A Japanese Case of COVID-19 Caused by Omicron Strain with Y453F Substitution.

Frequent mutations of SARS-CoV-2 change the strain more transmissible, leading to the pandemic in worldwide. We detected Y453F substitution on Omicron strain, isolated from a Japanese patient in July 2022. While Y453F substitution was identified B1.1.298 lineage in Netherlands and Denmark in 2020, the substitution has not been reported in Omicron strain especially in Japan. Y453F substitution is associated with higher viral infectivity because it is sited in the receptor-binding domain (RBD), and Y453F substitution contributes to increase binding affinity to angiotensin converting enzyme 2 (ACE2). Additionally, Y453F substitution has been reported to escape human leukocyte antigen (HLA), which is known to recognize non-self-antigens in virus-infected cells as cellular immunity, so it should be closely monitored.

An Adolescent Case of Anti-MDA5 Antibody-Positive Juvenile Dermatomyositis With Interstitial Lung Disease Successfully Treated by Multitarget Therapy Avoiding Cyclophosphamide: A Case Report and Literature Review.

Juvenile dermatomyositis (JDM) patients who test positive for the antimelanoma differentiation-associated gene 5 (MDA5) antibody have a poor prognosis because of rapidly progressing interstitial lung disease (ILD). However, agreement on the best treatment for this condition remains elusive. We encountered a 13-year-old girl with anti-MDA5 antibody-positive JDM who presented with arthritis and was already showing signs of ILD when she was admitted to the hospital. While cyclophosphamide (CY) is commonly used, it can cause gonadal disorders and other complications when administered to adolescent females. Consequently, we chose multitarget therapy, which includes tacrolimus and mycophenolate mofetil. Her ILD and skin symptoms gradually improved, and she was able to maintain remission and avoid CY administration for three years. We conducted a thorough literature review to determine the efficacy and safety of multitarget therapy for anti-MDA5 antibody-positive DM and JDM. Multitarget therapy shows promise as a potentially effective and relatively safe treatment. The ability to avoid CY, which is especially important for adolescent patients concerned about fertility preservation, highlights a significant benefit of this multitarget therapy for anti-MDA5 antibody-positive DM and JDM patients.

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.

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.