Tong-Xin Chen

Susceptibility to mycobacterial infections in children with x-linked chronic granulomatous disease: A review of 17 patients living in a region endemic for tuberculosis

Background: Chronic granulomatous disease (CGD) is a rare disorder of phagocytic oxidative bursts leading to recurrent pyogenic infections. Affected individuals are most prone to infections caused by staphylococci, Salmonella, Candida, and Aspergillus, but previously we observed a high incidence of Mycobacterium tuberculosis infection in Chinese children with CGD. Objective: To determine the spectrum of infections in patients with X-linked CGD, with an emphasis on mycobacterial infections, and to review all CYBB gene mutations identified in our center. Results: From 1988 to 2005, 17 Chinese male children were diagnosed to have X-linked CGD. Fifteen mutations were identified, including 3 splice site defects (IVS1-1G>C, 266G>A, IVS3-1G>A), 5 missense mutations (591T>C, 627T>A, 949T>A, 1039T>A, 1512G>C), 3 nonsense mutations (882C>T, 1451C>A, 1569G>T), 1 insertion (756_757insA), and 3 deletions (660_662delTTC, 727delT, 1341delT). Eight of these were novel mutations. Recurrent pneumonia, lymphadenitis, and bacterial skin abscess were the commonest types of infection. Seven patients had tuberculosis (TB). Seven patients had prolonged scarring or abscess formation at the Calmette-Guérin bacillus (BCG) injection site, and 1 had disseminated BCG infection. Three patients had pulmonary aspergillosis. Four patients underwent hemopoietic stem cell transplantation, but 2 died of complications. Conclusions: Patients with CGD are susceptible to TB and BCG complications. Our observation suggests that oxidative burst is probably important in host defense against mycobacterial infections. Because interferon-γ is the key cytokine involved in mycobacterial immunity, there may be a stronger indication for its use in CGD patients living in areas endemic for TB.

Clinical Characteristics and Genotype-phenotype Correlation in 62 Patients with X-linked Agammaglobulinemia

IntroductionX-linked agammagobulinemia (XLA) is a primary immunodeficiency disorder caused by Brutons tyrosine kinase (Btk) gene mutation. Recent studies suggested genotype-phenotype correlation in XLA, but a definitive association remains controversial.Patients and MethodsWe examined the relationship between specific Btk gene mutations and severity of clinical presentation in 62 patients with XLA. Disease severity was assessed by the age of disease onset and the presence of severe infections, while mutations were classified into severe and mild based on structural and functional consequence by bioinformatics analysis.ResultsFifty-six Btk mutations were identified in 62 patients from 57 kindreds. Variation in phenotypes was observed, and there was a tendency of association between genotype and age of disease onset as well as occurrence of severe infections.ConclusionA critical analysis of the circumstances upon presentation also revealed that under-recognition of recurrent infections and relevant family history are important hurdles to timely diagnosis of XLA.

Partially hydrolyzed cow’s milk formula has a therapeutic effect on the infants with mild to moderate atopic dermatitis: a randomized, double-blind study

To cite this article: Jin Y‐Y, Cao R‐M, Chen J, Kaku Y, Wu J, Cheng Y, Shimizu T, Takase M, Wu S‐M, Chen T‐X. Partially hydrolyzed cow’s milk formula has a therapeutic effect on the infants with mild to moderate atopic dermatitis: a randomized, double‐blind study. Pediatric Allergy Immunology 2011; 22: 688–694.

Clinical Features and Genetic Analysis of 20 Chinese Patients with X-Linked Hyper-IgM Syndrome

X-linked hyper-IgM syndrome (XHIGM) is one type of primary immunodeficiency diseases, resulting from defects in the CD40 ligand/CD40 signaling pathways. We retrospectively analyzed the clinical and molecular features of 20 Chinese patients diagnosed and followed up in hospitals affiliated to Shanghai Jiao Tong University School of Medicine from 1999 to 2013. The median onset age of these patients was 8.5 months (range: 20 days–21 months). Half of them had positive family histories, with a shorter diagnosis lag. The most common symptoms were recurrent sinopulmonary infections (18 patients, 90%), neutropenia (14 patients, 70%), oral ulcer (13 patients, 65%), and protracted diarrhea (13 patients, 65%). Six patients had BCGitis. Six patients received hematopoietic stem cell transplantations and four of them had immune reconstructions and clinical remissions. Eighteen unique mutations in CD40L gene were identified in these 20 patients from 19 unrelated families, with 12 novel mutations. We compared with reported mutation results and used bioinformatics software to predict the effects of mutations on the target protein. These mutations reflected the heterogeneity of CD40L gene and expanded our understanding of XHIGM.

Identification of sociodemographic and clinical factors associated with the levels of human β-defensin-1 and human β-defensin-2 in the human milk of Han Chinese.

Human milk provides infants with various immune molecules. The objective of the present study was to measure human β-defensin-1 (hBD-1) and human β-defensin-2 (hBD-2) levels in the colostrum and mature milk of healthy Han Chinese, to identify factors regulating milk hBD-1 and hBD-2 expression and to explore the potential protective effect of milk hBD-1 and hBD-2 on infants. A total of 100 mothers and their babies were recruited into the study. Sociodemographic characteristics and other factors were obtained by a questionnaire. Babies were followed up for a period of 6 months. Colostrum samples (n 100) and mature milk samples (n 82) were collected by hand expression. The hBD-1 and hBD-2 concentrations were measured by ELISA. The hBD-1 and hBD-2 levels differed in the colostrum and mature milk. In the colostrum, the concentration ranges of hBD-1 and hBD-2 were 1·04-12·81 μg/ml and 0·31-19·12 ng/ml, respectively. In mature milk, the hBD-1 and hBD-2 levels were 1·03-31·76 ng/ml and 52·65-182·29 pg/ml, respectively. Several independent factors influence their production. The multivariable analysis showed a strong association between pre-pregnancy BMI and hBD-1 levels in the colostrum (P=0·001), mode of delivery was significantly associated with hBD-2 levels in the colostrum (P=0·006) and gestational age was significantly associated with hBD-1 levels in mature milk (P= 0·010). During the first 6 months of life, the incidence rate of upper respiratory infection was found to be less in the high-colostrum hBD-1 group than in the low-colostrum hBD-1 group (χ²=4·995, P=0·025). The present study suggested that the abundance of hBD-1 in the colostrum may have a protective function against upper respiratory infection for infants younger than 6 months.

Effects of Epstein-Barr virus on the development of dendritic cells derived from cord blood monocytes: an essential role for apoptosis

OBJECTIVE Epstein-Barr virus (EBV) is a ubiquitous human γ-herpes virus, which can adapt and evade host immune defense. Dendritic cells (DCs) play a pivotal role in the initiation and maintenance of immune responses. This study investigated the effects of EBV on cord blood monocytes derived DCs (CBDC). METHODS Monocytes were isolated from cord blood and cultured in medium containing recombinant IL-4 and GM-CSF to induce DCs development. B95-8 supernatant was added in monocytes culture medium for EBV infection at day 0. Phenotypic characterization of DCs, apoptotic cells, and mitochondrial membrane potential (MMP) were detected by flow cytometry. The morphology was observed by Hoechst 33258 staining and TUNEL staining, the expression of X-linked inhibitor of apoptosis protein (XIAP) was detected by Western blotting assay and caspase 3, 8 and 9 activity was measured. RESULTS Phenotypic characterization of DCs was changed in EBV-treated group. Chromatin condensation and DNA fragmentation were observed in EBV induced CBDC apoptosis. In addition, caspase 3, caspase 8, and caspase 9 activation were enhanced in the EBV-treated group. This was accompanied by the loss of MMP. Furthermore, XIAP expression was down-regulated in the EBV-treated group and compared to mock-infected group. CONCLUSION These results suggested that EBV could inhibit CBDC phenotypic differentiation, and induce CBDC apoptosis in caspase-dependent manner with involvement of the mitochondrial pathway. This might help EBV to evade host immune responses to establish persistent infection.

Clinical Features and Genetic Analysis of 48 Patients with Chronic Granulomatous Disease in a Single Center Study from Shanghai, China (2005–2015): New Studies and a Literature Review

Chronic Granulomatous Disease (CGD) is a rare inherited primary immunodeficiency, which is characterized by recurrent infections due to defective phagocyte NADPH oxidase enzyme. Nowadays, little is known about Chinese CGD patients. Here we report 48 CGD patients in our single center study, which is the largest cohort study from Mainland China. The ratio of male to female was 11 : 1. The mean onset age was 0.29 years old, and 52% patients had an onset within the 1st month of life. The mean diagnosis age was 2.24 years old. 11 patients (23%) had died with an average age of 2.91 years old. 13 patients (28%) had positive family histories. The most prevalent infectious sites were the lungs (77%), followed by gastrointestinal tract (54%), lymph nodes (50%), and skin (46%). In addition, septicopyemia, thrush, and hepatosplenomegaly were also commonly observed, accounting for 23%, 23%, and 40% of the cases. Lesions due to BCG vaccination occurred in more than half of the patients. X-linked CGD due to CYBB gene mutations accounted for 75% of the cases, and 11 of them were novel mutations. Autosomal recessive inheritance accounted for 6% patients, including 1 patient with CYBA, 1 with NCF1, and 1 with NCF2 gene mutations.

Clinical characteristics and genetic profiles of 174 patients with X-linked agammaglobulinemia: Report from Shanghai, China (2000–2015)

AbstractX-linked agammaglobulinemia (XLA) is a humoral primary immunodeficiency. XLA patients typically present with very low numbers of peripheral B cells and a profound deficiency of all immunoglobulin isotypes. Most XLA patients carry mutations in Bruton tyrosine kinase (BTK) gene.The genetic background and clinical features of 174 Chinese patients with XLA were investigated. The relationship between specific BTK gene mutations and severity of clinical manifestations was also examined. Mutations were graded from mild to severe based on structural and functional prediction through bioinformatics analysis.One hundred twenty-seven mutations were identified in 142 patients from 124 families, including 45 novel mutations and 82 recurrent mutations that were distributed over the entire BTK gene sequence. Variation in phenotypes was observed, and there was a tendency of association between genotype and age of disease onset.This report constitutes the largest group of patients with BTK mutations in China. A genotype–phenotype correlation was observed in this study. Early diagnosis of congenital agammaglobulinemia should be based on clinical symptoms, family history, and molecular analysis of the BTK gene.

DNA induction of MDM2 promotes proliferation of human renal mesangial cells and alters peripheral B cells subsets in pediatric systemic lupus erythematosus

HIGHLIGHTSApoptotic and necrotic CD4+T cells are associated with plasma cell free DNA in pediatric SLE.Ds‐ISD induces MDM2 expression in human renal mesangial cells.MDM2 promotes cell proliferation in human renal mesangial cells.MDM2 alters peripheral B cells subsets. ABSTRACT The study is aimed to investigate the role of MDM2 in the pathogenesis of lupus nephritis (LN) in pediatric SLE (pSLE). We confirmed that MDM2 expression was increased in peripheral blood mononuclear cells (PBMCs) as well as renal specimen of SLE compared with that of controls by western blot and immunofluorescence staining. Percentage of apoptotic and necrotic CD4+T, CD8+T and B cells were detected by flow cytometry respectively and levels of plasma cell free DNA (cfDNA) were quantified in SLE and healthy controls (HC). We also proved that elevated apoptotic and necrotic CD4+T cells were the main cause for increased plasma levels of cfDNA in pSLE. Additionally, upon DNA transfection MDM2 increased while P53 and P21 decreased in human renal mesangial cells (HRMC), with concomitant increase in proliferation rate and proportion of cells in S phase, as demonstrated by cell proliferation assay and cell cycle analysis. However, MDM2 inhibition reversed the trend. Furthermore, percentage of switched memory B cells decreased and proportion of double negative B cells increased upon blockage of MDM2 in PBMC. In summary, our study provided the first evidence that DNA induction of MDM2 promotes proliferation of HRMC and alters peripheral B cells subsets in pSLE. Thus our study has not only elucidated the pathogenesis of MDM2 in pediatric LN but also provided a novel target for drug development. In conclusion, our data suggested that apoptosis, cfDNA and MDM2 could form a pathological axis in SLE, especially in pSLE.

Decreased PD-1 expression on circulating CD4 + T cell and PD-L1 expression on myeloid dendritic cell correlate with clinical manifestations in systemic juvenile idiopathic arthritis

OBJECTIVES Programmed cell death-1 (PD-1) and its ligand (PD-L1) mediate negative signal in autoimmune diseases. While little is known about its role in juvenile idiopathic arthritis (JIA). The study aimed to reveal the circulating cell profile and the relative PD-1/PD-L1 expression of JIA subsets, elucidating their underlying immunomodulatory mechanisms. METHODS We detected the circulating cells and the relative PD-1/PD-L1 signaling in 101 JIA patients and 50 controls by flow cytometry and analyzed their association with disease activity and clinical manifestations. RESULTS Different from other JIA types, active systemic JIA (sJIA) patients had lower percentage and count of CD4+T cells and lower PD-1 expression on them compared with healthy controls (P<0.05), active polyarthritis (P<0.05) and enthesitis-related arthritis (ERA) patients (P<0.05). Also, they had higher percentage and count of myeloid dendritic cell (mDC) and lower PD-L1 expression on mDC compared with healthy controls (P<0.05). Both PD-1 on CD4+T cell and PD-L1 on mDC were negatively correlated with JADAS-27 in sJIA patients (P<0.05). In addition, PD-1 expression on CD4+T cell was negatively associated with the number of involved joints (P<0.05) and PD-L1 on mDC was lower in patients with fever (P<0.01), which could further divide patients into two groups of different manifestations. CONCLUSIONS Our finding displayed decreased CD4+T cell, increased mDC and reduced PD-1/PD-L1 signal in sJIA PBMC comparing with other JIA subsets, which might be helpful in JIA differential diagnosis and responsible for distinct clinical manifestations via different mechanisms.