Dysregulated miR-155 and miR-125b Are Related to Impaired B-cell Responses in Down Syndrome.

Children with Down Syndrome (DS) suffer from immune deficiency with a severe reduction in switched memory B cells (MBCs) and poor response to vaccination. Chromosome 21 (HSA21) encodes two microRNAs (miRs), miR-125b, and miR-155, that regulate B-cell responses. We studied B- and T- cell subpopulations in tonsils of DS and age-matched healthy donors (HD) and found that the germinal center (GC) reaction was impaired in DS. GC size, numbers of GC B cells and Follicular Helper T cells (TFH) expressing BCL6 cells were severely reduced. The expression of miR-155 and miR-125b was increased in tonsillar memory B cells and miR-125b was also higher than expected in plasma cells (PCs). Activation-induced cytidine deaminase (AID) protein, a miR-155 target, was significantly reduced in MBCs of DS patients. Increased expression of miR-155 was also observed in vitro. MiR-155 was significantly overexpressed in PBMCs activated with CpG, whereas miR-125b was constitutively higher than normal. The increase of miR-155 and its functional consequences were blocked by antagomiRs in vitro. Our data show that the expression of HSA21-encoded miR-155 and miR-125b is altered in B cells of DS individuals both in vivo and in vitro. Because of HSA21-encoded miRs may play a role also in DS-associated dementia and leukemia, our study suggests that antagomiRs may represent pharmacological tools useful for the treatment of DS.

Radiation risks knowledge in resident and fellow in paediatrics: a questionnaire survey.

BACKGROUND: Analyse through a multi-choice anonymous questionnaire the knowledge's level in paediatric residents and fellows in two different main Italian hospital, looking mainly to the information to patients and relatives related to risks of ionizing radiation used in common radiological investigations in children. METHODS: 65 multi choice questionnaires were distributed to paediatric residents and fellows of two different hospitals, an University Hospital (A.O.U.P. "P. Giaccone"- University of Palermo) and a national reference centre for paediatrics (Ospedale Pediatrico Bambino Gesù - Rome). The questionnaire included twelve multiple-choice questions with the aim of analyzing the knowledge about ionizing radiation related risks in infants and children who undergo common diagnostic radiology investigations. The data obtained were processed using software Stata/MP version 11.2. In order to measure the level of expertise of each interviewee a binary indicator was built. The value 1 was assigned if the percentage of correct answers exceeds the median of the distribution and 0 for values not exceeding the median. The association between the level of competence and demographic characteristics (gender, age) and training experience was measured by means of α(2) test. RESULTS: 51/65 questionnaires were completed, returned and analysed (87.7%). Only 18 surveyed (35%), (95% IC = [22%-48%]) can be defined as competent in radiation risk knowledge for common radiological investigations, considering the percentage of correct answers at least of 50% (sufficient knowledge was given with a minimum score of 8 correct answers out of 12). CONCLUSIONS: The study demonstrates an urgent need to implement the radiation protection knowledge in the training programme of paediatricians, that improve if just a short targeted training is performed.

Reduced numbers of switched memory B cells with high terminal differentiation potential in Down syndrome.

Children with Down syndrome (DS) have increased susceptibility to infections and a high frequency of leukemia and autoimmune disorders, suggesting that immunodeficiency and immune dysfunction are integral parts of the syndrome. A reduction in B-cell numbers has been reported, associated with moderate immunodeficiency and normal immunoglobulin levels. Here, we compared B-cell populations of 19 children with DS with those in healthy age-matched controls. We found that all steps of peripheral B-cell development are altered in DS, with a more severe defect during the later stages of B-cell development. Transitional and mature-naïve B-cell numbers are reduced by 50% whereas switched memory B cells represent 10-15% of the numbers in age-matched controls. Serum IgM levels were slightly reduced, but all other immunoglobulin isotypes were in the normal range. The frequency of switched memory B cells specific for vaccine antigens was significantly lower in affected children than in their equivalently vaccinated siblings. In vitro switched memory B cells of patients with DS have an increased ability to differentiate into antibody-forming cells in response to TLR9 signals. Tailored vaccination schedules increasing the number of switched memory B cells may improve protection and reduce the risk of death from infection in DS.

Necrosis of the tongue as first symptom of Polyarteritis Nodosa (PAN): unusual presentation of a rare disease in children.

Polyarteritis or panarteritis nodosa (PAN) is a necrotizing, focal segmental vasculitis that affects predominantly medium-sized arteries in many different organ systems. It is extremely rare in childhood. Involvement of the oral mucosa at diagnosis is uncommon in PAN. Here, we report a case of a pediatric patient with tongue necrosis.

Use of the internet by Italian pediatricians: habits, impact on clinical practice and expectations.

BACKGROUND: Medical professionals go online for literature searches and communication with families.We administered a questionnaire to members of the Italian Society of Pediatrics to assess determinants of their use of the Internet, of social platforms and of personal health records during clinical practice. METHODS: All the 9180 members of the Italian Society of Pediatrics were invited to fill in a questionnaire concerning use of the Internet and usefulness of Internet-based tools during clinical practice. The questionnaire was administered through the SurveyMonkey® web platform. Logistic regression analysis was used to study factors affecting use and influence of the Internet in clinical practice. RESULTS: A total of 1335 (14.5%) members returned the questionnaire. Mean age was 49.2 years, 58.6% were female. 32.3% had access to the Internet through a Smartphone. 71.9% of respondents used the Internet during clinical practice, mainly searching for guidelines and drug references. Use of the Internet during clinical practice was more frequent among younger pediatricians (OR 0.964; 95% CI 0.591-0.978), males (OR 1.602; 95% CI 1.209-2.123) and those living in Northern and Central Italy (OR 1.441; 95% CI 1.111-1.869), while it was lower among family pediatricians. 94.6% of respondents were influenced in their clinical practice by information found on the Internet, in particular younger pediatricians (OR 0.96, 95% CI 0.932-0.989), hospital pediatricians (OR 2.929, 95% CI 1.708-5.024), and other pediatric profiles (OR 6.143, 95%CI 1.848-20.423). 15.9% of respondents stated that social networks may be useful in pediatric practice. Slightly more than half (50.5%) of respondents stated that personal health records may be clinically relevant. Registrars and hospital pediatricians were more likely to perceive personal health records as useful tools for clinical practice. Additional resources pediatricians would like to access were free bibliographic databases and tools for interacting with families. CONCLUSIONS: Italian pediatricians frequently use the Internet during their practice. One-third of them access the Internet through a Smartphone. Interaction with families and their empowerment can be improved by the use of Internet tools, including personal health records, toward which respondents show a significant interest. Though, they show a general resistance to the introduction of social networks in clinical practice.

Longitudinal myelitis in systemic lupus erythematosus: a paediatric case.

Acute transverse myelitis (ATM) is a very rare manifestation of the central nervous system in systemic lupus erythematosus (SLE), especially in case of involvement of continuous segments (longitudinal myelitis). We describe a 12-year-old female with lupus correlated with transverse myelitis with a longitudinal involvement of the spinal cord (D2 to D10) at the onset of the disease. Despite the administration of an early aggressive therapy, the outcome proved to be unfavourable. After 2 years of follow-up, the child still complains of paraplegia, sphincter incontinency and ipo-paresthesias of both legs.

Pediatric allergy and immunology in Italy.

In Italy, according to the International Study on Asthma and Allergies in Childhood study, the prevalence of current asthma, allergic rhinoconjunctivitis, and atopic eczema in 2006 was 7.9%, 6.5%, and 10.1% among children aged 6-7 and 8.4%, 15.5%, and 7.75% among children aged 13-14 yr. University education in this field is provided by the Postgraduate Schools of Pediatrics and those of Allergology and Clinical Immunology, as well as several annual Master courses. The Italian Society of Pediatric Allergology and Immunology (SIAIP) was founded in 1996 and counts about 1000 members. SIAIP promotes evidence-based management of allergic children and disseminates information to patients and their families through a quite innovative website and the National Journal 'Rivista Italiana di Allergologia Pediatrica'. In the last decade, four major regional, inter-regional, and national web-based networks have been created to link pediatric allergy centers and to share their clinical protocols and epidemiologic data. In addition, National Registers of Primary Immune-deficiencies and on Pediatric HIV link all clinical excellence centers. Research projects in the field of pediatric allergy and immunology are founded by the Italian Ministry of Education, University and Research (MIUR) and by the National Research Council (CNR), but the overall investments in this research area are quite low. Only a handful Italian excellence centers participate in European Projects on Pediatric Allergy and Immunology within the 7th Framework Program. The European Academy of Allergy and Clinical Immunology currently hosts two Italians in its Executive Committee (EC) and one in the EC of the Pediatric Section; moreover, major European Academy of Allergy and Clinical Immunology meetings and courses in the area of pediatrics (e.g., PAAM, Venice, 2009) have been held in Italy in the last 3 yr. Italian hallmarks in the management of allergic diseases in childhood are a quite alive and spread interest in Molecular Allergology and a remarkable predominance of sublingual (SLIT) compared to the subcutaneous (SCIT) immunotherapy.

Infliximab therapy in pediatric Takayasu's arteritis: report of two cases.

Takayasu arteritis (TA) is a chronic vasculitis of unknown etiology. Experience with anti-tumor necrosis factor alpha (anti-TNF) agents in difficult-to-treat patients with TA is limited and refers to adult patients. Here, we present two cases of pediatric TA treated with infliximab, in which clinical remission was observed. Anti-TNF treatment represents a useful therapy in pediatric Takayasu arteritis too, especially to avoid the risk of long-term corticosteroids toxicity.

Relapsing polychondritis: new therapeutic strategies with biological agents.

Relapsing polychondritis (RP) is a rare disease of unknown etiology characterized by recurrent episodes of inflammation resulting in the destruction of cartilaginous tissues. We describe a young girl with RP unresponsive to conventional therapy.

Attitudes towards HPV immunization of Italian mothers of adolescent girls and potential role of health professionals in the immunization program.

We assessed the knowledge of Italian mothers of adolescent girls about HPV and HPV vaccination, their willingness to immunize their daughters, and their perception of the role of different medical specialists in the HPV immunization strategy by a telephone interview. Fifty-four percent of the 807 interviewed mothers reported to have ever heard about HPV, and 84% of them were willing to immunize their daughters. Pediatricians most frequently provided information on HPV vaccine (31%), and were perceived as the preferred immunization providers (77%). Acceptance of HPV immunization was high and was not associated with knowledge of HPV.

Clinical features, long-term follow-up and outcome of a large cohort of patients with Chronic Granulomatous Disease: an Italian multicenter study.

A retrospective clinical and immunological survey was conducted in 60 patients with Chronic Granulomatous Disease. A prospective controlled non-randomized study of the efficacy of long-term IFNgamma treatment was carried out. The mean age at the time of diagnosis was 4.4 years; mean duration of follow-up was 10.4 years. Lung and skin infections were the most frequent manifestations both prior to diagnosis and during follow-up. Aspergillus species was the first cause of infection and of death in our cohort. The mortality rate was 13%. Long term prophylaxis with IFNgamma did not significantly change the rate of total infection per patient-year compared to controls (p=0.07). Our data provide clear evidence that protocols of continuing intensive surveillance and monitoring of compliance with anti-infective regimens may significantly improve the quality of life and long-term survival in patients with CGD. No evidence justifying long-term prophylaxis with IFNgamma was obtained.

Low serum levels of mannose binding lectin are a risk factor for neonatal sepsis.

Mannose binding lectin (MBL) is a soluble pattern recognition receptor of innate immunity that binds a wide range of pathogens and exerts opsonic effects. We investigated the association between serum MBL levels and development of sepsis in infants admitted to neonatal intensive care units (NICUs). Serum MBL levels on admission were measured by enzyme-linked immunosorbent assay (ELISA) in 206 neonates consecutively admitted to an NICU of whom 138 did not develop hospital-acquired sepsis and 68 did. Of these 68, 40 had confirmed sepsis with positive blood cultures, 19 clinically suspected sepsis, with negative blood cultures, and nine had clinically suspected sepsis with blood culture yielding coagulase-negative staphylococci (CoNS). Serum MBL levels on admission were significantly lower in infants with sepsis [0.45 microg/mL; interquartile range (IQR) 0.09-1.68], particularly in those with confirmed sepsis (0.17 microg/mL; IQR 0.05-0.96), compared with infants without sepsis (1.45 microg/mL; IQR 0.43-3.52), and infants with CoNS-positive blood culture (1.70 microg/mL: IQR 0.85-3.60). After adjusting for duration of exposure gestational age (GA) and birth weight (BW), the association of low MBL levels with development of sepsis was maintained [odds ratio (OR) = 0.52; 95% confidence interval (CI): 0.36-0.75]. The measurement of serum MBL levels on admission in NICU may help to identify neonates at higher risk of developing sepsis.

Mechanistic associations of a mild phenotype of immunodysregulation, polyendocrinopathy, enteropathy, x-linked syndrome.

BACKGROUND & AIMS: The syndrome of immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is a rare disorder resulting in the expression of multiple autoimmune and allergic features. Early onset enteropathy and type 1 diabetes (T1D) are the most common clinical features. The IPEX syndrome is caused by mutations of the FOXP3 gene, which is essential for the development of regulatory T cells (Treg). We describe 2 unrelated patients with IPEX syndrome with a mild clinical phenotype and with novel FOXP3 mutations and the phenotypic and functional characterization of their Treg cells. METHODS: The FOXP3 gene was analyzed by sequencing amplimers from genomic DNA. Treg cells were characterized by evaluating the number of CD4+CD25+ T cells and their functional ability to suppress the proliferation of autologous CD4+CD25- effector T cells stimulated with anti-CD3 and anti-CD28 antibodies. RESULTS: A 7-year-old boy and a 24-year-old man presented with autoimmune enteropathy characterized by early onset persistent diarrhea not associated with T1D or other endocrinopathies. These 2 patients carry novel FOXP3 mutations that do not abrogate the function of the forkhead domain. They have normal numbers of CD4+CD25+ T lymphocytes, however, these show severely defective suppressive function in vitro. CONCLUSIONS: Our 2 patients show that IPEX patients may present with early onset enteropathy and long-term survival without T1D or other endocrinopathies. This milder phenotype may be associated with FOXP3 mutations that do not abrogate the function of the forkhead domain.

Abnormal production of tumor necrosis factor (TNF) -- alpha and clinical efficacy of the TNF inhibitor etanercept in a patient with PAPA syndrome [corrected].

We report a family with pyogenic sterile arthritis, pyoderna and acne syndrome (PAPA). The proband presented several episodes of sterile pyogenic arthritis and became unresponsive to glucocorticoids. After treatment with the tumor necrosis factor inhibitor etanercept, the disease underwent rapid and sustained clinical remission. Production of tumor necrosis factor-alpha by mononuclear cells of the proband and of the affected relatives was abnormally elevated.

Mutations of the T-cell receptor constant region after in utero stem cell transplantation.

Like the immunoglobulin genes, the T-cell receptor genes are generated by rearrangements of non-contiguous genomic V, D and J regions, but unlike the immunoglobulin genes, somatic hypermutation is an infrequent event in T-cell receptor genes. Here, we describe the occurrence of spontaneous mutations in the constant regions of the T-cell receptor beta chains of T lymphocytes obtained from two babies who underwent in utero transplantation because of severe combined immunodeficiency. In view of the fact that in babies receiving transplants before birth, hematopoietic chimerism is consistently present, the lymphocytes are likely to be under chronic activation, which may represent a relevant biologic stimulus for generating the observed T-cell receptor hypermutation. This possibility is supported by the finding that the highest number of mutations was identified in clonally expanded T cells. These results provide further support indicating that hypermutation of the T-cell receptor genes may indeed occur, given the necessary conditions.

Reconstitution of T-cell compartment after in utero stem cell transplantation: analysis of T-cell repertoire and thymic output.

BACKGROUND AND OBJECTIVES: In utero transplantation of hematopoietic stem cells allows immune reconstitution of fetuses with severe combined immunodeficiency. The objective of this work was to study the quality of T-cell reconstitution following this procedure. DESIGN AND METHODS: We evaluated the kinetics and extent of T-cell reconstitution in five infants with severe combined immune deficiency (SCID), three with a B+ and two with a B- phenotype, who received haploidentical stem cell transplantation before birth. To this end, we measured the frequency of T-cell receptor excision circles (TREC) and the diversity of the T-cell repertoire. RESULTS: In utero transplantation led to engraftment of donor-derived T lymphocytes which attained normal numbers in four infants, who are in good health. In the three patients with a B+ phenotype, generation of a heterogeneous T-cell repertoire was associated with development of TREC levels comparable to those of SCID patients treated by post-natal transplantation and of healthy babies. Of the two patients with a B- phenotype, one developed mixed T-cell chimerism and a substantial number of circulating T cells, associated with a variable heterogeneity of the T-cell repertoire; TREC levels were normal soon after birth, but declined thereafter. The remaining B- patient remained lymphopenic with a skewed T-cell repertoire and very low TREC levels. This patient eventually required transplantation from a matched unrelated donor at 5 years of age, but died of EBV-related lymphoproliferative disease. INTERPRETATION AND CONCLUSIONS: These data indicate that in utero transplantation of fetuses with B+ SCID allows generation of newly diversified T lymphocytes and ensures long-term reconstitution of cell-mediated immunity.