Case report: A family of atypical hemolytic uremic syndrome involving a CFH::CFHR1 fusion gene and CFHR3-1-4-2 gene duplication.

Mutations in the complement factor H (CFH) gene are associated with complement dysregulation and the development of atypical hemolytic uremic syndrome (aHUS). Several fusion genes that result from genomic structural variation in the CFH and complement factor H-related (CFHR) gene regions have been identified in aHUS. However, one allele has both CFHR gene duplication and CFH::CFHR1 fusion gene have not been reported. An 8-month-old girl (proband) presented with aHUS and was treated with ravulizumab. Her paternal grandfather developed aHUS previously and her paternal great grandmother presented with anti-neutrophil cytoplasmic antibody-associated vasculitis and thrombotic microangiopathy (TMA). However, the proband's parents have no history of TMA. A genetic analysis revealed the presence of CFH::CFHR1 fusion gene and a CFHR3-1-4-2 gene duplication in the patient, her father, and her paternal grandfather. Although several fusion genes resulting from structural variations of the CFH-CFHR genes region have been identified, this is the first report of the combination of a CFH::CFHR1 fusion gene with CFHR gene duplication. Because the CFH-CFHR region is highly homologous, we hypothesized that CFHR gene duplication occurred. These findings indicate a novel pathogenic genomic structural variation associated with the development of aHUS.

CD169 expression on monocytes as a marker for assessing type I interferon status in pediatric inflammatory diseases.

BACKGROUND: Evaluation of type I interferons (IFNs) in inflammatory or autoimmune diseases is challenging because of their rapid clearance in peripheral blood. The IFN gene expression signature has recently been used to evaluate the IFN status; however, this is often a labor-intensive and time-consuming procedure. Therefore, we assessed the feasibility of measuring expression of an IFN-inducible protein, CD169 (Siglec-1), on monocytes and circulating levels of soluble CD169 as alternative markers for type I IFN status in various pediatric inflammatory diseases. METHODS: Data from flow cytometric analysis of surface CD169 on monocytes and an enzyme-linked immunosorbent assay of soluble CD169 in peripheral blood were compared with serum IFN-α levels in 8 patients with viral infections, 5 with bacterial infections, 10 with systemic lupus erythematosus (SLE), 5 with Kikuchi-Fujimoto disease (KFD), 7 with Kawasaki disease (KD), and 8 with inflammatory bowel disease (IBD), and in 8 healthy controls. RESULTS: Surface CD169 expression was detected mainly on CD14+ monocytes and was significantly increased in patients with viral infections, SLE, and KFD, but not in patients with bacterial infections, KD, and IBD. There were similar trends for circulating soluble CD169; however, there was a significant increase only in patients with viral infections. Surface CD169 levels were significantly correlated with serum levels of IFN-α and soluble CD169. CONCLUSION: Analysis of CD169 expression on CD14+ monocytes may be useful for rapid assessment of type I IFN status for differentiation of pediatric inflammatory diseases from type 1 IFN-mediated diseases.

Importance of History Taking and Physical Examination Before Rapid Laboratory Test for Seasonal Influenza Virus: A Single-Center Multiple Logistic Analysis.

Background Despite several rapid influenza diagnostic tests (RIDTs), they are predicting whether a patient has influenza before rapid testing is important. Here, we assessed factors predictive of a positive flu test via RIDTs by combining interviews and physical examination. Methods We analyzed the relationship between interviews and physical findings and results of RIDTs using multivariable logistic regression. Results Two hundred seventy-six children were enrolled throughout the 2018-2019 flu season. Accordingly, 115 patients (41.7%) were positive for flu A. Our logistic regression model identified age, body temperature, and the existence of upper respiratory symptoms as significant factors for predicting positive for RIDTs, with odds ratios (OR) of 1.17 [95% CI (confidence interval): 1.08-1.25]/+Δ1year old, 1.70 (95% CI: 1.27-2.27)/+Δ1 ℃, and 5.08 (95% CI: 2.57-10.00) for respiratory symptoms. In addition, the OR for sick contact was 7.67 (95% CI: 3.96-14.90). Our logistic regression model showed an area under the curve (AUC) of 0.84. History of vaccination was not identified as a significant factor in positive RIDTs. Conclusions The existence of sick contact was associated with a positive flu test via RIDTs. Although RIDTs are an easy and quick method for detecting the flu virus, we should perform the appropriate identification of cases for RIDTs by combining interviews and physical findings.

Rapid molecular diagnosis of Parechovirus infection using the reverse transcription loop-mediated isothermal amplification technique.

OBJECTIVES: Human parechovirus (HPeV), especially HPeV A3 (HPeV3), causes sepsis-like diseases and sudden infant death syndrome in neonates and young infants. Development of rapid and easier diagnostic laboratory tests for HPeVs is desired. METHODS: Original inner primers, outer primers, and loop-primers were designed on the 5' untranslated region of HPeV3. HPeV3 ribonucleic acids (RNAs), other viral RNAs, and clinical stool samples were used to confirm whether the designed primers would allow the detection of HPeV3 with the reverse transcription loop-mediated isothermal amplification (RT-LAMP) technique. RESULTS: Three combinations of primers were created and it was confirmed that all primer sets allowed the detection of HPeV3 RNAs. The primer sets had cross-reactivity with HPeV type 1 (HPeV1), but all sets showed negative results when applied to coxsackievirus, echovirus, enterovirus, norovirus, and adenovirus genomes. Four of six stool samples, obtained from newborn and infant patients with sepsis-like symptoms, showed positive results with our RT-LAMP technique. CONCLUSIONS: This manuscript is the first description of an RT-LAMP for the diagnosis of HPeVs, allowing a faster, easier, and cheaper diagnosis. This technique is clinically useful for newborns and infants who have sepsis-like symptoms.

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.

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.

Successful treatment of rituximab- and steroid-resistant nephrotic syndrome with leukocytapheresis.

Although rituximab (RTX) is a promising therapeutic agent for treating steroid-resistant nephrotic syndrome (SRNS) resistant to various immunosuppressive agents, some patients have shown resistance to RTX. We report the case of a patient with RTX-resistant nephrotic syndrome and SRNS who was successfully treated with leukocytapheresis (LCAP). After LCAP, there was a significant reduction in proteinuria and in the total number of lymphocytes, T cells, and HLA-DR+- activated T cells. Moreover, the patient became sensitive to steroids and RTX. LCAP reduced circulating immune cells including activated T cells and could be effective in treating rituximab-resistant nephrotic syndrome and SRNS and in achieving remission of proteinuria.

Disruption of vascular endothelial homeostasis in systemic juvenile idiopathic arthritis-associated macrophage activation syndrome: The dynamic roles of angiopoietin-1 and -2.

To assess the role of angiopoietin (Ang)-1 and Ang-2 and to investigate the clinical significance of serum levels of them in systemic juvenile idiopathic arthritis (s-JIA)-associated macrophage activation syndrome (MAS), we determined these levels in 51 patients with s-JIA, 11 patients with polyarticular JIA (poly-JIA), 12 patients with virus associated hemophagocytic syndrome (VAHS), 12 patients with Kawasaki disease (KD), and 15 age-matched healthy controls (HC). The results were compared with clinical features of MAS. During the MAS phase, serum Ang-1 levels were significantly decreased compared with those during the active and inactive phases. Serum Ang-2/1 ratio were significantly elevated during the MAS phase, compared with those during the active and inactive phases. There was a rapid increase in the Ang-2/1 ratio at the onset of MAS. Serum Ang-1 and the Ang-2/1 ratio significantly correlated with measures of disease activity, including AST and LDH. Ang-2/1 dysregulation was also observed in patients with VAHS, whereas not observed in most cases of KD. The homeostasis of vascular endothelial function by Ang-1 and Ang-2 is disrupted in MAS. Serum Ang-1 levels and the Ang-2/1 ratio might represent promising indicators of disease activity for MAS.

Urinary neopterin: an immune activation marker in mesangial proliferative glomerulonephritis.

BACKGROUND: To clarify in vivo neopterin expression within the human kidney and its clinical role as a biomarker for immune complex-mediated mesangial proliferative glomerulonephritis (mesPGN) in children. METHODS: We examined neopterin expression within the kidneys of 14 patients with mesPGN and five patients with minimal changes. We also measured the serum and urinary neopterin levels in fourteen patients with mesPGN and sixteen age-matched healthy controls and correlated the histological findings and clinical features. RESULTS: Neopterin expression was observed within the distal tubular epithelial cells. It was induced within the glomerular endothelial cells and infiltrated CD68-positive macrophages in the glomeruli and interstitial areas. Furthermore, urinary neopterin levels were significantly elevated and positively correlated with histopathological findings and the degree of proteinuria. CONCLUSIONS: These findings indicate that increased urinary neopterin may reflect macrophage activation and active inflammation within the kidney in immune complex-mediated glomerulonephritis. Neopterin may thus represent a useful biomarker of immune complex-mediated glomerulonephritis in the clinical setting.

Tolvaptan therapy for massive edema in a patient with nephrotic syndrome.

BACKGROUND: Nephrotic syndrome (NS) is characterized by water and sodium retention, which leads to edema. The non-osmotic stimulation of arginine vasopressin release from the pituitary gland has been implicated as one of the important factors in abnormal water retention in patients with NS. CASE-DIAGNOSIS/TREATMENT: We present the initial description of a patient with massive edema caused by refractory nephrotic syndrome, which was effectively treated with tolvaptan, a selective oral vasopressin V2 receptor antagonist. CONCLUSIONS: Tolvaptan is effective for the treatment of massive edema caused by NS. Larger studies are needed in the future to fully assess the value and safety of tolvaptan use for this condition.