Clinical characteristics and serum IgG, IgM antibody manifestations of patients infected with SARS-CoV-2 B.1.1.529 (Omicron) variant strain / 中国热带医学

@#Abstract: Objective　To analyze the clinical characteristics and changes of serum IgG, IgM antibodies in patients infected with the SARS-CoV-2 B.1.1.529 (Omicron) variant. Methods　The clinical data of 82 patients with SARS-CoV-2 B.1.1.529 variant was analyzed retrospectively. Based on the presence of pneumonia on chest CT, the patients were divided into pneumonia group and non-pneumonia group. Serum IgG, IgM antibodies were observed at 5 time points T1 (1~<4 d), T2 (4~<8 d), T3 (8~<15 d), T4 (15~<22 d) and T5 (22~<30 d) after admission. Results　Among the 82 patients infected with the SARS-CoV-2 B.1.1.529 variant strain, there were 62 cases of cough, 31 cases of fever, 33 cases of throat discomfort, 5 cases of muscle soreness and 3 cases of diarrhea. The serum IgG antibody levels at 5 time points were 50.22 (142.20) AU/mL, 326.50 (220.63) AU/mL, 368.23 (76.21) AU/mL, 368.65 (79) AU/mL, and 385.26 (113.10) AU/mL, respectively. The level of serum IgG antibody in the pneumonia group was lower than that of the non-pneumonia group at T1 and T4 time points, and the differences were statistically significant (P<0.05) , the positive rate of serum IgG antibody in the pneumonia group was lower than that of the non-pneumonia group at the T1 time point, and the difference was statistically significant (P<0.05) . The serum IgM antibody levels at 5 time points were 0.41 (0.81) AU/mL, 0.95 (1.62) AU/mL, 1.09 (2.42) AU/mL, 0.74 (3) AU/mL, and 0.81 (3.10) AU/mL respectively, and there was no significant difference between the two groups. Conclusion　The clinical symptoms of patients infected with the SARS-CoV-2 B.1.1.529 variant strain are mild. Serum IgG antibodies increased after infection, but there are some differences between the pneumonia group and the non-pneumonia group, whether serum IgG has a protective effect needs further research; the serum IgM antibodies do not increase highly after infection, there are some differences between individuals.

[Clinical features and chest CT findings of coronavirus disease 2019 in infants and young children].

OBJECTIVE: To study the clinical features and chest CT findings of coronavirus disease 2019 (COVID-19) in infants and young children. METHODS: A retrospective analysis was performed for the clinical data and chest CT images of 9 children, aged 0 to 3 years, who were diagnosed with COVID-19 by nucleic acid detection between January 20 and February 10, 2020. RESULTS: All 9 children had an epidemiological history, and family clustering was observed for all infected children. Among the 9 children with COVID-19, 5 had no symptoms, 4 had fever, 2 had cough, and 1 had rhinorrhea. There were only symptoms of the respiratory system. Laboratory examination showed no reductions in leukocyte or lymphocyte count. Among the 9 children, 6 had an increase in lymphocyte count and 2 had an increase in leukocyte count. CT examination showed that among the 9 children, 8 had pulmonary inflammation located below the pleura or near the interlobar fissure and 3 had lesions distributed along the bronchovascular bundles. As for the morphology of the lesions, 6 had nodular lesions and 7 had patchy lesions; ground glass opacity with consolidation was observed in 6 children, among whom 3 had halo sign, and there was no typical paving stone sign. CONCLUSIONS: Infants and young children with COVID-19 tend to have mild clinical symptoms and imaging findings not as typical as those of adults, and therefore, the diagnosis of COVID-19 should be made based on imaging findings along with epidemiological history and nucleic acid detection. Chest CT has guiding significance for the early diagnosis of asymptomatic children.

High performance of intravoxel incoherent motion diffusion MRI in detecting viral hepatitis-b induced liver fibrosis.

BACKGROUND: Recently a small cohort study demonstrated that intravoxel incoherent motion (IVIM) diffusion MRI can detect early stage liver fibrosis. Using modified IVIM data acquisition parameters, the current study aims to confirm this finding. METHODS: Twenty-six healthy volunteers, three patients of chronic viral hepatitis-b but without fibrosis and one mild liver steatosis subject, and 12 viral hepatitis-b patients with fibrosis (stage 1-2=7, stage 3-4=5) were included in this study. With a 1.5-T MR scanner and respiration-gating, IVIM diffusion imaging was acquired using a single-shot echo-planar sequence with a b-value series of 2, 0, 1, 15, 20, 30, 45, 50, 60, 80, 100, 200, 300, 600, 800 s/mm2. Signal measurement was performed on right liver parenchyma. The first three very low b-values were excluded to improve the curve fitting stability, and bi-exponential segmented fitting was performed using the 12 b-values of 15~800 s/mm2. Both threshold b-values of 60 s/mm2 and 200 s/mm2 were tested. With a 3-dimensional tool, Dslow (D), PF (f) and Dfast (D*) values were placed along the x-axis, y-axis, and z-axis, and a plane was defined to separate healthy volunteers from liver fibrosis patients. RESULTS: Threshold b-value of 60 s/mm2 was preferred over 200 s/mm2 for separating healthy volunteers and liver fibrosis patients. The IVIM measures of the four patients without fibrosis resembled those of healthy volunteers. When threshold b-value =60 s/mm2 was applied, PF (PF <6.49%) could differentiate healthy livers and all fibrotic livers with 100% sensitivity and specificity. For the patients' measurement, PF and Dfast were highly correlated with a Pearson correlation coefficient r of 0.865 (P<0.001); while the correlations between slow diffusion compartment (Dslow) and fast diffusion compartment (Dfast or PF) were not statistically significant. CONCLUSIONS: This study confirms previous report that IVIM diffusion MRI has high diagnostic performance in detecting viral hepatitis-b induced liver fibrosis.