Co-circulation of coxsackieviruses A-6, A-10, and A-16 causes hand, foot, and mouth disease in Guangzhou city, China.

BACKGROUND: Hand, foot, and mouth disease (HFMD) is a common infectious disease occurring in children under 5 years of age worldwide, and Enterovirus A71 (EV-A71) and Coxsackievirus A16 (CVA-16) are identified as the predominant pathogens. In recent years, Coxsackievirus A6 (CVA-6) and Coxsackievirus A10 (CVA-10) have played more and more important role in a series of HFMD outbreaks. This study aimed to understand the epidemic characteristics associated with HFMD outbreak in Guangzhou, 2018. METHODS: The clinical and laboratory data of 1220 enterovirus-associated HFMD patients in 2018 were analysed in this study. Molecular diagnostic methods were performed to identify its serotypes. Phylogenetic analyses were depicted based on the complete VP1 gene. RESULTS: There were 21 enterovirus serotypes detected in Guangzhou in 2018. Three serotypes of enterovirus, CVA-6 (364/1220, 29.8%), CVA-10 (305/1220, 25.0%), and CVA-16 (397/1220, 32.5%), were identified as the causative pathogens and accounted for 87.3% among all 1220 HFMD patients. In different seasons, CVA-6 was the predominant pathogen of HFMD during autumn, and CVA-10 as well as CVA-16 were more prevalent in summer. Patients infected by CVA-6, CVA-10 or CVA-16 showed similar clinical features and laboratory characteristics, and the ratios of severe HFMD were 5.8, 5.9, and 1.5% in the three serotypes. Phylogenetic analyses of VP1 sequences showed that the CVA-6, CVA-10, and CVA-16 sequences belonged to the sub-genogroup E2, genogroup E, and genogroup B1, respectively. CONCLUSIONS: CVA-6, CVA-10, and CVA-16 were the predominant and co-circulated serotypes in Guangzhou China, 2018, which should be the new target for prevention and control of HFMD. Our findings provide useful information for diagnosis, treatment, and prevention of HFMD.

Noninvasive prenatal detection of hemoglobin Bart hydrops fetalis via maternal plasma dispensed with parental haplotyping using the semiconductor sequencing platform.

BACKGROUND: Thalassemia is one of the most common monogenetic diseases in the south of China and Southeast Asia. Hemoglobin Bart's hydrops fetalis syndrome was caused by a homozygous Southeast Asian deletion (-/-) in the HBA gene. Few studies have proved the potential of screen for Bart's hydrops fetalis using fetal cell-free DNA. However, the number of cases is still relatively small. Clinical trials of large samples would be needed. OBJECTIVE: In this study, we aimed to develop a noninvasive method of target-captured sequencing and genotyping by the Bayesian method using cell-free fetal DNA to identify the fetal genotype in pregnant women who are at risk of having hemoglobin Bart hydrops fetalis in a large-scale study. STUDY DESIGN: In total, 192,173 couples from 30 hospitals were enrolled in our study and 878 couples were recruited, among whom both the pregnant women and their husbands were detected to be carriers of Southeast Asian type (-/αα) of α-thalassemia. Prenatal diagnosis was performed by chorionic villus sampling, amniocentesis, or cordocentesis using gap-polymerase chain reaction considered as the golden standard. RESULTS: As a result, we found that the sensitivity and specificity of our noninvasive method were 98.81% and 94.72%, respectively, in the training set as well as 100% and 99.31%, respectively, in the testing set. Moreover, our method could identify all of 885 maternal samples with the Southeast Asian carrier and 36 trisomy samples with 100% of sensitivity in T13, T18, and T21 and 99.89% (1 of 917) and 99.88% (1 of 888) of specificity in T18 and T21, respectively. CONCLUSION: Our method opens the possibility of early screening for maternal genotyping of α-thalassemia, fetal aneuploidies in chromosomes 13/18/21, and hemoglobin Bart hydrops fetalis detection in 1 tube of maternal plasma.

[Distribution of peripheral blood lymphocyte subsets in 826 healthy children aged 0-6 years].

OBJECTIVE: To study the distribution of peripheral blood lymphocyte subsets in healthy children aged 0-6 years. METHODS: A total of 826 healthy Han children aged 0-6 years were recruited. According to their age, the children were divided into four groups: newborn, infant, toddler and preschool. Their peripheral blood samples were collected to measure the percentages of lymphocyte subsets by flow cytometry. RESULTS: There were significant differences in the percentages of CD3+ T cells, CD3+CD4+ T cells and CD3-CD19+ B cells and the CD4+/CD8+ ratio between boys and girls (P<0.05). The girls had a lower percentage of CD3-CD19+ B cells, higher percentages of CD3+ T cells and CD3+CD4+ T cells and a higher CD4+/CD8+ ratio than the boys. The newborn group had the highest percentages of CD3+ T cells and CD3+CD4+ T cells and the highest CD4+/CD8+ ratio (P<0.05). The percentage of CD3+CD4+ T cells and the CD4+/CD8+ ratio gradually decreased with age and the preschool group had the lowest values (P<0.05). The newborn group had the lowest percentages of CD3-CD19+ B cells and CD3-CD16+CD56+ NK cells (P<0.05). The percentage of CD3-CD16+CD56+ NK cells gradually increased with age and the preschool group had the highest percentage (P<0.05). The percentage of CD3-CD19+ B cells reached the peak in the toddler period and then decreased with age (P<0.05). The preschool group had the highest percentage of CD3+CD8+ T cells (P<0.05). The variation trend of distribution of lymphocyte subsets in boys from different age groups was consistent with that in children from different age groups. For girls, the newborn group had the highest percentage of CD3+CD4+ T cells and CD4+/CD8+ ratio (P<0.05). CONCLUSIONS: The distribution of peripheral blood lymphocyte subsets in healthy children is significantly different across ages and sexes. Therefore, the reference values should be established according to age and sex.

[Value of Analyzing Hemoglobin A2 by ROC Curve for Screening Thalassemia].

OBJECTIVE: To investigate the value of hemoglobin A2(HbA2) for screening thalassemia. METHODS: A total of 2 000 adults' peripheral blood samples from Guangdong Women and Children Hospital from June 2013 to January 2014 were collected. The hemoglobin A2 (HbA2) level was analyzed by the full automatic capillary electrophoresis technique, and the genotypes of thalassemia were detected. RESULTS: The optimal cutoff values of HbA2 for screening silent α-thalassemia, α-thalassemia trait, intermedia α-thalassemia and ß-thalassemia trait were 2.85%, 2.65%, 2.25% and 3.45%, respectively; the areas under receiver operator characteristic (ROC) curve were 0.709, 0.839, 0.979 and 0.997 respectively; the sensitivities were 0.481, 0.721, 0.953 and 0.994, and the specificities were 0.846, 0.837, 0.929 and 0.969 respectively. CONCLUSION: The optimal cutoff values of HbA2 for screening different type of thalassemia based on our laboratory data are established by using ROC curve. According to the area under ROC curve, a satisfactory accuracy for screening intermedia α-thalassemia and ß-thalassemia trait can be achieved by detecting hemoglobin A2 level.

High prevalence of thalassemia in migrant populations in Guangdong Province, China.

BACKGROUND: The objectives of this study were to estimate the prevalence of thalassemia and to analyze the need for public health services for migrant populations in different cities in Guangdong Province, China. METHODS: A cross-sectional survey was conducted in 21 cities of Guangdong Province. Twenty-three types of a- and ß-globin gene mutations were detected in a total of 14,230 pregnant women and 14,249 husbands. RESULTS: There was a 16.45% prevalence of thalassemia among the 28,479 individuals, and the prevalences of α-, ß-, and combined α-/ß- thalassemia were 12.03%, 3.80%, and 0.63%, respectively. Compared with the native city residents in the province, the migrants from within the province and the immigrants from outside the province had lower prevalences of thalassemia, but the prevalence values were >11%. CONCLUSIONS: The prevalence values for thalassemia gene mutations were high in all three population groups studied in Guangdong Province. The results indicate that all segments of the Guangdong population should be screened for thalassemia.