Zhi-Yong Zhang

Genetic variability of respiratory syncytial viruses (RSV) prevalent in Southwestern China from 2006 to 2009: emergence of subgroup B and A RSV as dominant strains.

ABSTRACT Respiratory syncytial virus (RSV) is the most commonly identified viral agent in young children with acute respiratory tract infections (ARIs) and often causes repeated infections throughout life. This study investigated the genetic variability of the attachment (G) protein gene among RSV strains prevalent in southwestern China. Reverse transcription-PCR (RT-PCR) for a fragment of the RSV G gene was performed with nasopharyngeal aspirates (NPAs) collected from children with ARIs hospitalized in Chongqing Childrens Hospital, Chongqing, China. A total of 1,387 NPA specimens were collected from April 2006 to March 2009, and 439 (31.7%) were positive for RSV. During the study period, subgroup A and B viruses accounted for 79.5% (349/439) and 19.8% (87/439) of the total positive samples, respectively. Both subgroup A and B viruses were identified in three samples. Subgroup A viruses were predominant during two epidemic seasons (2006 to 2008), while subgroup B strains prevailed during the 2008-2009 epidemic season. Phylogenetic analyses showed that all 30 group A strains could be clustered into one genotype, genotype GA2, and 30 group B strains could be clustered into three genotypes, genotypes GB1, GB3, and BA, among which 17 genotype BA strains were detected from 23 group B strains selected during the 2008-2009 epidemic season. The G gene of genotype BA was predicted to encode proteins of five different lengths. These data suggest that group A RSV likely predominated in southwestern China and that a new genotype of subgroup B with a 60-nucleotide insertion, named BA-like virus, became the dominant genotype in the 2008-2009 epidemic season.

Acute Lower Respiratory Tract Infections by Human Metapneumovirus in Children in Southwest China: A 2-Year Study

Human metapneumovirus (hMPV) has been reported to cause both upper and lower respiratory tract diseases in susceptible populations, particularly in children and the elderly. In this study, we describe a hospital‐based epidemiological study of hMPV in patients presenting to a childrens hospital and show the demographic and clinical characteristics associated with hMPV infection in China, retrospectively. Specimens were collected over a 2‐year period from children hospitalized with acute lower respiratory tract infections (ALRTI) and analyzed for the presence of hMPV using real‐time RT‐PCR assays. The presence of hMPV was detected in 227 (25.9%) of the 878 children studied and may circulate year‐round in the area, peaking during the winter–spring season. Younger children (aged less than 6 months) had the highest positive rate. Infections by hMPV showed similar epidemiology and clinical manifestations as for respiratory syncytial virus (RSV) and were found in high co‐infections with RSV. Subgroup A2 hMPV was the most predominant genotype identified during the study period. This study indicates that hMPV is one of the major respiratory pathogens found in children in southwest China and vaccine development should be under consideration. Pediatr. Pulmonol. 2010; 45:824–831.

Detection and Genetic Diversity of Human Metapneumovirus in Hospitalized Children with Acute Respiratory Infections in Southwest China

ABSTRACT Human metapneumovirus (hMPV) is the main pathogen causing respiratory tract infection in susceptible populations, particularly in children and the elderly. Specimens were collected from hospitalized children with acute lower respiratory tract infections (ALRTI), and the hMPV was detected by using real-time reverse transcription-PCR (RT-PCR). The full-length G gene of hMPV was amplified by RT-PCR. A total of 1,410 nasopharyngeal aspirates (NPAs) were collected from April 2008 to March 2011, and 114 (10.2%) were positive for hMPV. Most hMPV-positive children were <5 years of age. The hMPV infection rate peaked in the spring-summer season of 2008 to 2009 and 2009 to 2010, while hMPV circulated predominantly during the winter-spring season of 2010 to 2011. The full-length G gene of 23 hMPV strains was amplified, and group A and B viruses accounted for 95.7% (22/23) and 4.3% (1/23), respectively. Genotype A2b of hMPV appeared to be predominant during the study period. Three genotypes (A2b, A1, and B1) were prevalent in the epidemic season of 2008 to 2009, and only genotype A2b was identified in the other two seasons (2009 to 2010 and 2010 to 2011). The G gene of hMPV was predicted to encode proteins with four different lengths, in which one with 210 amino acids was first identified in China. These findings suggest that hMPV was an important pathogen of ALRTI in pediatric patients, especially those <5 years of age. Genotype A2b of hMPV likely predominates in Southwest China, where other genotypes also circulate.

Clinical characteristics and molecular analysis of three Chinese children with Omenn syndrome.

To cite this article: Zhang Z‐Y, Zhao X‐D, Jiang L‐P, Liu E‐M, Cui Y‐X, Wang M, Wei H, Yu J, An Y‐F, Yang X‐Q. Clinical characteristics and molecular analysis of three Chinese children with Omenn syndrome. Pediatr Allergy Immunol 2011; 22: 482–487.

Clinical and Molecular Features of 38 Children with Chronic Granulomatous Disease in Mainland China

PurposeChronic granulomatous disease (CGD) is an inherited disorder, with phagocytes failing to produce antimicrobial superoxide due to deficient NADPH oxidase activity. Mutations in the gene encoding CYBB are responsible for the majority of the CGD cases. To date, there have been no reports on large samples of children with CGD in China. Therefore, in this study, we described the clinical and molecular features of 38 suspected CGD patients from 36 unrelated Chinese families.MethodsClinical diagnosis was performed using dihydrorhodamine assays detected by flow cytometry. Molecular analysis was used to identify underlying CGD-causative genes. ResultsThe mean age of onset in our 38 patients was 3.4xa0months, while the mean age at diagnosis was 31.7xa0months. Apart from recurrent pneumonia and abscesses, tuberculosis (TB) and Bacille Calmette-Guerin (BCG) infections were notable features in our cohort. Overall, 17 cases died and patient 1 did not participate in the follow-up period . In total, we identified 29 different CYBB gene mutations in 31 patients. We found NCF1 and CYBA mutations in 3 and 2 patients, respectively. In addition, we identified 31 carriers and prenatally diagnosed 4 CGD and 4 healthy fetuses.ConclusionsThe results of our study demonstrate that children with BCG infections or recurrent TB infections should have immune function screening tests performed. Moreover, newborns with family histories of primary immunodeficiency diseases should avoid of BCG vaccination. Molecular analysis is an important tool for identifying patients, carriers, and high-risk CGD fetuses.

Clinical and molecular characteristics of immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome in China.

Immunodysregulation, polyendocrinopathy, enteropathy, X‐linked (IPEX) syndrome is a rare X‐linked recessive disorder causing life‐threatening systemic autoimmunity because of immunodysregulation. The FOXP3 gene had been reported as the responsible gene, which was critical for the functions of CD4+CD25+FOXP3+ regulatory T cells (Tregs) and maintenance of peripheral immunologic tolerance. So far, no IPEX patients with definite mutations in the FOXP3 gene had been reported in China. In this study, the genotypes and phenotypes were investigated in three IPEX infants from three unrelated Chinese families. Patient 1 (P1) presented with a classical clinical phenotype, whose mutation was a novel frameshift insertion in exon 11, led to the complete abrogation of Tregs. Patient 2 (P2) showed incomplete IPEX phenotype. He carried a missense mutation in exon 11 with slightly increased frequency of Tregs, whereas Patient 3 (P3) presented with a relatively mild classical phenotype and had a previously reported missense mutation in exon 10 with decreased frequency of Tregs. We firstly report three Chinese IPEX patients with definite mutations of FOXP3 gene. Our study indicated the potential correlation between the genotype and the phenotype of IPEX, which was different from the previous reports.

Respiratory syncytial virus infection induces higher Toll-like receptor-3 expression and TNF-α production than human metapneumovirus infection.

Respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) are common causes of respiratory infections in children. Diseases caused by hMPV are generally considered to be less severe than those caused by RSV; the underlying mechanisms, however, remain unknown. In the present study, the expressions of TLRs in airway epithelial cells and lungs of BALB/c mice infected by hMPV or RSV were measured in an attempt to explore the differences in the airway inflammation caused by the two viruses. Our results demonstrate that both hMPV and RSV infection upregulated the expressions of TLRs and inflammatory cytokines. Specifically, the TLR3 expression was revealed to be elevated in vitro and in mouse lungs. IFN-α produced by A549 cells after RSV or hMPV infection remained undistinguishable, whereas production of TNF-α was significantly higher after RSV infection than hMPV infection either in the presence or absence of Poly I:C. This study provides a clue that more severe clinical syndrome of RSV infection may be due to the greater magnitude of induction of airway inflammation by RSV involving TLR3 activation and production of TNF-α.

Clinical Characteristics and Molecular Analysis of 21 Chinese Children with Congenital Agammaglobulinemia

Congenital agammaglobulinemia is a humoral primary immunodeficiency and affected patients have extremely low levels of peripheral B cells and profound deficiency of all immunoglobulin isotypes. Mutations of the Bruton’s tyrosine kinase (BTK) gene are responsible for most of the congenital agammaglobulinemia. In this study, the phenotypes of congenital agammaglobulinemia were investigated in 21 male children from 21 unrelated Chinese families. Sixteen different mutations of BTK gene were identified in 18 patients, and three patients did not have BTK gene mutations. Nine mutations had been reported previously including one gross deletion (c.722_2041del), one missense mutation (c.1764Gu2003>u2003T), three non‐sense mutations (c.194Cu2003>u2003A, c.895Cu2003>u2003T and c.1821Gu2003>u2003A) and four invariant splice‐site mutations (c.971u2003+u20032Tu2003>u2003C, c.1481u2003+u20032Tu2003>u2003A, c.1482‐2Au2003>u2003G, c.1699‐2Au2003>u2003G). Seven novel mutations were identified (c.373_441del, c. 504delG, c.537delC, c.851delA, c.1637Gu2003>u2003A, c.1879Tu2003>u2003C and c. 1482_1882 del). Ten of the eighteen mutations of BTK gene were located in the TK domain, four in the PH domain, three in the SH3 domain and one spanned the TH, SH3, SH2 and TK domain. Candidate genes of autosomal‐recessive agammaglobulinemia, including IGHM, CD79a, CD79b and IGLL1, were screened in three patients without mutations in the BTK gene. A compound heterozygosity mutation in the IGHM gene (c.1956Gu2003>u2003A, c.175_176insC) was identified in one patient. The results of our study further support that molecular genetic testing represents an important tool for early confirmed diagnosis of congenital agammaglobulinemia and may allow accurate carrier detection and prenatal diagnosis.

Distribution, clinical features and molecular analysis of primary immunodeficiency diseases in Chinese children: a single-center study from 2005 to 2011.

Methods: Two hundred three children with genetically proven primary immunodeficiency diseases (PIDs) from 197 unrelated families were enrolled from January 2005 to December 2011. Results: On the basis of criteria developed by the International Union of Immunological Societies, 79 patients were diagnosed as “other well-defined immunodeficiency syndromes” (38.9%), 62 (30.6%) with “predominant antibody deficiencies,” 26 (12.8%) with “congenital defects of phagocyte,” 25 (12.3%) with “T- and B-cell immunodeficiency” and 11 (5.4%) with “diseases of immune dysregulation.” The median time to the diagnosis was 27.9 months and the patients had a wide range of clinical presentations. In addition, a total of 23 pathogenic genes were identified and 213 mutations were detected, including 42 novel mutations. Conclusions: With the increase in the awareness of PIDs and diagnostic competence, more PID patients will be diagnosed and we will be able to more accurately identify the frequency and the distribution of PIDs in the most populous country in the world.

The early activation of memory B cells from Wiskott-Aldrich syndrome patients is suppressed by CD19 downregulation

Wiskott-Aldrich syndrome (WAS) pediatric patients exhibit a deficiency in humoral immune memory. However, the mechanism by which Wiskott-Aldrich syndrome protein (WASP) regulates the differentiation and activation of memory B cells remains elusive. Here we examine the early activation events of memory B cells from the peripheral blood mononuclear cells of WAS patients and age-matched healthy controls (HCs) using total internal reflection fluorescence microscopy. In response to stimulation through the B-cell receptor (BCR), memory B cells from HCs showed significantly higher magnitudes of BCR clustering and cell spreading than naive B cells from the same individuals. This was associated with increases in CD19 recruitment to the BCR and the activation of its downstream signaling molecule Btk and decreases in FcγRIIB recruitment and the activation of its downstream molecule Src homology 2-containing inositol 5 phosphatase (SHIP). However, these enhanced signaling activities mediated by CD19 and Btk are blocked in memory B cells from WAS patients, whereas the activation of FcγRIIB and SHIP was increased. Although the expression levels of CD19, Btk, and FcγRIIB did not change between CD27(-) and CD27(+) B cells of HCs, the protein and mRNA levels of CD19 but not Btk and FcγRIIB were significantly reduced in both CD27(-) and CD27(+) B cells of WAS patients, compared with those of HCs. Overall, our study suggests that WASP is required for memory B-cell activation, promoting the activation by positive regulating CD19 transcription and CD19 recruitment to the BCR.