Xiaodong Zhao

Characterization of Epstein-Barr virus (EBV)-infected cells in EBV-associated hemophagocytic lymphohistiocytosis in two patients with X-linked lymphoproliferative syndrome type 1 and type 2

BackgroundX-linked lymphoproliferative syndrome (XLP) is a rare inherited immunodeficiency by an extreme vulnerability to Epstein-Barr virus (EBV) infection, frequently resulting in hemophagocytic lymphohistiocytosis (HLH). XLP are now divided into type 1 (XLP-1) and type 2 (XLP-2), which are caused by mutations of SH2D1A/SLAM-associated protein (SAP) and X-linked inhibitor of apoptosis protein (XIAP) genes, respectively. The diagnosis of XLP in individuals with EBV-associated HLH (EBV-HLH) is generally difficult because they show basically similar symptoms to sporadic EBV-HLH. Although EBV-infected cells in sporadic EBV-HLH are known to be mainly in CD8+ T cells, the cell-type of EBV-infected cells in EBV-HLH seen in XLP patients remains undetermined.MethodsEBV-infected cells in two patients (XLP-1 and XLP-2) presenting EBV-HLH were evaluated by in EBER-1 in situ hybridization or quantitative PCR methods.ResultsBoth XLP patients showed that the dominant population of EBV-infected cells was CD19+ B cells, whereas EBV-infected CD8+ T cells were very few.ConclusionsIn XLP-related EBV-HLH, EBV-infected cells appear to be predominantly B cells. B cell directed therapy such as rituximab may be a valuable option in the treatment of EBV-HLH in XLP patients.

Clinical features, STAT3 gene mutations and Th17 cell analysis in nine children with hyper-IgE syndrome in mainland China.

Hyper‐IgE syndrome (HIES) is a rare primary immunodeficiency disease characterized by eczema, recurrent staphylococcal aureus skin abscesses, pneumonia with pneumatocele formation, remarkably high serum IgE levels, eosinophilia and involvement of skeleton and connective tissues. Heterozygous signal transducer and activator of transcription 3 (STAT3) mutations were shown to be the cause of autosomal dominant HIES (AD‐HIES). In this study, we diagnosed nine patients with HIES from 9 unrelated families on the basis of a National Institutes of Health (NIH) score of ≥40 points, sequenced the STAT3 gene of all nine patients, and quantified Th17 cells in peripheral blood of seven patients by flow cytometry in mainland China. All nine patients had characteristic manifestation of HIES with the range of NIH scores 45–77 points. STAT3 hot mutations V637M or R382W/Q were identified in five patients. We identified two novel heterozygous missense mutations (T620S and R609G) located in Src homology 2 (SH2) domain in two patients, respectively. In two other patients, no STAT3 mutations were found. Quantified Th17 cell numbers were markedly decreased or absent (0–0.28% of CD4+T cells) in six patients with STAT3 mutations and almost normal (0.53% of CD4+T cells) in one wild‐type STAT3 patient compared with healthy controls (0.40–2.25% of CD4+T cells). These results suggest that not all patients with HIES who had NIH scores over 40 points carry STAT3 mutations, those whose Th17 cell numbers strikingly decreased probably had AD‐HIES with STAT3 mutations.

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.

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.1764G > T), three non‐sense mutations (c.194C > A, c.895C > T and c.1821G > A) and four invariant splice‐site mutations (c.971 + 2T > C, c.1481 + 2T > A, c.1482‐2A > G, c.1699‐2A > G). Seven novel mutations were identified (c.373_441del, c. 504delG, c.537delC, c.851delA, c.1637G > A, c.1879T > C 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.1956G > A, 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.

Effects of Wiskott–Aldrich Syndrome Protein Deficiency on IL‐10‐Producing Regulatory B Cells in Humans and Mice

The Wiskott–Aldrich syndrome protein (WASp) is an important regulator of the actin cytoskeleton and is required for immune cell function. WASp deficiency causes a marked reduction in major mature peripheral B cell subsets, particularly marginal zone (MZ) B cells. We hypothesized that WASp deficiency may also lead to a reduction of regulatory B cells (known as B10 cells) belonging to a novel subset of B cells. And in consideration of the key role of B10 cells play in maintaining peripheral tolerance, we conjectured that a deficit of these cells could contribute to the autoimmunity in patients with Wiskott–Aldrich syndrome (WAS). The effects of WASp deficiency on B10 cells have been reported by only one group, which used an antigen‐induced arthritis model. To add more information, we measured the percentage of B10 cells, regulatory T cells (Tregs) and Th1 cells in WASp knockout (WASp KO) mice. We also measured the percentage of B10 cells in patients with WAS by flow cytometry. Importantly, we used the non‐induced autoimmune WASp KO mouse model to investigate the association between B10 cell frequency and the Treg/Th1 balance. We found that the percentage of B10 cells was reduced in both mice (steady state and inflammatory state) and in humans and that the lower B10 population correlated with an imbalance in the Treg/Th1 ratio in old WASp KO mice with autoimmune colitis. These findings suggest that WASp plays a crucial role in B10 cell development and that WASp‐deficient B10 cells may contribute to autoimmunity in WAS.

Wiskott-Aldrich syndrome/X-linked thrombocytopenia in China: Clinical characteristic and genotype-phenotype correlation.

Wiskott–Aldrich syndrome (WAS) and X‐linked thrombocytopenia (XLT) are caused by mutations of the WAS gene. The genotype–phenotype association of WAS and XLT have not been fully elucidated. Here, we established the largest database of WAS in China to further determine the potential correlation between genotype and phenotype and long‐term outcome.

The clinical features of autoimmunity in 53 patients with Wiskott–Aldrich syndrome in China: a single-center study

AbstractAutoimmune disease (AD) is common in patients with Wiskott-Aldrich syndrome (WAS) and patients with WAS who has an AD usually constitute a high-risk group with poor outcome. However, knowledge of AD in WAS is limited in China. In this study, medical records of 53 patients with WAS at Children´s Hospital of Chongqing Medical University from April 2004 to January 2014 were evaluated retrospectively and 14 patients (26%) had at least one AD. Autoimmune hemolytic anemia (AIHA) was the most common and detected in 12 patients (23%), other complications included immune thrombocytopenia (n = 1), immune neutropenia (n = 1), autoimmune arthritis (n = 1), and renal injury (n = 1). No significant differences were found in the level of serum immunoglobulins and lymphocyte subsets between the AD group and non-AD group. Although eight patients with AD received hematopoietic stem cell transplantation (HSCT), three patients died of pulmonary infection after HSCT. Conclusions: AD is frequent in Chinese patients with WAS and AIHA was the most common. AD is a poor prognosis factor for WAS and should be treated as early as possible by HSCT.What is Known:• Autoimmune disease is common in patients with WAS.• Manifestations, follow-up finding, and treatment approaches of autoimmune disease in Chinese patients with WAS have received less attention in the literature.What is New:• This study is firstly intended for evaluation of the clinical and immune characteristics of autoimmune disease in a large series Chinese patients with WAS.• AD is frequent in Chinese patients with WAS and AIHA is the most common.

Clinical, molecular, and T cell subset analyses in a small cohort of Chinese patients with hyper-IgM syndrome type 1

Type 1 hyper-IgM syndrome (HIGM1) is a rare primary immunodeficiency disease caused by mutations in the CD40L gene. Patients often present with recurrent infections and autoimmune manifestations. We investigated the clinical and molecular characteristics of HIGM1 in thirteen patients from the Chinese mainland and examined the proportion of CD4(+)CD25(+)FoxP3(+)Treg, Th17, and Th1 cells in the peripheral blood. We identified ten distinct CD40L mutations in eleven patients: one missense mutation, one nonsense mutation, one insertion mutation (in frame), and seven deletions. Six of these mutations were novel. We observed the percentage of Tregs in the peripheral blood of HIGM1 patients decreased markedly compared with that in healthy controls, but no statistically significant differences was found in the percentages of Th17 and Th1. The identified mutations reflect the heterogeneity of the CD40L gene in HIGM1. Precise genetic diagnosis of HIGM1 will enable appropriate therapeutic interventions, reliable detection of carriers, and genetic counseling. Skewed Treg, Th17/Treg, and Th1/Treg profiles may be associated with immune responses to autoimmunity or infection, which requires replication in larger studies.

Molecular and immunological characterization of DNA ligase IV deficiency

DNA ligase IV (LIG4) deficiency is an extremely rare autosomal recessive primary immunodeficiency disease caused by the LIG4 mutation. To date, fewer than 30 cases of patients have been reported worldwide. No reversion mutations have been previously identified in LIG4. This study enrolled seven Chinese patients with LIG4 deficiency who presented with combined immunodeficiency, microcephaly, and growth retardation. One patient (P1) acquired non-Hodgkin lymphoma. Four patients had impaired T cell proliferation function and skewed T cell receptor diversity. Five novel mutations in LIG4 and a potential hotspot mutation (c.833G>T; p.R278L) in the Chinese population were identified. TA cloning analysis of T cells, NK cells, granulocytes, and oral mucosa cells in P6 revealed wild-type clones and clones that contained both maternally and paternally inherited mutations, indicating possible somatic reversion which need further investigation since no functional or protein assays were possible for all the patients died and no cell lines were available.