Presence of rhinovirus in the respiratory tract of adolescents and young adults with asthma without symptoms of infection.

BACKGROUND: Viral respiratory infections have been associated with up to 80% of wheezing episodes and asthma exacerbations. However, studies on the role of these viruses in asthmatic patients in the interval between exacerbations are sparse. This study aimed to determine the presence of respiratory viruses, without symptoms of infection, in the airways of young asthmatics as compared to healthy controls. MATERIAL AND METHODS: Patients 10-35 years of age with stable asthma and a group of healthy controls were analyzed regarding the presence of RNA from common respiratory viruses in nasopharyngeal aspirates by PCR. Self-reported asthma control and quality of life, fraction of exhaled nitric oxide (FeNO), spirometry, and bronchial responsiveness to methacholine were recorded. Blood samples were collected to assess IgE sensitisation and eosinophil cationic protein (ECP) levels. RESULTS: In 354 patients with asthma and 108 healthy controls, human rhinovirus (HRV) was the only virus detected (4.5% of asthmatics vs. 0.9% of controls; p = 0.08). HRV(+) asthma patients had a higher degree of aeroallergen IgE sensitisation (median 37.7 vs. 10.4 kUA/L, p = 0.04), and a tendency for higher levels of serum ECP (median 17.2 vs. 12.6 µg/L, p = 0.07), as compared to their HRV(-) counterparts. CONCLUSIONS: Absence of symptoms of respiratory tract infection notwithstanding, HRV seems to be more prevalent in the airways of adolescents and young adults with asthma and a high degree of aeroallergen IgE sensitisation than in controls. The presence of HRV seems also to be related to systemic eosinophilic inflammation despite ongoing treatment with inhaled corticosteroids.

Metagenomic analysis of bloodstream infections in patients with acute leukemia and therapy-induced neutropenia.

Leukemic patients are often immunocompromised due to underlying conditions, comorbidities and the effects of chemotherapy, and thus at risk for developing systemic infections. Bloodstream infection (BSI) is a severe complication in neutropenic patients, and is associated with increased mortality. BSI is routinely diagnosed with blood culture, which only detects culturable pathogens. We analyzed 27 blood samples from 9 patients with acute leukemia and suspected BSI at different time points of their antimicrobial treatment using shotgun metagenomics sequencing in order to detect unculturable and non-bacterial pathogens. Our findings confirm the presence of bacterial, fungal and viral pathogens alongside antimicrobial resistance genes. Decreased white blood cell (WBC) counts were associated with the presence of microbial DNA, and was inversely proportional to the number of sequencing reads. This study could indicate the use of high-throughput sequencing for personalized antimicrobial treatments in BSIs.

Decreased functional T lymphocyte-mediated cytokine responses in patients with chemotherapy-induced neutropenia.

OBJECTIVES: The degree of immunosuppression in patients with haematological malignancies treated with chemotherapy is routinely measured as number of circulating cells (preferable neutrophils) in peripheral blood. A parallel decline in the number of T cells is expected, but a possible alteration in their functionality has been less well explored. The ability of T cells to secrete more than one cytokine simultaneously is known to indicate protective immunity. The aim of this study was to determine whether the function of circulating T cells is altered in patients with chemotherapy-induced neutropenia. DESIGN, SETTING AND SUBJECTS: In this cross-sectional study, we used the FluoroSpot assay to investigate the proportion of T cells secreting either interferon-γ or interleukin-2, or both cytokines simultaneously, after anti-CD3 stimulation. Peripheral blood mononuclear cells from 53 adult patients with chemotherapy-induced neutropenia and 20 healthy individuals were investigated. RESULTS: There were significantly fewer T cells secreting interferon-γ in patients with neutropenia compared with healthy control subjects (P = 0.02), but the difference was greatest for dual cytokine-secreting T cells (P = 0.001). Furthermore, the amount of secreted cytokine per T cell appeared to be reduced in patients, compared with control subjects. CONCLUSION: Our results suggest that the functionality of T cells is altered in patients with haematological malignancies with chemotherapy-induced neutropenia. In parallel with a decline in T cell count, this may further increase the risk of severe infections.

Evaluation of a surveillance strategy for early detection of adenovirus by PCR of peripheral blood in hematopoietic SCT recipients: incidence and outcome.

Adenoviruses (AdV) have emerged as important causes of morbidity and mortality in patients after hematopoietic SCT (HSCT). Early diagnosis of the infection by detection of viral DNA may improve the prognosis. A surveillance strategy was evaluated for detection of AdV DNA by PCR in a prospective study of unselected allogeneic HSCT recipients. In parallel with a routine CMV surveillance program, plasma from 20 children and 77 adults was analyzed by quantitative PCR for detection of AdV DNA. In addition, in 12 unselected patients, the presence of AdV-specific T cells were analyzed by enzyme-linked immunosorbent spot (ELISPOT) at 1 to 3 months after transplantation. A total of 5 of 97 (5%) patients had detectable AdV DNA in peripheral blood. Only one patient had high titers and none developed AdV disease. BM as a source of stem cells and myelodysplastic syndrome as the indication for transplantation were independently associated with higher risk of acquiring AdV infection. AdV-specific T cells were detected in 7 (58%) of 12 patients. Although AdV DNA was found in peripheral blood by quantitative PCR in 5% of patients undergoing allogeneic HSCT, the present surveillance program did not have a significant effect on the clinical outcome.