Natural and hybrid immunity after SARS-CoV-2 infection in children and adolescents.

PURPOSE: In contrast to adults, immune protection against SARS-CoV-2 in children and adolescents with natural or hybrid immunity is still poorly understood. The aim of this study was to analyze different immune compartments in different age groups and whether humoral immune reactions correlate with a cellular immune response. METHODS: 72 children and adolescents with a preceding SARS-CoV-2 infection were recruited. 37 were vaccinated with an RNA vaccine (BNT162b2). Humoral immunity was analyzed 3-26 months (median 10 months) after infection by measuring Spike protein (S), nucleocapsid (NCP), and neutralizing antibodies (nAB). Cellular immunity was analyzed using a SARS-CoV-2-specific interferon-γ release assay (IGRA). RESULTS: All children and adolescents had S antibodies; titers were higher in those with hybrid immunity (14,900 BAU/ml vs. 2118 BAU/ml). NCP antibodies were detectable in > 90%. Neutralizing antibodies (nAB) were more frequently detected (90%) with higher titers (1914 RLU) in adolescents with hybrid immunity than in children with natural immunity (62.5%, 476 RLU). Children with natural immunity were less likely to have reactive IGRAs (43.8%) than adolescents with hybrid immunity (85%). The amount of interferon-γ released by T cells was comparable in natural and hybrid immunity. CONCLUSION: Spike antibodies are the most reliable markers to monitor an immune reaction against SARS-CoV-2. High antibody titers of spike antibodies and nAB correlated with cellular immunity, a phenomenon found only in adolescents with hybrid immunity. Hybrid immunity is associated with markedly higher antibody titers and a higher probability of a cellular immune response than a natural immunity.

Pathogen-specific antibody profiles in patients with severe systemic infections.

Infections are often caused by pathobionts, endogenous bacteria that belong to the microbiota. Trauma and surgical intervention can allow bacteria to overcome host defences, ultimately leading to sepsis if left untreated. One of the main defence strategies of the immune system is the production of highly specific antibodies. In the present proof-of-concept study, plasma antibodies against 9 major pathogens were measured in sepsis patients, as an example of severe systemic infections. The binding of plasma antibodies to bacterial extracellular proteins was quantified using a semi-automated immunoblot assay. Comparison of the pathogen-specific antibody levels before and after infection showed an increase in plasma IgG in 20 out of 37 tested patients. This host-directed approach extended the results of pathogen-oriented microbiological and PCR diagnostics: a specific antibody response to additional bacteria was frequently observed, indicating unrecognised poly-microbial invasion. This might explain some cases of failed, seemingly targeted antibiotic treatment.

Kappa free light chains in cerebrospinal fluid to identify patients with oligoclonal bands.

BACKGROUND AND PURPOSE: The gold standard for detection of intrathecal immunoglobulin synthesis is the measurement of oligoclonal bands (OCB). In the diagnosis of multiple sclerosis, the kappa free light chains (KFLC) index has a similar sensitivity and specificity as OCB. This study investigated whether determination of the KFLC index could be used to predict the presence of OCB. METHODS: The KFLC index was determined prospectively from 295 paired serum and cerebrospinal fluid samples. KFLC were determined by nephelometry using the N Latex FLC kappa kit (Siemens Healthcare Diagnostics Products GmbH) on the BN Prospec analyzer (Siemens Healthcare Diagnostics Products GmbH) (cohort I). A cut-off value was determined using receiver operating characteristic analysis in relation to OCB positivity. These results were validated prospectively in 96 samples (cohort II) as well as retrospectively in samples of 46 patients known to be OCB positive (cohort III). We also compared the agreement of two commercially available nephelometric KFLC assays. RESULTS: In cohort I, a KFLC index of 3.61 yielded 100% sensitivity and 88% specificity. Prospective validation of this cut-off value in cohort II showed 92% sensitivity and 96% specificity. In cohort III, a sensitivity of 93% was achieved. Comparison of Siemens and Binding Site (Birmingham, UK) assays revealed good agreement (r2  = 0.86). CONCLUSIONS: The KFLC index with a cut-off value of 3.61 had high diagnostic accuracy to predict immunoglobulin G synthesis via OCB analysis. Determination of the KFLC index provided a quantitative parameter that could be used as an initial diagnostic step in inflammatory central nervous system disorders before measuring OCB.

Tolerance of platelet concentrates treated with UVC-light only for pathogen reduction--a phase I clinical trial.

BACKGROUND: The THERAFLEX UV-Platelets pathogen reduction system for platelet concentrates (PCs) operates with ultraviolet C light (UVC; 254 nm) only without addition of photosensitizers. This phase I study evaluated safety and tolerability of autologous UVC-irradiated PCs in healthy volunteers. METHODS: Eleven volunteers underwent two single (series 1 and 2) and one double apheresis (series 3). PCs were treated with UVC, stored for 48 h and retransfused in a dose-escalation scheme: 12·5, 25% and 50% of a PC (series 1); one complete PC (series 2); two PCs (series 3). Platelet counts, fibrinogen, activated partial thromboplastin time, prothrombin time, D-dimer, standard haematology, temperature, heart rate, blood pressure and clinical chemistry parameters were measured. One- and 24-h corrected count increments were determined in series 2 and 3. Platelet-specific antibodies were assessed before and at the end of the study. RESULTS: Neither adverse reactions related to transfusions nor antibodies against UVC-treated platelets were observed. Corrected count increments did not differ between series 2 and 3. CONCLUSIONS: Repeated transfusions of autologous UVC-treated PCs were well tolerated and did not induce antibody responses in all volunteers studied. EudraCT No. 2010-023404-26.

Genome-wide association analysis of coffee drinking suggests association with CYP1A1/CYP1A2 and NRCAM.

Coffee consumption is a model for addictive behavior. We performed a meta-analysis of genome-wide association studies (GWASs) on coffee intake from 8 Caucasian cohorts (N=18 176) and sought replication of our top findings in a further 7929 individuals. We also performed a gene expression analysis treating different cell lines with caffeine. Genome-wide significant association was observed for two single-nucleotide polymorphisms (SNPs) in the 15q24 region. The two SNPs rs2470893 and rs2472297 (P-values=1.6 × 10(-11) and 2.7 × 10(-11)), which were also in strong linkage disequilibrium (r(2)=0.7) with each other, lie in the 23-kb long commonly shared 5' flanking region between CYP1A1 and CYP1A2 genes. CYP1A1 was found to be downregulated in lymphoblastoid cell lines treated with caffeine. CYP1A1 is known to metabolize polycyclic aromatic hydrocarbons, which are important constituents of coffee, whereas CYP1A2 is involved in the primary metabolism of caffeine. Significant evidence of association was also detected at rs382140 (P-value=3.9 × 10(-09)) near NRCAM-a gene implicated in vulnerability to addiction, and at another independent hit rs6495122 (P-value=7.1 × 10(-09))-an SNP associated with blood pressure-in the 15q24 region near the gene ULK3, in the meta-analysis of discovery and replication cohorts. Our results from GWASs and expression analysis also strongly implicate CAB39L in coffee drinking. Pathway analysis of differentially expressed genes revealed significantly enriched ubiquitin proteasome (P-value=2.2 × 10(-05)) and Parkinson's disease pathways (P-value=3.6 × 10(-05)).

Do pneumatic tube transport systems transmit potential pathogens? A hygienic risk assessment in a university hospital.

BACKGROUND: Prompted by an outbreak of vancomycin-resistant enterococci (VRE) in a medical facility, this study examined a pneumatic tube transport system (PTS) as a potential transmission channel. METHOD: Samples from the receiving station and entry racks were gathered via smear technique. Sponges used for PTS decontamination were soaked with 0.89% NaCl and transported through the channel. Micro-organisms were recovered from the tubes and cleaning sponges using a wash-away technique. Air sampling was performed at the receiving station in order to detect any airborne contamination. Tubes were artificially inoculated with Escherichia coli K12 NCTC 10538 and Staphylococcus epidermidis DSM 20044 and sent through the PTS to investigate channel contamination. RESULTS: No pathogens were detected in effluent air from the PTS or in tubes during routine operation. Entry racks for the test tubes were contaminated with coagulase-negative staphylococci (CNS), aerobic bacilli, moulds and vancomycin-susceptible Enterococcus faecium. E. coli proved to be unsuitable for detecting bacterial transmission by the PTS due to low persistence, but S. epidermidis was more resilient. After sending contaminated test tubes through the PTS, levels of S. epidermidis only decreased marginally. Subsequently, sponges soaked with disinfectant solution were put through the system and these eliminated S. epidermidis completely from the first attempt. DISCUSSION: Routine hygienic maintenance of the PTS makes pathogen transmission highly unlikely, although entry racks should be disinfected regularly. Any involvement of the PTS in the VRE outbreak at the study institution was unlikely.

Effect of Periodontal Treatment on HbA1c among Patients with Prediabetes.

Evidence is limited regarding whether periodontal treatment improves hemoglobin A1c (HbA1c) among people with prediabetes and periodontal disease, and it is unknown whether improvement of metabolic status persists >3 mo. In an exploratory post hoc analysis of the multicenter randomized controlled trial "Antibiotika und Parodontitis" (Antibiotics and Periodontitis)-a prospective, stratified, double-blind study-we assessed whether nonsurgical periodontal treatment with or without an adjunctive systemic antibiotic treatment affects HbA1c and high-sensitivity C-reactive protein (hsCRP) levels among periodontitis patients with normal HbA1c (≤5.7%, n = 218), prediabetes (5.7% < HbA1c < 6.5%, n = 101), or unknown diabetes (HbA1c ≥ 6.5%, n = 8) over a period of 27.5 mo. Nonsurgical periodontal treatment reduced mean pocket probing depth by >1 mm in both groups. In the normal HbA1c group, HbA1c values remained unchanged at 5.0% (95% CI, 4.9% to 6.1%) during the observation period. Among periodontitis patients with prediabetes, HbA1c decreased from 5.9% (95% CI, 5.9% to 6.0%) to 5.4% (95% CI, 5.3% to 5.5%) at 15.5 mo and increased to 5.6% (95% CI, 5.4% to 5.7%) after 27.5 mo. At 27.5 mo, 46% of periodontitis patients with prediabetes had normal HbA1c levels, whereas 47.9% remained unchanged and 6.3% progressed to diabetes. Median hsCRP values were reduced in the normal HbA1c and prediabetes groups from 1.2 and 1.4 mg/L to 0.7 and 0.7 mg/L, respectively. Nonsurgical periodontal treatment may improve blood glucose values among periodontitis patients with prediabetes (ClinicalTrials.gov NCT00707369).

Does periodontitis affect diabetes incidence and haemoglobin A1c change? An 11-year follow-up study.

AIM: As periodontitis may contribute to the pathogenesis of diabetes, the effects of periodontitis on diabetes incidence and HbA1c change was quantified in a prospective cohort. METHODS: Data from an 11-year follow-up of the Study of Health in Pomerania were analyzed to evaluate the effects of periodontitis on incident diabetes and long-term HbA1c changes in 2047 subjects aged 20-81years. Diabetes was based on self-reported physician diagnoses, antidiabetic medication use, or HbA1c≥6.5% or non-fasting blood glucose levels ≥11.1mmol/L. To assess periodontal status, periodontal pockets were probed, and their depth and clinical attachment levels measured. For both measures, means and percentages of sites≥3mm were calculated. In addition, all probing depths≥4mm were summed (cumulative probing depth). Modified Poisson and multivariable linear models were applied, adjusted for age, gender, highest level of general education, marital status, waist circumference, physical activity, smoking status and follow-up time. RESULTS: Over a mean follow-up period of 11.1years, 207 subjects developed diabetes. Baseline mean clinical attachment levels (CAL) and probing depths (PPD) were not significantly associated with either diabetes incidence [mean CALs, fourth quartile, incidence rate ratio=0.819, 95% confidence interval (CI): 0.489-1.370; P=0.446] or long-term changes in HbA1c (mean CAL, fourth quartile, ß=-0.086, 95% CI: -0.187, -0.016; P=0.098). Sensitivity analyses using alternative exposure definitions confirmed these results. CONCLUSION: Contrary to the currently available literature, no convincing evidence was found of any potential association between periodontitis and diabetes incidence or HbA1c change.

Exome Variant Analysis of Chronic Periodontitis in 2 Large Cohort Studies.

Periodontitis is characterized by inflammation of the gingival tissue. The main risk factors are socioeconomic factors, sex, age, smoking, and diabetes, but periodontal disease has also a genetic background. Previous genome-wide association studies failed to reveal genome-wide significant associations of single common single-nucleotide polymorphisms with chronic periodontitis. Using the Illumina ExomeChip data of 6,576 participants of the German population-based cohort studies Study of Health in Pomerania (SHIP) and SHIP-Trend, the authors performed single variant and also gene-based association studies of rare and common exonic variations on different periodontal case definitions. Although our study comprised the largest sample size to date to assess genetic predisposition for chronic periodontitis, the authors found no significant association. This study emphasizes that for chronic periodontitis, large sample sizes will be necessary to find genetic associations, even when examining rare genetic variants.

Do Genetic Markers of Inflammation Modify the Relationship between Periodontitis and Nonalcoholic Fatty Liver Disease? Findings from the SHIP Study.

An association between periodontitis and nonalcoholic fatty liver disease (NAFLD) has been reported by experimental animal and epidemiologic studies. This study investigated whether circulating levels of serum C-reactive protein (CRP) and a weighted genetic CRP score representing markers of inflammatory burden modify the association between periodontitis and NAFLD. Data came from 2,481 participants of the Study of Health in Pomerania who attended baseline examination that occurred between 1997 and 2001. Periodontitis was defined as the percentage of sites (0%, <30%, ≥30%) with probing pocket depth (PD) ≥4 mm, and NAFLD status was determined using liver ultrasound assessment. Serum CRP levels were assayed at a central laboratory, and single-nucleotide polymorphisms previously identified through genome-wide association studies as robustly associated with serum CRP were combined into a weighted genetic CRP score (wGSCRP). Logistic regression models estimated the association between periodontitis and NAFLD within strata of serum CRP and separately within strata of the wGSCRP. The prevalence of NAFLD was 26.4% (95% confidence interval [CI], 24.6, 28.1) while 17.8% (95% CI, 16.0-19.6) had ≥30% of sites with PD ≥4 mm. Whereas the wGSCRP was not a modifier ( Pinteraction = 0.8) on the multiplicative scale, serum CRP modified the relationship between periodontitis and NAFLD ( Pinteraction = 0.01). The covariate-adjusted prevalence odds ratio of NAFLD comparing participants with ≥30% of sites with PD ≥4 mm to those with no site affected was 2.39 (95% CI, 1.32-4.31) among participants with serum CRP <1 mg/L. The corresponding estimate was 0.97 (95% CI, 0.57-1.66) for participants with serum CRP levels of 1 to 3 mg/L and 1.12 (95% CI, 0.65-1.93) for participants with serum CRP >3 mg/L. Periodontitis was positively associated with higher prevalence odds of NAFLD, and this relationship was modified by serum CRP levels.

Impaired expression of the plastidic ferrochelatase by antisense RNA synthesis leads to a necrotic phenotype of transformed tobacco plants.

Protoporphyrin IX is the last common intermediate of tetrapyrrole biosynthesis. The chelation of a Mg2+ ion by magnesium chelatase and of a ferrous ion by ferrochelatase directs protoporphyrin IX towards the formation of chlorophyll and heme, respectively. A full length cDNA clone encoding a ferrochelatase was identified from a Nicotiana tabacum cDNA library. The encoded protein consists of 497 amino acid residues with a molecular weight of 55.4 kDa. In vitro import of the protein into chloroplasts and its location in stroma and thylakoids confirm its close relationship to the previously described Arabidopsis thaliana plastid-located ferrochelatase (FeChII). A 1700-bp tobacco FeCh cDNA sequence was expressed in Nicotiana tabacum cv. Samsun NN under the control of the CaMV 35S promoter in antisense orientation allowing investigation into the consequences of selective reduction of the plastidic ferrochelatase activity for protoporphyrin IX channeling in chloroplasts and for interactions between plastidic and mitochondrial heme synthesis. Leaves of several transformants showed a reduced chlorophyll content and, during development, a light intensity-dependent formation of necrotic leaf lesions. In comparison with wild-type plants the total ferrochelatase activity was decreased in transgenic lines leading to an accumulation of photosensitizing protoporphyrin IX. Ferrochelatase activity was reduced only in plastids but not in mitochondria of transgenic plants. By means of the specifically diminished ferrochelatase activity consequences of the selective inhibition of protoheme formation for the intracellular supply of heme can be investigated in the future.