Assessment of SARS-CoV-2 Immunity in Convalescent Children and Adolescents.

Persistence of protective immunity for SARS-CoV-2 is important against reinfection. Knowledge on SARS-CoV-2 immunity in pediatric patients is currently lacking. We opted to assess the SARS-CoV-2 adaptive immunity in recovered children and adolescents, addressing the pediatrics specific immunity towards COVID-19. Two independent assays were performed to investigate humoral and cellular immunological memory in pediatric convalescent COVID-19 patients. Specifically, RBD IgG, CD4+, and CD8+ T cell responses were identified and quantified in recovered children and adolescents. SARS-CoV-2-specific RBD IgG detected in recovered patients had a half-life of 121.6 days and estimated duration of 7.9 months compared with baseline levels in controls. The specific T cell response was shown to be independent of days after diagnosis. Both CD4+ and CD8+ T cells showed robust responses not only to spike (S) peptides (a main target of vaccine platforms) but were also similarly activated when stimulated by membrane (M) and nuclear (N) peptides. Importantly, we found the differences in the adaptive responses were correlated with the age of the recovered patients. The CD4+ T cell response to SARS-CoV-2 S peptide in children aged <12 years correlated with higher SARS-CoV-2 RBD IgG levels, suggesting the importance of a T cell-dependent humoral response in younger children under 12 years. Both cellular and humoral immunity against SARS-CoV-2 infections can be induced in pediatric patients. Our important findings provide fundamental knowledge on the immune memory responses to SARS-CoV-2 in recovered pediatric patients.

Rapid and cost-effective molecular diagnosis using exome sequencing of one proband with autosomal dominant congenital cataract.

PURPOSE: Due to high genetic heterogeneity, to exclude known mutations and map novel mutations in autosomal dominant congenital cataract (ADCC) using conventional candidate gene screening requires laborious laboratory work. We attempted to use a cost-effective exome sequencing strategy to identify disease-causing mutations in an ADCC pedigree. METHODS: An ADCC pedigree affected by nuclear cataract and 200 unrelated senile cataract controls were recruited and given comprehensive ophthalmic examination. Whole exome of the proband of the family was captured by the Illumina TruSeq Exome Enrichment Kit, followed by sequencing using Illumina HiSeq 2000 sequencer. Validation was performed by direct sequencing. RESULTS: The whole exome, including all exons of known ADCC disease-causing genes, was screened for possible disease-causing mutations. A recurrent missense mutation c.773C>T (p.S258F) in exon 2 of the gap junction protein alpha 8 gene (GJA8) was identified in the proband with nuclear cataract. The result was confirmed by direct sequencing. The mutation showed complete co-segregation with the disease phenotype in the family but was not observed in unrelated unaffected controls. CONCLUSION: By successfully sequencing whole exome of only one proband and identifying a GJA8 mutation in one ADCC pedigree, the current study demonstrated that exome sequencing could serve as a rapid, robust, and cost-effective approach in clinical diagnosis and disease-causing gene discovery for ADCC.

Quantitative assessment of lens opacities with anterior segment optical coherence tomography.

AIM: To evaluate the reliability of lens density measurement with anterior segment optical coherence tomography (OCT) and its association with the Lens Opacity Classification System Version III (LOCS III) grading. METHODS: Fifty-five eyes from 55 age-related cataract patients were included. One eye from each subject was selected at random for lens evaluation. After dilation, lens photographs were taken with a slit lamp and graded against the LOCS III standardised condition. Anterior segment OCT imaging was performed on the same eyes with a high-resolution scan. The association between the anterior segment OCT nucleus density measurement and LOCS III nuclear opalescence (NO) and nuclear colour (NC) scores was evaluated with the Spearman correlation coefficient. Anterior segment OCT measurement precision, coefficient of variation (CVw), and intraclass correlation coefficient (ICC) were calculated. RESULTS: The mean NO and NC scores were 3.39 (SD 1.10) and 3.37 (SD 1.27), respectively. Significant correlations were found between anterior segment OCT nuclear density measurements and the LOCS III NO and NC scores (r = 0.77 and 0.60, respectively, both with p<0.001). The precision, CVw and ICC of anterior segment OCT measurement were 2.05 units, 4.55% and 0.98, respectively. CONCLUSION: Anterior segment OCT nucleus density measurement is reliable and correlates with the LOCS III NO and NC scores.

The prevalence of diabetes mellitus and an assessment of methods of detection among a community of elderly Chinese in Hong Kong.

This study provides information on the prevalence of diabetes mellitus in a group of elderly Chinese subjects aged 60 and above living in the community in Hong Kong, and investigates the sensitivity of the urine sugar, random blood glucose, glycosylated haemoglobin, and fructosamine measurements compared to a glucose tolerance test in screening for diabetes mellitus in this population. Four hundred twenty-seven subjects aged 60 and above were studied. The National Diabetes Data Group Criteria were used for the diagnosis of diabetes. Those with a random blood glucose exceeding 12.5 mmol/l were considered diabetic, and all of these patients had glycosuria together with elevated total glycosylated haemoglobin and fructosamine concentrations. A diagnostic 75 g oral glucose tolerance test was performed on patients with one or more of the following abnormalities: glycosuria, random plasma blood glucose 7.8 mmol/l to 12.5 mmol/l, glycosylated haemoglobin 8.5%, and fructosamine 2.20 mmol/l. By these criteria, the prevalence of diabetes in this community was found to be 9.8%. An elevated random glucose greater than 11.1 mmol/l proved to be the only specific method of screening and glycosuria was found to be at least as good as fructosamine and HbA1. However, HbA1 is more sensitive than random glucose, glycosuria or fructosamine in detecting impaired glucose tolerance. On the basis of this study, a higher reference range for glycosylated haemoglobin for the elderly alone is also suggested (5.74-9.34%).