Antiviral and regulatory T cell immunity in a patient with stromal interaction molecule 1 deficiency.

Stromal interaction molecule 1 (STIM1) deficiency is a rare genetic disorder of store-operated calcium entry, associated with a complex syndrome including immunodeficiency and immune dysregulation. The link from the molecular defect to these clinical manifestations is incompletely understood. We report two patients with a homozygous R429C point mutation in STIM1 completely abolishing store-operated calcium entry in T cells. Immunological analysis of one patient revealed that despite the expected defect of T cell proliferation and cytokine production in vitro, significant antiviral T cell populations were generated in vivo. These T cells proliferated in response to viral Ags and showed normal antiviral cytotoxicity. However, antiviral immunity was insufficient to prevent chronic CMV and EBV infections with a possible contribution of impaired NK cell function and a lack of NKT cells. Furthermore, autoimmune cytopenia, eczema, and intermittent diarrhea suggested impaired immune regulation. FOXP3-positive regulatory T (Treg) cells were present but showed an abnormal phenotype. The suppressive function of STIM1-deficient Treg cells in vitro, however, was normal. Given these partial defects in cytotoxic and Treg cell function, impairment of other immune cell populations probably contributes more to the pathogenesis of immunodeficiency and autoimmunity in STIM1 deficiency than previously appreciated.

Complications in hospitalized children with acute gastroenteritis caused by rotavirus: a retrospective analysis.

UNLABELLED: Acute gastroenteritis (AGE) caused by rotavirus (RV) is a common disease among infants and toddlers, often leading to hospitalization and, in resource-poor countries, to death. However, little is known on specific complications of severe RV-positive (RV+) AGE and on the clinical course in chronically ill children. This was a retrospective analysis of data for children <5 years of age hospitalized due to AGE during six rotavirus seasons in three large German pediatric hospitals. The primary study end point was the incidence and type of complications in RV+ versus RV-negative (RV-) cases. A total of 6,884 episodes of AGE in hospitalized children aged <5 years were included in this analysis. Of the 4,880 stools tested for RV, 2,118 (43.4%) were RV+. Hypernatremia was significantly more common in RV+ AGE (P < 0.001) and was associated with severe disease, need for intensive care treatment, and longer duration of hospitalization. Metabolic disorders, particularly hypoglycemia, were more common in RV+ AGE. In contrast, symptoms such as respiratory infections, neurological, and abdominal symptoms were more common in children with RV- AGE. CONCLUSIONS: Hypernatremia is a specific complication of RV+ AGE. RV would therefore appear to be the cause of infant toxicosis, the traditional descriptive term for severe dehydration and clinical deterioration following AGE.

Alu-repeat-induced deletions within the NCF2 gene causing p67-phox-deficient chronic granulomatous disease (CGD).

Mutations that impair expression or function of the components of the phagocyte NADPH oxidase complex cause chronic granulomatous disease (CGD), which is associated with life-threatening infections and dysregulated granulomatous inflammation. In five CGD patients from four consanguineous families of two different ethnic backgrounds, we found similar genomic homozygous deletions of 1,380 bp comprising exon 5 of NCF2, which could be traced to Alu-mediated recombination events. cDNA sequencing showed in-frame deletions of phase zero exon 5, which encodes one of the tandem repeat motifs in the tetratricopeptide (TPR4) domain of p67-phox. The resulting shortened protein (p67Delta5) had a 10-fold reduced intracellular half-life and was unable to form a functional NADPH oxidase complex. No dominant negative inhibition of oxidase activity by p67Delta5 was observed. We conclude that Alu-induced deletion of the TPR4 domain of p67-phox leads to loss of function and accelerated degradation of the protein, and thus represents a new mechanism causing p67-phox-deficient CGD.

Prevalence of hepatitis E virus antibodies in children in Germany.

BACKGROUND: Since asymptomatic hepatitis E virus (HEV) infections particularly affect children, there is a need for studies to determine the HEV seroprevalence among infants, children and adolescents. METHODS: The prevalence of anti-HEV IgG antibodies was determined in sera taken in 2008-2010 from 1646 children aged 0-17 years living in Germany. Antibody testing was carried out using the enzyme-linked immunosorbent assay recomWell HEV IgG as well as the recomLine HEV IgG/IgM distributed by Mikrogen. Furthermore, the performance of MP Biomedicals enzyme-linked immunosorbent assay HEV and the HEV-Ab enzyme-linked immunosorbent assay from Axiom was analyzed in comparison with the recomWell/recomLine test system using a defined subset of sera. RESULTS: In children, the overall prevalence of antibodies was 1.0%. Starting with the 5- to 6-year olds, there was a significant increase of HEV seroprevalence to 1.5% in the group of the 15- to 17-year olds. There was no statistically significant difference between seroprevalences of boys (1.2%) and girls (0.7%). Passively transmitted maternal antibodies persisted for about 3 months. The strength of agreement between the recomWell/recomLine system and the ELISAs from MP Biomedicals or Axiom varied between 0.229 and 0.542 and was calculated at 0.111 when the assays from MP Biomedicals and Axiom were compared. CONCLUSIONS: In Germany, only a very small number of HEV infections occur in children. Many infections occur in adults with increasing age. Because of considerable variations in assay accordance, there is an urgent need for standardization of HEV serology.

Mechanical damage to Gram-negative bacteria by surface plating with the Drigalski-spatula technique.

Colony counting by spreading bacterial suspensions on plating media by various techniques is of general concern. Comparative studies between hand plating (Drigalski-spatula technique) for different time intervals and spiral plating resulted in significant differences in colony counts. Lower counts of Gram-negative bacteria were obtained by using hand plating for more than 10s, compared with short time hand plating (5s) or spiral plating. Colony counting of Gram-positive bacteria showed no differences between both techniques. Further characterisation of Escherichia coli cells spread with the Drigalski-spatula technique by electron microscopy revealed a large number of damaged cells compared to control samples. The data clearly shows that the mechanical forces during hand plating are sufficient to damage E. coli cells.

Post-pandemic seroprevalence of pandemic influenza A (H1N1) 2009 infection (swine flu) among children <18 years in Germany.

BACKGROUND: We determined antibodies to the pandemic influenza A (H1N1) 2009 virus in children to assess: the incidence of (H1N1) 2009 infections in the 2009/2010 season in Germany, the proportion of subclinical infections and to compare titers in vaccinated and infected children. METHODOLOGY/PRINCIPAL FINDINGS: Eight pediatric hospitals distributed over Germany prospectively provided sera from in- or outpatients aged 1 to 17 years from April 1(st) to July 31(st) 2010. Vaccination history, recall of infections and sociodemographic factors were ascertained. Antibody titers were measured with a sensitive and specific in-house hemagglutination inhibition test (HIT) and compared to age-matched sera collected during 6 months before the onset of the pandemic in Germany. We analyzed 1420 post-pandemic and 300 pre-pandemic sera. Among unvaccinated children aged 1-4 and 5-17 years the prevalence of HI titers (≥1∶10) was 27.1% (95% CI: 23.5-31.3) and 53.5% (95% CI: 50.9-56.2) compared to 1.7% and 5.5%, respectively, for pre-pandemic sera, accounting for a serologically determined incidence of influenza A (H1N1) 2009 during the season 2009/2010 of 25,4% (95% CI : 19.3-30.5) in children aged 1-4 years and 48.0% (95% CI: 42.6-52.0) in 5-17 year old children. Of children with HI titers ≥1∶10, 25.5% (95% CI: 22.5-28.8) reported no history of any infectious disease since June 2009. Among vaccinated children, 92% (95%-CI: 87.0-96.6) of the 5-17 year old but only 47.8% (95%-CI: 33.5-66.5) of the 1-4 year old children exhibited HI titers against influenza A virus (H1N1) 2009. CONCLUSION: Serologically determined incidence of influenza A (H1N1) 2009 infections in children indicates high infection rates with older children (5-17 years) infected twice as often as younger children. In about a quarter of the children with HI titers after the season 2009/2010 subclinical infections must be assumed. Low HI titers in young children after vaccination with the AS03(B)-adjuvanted split virion vaccine need further scrutiny.