Necrotic Change of Tunica Media Plays a Key Role in the Development of Coronary Artery Lesions in Kawasaki Disease.

BACKGROUND: Alarmins resulting from cell death or oxidative stress are involved in the development of Kawasaki disease (KD) vasculitis. In a previous study, we demonstrated the potential role of interleukin (IL)-33 as an alarmin in the development of KD vasculitis. Although edematous dissociation (necrotic change) of the tunica media is thought to be a major source of IL-33 in KD vasculitis, it has not yet been elucidated. METHODS AND RESULTS: We investigated the impact of IL-33 released from necrotic human coronary artery smooth muscle cells (HCASMCs) on human coronary artery endothelial cells (HCAECs) using a coculture assay. Subsequently, we evaluated the anti-inflammatory effects of anti-IL-33 and anti-suppression of tumorigenicity 2 (ST2) antibodies compared with conventional therapies of KD, such as high-dose IgG or anti-tumor necrosis factor (TNF)-α antibody. Primary necrosis of HCASMCs induced significant release of IL-33. In cocultures of necrotic HCASMCs with HCAECs, the necrotic HCASMCs significantly induced the production of various proinflammatory cytokines in the HCAECs. Anti-IL-33 and anti-ST2 antibodies exhibited unique inhibitory effects on the production of platelet-derived growth factor-BB or IL-12(p70) in HCAECs. CONCLUSIONS: There is potential involvement of edematous dissociation of the tunica media in the development of KD vasculitis. Furthermore, the distinctive anti-inflammatory effects of the anti-IL-33/ST2 axis drugs suggest novel therapeutic options for patients with refractory KD.

Histological characteristics of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in asthmatic murine model during A(H1N1)pdm09 infection.

Pandemic influenza virus A(H1N1)pdm09 infection occurred in healthy children and young adults, but asthmatic patients presented more rapid progression of respiratory distress and plastic bronchitis. To investigate the pathogenesis of worsening respiratory symptoms after A(H1N1)pdm09 infection, we focused on matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1). MMP-9 and TIMP-1 levels in bronchoalveolar lavage fluid and serum from mice with and without asthma were evaluated after A(H1N1)pdm09 or seasonal A(H1N1) infection. MMP-9 levels were more elevated in Asthma/A(H1N1)pdm09-infected mice than in non-Asthma/A(H1N1)pdm09-infected mice on both 3 and 7 days post-infection. Immunohistochemical findings in this pneumonia model showed that MMP-9 and TIMP-1 positive cells were observed in blood vessels and bronchus of lung tissue in severe pathological findings of pneumonia with asthma. Microscopically, shedding cells and secretions were conspicuous in the trachea on days 3 and 7 post-infection, in the A(H1N1)pdm09-infected mice with asthma. Our results suggest that MMP-9 and TIMP-1 expressions are related to severe pneumonia in the A(H1N1)pdm09 infection with asthma, leading to cause epithelial cell shedding.

Diversities of allergic pathologies and their modifiers: Report from the second DGAKI-JSA meeting.

In October 2021, researchers from the German Society of Allergy and Clinical Immunology (DGAKI) and from the Japanese Society of Allergology (JSA) focused their attention on the pathological conditions and modifiers of various allergic diseases. Topics included 1) the pathophysiology of IgE/mast cell-mediated allergic diseases; 2) the diagnosis and prevention of IgE/mast cell-mediated diseases; 3) the pathophysiology, diagnosis, and treatment of eosinophilic airway diseases; and 4) host-pathogen interaction and allergic diseases. This report summarizes the panel discussions, which highlighted the importance of recognizing the diversity of genetics, immunological mechanisms, and modifying factors underlying allergic diseases.

Phospholipase C-ß3 regulates FcɛRI-mediated mast cell activation by recruiting the protein phosphatase SHP-1.

Mast cells are major effectors in high-affinity IgE receptor (FcɛRI)-dependent allergic reactions. Here we show that phospholipase C (PLC)-ß3 is crucial for FcɛRI-mediated mast cell activation. Plcb3(-/-) mice showed blunted FcɛRI-dependent late-phase, but not acute, anaphylactic responses and airway inflammation. Accordingly, FcɛRI stimulation of Plcb3(-/-) mast cells exhibited reduced cytokine production but normal degranulation. Reduced cytokine production in Plcb3(-/-) cells could be accounted for by increased activity of the negative regulatory Src family kinase Lyn and reduced activities of the positive regulatory protein kinases MAPKs. Mechanistically, PLC-ß3 constitutively interacts with FcɛRI, Lyn, and SHP-1 (protein phosphatase). SHP-1 probably recognizes its substrates Lyn and MAPKs via the recently described kinase tyrosine-based inhibitory motif, KTIM. Consistent with PLC-ß3- and SHP-1-mediated repression of Lyn activity by dephosphorylation at Tyr396, FcɛRI-mediated phenotypes were similar in Plcb3(-/-) and SHP-1 mutant mast cells. Thus, we have defined a PLC-ß3- and SHP-1-mediated signaling pathway for FcɛRI-mediated cytokine production.

Nonosmotic secretion of arginine vasopressin and salt loss in hyponatremia in Kawasaki disease.

BACKGROUND: The precise mechanism of hyponatremia in Kawasaki disease (KD) remains elusive because assessment of volume status based on serial changes in body weight is lacking in previous reports. METHODS: Seventeen patients who were diagnosed with KD and hyponatremia (serum sodium levels <135 mmol/L) were analyzed. Volume status was assessed based on serial changes in body weight. Plasma arginine vasopressin (ADH), urine electrolytes, and serum cytokine levels were measured on diagnosis of hyponatremia. An increase in body weight by >3% was defined as hypervolemia and a decrease in body weight by >3% was defined as hypovolemia. RESULTS: The volume status was hypervolemic in three patients (18%), euvolemic in 14 (82%), and hypovolemic in none (0%). Five (29%) patients were diagnosed with "syndrome of inappropriate secretion of antidiuretic hormone" (SIADH) and no patients were diagnosed with hypotonic dehydration. The contribution of decreased total exchangeable cations (salt loss) to hyponatremia (5.9% [interquartile range, 4.3%, 6.7%]) was significantly larger than that of increased total body water (-0.7% [-1.8%, 3.1%]) (P = 0.004). Serum interleukin-6 levels were elevated in all of the nine patients who were evaluated. Among the 12 (71%) patients who did not meet the criteria of SIADH and hypotonic dehydration, plasma ADH levels were inappropriately high in ten patients. These patients were also characterized by euvolemic or hypervolemic hyponatremia and salt loss, which might be compatible with a diagnosis of SIADH. CONCLUSIONS: Our study shows that hyponatremia in KD is euvolemic or hypervolemic and is associated with nonosmotic secretion of ADH and salt loss in the majority of patients.

Pulmonary Hypertension Following Increased Dosing of Diazoxide in an Infant.

Diazoxide, a drug used to treat hyperinsulinemic hypoglycemia (HH), is associated with pulmonary hypertension (PH), as reported by the US Food and Drug Administration. However, no report has detailed the association between diazoxide dose and PH development. We report a case of an infant with HH, subsequently complicated by diazoxide-induced PH. When diazoxide was introduced, PH did not appear initially, but it developed during increased dosing. We monitored PH via regular echocardiography examinations. PH gradually improved with tapering of the diazoxide dose and disappeared after drug discontinuation. Our case suggests a diazoxide dose threshold might induce PH. Therefore, close echocardiography examinations should accompany diazoxide treatment.

Responses to Treatment According to the Cytokine Profiles of Pericardial Effusion in Two Children with Idiopathic Pericarditis.

Acute pericarditis is inflammation of the pericardium with or without pericardial effusion. In the pediatric population, most patients with acute pericarditis are diagnosed with idiopathic pericarditis. Herein, we present two children with idiopathic pericarditis who underwent immunological assessment of pericardial effusion for the first time. Both patients showed equally high levels of interleukin-6 in the pericardial effusion. However, they had different treatment responses, in accordance with the pericardial effusion and serum interleukin-10 concentrations. Our present cases suggest that interleukin-10 may be associated with the response to anti-inflammatory therapy in idiopathic acute pericarditis.

Serum soluble ST2 as a marker of renal scar in pediatric upper urinary tract infection.

BACKGROUND AND OBJECTIVES: Upper urinary tract infection is the most common serious bacterial infection in childhood. Patients with upper urinary tract infection have a risk for renal scarring with subsequent complications including hypertension, proteinuria, and progressive renal failure. However, the predictive biomarkers of renal scarring in children with upper urinary tract infection are still unknown. In this study, we evaluated whether soluble ST2 levels can be biomarkers of subsequent renal scarring in patients with upper urinary tract infection. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We retrospectively studied pediatric patients with upper urinary tract infection at a tertiary center. Twenty-eight children had an upper urinary tract infection with (n = 14) and without (n = 14) renal scarring and underwent 99mtechnetium dimercaptosuccinic acid imaging. In addition, 13 control subjects were enrolled. The clinical data and serum cytokine levels, including soluble ST2 levels, were compared between those with and without renal scars. RESULTS: Serum soluble ST2 levels were significantly higher in the scar group than in the non-scar group, whereas there was no difference in the levels of serum interferon-γ, interleukin-6, interleukin-10, soluble tumor necrosis factor receptor 1, and transforming growth factor-ß between the scar and non-scar groups. The area under the curve for differentiating between the non-scar and scar groups on the basis of measurements of serum soluble ST2 was 0.79, with a sensitivity and specificity of 92.9% and 64.3%, respectively. CONCLUSION: These results suggest that serum soluble ST2 levels on admission could be a useful biomarker of subsequent renal scarring in pediatric patients with upper urinary tract infection.

Multi-season analyses of causative pathogens in children hospitalized with asthma exacerbation.

BACKGROUND: Respiratory viral and mycoplasma infections are associated with childhood asthma exacerbations. Here, we explored epidemiologic profile of causative pathogens and possible factors for exacerbation in a single center over a three-year period. METHODS: Hospitalized asthmatic children with attack aged 6 months-17 years were recruited between 2012 and 2015 (n = 216). Nasopharyngeal mucosa cell samples were collected from the participants and examined by reverse transcription-polymerase chain reaction to detect rhinovirus (RV), respiratory syncytial virus (RSV), enterovirus (EV), parainfluenza virus (PIV), Mycoplasma pneumoniae, and others. Clinical features, laboratory data, asthma exacerbation intensity, and asthma severity were compared among participants. Epidemiologic profile of causative pathogens and possible factors for exacerbation were explored. RESULTS: Viruses and/or Mycoplasma pneumoniae were detected in 75% of the participants. Rhinovirus (48%) was the most commonly detected virus in the participants with single infection, followed by RSV (6%). The median age at admission in the RV group was significantly higher than that in the RSV group. Insufficient asthma control and allergen sensitization were significantly related to RV-associated asthma exacerbation. There was no seasonality of pathogen types associated with asthma exacerbation although a sporadic prevalence of EV-D68 was observehinovirud. Rhinovirus were repeatedly detected in multiple admission cases. CONCLUSION: Our three-year analysis revealed that patients with RV infection were significantly prone to repeated RV infection in the subsequent exacerbation and good asthma control could prevent RV-associated asthma development and exacerbation. Multiple-year monitoring allowed us to comprehend the profile of virus- and/or mycoplasma-induced asthma exacerbation.

Randomized controlled trial of oral immunotherapy for egg allergy in Japanese patients.

BACKGROUND: Egg allergy is one of the most common food allergies in young children. While oral immunotherapy (OIT) is not routinely recommended in current guidelines, it has been considered as a potential alternative treatment strategy. Studies on OIT for food allergy have been explored, but no controlled trials have been reported in Japan. METHODS: The first oral food challenge (OFC) was performed before treatment to ensure diagnosis and evaluate the threshold dose for egg using the double-blind, placebo-controlled food challenge. Participants were randomly assigned by computerized algorithm to receive OIT using egg (OIT group) or no egg (egg elimination [EE] group). A second OFC was performed in both groups approximately 6 months after therapy. Blood samples were collected and egg white-specific immunoglobulin (Ig)E and IgG4 were measured before and after the treatment period. RESULTS: Eight of the 14 patients (57%) in the OIT group had no allergic reaction to 4 g dry egg powder whereas none of the 16 patients in the EE group did. All 14 patients in the OIT group had increased threshold for egg powder in the second OFC compared with baseline. There was no significant change in egg white-specific IgE level during therapy. After therapy, egg white-specific IgG4 increased significantly in the OIT group, but not in the EE group. CONCLUSION: OIT is effective in increasing the threshold for allergens and inducing desensitization in Japanese egg allergy patients, similarly to North American and European patients.

Systemic lupus erythematosus presenting with mixed-type fulminant autoimmune hemolytic anemia.

We report the case of a 9-year-old girl who presented with mixed-type fulminant autoimmune hemolytic anemia (AIHA) at the onset of systemic lupus erythematosus (SLE). On admission, laboratory investigations indicated very severe anemia (Hb, 2.7 g/dL) with reticulocytosis and positive direct/indirect Coombs tests. In addition, agglutinative reaction was clinically observed. Based on further examinations, the patient was diagnosed with AIHA complicated with SLE, and mixed-type AIHA was clinically identified. With oral prednisolone and methylprednisolone pulse therapy, the patient entered remission.

Suplatast tosilate for treating cutaneous mastocytosis.

Pediatric cutaneous mastocytosis is a rare disease caused by mast cell hyperplasia. We report the case of an infant diagnosed as cutaneous mastocytosis and seasonal allergies. The wheals, flushing, and pruritus of the mastocytosis were unresponsive to combination therapy with an antihistamine, a mast cell stabilizer (sodium cromoglycate), and a leukotriene antagonist. Addition of suplatast tosilate as a treatment for the seasonal allergy also dramatically improved his cutaneous symptoms and signs. Further trials of suplatast tosilate in selected cases of cutaneous mastocytosis are warranted.

Interleukin-33/ST2 Axis as Potential Biomarker and Therapeutic Target in Kawasaki Disease.

Kawasaki disease (KD) is an acute, self-limiting, febrile systemic vasculitis of unknown cause associated with the development of coronary artery lesions (CALs) during childhood. Damage-associated molecular patterns (DAMPs) from cell death and oxidative stress have been shown to be involved in the development of KD vasculitis. Interleukin (IL)-33 is released from damaged endothelial cells and acts as a DAMP. We studied whether IL-33 and its receptor (ST2) might be involved in KD pathogenesis. Serum levels of soluble ST2 (sST2) in KD patients were measured before their first therapy. Furthermore, we investigated the impact of IL-33 on human coronary artery endothelial cells (HCAECs). Serum levels of sST2 were significantly higher in KD patients with CALs than in those with normal coronary arteries. In vitro, IL-33 upregulated the expression of ST2L and increased production of sST2, IL-6, IL-8, and monocyte chemoattractant protein-1 in HCAECs in a time- and concentration-dependent manner. Moreover, IL-33 induced significantly greater production of IL-6 and IL-8 in HCAECs compared to the condition stimulated with isoconcentration of tumor necrosis factor-α. The results of the present study suggest that the IL-33/ST2 axis might be involved in the development of KD vasculitis. The IL-33/ST2 axis may be a therapeutic target for the treatment of KD.