Frequency of infection with Helicobacter pylori isolates of different antimicrobial profiles in children and adolescents: A preliminary study

BACKGROUND

Helicobacter pylori (H. pylori) infection can occur as a mixed infection caused by several strains of H. pylori.

OBJECTIVES

The aim of the study was to determine the frequency of colonization of the gastric mucosa by strains of H. pylori with different susceptibility to antimicrobial agents.

MATERIAL AND METHODS

The study was carried out on gastric biopsies taken from 54 previously untreated Polish children and adolescents. Of the 15 positive cultures, from each primary medium, 6 single H. pylori colonies were isolated, making a total of 90 isolates, and the susceptibility to metronidazole (MZ), amoxicillin (AC) and clarithromycin (CH) was determined by E-test method. The presence of the cagA gene and vacA alleles (s1, s2, m1, m2) was determined by PCR.

RESULTS

Positive culture for H. pylori was noted in 15/54 (27.7%) of patients. All H. pylori isolates were susceptible to AC, 27.8% were resistant to MZ and 38.9% to CH. The results showed 7/15 (46.7%) of children were infected with H. pylori strains with antibiotic heteroresistance, resistant to CH (5/15, 33.3%) and to MZ (2/15, 13.3%). The cagA + vacA s1/m2 combination was predominant genotype among detected H. pylori strains. The isolates possessing different antimicrobial susceptibility profiles in the same patient were identified.

CONCLUSIONS

Microbiological analyses confirmed the presence of isolates possessing different antimicrobial susceptibility profiles in 47% of examined children with H. pylori infection. Different antimicrobial susceptibility profiles of H. pylori isolates detected in the same patient may influence the success of eradication therapy.

TLR engagement prior to virus infection influences MHC-I antigen presentation in an epitope-dependent manner as a result of nitric oxide release

Microorganisms contain PAMPs that can interact with different TLR-Ls. Cooperative signals from these receptors may modify innate and adaptive immune responses to invading pathogens. Therefore, a better understanding of the role TLRs play in initiating host defense during infections requires assessing the influence of multiple TLR engagement on pAPC activation and antigen presentation. In this study, we investigated the effects of combined TLR2, TLR3, or TLR4 engagement on DC activation and the presentation of LCMV antigens focusing on the major epitopes derived from NP and GP proteins encoded by the virus. Our results demonstrate that combined TLR ligation affected antigen presentation of NP(205-212), GP(33-41), and GP(276-286), but not NP(396-404). The altered antigen presentation was associated with changes in proteasomal activities and NO production as a result of TLR engagement. Taken together, the data demonstrate that combined TLR ligation could result in changes of innate effectors that may directly influence the adaptive immune response.

Activation of the NF-κB system in peripheral blood leukocytes from patients with chronic heart failure

AIM

To evaluate the activation of transcriptional nuclear factor kappa-B (NF-kappaB) in peripheral blood leukocytes (PBL) from patients with chronic heart failure (CHF). In vitro experiments were used to elucidate the role of lipopolysaccharide (LPS) as a stimulus for the NF-kappaB system in PBL.

METHODS AND RESULTS

We examined 46 CHF patients (age: 62+/-1 years, LVEF: 31+/-1%, NYHA class: 2.7+/-0.1), 11 coronary artery disease (CAD) patients without CHF, and 13 healthy young subjects. The immunocytochemical localisation of NF-kappaB in PBL was assessed using a polyclonal rabbit IgG anti-c-Rel-subunit antibody. NF-kappaB activation was expressed as the percentage of PBL nuclei stained positively for c-Rel (NF-kappaB+cell). PBL from healthy controls were exposed in vitro to the following concentrations of LPS from Escherichia coli (strain O111:B4): 0.1, 10 and 5000 ng/mL. CHF patients demonstrated the highest NF-kappaB activation in PBL (NF-kappaB+cells [%]: 37.1+/-1.5) as compared to CAD patients (29.1+/-3.0%) and controls (12.6+/-1.5%) (all p<0.05). There were three main clinical determinants of NF-kappaB activation in PBL from CHF patients: peak oxygen consumption (r=0.53, p=0.025), presence of peripheral oedema (r=0.37, p<0.05) and serum C-reactive protein (r=0.40, p=0.02). In PBL from healthy subjects, LPS at all concentrations increased NF-kappaB activity towards the pattern detected in CHF.

CONCLUSIONS

The NF-kappaB system is highly overactive in PBL from CHF patients. LPS at low concentrations in peripheral blood may be involved in NF-kappaB activation in PBL, and is a potential target for future therapeutic applications.

Outcome and prognostic factors in advanced Hodgkin's disease treated with high-dose chemotherapy and autologous stem cell transplantation: a study of 341 patients

BACKGROUND

The reported probability of survival of patients with Hodgkin's disease (HD) following high-dose chemotherapy with autologous stem cell transplantation (HDC/ASCT) is 35-65% at 5 years. The Polish Lymphoma Research Group investigated retrospectively prognostic factors for overall survival (OS) and event-free survival (EFS), and the risk of secondary malignancies in a large series of patients who underwent HDC/ASCT.

PATIENTS AND METHODS

The data of 341 consecutive patients treated in 10 centers from 1990 to 2002 were collected and analyzed.

RESULTS

The actuarial 5-year OS and EFS were 64% [95% confidence interval (CI) 57% to 71%] and 45% (95% CI 39% to 51%), respectively. In the multivariate model, unfavorable prognostic factors for EFS were less than partial response at the time of ASCT [relative risk (RR), 2.92 (95% CI 1.68-5.08); P<0.001] and three or more previous chemotherapy lines (RR, 2.16; 95% CI 1.42-3.30; P<0.001). These two factors were also associated with unfavorable OS (RR, 3.32; 95% CI 1.90-5.79; P<0.001 and RR, 2.34, 95% CI 1.51-3.64; P<0.001). Five-year cumulative risk of secondary malignancy was 8.4% (95% CI 2% to 13%) and the only identified risk factor was splenectomy (P=0.02).

CONCLUSIONS

HDC/ASCT should be considered early in the course of disease for patients with a response after standard therapy.