Kae Takagi

Increased CD40 Expression on Muscle Cells of Polymyositis and Dermatomyositis: Role of CD40-CD40 Ligand Interaction in IL-6, IL-8, IL-15, and Monocyte Chemoattractant Protein-1 Production

In polymyositis (PM)/dermatomyositis (DM), T cells infiltrate the muscle tissues and interact with muscle cells via cell surface molecules. Recently, myoblasts have been reported to express CD40, but little is known about the role of CD40 in myoblasts. In the present study we examined the expression and involvement of CD40 and CD40 ligand (CD40L) in the interaction between muscle cells and T cells in PM/DM. Immunohistochemical staining revealed that CD40 was expressed on muscle cells in five of five PM and four of five DM patients, and that infiltrating mononuclear cells (MNCs) expressed CD40L in all cases of PM/DM. These CD40L-expressing MNCs were primarily CD4+ T cells. IFN-γ, which is known to induce CD40 expression on various types of cells, was also expressed on the MNCs in four of the PM and four of the DM patients. Although cultured human myoblasts (SkMC 2859) did not express CD40 constitutively, IFN-γ induced CD40 expression in a dose-dependent manner. To clarify the functional roles of CD40-mediated signals, the effects of a trimeric form of recombinant human CD40L on cytokine production were studied in SkMC 2859 that were prestimulated with IFN-γ to express CD40. Recombinant human CD40L markedly increased the production of IL-6, IL-8, IL-15, and monocyte chemoattractant protein-1 of SkMC 2859. The expression of these humoral factors in muscle cells of PM and DM was demonstrated by immunohistochemistry. These results suggest that interaction between T cells and muscle cells via the CD40-CD40L system contributes to the immunopathogenesis of PM/DM by augmenting inflammation via cytokine production by the muscle cells.

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.

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.

Increased CD40 expression in skin fibroblasts from patients with systemic sclerosis (SSc): role of CD40‐CD154 in the phenotype of SSc fibroblasts

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology that is characterized by tissue fibrosis, which may result from the activation of lesional fibroblasts exhibiting excessive production of extracellular matrix components. However, it has yet to be determined how SSc fibroblasts are activated. CD40 is a cell surface molecule expressed on various cells that is important for the response to activated T cells through CD154. CD40 mRNA was found to be constitutively expressed in both SSc and normal fibroblasts by reverse transcription PCR. Expression of CD40 protein was increased on SSc fibroblasts compared to normal fibroblasts as measured by flow cytometry. Ligation of CD40 by recombinant human CD154 (0.5–2 μg/ml) resulted in increased production of IL‐6, IL‐8, and monocyte chemoattractant protein‐1 in SSc fibroblasts in a dose‐dependent manner, whereas these phenomena were not shown in normal fibroblasts even with the addition of CD154. CD80, a costimulatory molecule, was also induced on SSc fibroblasts by CD40 ligation. In the present study, our findings suggest the possibility of a cell‐mediated response between fibroblasts and T cells in the lesional skin of SSc patients. Since it is suggested that the CD40‐CD154 system may play a crucial role in the aberrant production of immune mediators by SSc fibroblasts, blockage of CD40‐CD154 may be a novel therapeutic strategy for SSc.

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.

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.

Association of the diplotype configuration at the N-acetyltransferase 2 gene with adverse events with co-trimoxazole in Japanese patients with systemic lupus erythematosus

Although co-trimoxazole (trimethoprim-sulphamethoxazole) is an effective drug for prophylaxis against and treatment of Pneumocystis pneumonia, patients often experience adverse events with this combination, even at prophylactic doses. With the aim being to achieve individual optimization of co-trimoxazole therapy in patients with systemic lupus erythematosus (SLE), we investigated genetic polymorphisms in the NAT2 gene (which encodes the metabolizing enzyme of sulphamethoxazole). Of 166 patients with SLE, 54 patients who were hospitalized and who received prophylactic doses of co-trimoxazole were included in the cohort study. Adverse events occurred in 18 patients; only two experienced severe adverse events that lead to discontinuation of the drug. These two patients and three additional ones with severe adverse events (from other institutions) were added to form a cohort sample and were analyzed in a case-control study. Genotype was determined using TaqMan methods, and haplotype was inferred using the maximum-likelihood method. In the cohort study, adverse events occurred more frequently in those without the NAT2*4 haplotype (5/7 [71.4%]) than in those with at least one NAT2*4 haplotype (13/47 [27.7%]; P = 0.034; relative risk = 2.58, 95% confidence interval = 1.34–4.99). In the case-control study the proportion of patients without NAT2*4 was significantly higher among those with severe adverse events (3/5 [60%]) than those without severe adverse events (6/52 [11.5%]; P = 0.024; odds ratio = 11.5, 95% confidence interval = 1.59–73.39). We conclude that lack of NAT2*4 haplotype is associated with adverse events with co-trimoxazole in Japanese patients with SLE.

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.

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.