Short telomere syndromes cause a primary T cell immunodeficiency.

The mechanisms that drive T cell aging are not understood. We report that children and adult telomerase mutation carriers with short telomere length (TL) develop a T cell immunodeficiency that can manifest in the absence of bone marrow failure and causes life-threatening opportunistic infections. Mutation carriers shared T cell-aging phenotypes seen in adults 5 decades older, including depleted naive T cells, increased apoptosis, and restricted T cell repertoire. T cell receptor excision circles (TRECs) were also undetectable or low, suggesting that newborn screening may identify individuals with germline telomere maintenance defects. Telomerase-null mice with short TL showed defects throughout T cell development, including increased apoptosis of stimulated thymocytes, their intrathymic precursors, in addition to depleted hematopoietic reserves. When we examined the transcriptional programs of T cells from telomerase mutation carriers, we found they diverged from older adults with normal TL. Short telomere T cells upregulated DNA damage and intrinsic apoptosis pathways, while older adult T cells upregulated extrinsic apoptosis pathways and programmed cell death 1 (PD-1) expression. T cells from mice with short TL also showed an active DNA-damage response, in contrast with old WT mice, despite their shared propensity to apoptosis. Our data suggest there are TL-dependent and TL-independent mechanisms that differentially contribute to distinct molecular programs of T cell apoptosis with aging.

Variant PIK3R1 Hypermorphic Mutation and Clinical Phenotypes in a Family with Short Statures, Mild Immunodeficiency and Lymphoma.

Background Heterozygous point mutations in the GT splice donor consensus sequence of exon 11 of the PIK3R1 gene (coding for p85α, p55α, and p50α regulatory subunits of PI3K) lead to exon skipping and thereby to an aberrant protein that leaves PI3K hyperactivated. Several patients with this particular variant of PI3 kinase delta syndrome (APDS) suffering from sinopulmonary infections and lymphoproliferation have been described. Methods (Whole exome) sequencing, evaluation of cellular and clinical phenotypes. Results We here report a family with a new heterozygous mutation in this gene, a 9 bp deletion (c.1418_1425+1del) that, however, leads to the same skipping of exon 11. The clinical phenotypes of their members partly overlap features of patients of other reports. Conclusions We found a new mutation in PIK3R1 and show how broad the resulting clinical spectrum can be.

Molecular mimicry in Helicobacter pylori infections.

Gram-negative bacteria Helicobacter pylori (H. pylori) colonize gastric mucosa in humans and increase the risk of serious diseases such as gastric and duodenal ulcers, stomach cancers and mucosa associated lymphoid tissue lymphoma. The role of H. pylori infection in the pathogenesis of several extragastric diseases has been suggested including immune thrombocytopenic purpura, iron deficiency anemia, vitamin D deficiency, cardiovascular diseases, diabetes mellitus and dermatological disorders. Also neurological diseases and even lung cancer have attracted researchers concern. The relation between H. pylori infection and a growth retardation in children has also been suggested. Many mechanisms of molecular mimicry between H. pylori and the host have been proposed as a pathogen strategy to manipulate the immune system of the host in order to remain unrecognized and avoid eradication. A lot of effort has been put into the demonstration of homologous sequences between H. pylori and host compounds. However, knowledge about how often autoantibodies or autoreactive T lymphocytes induced during H. pylori infections cause pathological disorders is insufficient. This review provides data on H. pylori antigenic mimicry and possible deleterious effects due to the induction of immune response to the components common to these bacteria and the host.

Growth and the Growth Hormone-Insulin Like Growth Factor 1 Axis in Children With Chronic Inflammation: Current Evidence, Gaps in Knowledge, and Future Directions.

Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt are often seen during adolescence. The underlying inflammatory state mediated by proinflammatory cytokines, prolonged use of glucocorticoid, and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the GH-IGF axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biological therapy may lead to improvement of growth in some of these children, but approximately one-third continue to grow slowly. There is increasing evidence that the use of relatively high-dose recombinant human GH may lead to partial catch-up growth in chronic inflammatory conditions, although long-term follow-up data are currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis, systemic abnormalities of the GH-IGF axis, and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human GH in these conditions and discussed the role of recombinant human IGF-1.

Clinical and structural impact of mutations affecting the residue Phe367 of FOXP3 in patients with IPEX syndrome.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a monogenic autoimmune disease characterized by early-onset life-threatening multisystemic autoimmunity. This rare hereditary disorder is caused by loss-of-function mutations in the gene encoding the forkhead box P3 (FOXP3) transcription factor, which plays a key role in the differentiation and function of CD4(+)CD25(+) natural regulatory T cells (Tregs), essential for the establishment and maintenance of natural tolerance. We identified a novel mutation in the FOXP3 gene affecting the Phe367 residue of the protein (F367V) in a family with three male siblings affected by IPEX. Two other mutations affecting the FOXP3 Phe367 residue (F367L and F367C) have been described previously. This unique situation of three mutations affecting the same residue in FOXP3 led us to study the molecular impact of these mutations on the structure of FOXP3 protein. Structure analysis showed that Phe367 is involved in a rich interaction network related to both monomer and dimer structure stabilization, and is crucial for FOXP3 regulatory activity. The relevance of this location is confirmed by the results of SIFT and PolyPhen-2 pathogenicity predictions for F367V mutation. In summary, as assessment of the pathogenicity of a novel mutation is crucial to achieve a proper molecular diagnosis, we analysed the impact of mutations affecting the Phe367 residue using a combined approach that provides a mechanistic view of their pathogenic effect.

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.

Induction of Heme Oxygenase-1 Deficiency and Associated Glutamate-Mediated Neurotoxicity Is a Highly Conserved HIV Phenotype of Chronic Macrophage Infection That Is Resistant to Antiretroviral Therapy.

UNLABELLED: Expression of the cytoprotective enzyme heme oxygenase-1 (HO-1) is significantly reduced in the brain prefrontal cortex of HIV-positive individuals with HIV-associated neurocognitive disorders (HAND). Furthermore, this HO-1 deficiency correlates with brain viral load, markers of macrophage activation, and type I interferon responses. In vitro, HIV replication in monocyte-derived macrophages (MDM) selectively reduces HO-1 protein and RNA expression and induces production of neurotoxic levels of glutamate; correction of this HO-1 deficiency reduces neurotoxic glutamate production without an effect on HIV replication. We now demonstrate that macrophage HO-1 deficiency, and the associated neurotoxin production, is a conserved feature of infection with macrophage-tropic HIV-1 strains that correlates closely with the extent of replication, and this feature extends to HIV-2 infection. We further demonstrate that this HO-1 deficiency does not depend specifically upon the HIV-1 accessory genes nef, vpr, or vpu but rather on HIV replication, even when markedly limited. Finally, antiretroviral therapy (ART) applied to MDM after HIV infection is established does not prevent HO-1 loss or the associated neurotoxin production. This work defines a predictable relationship between HIV replication, HO-1 loss, and neurotoxin production in MDM that likely reflects processes in place in the HIV-infected brains of individuals receiving ART. It further suggests that correcting this HO-1 deficiency in HIV-infected MDM could provide neuroprotection above that provided by current ART or proposed antiviral therapies directed at limiting Nef, Vpr, or Vpu functions. The ability of HIV-2 to reduce HO-1 expression suggests that this is a conserved phenotype among macrophage-tropic human immunodeficiency viruses that could contribute to neuropathogenesis. IMPORTANCE: The continued prevalence of HIV-associated neurocognitive disorders (HAND) underscores the need for adjunctive therapy that targets the neuropathological processes that persist in antiretroviral therapy (ART)-treated HIV-infected individuals. To this end, we previously identified one such possible process, a deficiency of the antioxidative and anti-inflammatory enzyme heme oxygenase-1 (HO-1) in the brains of individuals with HAND. In the present study, our findings suggest that the HO-1 deficiency associated with excess glutamate production and neurotoxicity in HIV-infected macrophages is a highly conserved phenotype of macrophage-tropic HIV strains and that this phenotype can persist in the macrophage compartment in the presence of ART. This suggests a plausible mechanism by which HIV infection of brain macrophages in ART-treated individuals could exacerbate oxidative stress and glutamate-induced neuronal injury, each of which is associated with neurocognitive dysfunction in infected individuals. Thus, therapies that rescue the HO-1 deficiency in HIV-infected individuals could provide additional neuroprotection to ART.

IGF1 deficiency in newly diagnosed Graves' disease patients.

OBJECTIVE: Thyroid hormones influence the GH/IGF1 axis, but previous studies have reported discrepant results regarding serum IGF1 levels in hyperthyroidism. We have therefore investigated, at diagnosis, the relationship between serum IGF1 levels and the main characteristics of Graves' disease (GD): severity of hyperthyroidism, goiter size, presence of active Graves' ophthalmopathy (GO), antythyroid antibodies status and titer. DESIGN AND METHODS: This cross-sectional study included 98 newly diagnosed hyperthyroid patients with GD who presented consecutively at our clinic. The main measured parameters were: TSH, FT4, FT3, TT3, thyroglobulin,anti-thyroid peroxidase antibodies (TPOAb), anti-thyroglobulin antibodies (ATA), thyrotropin receptor antibodies (TRAb), IGF1. Patients were considered IGF deficient if IGF1 z score was ≤-2SD from mean for age. RESULTS: In GD patients, men had higher IGF1 levels (p=0.023) and IGF1 z scores (p=0.013) than women. 18.4% of GD patients were, at diagnosis, IGF1 deficient. Compared to patients without IGF1 deficiency, these patients presented higher thyroglobulin (median=72.55, IQR=116.02 vs median=11.40, IQR=80.74 ng/ml, p=0.002) and FT3 (median=11.30, IQR=7.64 vs median=7.33, IQR=5.72 pg/ml, p=0.027), and lower ATA (median=20, IQR=0 vs median=34.05, IQR=161 iu/ml, p<0.001) levels. Thyroglobulin was independently associated with IGF1 deficiency (AUROC=0.732, 95% CI: 0.620-0.844, p=0.002; cut-off for thyroglobulin=50.40 ng/ml, Se=77.8%, Sp=70%). IGF1 status was not influenced by gender (p=0.084), current smoking (p=0.558), goiter size (p=0.533), active ophthalmopathy (p=0.334), TRAb (p=0.239) or TPOAb status (p=0.367). CONCLUSIONS: Nearly one fifth of newly diagnosed GD patients had IGF1 deficiency. IGF1 deficiency was associated with lower ATA titers, higher thyroglobulin levels and more severe FT3 hyperthyroidism at diagnosis.

Growth problems in children with IBD.

Crohn's disease in childhood causes linear growth retardation, which has a substantial effect on management of this disease. By contrast, growth is rarely a problem in children presenting with ulcerative colitis. Depending on how growth failure is defined, approximately one-third of children with Crohn's disease have growth retardation at diagnosis. Although corticosteroids can suppress growth, decreased height at diagnosis demonstrates that this finding is a consequence of the disease and not merely an adverse effect of treatment. Both inflammation and undernutrition contribute to decreased height velocity. Increased cytokine production acts both on the hepatic expression of insulin-like growth factor 1 (IGF-1) and at chondrocytes of the growth plates of long bones. Growth hormone insensitivity caused by deranged immune function is a major mechanism in growth retardation. Resolution of inflammation is the cornerstone of treatment, but current studies on growth hormone and IGF-1 might yield therapies for those children whose inflammation is refractory to treatment.

Prepubertal children with a history of extra-uterine growth restriction exhibit low-grade inflammation.

Intra-uterine growth restriction (IUGR) may induce significant metabolic and inflammatory anomalies, increasing the risk of obesity and CVD later in life. Similarly, alterations in the adipose tissue may lead to metabolic changes in children with a history of extra-uterine growth restriction (EUGR). These mechanisms may induce alterations in immune response during early life. The aim of the present study was to compare pro-inflammatory markers in prepubertal EUGR children with those in a reference population. A total of thirty-eight prepubertal children with a history of EUGR and a reference group including 123 healthy age- and sex-matched children were selected. Perinatal data were examined. In the prepubertal stage, the concentrations of inflammatory biomarkers were measured in both groups. The serum concentrations of C-reactive protein (CRP) and plasma concentrations of hepatocyte growth factor (HGF), IL-6, IL-8, monocyte chemotactic protein type 1 (MCP-1), neural growth factor, TNF-α and plasminogen activator inhibitor type 1 were determined. The plasma concentrations of inflammatory biomarkers CRP, HGF, IL-8, MCP-1 and TNF-α were higher in the EUGR group than in the reference group (P< 0·001). After adjustment for gestational age, birth weight and length, blood pressure values and TNF-α concentrations remained higher in the EUGR group than in the reference group. Therefore, further investigations should be conducted in EUGR children to evaluate the potential negative impact of metabolic, nutritional and pro-inflammatory changes induced by the EUGR condition.

Persistent G. lamblia impairs growth in a murine malnutrition model.

Giardia lamblia infections are nearly universal among children in low-income countries and are syndemic with the triumvirate of malnutrition, diarrhea, and developmental growth delays. Amidst the morass of early childhood enteropathogen exposures in these populations, G. lamblia­specific associations with persistent diarrhea, cognitive deficits, stunting, and nutrient deficiencies have demonstrated conflicting results, placing endemic pediatric giardiasis in a state of equipoise. Many infections in endemic settings appear to be asymptomatic/ subclinical, further contributing to uncertainty regarding a causal link between G. lamblia infection and developmental delay. We used G. lamblia H3 cyst infection in a weaned mouse model of malnutrition to demonstrate that persistent giardiasis leads to epithelial cell apoptosis and crypt hyperplasia. Infection was associated with a Th2-biased inflammatory response and impaired growth. Malnutrition accentuated the severity of these growth decrements. Faltering malnourished mice exhibited impaired compensatory responses following infection and demonstrated an absence of crypt hyperplasia and subsequently blunted villus architecture. Concomitantly, severe malnutrition prevented increases in B220+ cells in the lamina propria as well as mucosal Il4 and Il5 mRNA in response to infection. These findings add insight into the potential role of G. lamblia as a "stunting" pathogen and suggest that, similarly, malnourished children may be at increased risk of G. lamblia­ potentiated growth decrements.

A 5-year-old boy with atrophic autoimmune thyroiditis caused by thyroid-stimulation blocking antibodies.

A 5-year-old boy was presented for a growth disturbance, which was initially noted at 3 years of age. Endocrinological testing identified severe hypothyroidism, defined by the following levels: TSH 990.5 microU/mL, F-T3 0.26 pg/mL, and F-T4 0.09 ng/dL. Serum anti-thyroid peroxidase (TPO) antibodies were 158 IU/mL and serum thyroid-stimulation blocking antibodies (TSBab) levels were 82.1 IU/mL (normal range < 45.6). Thyroid scintigraphy with 99mTc showed markedly decreased uptake, and magnetic resonance imaging (MRI) revealed pituitary hyperplasia. He was diagnosed with atrophic autoimmune thyroiditis. His thyroid function and pituitary size normalized following thyroid hormone replacement therapy. We report a rare case of a young boy with atrophic thyroiditis caused by TSBab.

Long-term clinical significance of thyroid autoimmunity in children with celiac disease.

OBJECTIVE: To evaluate the long-term outcome of thyroid function and autoimmunity in a large series of children with celiac disease. STUDY DESIGN: This longitudinal, retrospective study (duration of follow-up, 8.9 +/- 4.0 years) was conducted at the Pediatric Department, University of Bologna, Italy. One hundred thirty-five consecutive patients diagnosed between June 1990 and December 2004 and followed on a gluten-free diet were examined. Inclusion criteria were good dietary compliance and duration of follow-up for at least 3 years. RESULTS: Of 101 patients who never showed positive antithyroid titers during the follow-up, 86 remained euthyroid; 15 showed high thyroid-stimulating hormone values at diagnosis that normalized in 11 cases after 12 to 18 months of gluten withdrawal. Of 31 patients with persistently positive antibody titers, 23 (74%) remained consistently euthyroid during the follow-up and 8 (26%) had a subclinical hypothyroidism. The prevalence of cases with positive antibodies was similar in children with growth retardation or gastroenterological symptoms at diagnosis and different durations of gluten exposure. CONCLUSIONS: The presence of antithyroid antibodies in children with celiac disease has a low predictive value for the development of thyroid hypofunction during the indicated surveillance period. Longer follow-up is needed.

SCID dogs: similar transplant potential but distinct intra-uterine growth defects and premature replicative senescence compared with SCID mice.

We have previously described DNA-dependent protein kinase (DNA-PKcs) mutations in horses and dogs that result in deficits in V(D)J recombination, DNA repair, and SCID. In this paper, we document substantial developmental growth defects in DNA-PKcs-deficient dogs that are not apparent in SCID mice. Fibroblast cell strains derived from either fetal or adult SCID dogs proliferate poorly in culture and undergo premature replicative senescence, somewhat reminiscent of cells derived from Ku-deficient mice. A limited number of animals have been immune reconstituted (by bone marrow transplantation) so that they can be maintained in a normal environment for long periods. Several of these animals have developed conditions associated with premature ageing at 2-3 years of age, roughly 20% of their expected lifespan. These conditions include intestinal malabsorption and primary neural cell neoplasia. These results suggest that DNA-PKcs deficiency is not tolerated equally in all species, perhaps providing insight into why DNA-PKcs deficiency has not been observed in humans. Finally, this study demonstrates the feasibility of maintaining SCID dogs for extended periods of time and documents their utility for bone marrow transplantation studies and as hosts for the propagation of xenografts. In sum, SCID dogs may present researchers with new possibilities for the development of animal models of human disease.

Hyperimmunoglobulinaemia in Babinga Pygmies is present from infancy.

Pygmies, a population characterized by short stature, have high immunoglobulin (Ig) concentrations. In this study, we evaluated Ig levels in Cameroons Babinga Pygmies from infancy to adulthood and the effects of a national health program on these Ig levels. We found that IgG and IgM levels were outside the normal range for Italians of the same age and were comparable to those measured in Babinga Pygmies living in the same region by Siccardi in 1975. In conclusion, the hypergammaglobulinaemia of Babinga Pygmies is already present in infants and is not affected by sanitation improvements, suggesting that it could be partly genetically-determined.

Impaired function of primitive hematopoietic cells in mice lacking the Mixed-Lineage-Leukemia homolog MLL5.

The human Mixed-Lineage-Leukemia-5 (MLL5) gene is located in a genomic region frequently deleted in patients with myeloid malignancies and encodes a widely expressed nuclear protein most closely related to MLL1, a Trithorax transcriptional regulator with established involvement in leukemogenesis. Although the physiologic function of MLL5 is completely unknown, domain structure and homology to transcriptional regulators with histone methyltransferase activity suggest a role in epigenetic gene regulation. To investigate physiologic functions of Mll5, we have generated a knockout mouse mutant using Cre/loxP technology. Adult homozygous Mll5-deficient mice are obtained at reduced frequency because of postnatal lethality. Surviving animals display a variety of abnormalities, including male infertility, retarded growth, and defects in multiple hematopoietic lineages. Interestingly, Mll5(-/-) mice die of sublethal whole-body irradiation but can be rescued with wild-type bone marrow grafts. Flow cytometric ana-lysis, bone marrow reconstitution, and in vivo BrdU-labeling experiments reveal numerical, functional, and cell-cycle defects in the lineage-negative Sca-1(+), Kit(+) (LSK) population, which contains short- and long-term hematopoietic stem cells. Together, these in vivo findings establish several nonredundant functions for Mll5, including an essential role in regulating proliferation and functional integrity of hematopoietic stem/progenitor cells.

Corticosteroids usage in pediatric liver transplantation: To be or not to be!

The theoretical risks of early SW, <3 months post-LT, and complete elimination (steroid-free LT) lie in mainly three areas, namely the risks of AGR, CGR, and the development of d-AIH that has been described in SW post-LT in children. These should be balanced against the benefits of early SW mainly manifested as effects on growth post-LT. In this paper, we focused on the clinical trials that included CS therapy risks and benefits in pediatric LT. Focusing mainly on CGR and d-AIH as risks, and the beneficial effects on growth post-LT with either low-dose CS, SW, or steroid-free regimens. Main conclusions from comparing a large number of studies are: early SW or elimination from immunosuppression protocols was neither harmful to the patient nor to the graft survival rate in the short term, the overall impression is that steroids negatively affect growth in LT recipients when used in high doses and prolonged course, and that development of d-AIH is not associated with CS therapy with evidence that chronic low dose steroids post-LT have no preventative role against d-AIH.

Impact of intestinal permeability, inflammation status and parasitic infections on infant growth faltering in rural Bangladesh.

A longitudinal study of 298 rural Bangladeshi infants found evidence of growth faltering starting at 3 months of age. Anthropometric status declined substantially in the first 2 years of life, with weight-for-height (WHZ) falling from - 0.49 to - 1.75, weight-for-age (WAZ) from - 1.18 to - 2.87 and height-for-age (HAZ) from - 1.00 to - 1.88. Higher concentrations of the acute-phase protein alpha-1-acid glycoprotein (AGP) and higher gut mucosal damage (as signified by raised lactulose:mannitol (L:M) ratios) were both associated with chronic malnutrition as indicated by poorer HAZ and WAZ scores (P = 0.011 and 0.005 for AGP and 0.039 and 0.019 for L:M ratio, respectively). Higher Hb levels were related to improved z-scores, while elevation of Giardia-specific IgM titre (GSIgM) was associated with poor WAZ and WHZ (P = 0.015 and 0.039, respectively). IgG did not show any significant association with z-scores and the L:M ratio did not correlate with any of the inflammation markers or Giardia infection. The prevalence of geohelminth infections was low (only 4 % in the total study period). However, the level of GSIgM indicated high endemicity of Giardia infection from early in life, although very few cysts were detected from stool samples. These findings suggest that rural Bangladeshi infants are being exposed to high levels of infection with concomitant gut damage and growth faltering.

Growth velocity and interleukin 6 concentrations in juvenile idiopathic arthritis.

OBJECTIVE: .To evaluate associations of growth velocity with inflammatory markers and cumulative dose of glucocorticoid in a cohort of patients with juvenile idiopathic arthritis (JIA) followed during 1 year. METHODS: Seventy-nine patients were evaluated. Disease activity was evaluated by a pediatric rheumatologist. Anthropometric data were classified according to the World Health Organization standards. Tanner growth velocity curves were used; values below the Z-score < or = -2 were considered low growth velocity. Serum concentrations of interleukin 6 (IL-6) were measured by ELISA, and values > 1 pg/ml were considered elevated. RESULTS: The prevalence of low growth velocity was 25.3%, and it was associated with active disease on followup visit, elevated IL-6, erythrocyte sedimentation rate and C-reactive protein, and higher cumulative glucocorticoid doses. In the multiple linear regression with growth velocity as the dependent variable, only elevated IL-6 level was independently and negatively associated with growth velocity. CONCLUSION: Low growth velocity is highly prevalent in children with JIA. Elevated IL-6 levels seem to have an important negative influence on growth in these children, while total glucocorticoid exposure appears to be a secondary factor.