Yelda A. Leal

Antibody-Based Detection Tests for the Diagnosis of Helicobacter pylori Infection in Children: A Meta-Analysis

Background Numerous serologic tests are available for the diagnosis of H. pylori infection in children. Common designs of antibody-based detection tests are ELISA and Western Blot (WB). For developing countries with limited laboratory resources and access, ELISA would be the preferred method because of its simplicity, lower cost and speed. Although in adults ELISA has proven to be highly accurate in diagnosing H. pylori infection; in children, it has shown variable accuracy. Methods/Findings We conducted a systematic review and meta-analysis to assess the accuracy of antibody-based detection tests for the diagnosis of H. pylori infection in children. Selection criteria included participation of at least 30 children and the use of a gold standard for H. pylori diagnosis. In a comprehensive search we identified 68 studies. Subgroup analyses were carried out by technique, immunoglobulin class, and source of test (commercial and in-house). The results demonstrated: 1) WB tests showed high overall performance, sensitivity 91.3% (95% CI, 88.9–93.3), specificity 89% (95% CI, 85.7–91.9), LR+ 8.2 (95% CI, 5.1–13.3), LR− 0.06 (95% CI, 0.02–0.16), DOR 158.8 (95% CI, 57.8–435.8); 2) ELISA-IgG assays showed low sensitivity 79.2% (95% CI, 77.3–81.0) and high specificity (92.4%, 95% CI, 91.6–93.3); 3) ELISA commercial tests varied widely in performance (test for heterogeneity p<0.0001); and 4) In-house ELISA with whole-cell antigen tests showed the highest overall performance: sensitivity 94% (95% CI, 90.2–96.7), specificity 96.4% (95% CI, 94.2–97.9), LR+ 19.9 (95% CI, 7.9–49.8), LR− 0.08 (95% CI, 0.04–0.15) DOR 292.8 (95% CI, 101.8–841.7). Conclusions/Significance WB test and in-house ELISA with whole-cell antigen tests are the most reliable tests for the diagnosis of H. pylori infection in children. Antigens obtained from local strains of the community could partially explain the good overall accuracy of the in-house ELISA. Because of its cost and technical demands, in-house ELISA might be more suitable for use in developing countries.

13C-Urea Breath Test for the Diagnosis of Helicobacter pylori Infection in Children: A Systematic Review and Meta-Analysis

Background:  The 13C‐urea breath test (13C‐UBT) is a safe, noninvasive and reliable method for diagnosing H. pylori infection in adults. However, the test has shown variable accuracy in the pediatric population, especially in young children. We aimed to carry out a systematic review and meta‐analysis to evaluate the performance of the 13C‐UBT diagnostic test for H. pylori infection in children.

Utility of Stool Sample-based Tests for the Diagnosis of Helicobacter pylori Infection in Children

Objective:Helicobacter pylori antigen or DNA in stool are meant to detect the bacteria; however, in children the colonization of the gastric mucosa by H pylori is usually weak and fecal excretion of antigen or DNA varies considerably, challenging the utility of these tests in this age group. The aim of the present study was to carry out a systematic review and meta-analysis to evaluate the performance of stool H pylori DNA and antigen tests for the diagnosis of infection in children. Methods:We conducted a systematic review and meta-analysis to assess the accuracy of stool tests for diagnosis of H pylori infection in children. We searched PubMed, EMBASE, and LILACS databases. Selection criteria included participation of at least 30 children and the use of a criterion standard for H pylori diagnosis. In a comprehensive search, we identified 48 studies. Results:Regarding antigen-detection tests, enzyme-linked immunosorbent assay (ELISA) monoclonal antibodies showed the best performance, with sensitivity and specificity of 97%, positive likelihood ratio (LR+) of 29.9, and negative likelihood ratio (LR−) of 0.03. ELISA polyclonal antibodies had sensitivity of 92%, specificity of 93%, LR+ of 16.2, LR− of 0.09, and high heterogeneity (P < 0.0001). One-step monoclonal antibody tests demonstrated sensitivity of 88%, specificity of 93%, LR+ of 10.6, and LR− of 0.11. For DNA detection, polymerase chain reaction–based test showed sensitivity of 80.8%, specificity of 98%, LR+ of 17.1, and LR− of 0.18. Conclusions:Detection of H pylori antigen in stools with ELISA monoclonal antibodies is a noninvasive efficient test for diagnosis of infection in children. One-step tests showed low accuracy and more studies are needed to obtain a useful office-based screening test. The available molecular tests are still unreliable.

Risk factors and prognosis for neonatal sepsis in southeastern Mexico: analysis of a four-year historic cohort follow-up.

BackgroundNeonatal sepsis is a worldwide public health issue in which, depending on the studied population, marked variations concerning its risk and prognostic factors have been reported. The aim of this study was to assess risk and prognostic factors for neonatal sepsis prevailing at a medical unit in southeastern Mexico. Thus, we used a historic cohort design to assess the association between a series of neonates and their mothers, in addition to hospital evolution features and the risk and prognosis of neonatal sepsis (defined by Pediatric Sepsis Consensus [PSC] criteria) in 11,790 newborns consecutively admitted to a Neonatology Service in Mérida, Mexico, between 2004 and 2007.ResultsSepsis was found in 514 of 11,790 (4.3%) newborns; 387 of these cases were categorized as early-onset (<72 h) (75.3%) and 127, as late-onset (>72 h) (24.7%). After logistic regression, risk factors for sepsis included the following: low birth weight; prematurity; abnormal amniotic fluid; premature membrane rupture (PMR) at >24 h; respiratory complications, and the requirement of assisted ventilation, O2 Inspiration fraction (IF) >60%, or a surgical procedure. Some of these factors were differentially associated with early- or late-onset neonatal sepsis. The overall mortality rate of sepsis was 9.5%. A marked difference in the mortality rate was found between early- and late-onset sepsis (p >0.0001). After Cox analysis, factors associated with mortality in newborns with sepsis comprised the following: prematurity; low birth weight; low Apgar score; perinatal asphyxia, and the requirement of any invasive medical or surgical procedure.ConclusionsThe incidence of neonatal sepsis in southeastern Mexico was 4.3%. A different risk and prognostic profile between early- and late-onset neonatal sepsis was found.

No association between Epstein-Barr Virus and Mouse Mammary Tumor Virus with breast cancer in Mexican women.

Breast cancer is the most frequent malignancy affecting women worldwide. It has been suggested that infection by Epstein Barr Virus (EBV), Mouse Mammary Tumor Virus or a similar virus, MMTV-like virus (MMTV-LV), play a role in the etiology of the disease. However, studies looking at the presence of these viruses in breast cancer have produced conflicting results, and this possible association remains controversial. Here, we used polymerase chain reaction assay to screen specific sequences of EBV and MMTV-LV in 86 tumor and 65 adjacent tissues from Mexican women with breast cancer. Neither tumor samples nor adjacent tissue were positive for either virus in a first round PCR and only 4 tumor samples were EBV positive by a more sensitive nested PCR. Considering the studys statistical power, these results do not support the involvement of EBV and MMTV-LV in the etiology of breast cancer.

Evidence of Epstein-Barr Virus Association with Gastric Cancer and Non-Atrophic Gastritis

Different lines of evidence support an association between Epstein-Barr virus (EBV) and gastric cancer (GC). The main understood risk factor to develop GC is infection by Helicobacter pylori (H. pylori), which triggers a local inflammatory response critical for progression from gastritis to GC. The role of EBV in early inflammatory gastric lesions has been poorly studied. A recent study proposed a cutoff value of 2000 EBV particles to identify patients with increased chances of infection of the gastric epithelium, which may favor the inflammatory process. To better understand the role of EBV in cancer progression, we analyzed 75 samples of GC, 147 control samples of non-tumor gastric tissue derived from GC patients and 75 biopsies from patients with non-atrophic gastritis (NAG). A first-round PCR was used for EBV detection in tumor and non-tumor controls and a more sensitive nested PCR for gastritis samples; both PCRs had lower detection limits above the proposed cutoff value. With this strategy 10.67% of GC, 1.3% of non-tumor controls and 8% of gastritis samples were found positive. An EBER1 in situ hybridization showed EBV infection of epithelial cells in GC and in a third of NAG samples, while in the other NAGs infection was restricted to the mononuclear cell infiltrate. EBV-positive GCs were enriched in lace and cribriform patterns, while these rare patterns were not observed in EBV negative samples. Our results support a role for EBV in GC and early precursor lesions, either as directly oncogenic infecting epithelial cells or indirectly as an inflammatory trigger.

An amebic anti-inflammatory peptide down-regulates ex vivo IL-1β expression in patients with rheumatoid arthritis

UNLABELLED The monocyte locomotion inhibitory factor (MLIF) is a heat-stable pentapeptide produced by Entamoeba histolytica in culture. This factor displays several anti-inflammatory properties (i.e., inhibition of locomotion and respiratory burst in monocytes, reduction of skin hypersensitivity and delay of mononuclear cells in human Rebuck skin windows) with inhibition of adhesion molecules, chemokines, and other genes including interleukin-1β (IL-1β). In animal models, it reduces carragenin-induced inflammation and delays the inflammatory process in murine collagen-induced arthritis (CIA). OBJECTIVES To test, in vitro, the anti-inflammatory capacity of MLIF on a promonocytic human cell line (U-937) cells and peripheral blood mononuclear cells (PBMC) from healthy subjects and from patients with rheumatoid arthritis (RA). MATERIAL AND METHODS IL-1β gene expression was evaluated in cell cultures either in the presence of MLIF, lipopolysaccharide (LPS), or both. Relative gene expression and immunoreactivity of IL-1β were assayed in cells and supernatants, respectively. RESULTS Amebic peptide was able to down-regulate LPS-induced expression of IL-1β, in U-937 cells without a detectable effect upon the bioavailability of the cytokine. In similar culture conditions, MLIF was capable to down-regulate baseline and LPS-induced expression of IL-β only in PBMC from patients with RA. Peptide effect on immunoreactivity of IL-1β was not statistically significant. CONCLUSIONS MLIF exerts, in primed cells, exquisite anti-inflammatory properties that deserve to be explored mechanistically.

Cytokine profile as diagnostic and prognostic factor in neonatal sepsis

Abstract Antecedents: The serum levels of some cytokines can be useful in the diagnosis of neonatal sepsis; the prognostic value of a cytokine profile has not, to our knowledge, been explored in this disease. Objective: The objective of this study is to evaluate the diagnostic value of the serum levels of cytokines IL-1, -2, -4, -5, -6, -7, -8, -10, -12, -13, and -17, TNF, IFNγ, G-CSF, GM-CSF, MCP1, and MIP1β in neonates with high risk of developing sepsis. Methods: Sepsis was evaluated in 96 high-risk neonates. We assessed cytokine levels on hospital admission and during or not during sepsis. Results: Fifty (52%) presented sepsis (26 early and 24 late). Sepsis was associated with high levels of IL-6, IL-10, G-CSF, and MCP1 and low levels of IFNγ, early sepsis with high levels of IL-6 and G-CSF, severe sepsis with high levels of IL-6 and IL-10, while deaths or sequelae was associated with low levels of IL-4, IL-12, IFNγ, and high levels of GM-CSF. IL-6 values of ≥40.1 pg/mL were associated with the development of any type of sepsis (relative risk [RR]: 1.70; 95% confidence interval [95% CI]: 1.18–2.24; p = .01), while IL-6 values of ≥44.9 pg/mL were associated with early sepsis (RR: 1.29; 95% CI: 1.29–4.56; p = .01). Conclusion: In neonates with high risk for the development of sepsis, there is an association between levels of IL-6, IL-10, and G-SCF and the disease development/outcome.