Distinct roles of IL-18 and IL-1ß in murine model of macrophage activation syndrome.

BACKGROUND: IL-18 and IL-1ß play a central role in the pathogenesis of systemic juvenile idiopathic arthritis and its life-threatening complication, macrophage activation syndrome (MAS). OBJECTIVES: This study aimed to clarify the role of IL-18 and IL-1ß in the pathogenesis of MAS. METHODS: We developed a mouse model to evaluate the role of each cytokine with Toll-like receptor 9 stimulation after continuous infusion with IL-18, IL-1ß, and a combination of both for 7 days. The symptoms and laboratory findings were compared among the IL-18, IL-1ß, and combination (IL-18+IL-1ß) groups. RESULTS: Body weight was significantly decreased in the IL-1ß and combination groups. Splenomegaly was observed in all groups, whereas hepatomegaly was noted in the IL-18 group only. Decreased T-cell numbers, anemia, and thrombocytopenia were observed in the combination group. IFN-γ, CXCL9, and IL-12A mRNA levels were upregulated and IL-10 mRNA levels in the spleen were downregulated in the IL-18 group. Hepatomegaly and splenomegaly in the IL-18 group were observed in a dose-dependent manner. TNF-α, CXCL9, and IL-12A mRNA levels were upregulated only in those mice with extremely elevated plasma IL-18 levels. CONCLUSION: IL-18 and IL-1ß have distinct roles in the pathogenesis of MAS. Dual blockade of IL-18 and IL-1ß might be necessary to treat MAS.

Intellectual disability and abnormal cortical neuron phenotypes in patients with Bloom syndrome.

Bloom syndrome (BS) is a rare autosomal recessive disorder characterized by genomic instability that leads to various complications, including cancer. Given the low prevalence of BS in Japan, we conducted a nationwide survey. We recruited eight patients with BS, three of whom exhibited intellectual disability. The 631delCAA mutation in the BLM gene was detected in 9 out of 16 alleles. To investigate neuronal development in patients with BS, we generated induced pluripotent stem cells derived from one of these patients (BS-iPSCs). We examined the phenotypes of the induced cortical neurons derived from the generated BS-iPSCs using a previously reported protocol; the generated BS-iPSCs showed an approximately 10-times higher frequency of sister-chromatid exchange (SCE) than the control iPSCs. Immunocytochemistry revealed shorter axons and higher proliferative potential in BS-iPSC-derived cortical neurons compared with control iPSCs. To our knowledge, our study is the first to clarify the abnormality of the cortical neuron phenotypes derived from patients with BS. Our findings may help identify the pathogenesis of neuronal differentiation in BS and aid in the development of novel therapeutic agents.

A randomised, double-blind, placebo-controlled phase III trial on the efficacy and safety of tocilizumab in patients with familial Mediterranean fever.

OBJECTIVES: To evaluate the efficacy and safety of tocilizumab (TCZ), an interleukin 6 receptor monoclonal antibody, in a subset of Japanese patients with familial Mediterranean fever (FMF). METHODS: We performed a double-blind, randomised, parallel-group trial, followed by an open-label extension trial, in patients with colchicine-resistant or -intolerant FMF (crFMF) (UMIN000028010). Patients were randomly assigned (1:1) to receive TCZ (162 mg every week) or placebo, administered subcutaneously, for 24 weeks. Rescue treatment was allowed if the rescue criteria were met. The primary endpoint was the number of fever attacks over the 24 weeks of treatment. Secondary endpoints included the frequency of accompanying symptoms during attacks, serum CRP and SAA values, and adverse events (AEs). The open-label extension study evaluated the long-term safety and efficacy of TCZ in patients who had completed the preceding study (UMIN000032557). RESULTS: We randomly assigned 23 patients to either TCZ (n=1) or placebo (n=12). The TCZ-placebo rate ratios were 0.691 (95% confidence intervals (CI), 0.189-2.531; p=0.577) for the fever attacks, based on the group rates per week. The recurrence of attacks was significantly lower in the TCZ group (hazard ratio = 0.457; 95% CI, 0.240-0.869). Fever attacks, accompanying symptoms, serum CRP and SAA values were controlled in most of the patients who received long-term TCZ. In these trials, the numbers and severity of AEs did not differ between groups. CONCLUSIONS: Although a primary endpoint was not met in the preceding trial, long-term administration of TCZ showed stable efficacy and safety for patients with crFMF.

Role of E148Q in familial Mediterranean fever with an exon 10 mutation in MEFV.

BACKGROUND: Familial Mediterranean fever (FMF) is an autosomal recessive disease caused by mutations in the MEFV gene. Mutations in exon 10 are associated with typical FMF. Most Japanese patients with typical FMF are compound heterozygotes of M694I in exon 10 and E148Q in exon 2. However, the pathogenic role of E148Q remains controversial. METHODS: We assessed symptoms and serum cytokines among patients with FMF and their family members. They were divided into three subgroups, based on MEFV mutations: individuals carrying M694I and E148Q (group A, n = 14), individuals carrying M694I, but not E148Q (group B, n = 10), and individuals carrying E148Q, but not M694I (group C, n = 11). RESULTS: All but one individual in group A had typical FMF phenotypes, whereas no individual in groups B and C exhibited any episodes of fever or serositis. The serum levels of interleukin-18 during the afebrile phase were significantly elevated in group A (2,806 ± 2,107 pg/mL), compared to those in groups B (499 ± 369 pg/mL) and C (427 ± 410 pg/mL). No difference in interleukin-6 levels was observed among the three groups. CONCLUSIONS: These findings indicated that E148Q may contribute to disease development of FMF in Japanese patients carrying the heterozygous M694I mutation in MEFV and that genetic testing of both parents would lead to better counseling for their children.

Clinical significance of interleukin-18 for the diagnosis and prediction of disease course in systemic juvenile idiopathic arthritis.

OBJECTIVE: To investigate the clinical significance of serum IL-18 levels for the diagnosis of systemic JIA (s-JIA) and to predict the disease course of s-JIA. METHODS: Overall, 116 patients with s-JIA, 151 with other diseases and 20 healthy controls were analysed. Serum IL-18 levels were measured longitudinally in 41 patients with s-JIA from active phase through remission phase. Serum IL-18 levels were quantified via enzyme-linked immunosorbent assay and the results were compared with clinical features and the disease course of s-JIA. RESULTS: The serum IL-18 level cut-off value for differentiation of s-JIA from other diseases was 4800 pg/ml. In patients with a monocyclic course, serum IL-18 levels steadily decreased during the inactive phase and low levels were sustained during remission. In contrast, in patients with a chronic course, elevated serum IL-18 levels were sustained even during the inactive phase. In patients with a polycyclic course, serum IL-18 levels were elevated during disease flares and normalized during the inactive phase. The serum IL-18 level cut-off value for diagnosis of remission in s-JIA was 595 pg/ml. CONCLUSION: Serum IL-18 levels of >4800 pg/ml may be useful for differentiating between s-JIA and other diseases. Monitoring of serum IL-18 levels might be useful for predicting the disease course and assessing remission in s-JIA.

Comparison of serum cytokine profiles in macrophage activation syndrome complicating different background rheumatic diseases in children.

OBJECTIVES: To compare the cytokines involved in the development of macrophage activation syndrome (MAS) in different background rheumatic diseases and to identify serum biomarkers for MAS diagnosis. METHODS: Serum neopterin, IL-6, IL-18 and soluble TNF receptor (sTNFR) type I (sTNFR-I) and type II (sTNFR-II) levels were determined using ELISA in 12 patients with SLE, including five with MAS; 12 patients with JDM, including four with MAS; 75 patients with Kawasaki disease (KD), including six with MAS; and 179 patients with systemic JIA (s-JIA), including 43 with MAS. These results were compared with the clinical features of MAS. RESULTS: Serum neopterin, IL-18 and sTNFR-II levels were significantly higher during the MAS phase than during the active phase in patients with all diseases. Furthermore, serum sTNFR-I levels were significantly higher during the MAS phase than during the active phase in patients with SLE, KD and s-JIA. Receiver operating characteristic (ROC) curve analysis revealed that serum sTNFR-I levels for SLE, serum IL-18 levels for JDM, and serum sTNFR-II levels for KD and s-JIA had the highest areas under the ROC curve. Serum levels of these cytokines were significantly and positively correlated with serum ferritin levels. CONCLUSIONS: Overproduction of IFN-γ, IL-18 and TNF-α might be closely related to the development of MAS. Serum levels of sTNFR-I for SLE, IL-18 for JDM, and sTNFR-II for KD and s-JIA might be useful diagnostic markers for the transition from active phase to MAS.

Apoptosis inhibitor of macrophage as a biomarker for disease activity in Japanese children with IgA nephropathy and Henoch-Schönlein purpura nephritis.

BACKGROUND: To evaluate the apoptosis inhibitor of macrophage (AIM) deposition patterns on the kidneys of children with IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis (HSPN) and to investigate the clinical usefulness of serum and/or urinary AIM levels as biomarkers for the disease activity. METHODS: Immunohistochemical study was performed in the kidneys of 37 patients with IgAN and 10 patients with HSPN. Serum and urinary AIM levels in the patients and 20 healthy controls (HCs) were quantified by enzyme-linked immunosorbent assay. The results were compared with clinical features. RESULTS: In patients with IgAN and HSPN, AIM expression was observed in various areas, including the glomerular mesangial and capillary areas, the proximal and distal tubular epithelial cells, and on infiltrating macrophages in the glomeruli and interstitial areas. Serum and urinary AIM levels were significantly elevated in these patients compared with the HCs. Urinary AIM levels were positively correlated with the histological severity and degree of proteinuria and hematuria as well as urinary ß2 microglobulin and urinary N-acetyl-ß-D-glucosaminidase levels. CONCLUSIONS: AIM plays an important role in the pathogenesis of IgAN and HSPN. Urinary AIM levels can potentially reflect active renal inflammation in these diseases and may represent a useful biomarker for disease activity. IMPACT: Urinary AIM levels may represent a useful biomarker for disease activity of IgAN and HSPN. AIM expression was observed in the glomeruli, tubular epithelial cells, and infiltrating macrophages in glomeruli and interstitial area. U-AIM/Cr were significantly correlated not only with proteinuria, hematuria, and u-ß2MG and u-NAG levels but also with the activity index of histological findings in kidney biopsy specimens. Our results can emphasize the important role of AIM in the pathogenesis of IgAN and HSPN.

Toxic shock syndrome with a cytokine storm caused by Staphylococcus simulans: a case report.

BACKGROUND: Exotoxins secreted from Staphylococcus aureus or Streptococcus pyogenes act as superantigens that induce systemic release of inflammatory cytokines and are a common cause of toxic shock syndrome (TSS). However, little is known about TSS caused by coagulase-negative staphylococci (CoNS) and the underlying mechanisms. Here, we present a rare case of TSS caused by Staphylococcus simulans (S. simulans). CASE PRESENTATION: We report the case of a 75-year-old woman who developed pneumococcal pneumonia and bacteremia from S. simulans following an influenza infection. The patient met the clinical criteria for probable TSS, and her symptoms included fever of 39.5 °C, diffuse macular erythroderma, conjunctival congestion, vomiting, diarrhea, liver dysfunction, and disorientation. Therefore, the following treatment was initiated for bacterial pneumonia complicating influenza A with suspected TSS: meropenem (1 g every 8 h), vancomycin (1 g every 12 h), and clindamycin (600 mg every 8 h). Blood cultures taken on the day after admission were positive for CoNS, whereas sputum and pharyngeal cultures grew Streptococcus pneumoniae (Geckler group 4) and methicillin-sensitive S. aureus, respectively. However, exotoxins thought to cause TSS, such as TSS toxin-1 and various enterotoxins, were not detected. The patient's therapy was switched to cefazolin (2 g every 8 h) and clindamycin (600 mg every 8 h) for 14 days based on microbiologic test results. She developed desquamation of the fingers on hospital day 8 and was diagnosed with TSS. Conventional exotoxins, such as TSST-1, and S. aureus enterotoxins were not detected in culture samples. The serum levels of inflammatory cytokines, such as neopterin and IL-6, were high. CD8+ T cells were activated in peripheral blood. Vß2+ population activation, which is characteristic for TSST-1, was not observed in the Vß usage of CD8+ T cells in T cell receptor Vß repertoire distribution analysis. CONCLUSIONS: We present a case of S. simulans-induced TSS. Taken together, we speculate that no specific exotoxins are involved in the induction of TSS in this patient. A likely mechanism is uncontrolled cytokine release (i.e., cytokine storm) induced by non-specific immune reactions against CoNS proliferation.

Serum insulin-like growth factor-binding protein 2 levels as an indicator for disease severity in enterohemorrhagic Escherichia coli induced hemolytic uremic syndrome.

BACKGROUND: Insulin-like growth factor-binding protein (IGFBP) 2 plays an important role in the regulation of cell adhesion, migration, growth, and apoptosis. This study aimed to investigate the clinical significance of serum IGFBP2 as a biomarker for disease activity and severity in hemolytic uremic syndrome (HUS) induced by enterohemorrhagic Escherichia coli (EHEC). METHODS: IGFBP2 production by human renal glomerular endothelial cells (RGECs) after exposure to Shiga toxin 2 (Stx-2) was investigated in vitro. Serum IGFBP2 levels in blood samples obtained from 22 patients with HUS and 10 healthy controls (HCs) were quantified using an enzyme-linked immunosorbent assay. The results were compared to the clinical features of HUS and serum tau and cytokine levels. RESULTS: Stx-2 induced the production of IGFBP2 in RGECs in a dose-dependent manner. Serum IGFBP2 levels were significantly higher in patients with HUS than in HCs and correlated with disease severity. Additionally, serum IGFBP2 levels were significantly higher in patients with encephalopathy than in those without encephalopathy. A serum IGFBP2 level above 3585 pg/mL was associated with a high risk of encephalopathy. Furthermore, serum IGFBP2 levels significantly correlated with serum levels of tau and inflammatory cytokines associated with the development of HUS. CONCLUSIONS: Correlation of serum IGFBP2 level with disease activity in patients with HUS suggests that IGFBP2 may be considered as a possible indicator for disease activity and severity in HUS. Larger studies and additional experiments using various cells in central nervous system should elucidate the true value of IGFBP2 as a clinical diagnostic marker. ABBREVIATIONS: IGFBP: insulin-like growth factor-binding protein; HUS: hemolytic uremic syndrome; EHEC: enterohemorrhagic Escherichia coli; RGECs: renal glomerular endothelial cells; STx-2: Shiga toxin 2; HCs: healthy controls; LPS: lipopolysaccharide; ROC: receiver operating characteristic; sTNFR: soluble tumor necrosis factor receptor.

Heme Oxygenase-1 Deficiency and Oxidative Stress: A Review of 9 Independent Human Cases and Animal Models.

Since Yachie et al. reported the first description of human heme oxygenase (HO)-1 deficiency more than 20 years ago, few additional human cases have been reported in the literature. A detailed analysis of the first human case of HO-1 deficiency revealed that HO-1 is involved in the protection of multiple tissues and organs from oxidative stress and excessive inflammatory reactions, through the release of multiple molecules with anti-oxidative stress and anti-inflammatory functions. HO-1 production is induced in vivo within selected cell types, including renal tubular epithelium, hepatic Kupffer cells, vascular endothelium, and monocytes/macrophages, suggesting that HO-1 plays critical roles in these cells. In vivo and in vitro studies have indicated that impaired HO-1 production results in progressive monocyte dysfunction, unregulated macrophage activation and endothelial cell dysfunction, leading to catastrophic systemic inflammatory response syndrome. Data from reported human cases of HO-1 deficiency and numerous studies using animal models suggest that HO-1 plays critical roles in various clinical settings involving excessive oxidative stress and inflammation. In this regard, therapy to induce HO-1 production by pharmacological intervention represents a promising novel strategy to control inflammatory diseases.

Comparison of serum biomarkers for the diagnosis of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis during tocilizumab therapy.

BACKGROUND: To compare the accuracy of serum biomarkers for the diagnosis of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (s-JIA) during tocilizumab therapy. METHODS: Serum cytokine levels of neopterin, IL-18, C-X-C motif chemokine ligand 9, soluble tumor necrosis factor receptor (sTNFR)-I, and sTNFR-II were determined by enzyme-linked immunosorbent assay in 36 patients with MAS complicating s-JIA including 12 patients receiving tocilizumab. Furthermore, the serum sTNFR-II/I ratio was compared with the clinical features of MAS. RESULTS: The levels of all serum cytokines at MAS diagnosis were significantly lower in the tocilizumab-treated group than in the tocilizumab-untreated group. In contrast, the serum sTNFR-II/I ratio at MAS diagnosis was comparable between the tocilizumab-treated and the tocilizumab-untreated groups. The receiver operating characteristic curve analysis revealed that the area under the curve and cut-off values of sTNFR-II/I ratio were 0.9722 and 4.71, respectively. The serum sTNFR-II/I ratio, which was significantly elevated in patients with MAS complicating s-JIA, was correlated positively with disease activity. CONCLUSIONS: These findings suggest that the serum sTNFR-II/I ratio might be a useful indicator to evaluate disease activity in MAS complicating s-JIA and a useful diagnostic marker for the transition from active-phase s-JIA to MAS even in tocilizumab-treated patients. IMPACT: This is the first study to analyze the role of tocilizumab in modifying the serum levels of biomarkers used for the diagnosis of MAS complicating s-JIA. We found the biomarker for the diagnosis of MAS complicating s-JIA during tocilizumab therapy. We hope our results might be useful for the development of a new criteria for the diagnosis of MAS complicating s-JIA in patients treated with tocilizumab in future.

The possession of exon 2 or exon 3 variants in the MEFV gene promotes inflammasome activation in Japanese patients with familial Mediterranean fever with a heterozygous exon 10 mutation.

OBJECTIVES: The modification and pathogenesis of MEFV exon 2 or 3 variants in familial Mediterranean fever (FMF) remains unclear. We compared the clinical and laboratory characteristics between the coexistence and noncoexistence of MEFV exon 2 or 3 variants in patients with FMF that had a heterozygous MEFV exon 10 mutation. METHODS: We excluded patients with FMF that had two MEFV exon 10 mutations in one or more alleles and/or MEFV mutations in exons other than in exons 2, 3, or 10. Finally, we reviewed 131 Japanese patients with FMF that had a heterozygous MEFV exon 10 mutation, and they were divided into the groups with and without MEFV exon 2 or 3 variants of 97 and 34, respectively. RESULTS: All patients with MEFV exon 2 variants had either E148Q and/or L110P variants, none of patients had exon 3 variants. In the univariate analysis, the group with variants had significantly earlier onset, a higher percentage of thoracic pain with febrile attacks, a higher frequency of attack, and a higher IL-18 level at remission compared to the group without variants (all, p<0.05). Importantly, multivariate analyses showed that the coexistence of MEFV exon 2 variants was independently and significantly associated with earlier onset of FMF and thoracic pain (both, p<0.05). CONCLUSIONS: Our results suggested that coexistence of MEFV exon 2 variants have additional effects on manifestations of FMF with MEFV exon 10 mutations. Our findings highlighted the modifications and pathogenesis of such MEFV variants in FMF.

Next-generation sequencing of the whole MEFV gene in Japanese patients with familial Mediterranean fever: a case-control association study.

OBJECTIVES: We aimed to identify the whole nucleotide sequence of the Mediterranean fever (MEFV) gene in familial Mediterranean fever (FMF) and reveal novel single nucleotide variants (SNVs) associated with the susceptibility of FMF. METHODS: SeqCap capturing technique followed by Illumina next-generation sequencing have been used to assess two hundred SNVs in the whole region of MEFV in 266 Japanese patients with FMF and 288 ethnically matched controls. We performed an association analysis using these SNVs to identify genetic variants that predispose to FMF. RESULTS: We identified the two most significant SNVs [rs28940578; M694I in exon 10, odds ratio (OR) = 153, p=2.47×10-21 and rs3743930; E148Q in exon 2, OR = 1.65, p<0.0005]. Stratified analysis identified rs28940578 as a risk allele in typical FMF. Haplotype AG, defined by rs401298 and rs28940578, was the most significant and prevalent among patients with typical FMF compared with controls (22.4% vs. 0%, respectively; OR = 137, p=1.44×10-31). Haplotype GTC, defined by rs11466018, rs224231, and rs401877, was the most significant among patients with typical FMF without the rs28940578 mutation compared with controls (15.9% vs. 6%, respectively; OR = 12.4, p=0.004). CONCLUSIONS: rs28940578 is associated with the highest risk in typical FMF cases. This is consistent with results from previous studies in Japan. We found a novel MEFV gene haplotype that confers susceptibility of FMF among typical FMF without the rs28940578 mutation. There were no relevant SNVs identified in MEFV among the atypical FMF group.

Half of 'Micrococcus spp.' cases identified by conventional methods are revealed as other life-threatening bacteria with different drug susceptibility patterns by 16S ribosomal RNA gene sequencing.

Bacterial infection during chemotherapy is a fatal complication, therefore precise identification of the pathogenic microorganism is required for treatment. We report that 2 of 4 pediatric patients with malignancy who were diagnosed with Micrococcus spp. infection by conventional methods were finally revealed to have Kytococcus schroeteri and Kocuria marina infection by 16S ribosomal RNA gene sequence analysis (16S rRNA analysis). Although K. schroeteri is morphologically similar to Micrococcus spp., its drug susceptibility profile is quite different from that of Micrococcus spp. K. schroeteri is resistant to penicillin and cephalosporin, which are effective for Micrococcus spp. In fact, penicillin-resistant lethal pneumonia caused by K. schroeteri has been reported in compromised hosts. Based on our results, Micrococcus spp. determined by conventional methods could contain other life-threatening bacteria with different drug susceptibility patterns from Micrococcus spp. To develop an effective empirical treatment for immunocompromised hosts, accumulation of pathogen data by 16S rRNA analysis is required.

One-month-old boy with group B streptococcal meningitis, subdural effusion, and high levels of interleukin-6.

Meningitis is associated with elevated levels of inflammatory cytokines in the blood, cerebrospinal fluid (CSF), and subdural fluid. Subdural effusion prolongs fever in patients with meningitis. However, the reason for this remains unclear. A healthy one-month-old boy was admitted after presenting with bacterial meningitis. He was administered meropenem, cefotaxime, and dexamethasone intravenously. On the 3rd day, blood and CSF cultures revealed the presence of Group B Streptococcus from samples collected on day 1. Subsequently, ampicillin and gentamicin replaced the previous combination of antimicrobials used. On the 4th day, brain magnetic resonance imaging with contrast showed bilateral cerebral ventriculitis and left subdural effusion. On the 11th day, since the subdural effusion had worsened, we performed a subdural puncture from the anterior fontanelle. Owing to the prolonged fever, he was intravenously injected immunoglobulin on day 13. He was afebrile on day 23. Antimicrobials were administered for 28 days. Levels of interleukin-6 (IL-6) in the serum and CSF were the highest on the 1st day at 20,600 pg/mL and 170,000 pg/mL, respectively, and decreased upon treatment. IL-6 concentration in the subdural fluid (30,000 pg/mL) was much higher than that in the serum (9 pg/mL) and CSF (2600 pg/mL). To the best of our knowledge, this is the first report on the cytokines in subdural fluid in patients with group B Streptococcal meningitis. Subdural effusion maintained high levels of IL-6 even after the levels in the blood and CSF decreased dramatically. This could explain why subdural effusion prolongs fever in patients with meningitis.

Adult-onset Still's disease with macrophage activation syndrome diagnosed and treated based on cytokine profiling: a case-based review.

Adult-onset Still's disease (AOSD) is a relatively rare systemic inflammatory disorder and is diagnosed using various sets of classification criteria, with the Yamaguchi criteria as the most widely used criteria. Herein, we present the case of a 21-year-old woman admitted with a high fever, lasting for over 1 month, who did not fulfill the Yamaguchi criteria. However, by analyzing the inflammatory cytokine profile, we defined this case as AOSD based on a greatly elevated serum interleukin-18 level. In addition, we predicted the occurrence of macrophage activation syndrome by a characteristic increase in the soluble tumor necrosis factor receptor II level, which allowed a timely intervention for this malicious complication. Therefore, we suggest that cytokine profiling will be useful for the diagnosis and management of AOSD.

Macrophage activation syndrome in neonates born to mothers with adult-onset Still's disease: Perinatal effect of maternal IL-18.

Overproduction of interleukin (IL)-18 is closely related to the pathogenesis of adult-onset Still's disease (AOSD) and the development of macrophage activation syndrome (MAS), a life-threating complication of AOSD. We reported three cases of MAS occurring in infants born to mothers with AOSD. The infants developed MAS at age 13 and 8 days and at birth. Serum IL-18 levels were extremely elevated in all infants (147,000 pg/mL; 378,000 pg/mL; 95,000 pg/mL) as well as in their mothers (58,500 pg/mL; 367,000 pg/mL; 84,000 pg/mL). Physicians should be aware that infants born to mothers with AOSD are at a risk of developing MAS. Serum IL-18 levels in mothers with AOSD and their infants should be monitored.

Comparison of serum biomarkers for the diagnosis of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis.

Our study aimed to compare the accuracy of serum biomarkers for the diagnosis of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (s-JIA). Serum cytokine levels (neopterin, IL-18, and CXCL9 and soluble tumor necrosis factor receptor type I (sTNFR-I) and II) were determined by enzyme-linked immunosorbent assay in 78 patients with s-JIA, including 21 with MAS. Receiver operating characteristic curve analysis revealed area under the curve values and cut off values of neopterin, IL-18, CXCL9, sTNFR-II/I ratio and ferritin were 0.9465/19.5 nmol/l, 0.8895/69250 ng/ml, 0.9333/3130 pg/ml, 0.9395/3.796 and 0.8671/2560 ng/ml, respectively. Serum neopterin levels were significantly elevated in patients with MAS and those were correlated positively with disease activity. In conclusion, serum neopterin levels may be used as a promising indicator of disease activity in s-JIA and MAS and for evaluating it. It may also be a useful marker to diagnose the transition to MAS from active-phase s-JIA.

Extensive serum biomarker analysis in patients with macrophage activation syndrome associated with systemic lupus erythematosus.

The present study employed an antibody array that simultaneously detects 174 cytokines to identify cytokines involved in the development of macrophage activation syndrome (MAS) associated with systemic lupus erythematosus (SLE) with a view to elucidating potential predictive markers. Eight SLE patients, including four with MAS, were analyzed. Levels of 31 cytokines were significantly elevated in the MAS phase compared with those in the active phase of SLE. Among these cytokines, the MAS/active phase ratios of CXCL9 and soluble tumor necrosis factor receptor II (sTNFR-II) were highest. Elevated serum CXCL9 and sTNFR-II levels during the MAS phase were confirmed by ELISA and were strongly correlated with other inflammatory markers, reflecting the disease activity of MAS associated with SLE. These results highlight the clinical significance of serum CXCL-9 and sTNFR-II levels, and indicate they may be useful biomarkers for the diagnosis of MAS associated with SLE.

C/EBPε ΔRS derived from a neutrophil-specific granule deficiency patient interacts with HDAC1 and its dysfunction is restored by trichostatin A.

CCAAT/enhancer binding protein epsilon (C/EBPε), a myeloid-specific transcription factor, plays an important role in granulopoiesis. A loss-of-function mutation in this protein can result in an abnormal development of neutrophils and eosinophils, known as neutrophil-specific granule deficiency (SGD). The transcriptional activity of C/EBPε is regulated by interactions with other transcription factors and/or post-translational modification, including acetylation. Previously, we reported a novel SGD patient who had a homozygous mutation for two amino acids, arginine (R247) and serine (S248), which were deleted in the basic leucine zipper domain of C/EBPε (ΔRS) and exhibited loss of transcriptional activity with aberrant protein-protein interactions. In the present study, we found that a single amino acid deletion of either R247 (ΔR) or S248 (ΔS) was sufficient for the loss of C/EBPε transcriptional activity, while an amino acid substitution at S248 to alanine in C/EBPε (SA) had comparable transcriptional activity with the wild-type C/EBPε (WT). Although acetylation at lysine residues (K121 and K198) is indispensable for C/EBPε transcriptional activity, an acetylation mimic form of ΔRS (ΔRS-K121/198Q) did not exhibit the transcriptional activity. Interestingly, we discovered that ΔRS, ΔR, ΔS, and ΔRS-K121/198Q interacted with histone deacetylase 1 (HDAC1), whereas WT and SA did not. Furthermore, the proteoglycan 2/eosinophil major basic protein induction activity of ΔRS, ΔR, and ΔS could be restored by the HDAC inhibitor, trichostatin A (TSA), and protein-protein interactions between ΔRS and Gata1 could also be recovered by TSA treatment. Taken together, our results show that TSA has the potential to restore the transcriptional activity of ΔRS, indicating that the inhibition of HDAC1 could be a molecularly targeted treatment for SGD with ΔRS.