levels and the IgG index showed statistical associations with ACS. Use of CSF tests combined with careful history and clinical examinations is recommended for proper diagnosis of ACS in SLE.

Expression and function of inducible co-stimulator in patients with systemic lupus erythematosus: possible involvement in excessive interferon-gamma and anti-double-stranded DNA antibody production.

Inducible co-stimulator (ICOS) is the third member of the CD28/cytotoxic T-lymphocyte associated antigen-4 family and is involved in the proliferation and activation of T cells. A detailed functional analysis of ICOS on peripheral blood T cells from patients with systemic lupus erythematosus (SLE) has not yet been reported. In the present study we developed a fully human anti-human ICOS mAb (JTA009) with high avidity and investigated the immunopathological roles of ICOS in SLE. JTA009 exhibited higher avidity for ICOS than a previously reported mAb, namely SA12. Using JTA009, ICOS was detected in a substantial proportion of unstimulated peripheral blood T cells from both normal control individuals and patients with SLE. In CD4+CD45RO+ T cells from peripheral blood, the percentage of ICOS+ cells and mean fluorescence intensity with JTA009 were significantly higher in active SLE than in inactive SLE or in normal control individuals. JTA009 co-stimulated peripheral blood T cells in the presence of suboptimal concentrations of anti-CD3 mAb. Median values of [3H]thymidine incorporation were higher in SLE T cells with ICOS co-stimulation than in normal T cells, and the difference between inactive SLE patients and normal control individuals achieved statistical significance. ICOS co-stimulation significantly increased the production of IFN-gamma, IL-4 and IL-10 in both SLE and normal T cells. IFN-gamma in the culture supernatants of both active and inactive SLE T cells with ICOS co-stimulation was significantly higher than in normal control T cells. Finally, SLE T cells with ICOS co-stimulation selectively and significantly enhanced the production of IgG anti-double-stranded DNA antibodies by autologous B cells. These findings suggest that ICOS is involved in abnormal T cell activation in SLE, and that blockade of the interaction between ICOS and its receptor may have therapeutic value in the treatment of this intractable disease.

A promoter haplotype of the interleukin-18 gene is associated with juvenile idiopathic arthritis in the Japanese population.

Recently, we reported that genetic polymorphisms within the human IL18 gene were associated with disease susceptibility to adult-onset Still's disease (AOSD), which is characterized by extraordinarily high serum levels of IL-18. Because high serum IL-18 induction has also been observed in the systemic type of juvenile idiopathic arthritis (JIA), we investigated whether similar genetic skewing is present in this disease. Three haplotypes, S01, S02, and S03, composed of 13 genetic polymorphisms covering two distinct promoter regions, were determined for 33 JIA patients, including 17 with systemic JIA, 10 with polyarthritis, and 6 with oligoarthritis. Haplotypes were also analyzed for 28 AOSD patients, 164 rheumatoid arthritis (RA) patients, 102 patients with collagen diseases, and 173 healthy control subjects. The frequency of individuals carrying a diplotype configuration (a combination of two haplotypes) of S01/S01 was significantly higher in the JIA patients, including all subgroups, than in the healthy controls (P = 0.0045, Fischer exact probability test; odds ratio (OR) = 3.55, 95% confidence interval (CI) = 1.55-8.14). In patients with systemic JIA, its frequency did not differ statistically from that of normal controls. Nevertheless, it is possible that haplotype S01 is associated with the phenotype of high IL-18 production in systemic JIA because the patients carrying S01/S01 showed significantly higher serum IL-18 levels compared with patients with other diplotype configurations (P = 0.017, Mann-Whitney U test). We confirmed that the frequency of the diplotype configuration of S01/S01 was significantly higher in AOSD patients than in healthy control subjects (P = 0.011, OR = 3.45, 95% CI = 1.42-8.36). Furthermore, the RA patients were also more predisposed to have S01/S01 (P = 0.018, OR = 2.00, 95% CI = 1.14-3.50) than the healthy control subjects, whereas the patients with collagen diseases did not. In summary, the diplotype configuration of S01/S01 was associated with susceptibility to JIA as well as AOSD and RA, and linked to significantly higher IL-18 production in systemic JIA. Possession of the diplotype configuration of S01/S01 would be one of the genetic risk factors for susceptibility to arthritis in the Japanese population.

Amplification of the synovial inflammatory response through activation of mitogen-activated protein kinases and nuclear factor kappaB using ligation of CD40 on CD14+ synovial cells from patients with rheumatoid arthritis.

OBJECTIVE: To determine the signal transduction pathways in CD14+ synovial cells from patients with rheumatoid arthritis (RA) after CD40 ligation, and to examine their role in amplifying synovial inflammation in affected joints. METHODS: Expression of messenger RNA was analyzed using quantitative reverse transcription-polymerase chain reaction. Cytokines and chemokines were measured using enzyme-linked immunosorbent assay. Activation of kinases was detected using Western blotting. Nuclear translocation of NF-kappaB was examined using immunohistochemistry. CD14+ synovial cells were enriched using magnetic cell sorting. Fibroblast-like synoviocytes (FLS) were obtained by passaging primary synovial cell culture. RESULTS: Stimulation of CD14+ synovial cells from RA patients by recombinant soluble CD154 (rsCD154) significantly induced expression of tumor necrosis factor alpha (TNFalpha), interleukin-1alpha (IL-1alpha), and IL-1beta. CD14+ RA synovial cells stimulated with rsCD154 plus interferon-gamma (IFNgamma) induced significantly higher production of IL-6, IL-8, and monocyte chemoattractant protein 1 by FLS compared with unstimulated CD14+ synovial cells, through TNFalpha-, IL-1alpha-, and IL-1beta-mediated pathways. Stimulation with rsCD154 plus IFNgamma induced the activation of ERK-1/2, p38 MAPK, and NF-kappaB. Specific inhibitors of MAPK/ERK-1/2 kinases and p38 MAPK significantly reduced the production of TNFalpha and IL-1beta by rsCD154 plus IFNgamma-stimulated CD14+ synovial cells, and also inhibited production of these cytokines by freshly isolated synovial cells from RA patients. CONCLUSION: These data indicate that the CD40-CD154 interaction activates the ERK, p38, and NF-kappaB pathways in CD14+ synovial cells from RA patients to produce TNFalpha, IL-1alpha, and IL-1beta, which in turn amplifies inflammatory responses by stimulating FLS. Inhibition of the CD40-CD154 interaction or its signal transduction pathways would be a strong and efficient strategy for the management of synovial inflammation in RA.