Untargeted metabolomics of human plasma reveal lipid markers unique to chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis.

Chronic obstructive pulmonary disease (COPD) is characterised by airway inflammation and progressive airflow limitation, whereas idiopathic pulmonary fibrosis (IPF) is characterised by a restrictive pattern due to fibrosis and impaired gas exchange. We undertook metabolomic analysis of blood samples in IPF, COPD and healthy controls (HC) to determine differences in circulating molecules and identify novel pathogenic pathways. An untargeted metabolomics using an ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometer (UHPLC-QTOF-MS) was performed to profile plasma of patients with COPD (n = 21), and IPF (n = 24) in comparison to plasma from healthy controls (HC; n = 20). The most significant features were identified using multiple database matching. One-way ANOVA and variable importance in projection (VIP) scores were also used to highlight metabolites that influence the specific disease groups. Non-polar metabolites such as fatty acids (FA) and membrane lipids were well resolved and a total of 4805 features were identified. The most prominent metabolite composition differences in lipid mediators identified at ∼2-3 fold higher in both diseases compared to HC were palmitoleic acid, oleic acid and linoleic acid; and dihydrotestosterone was lower in both diseases. We demonstrated that COPD and IPF were characterised by systemic changes in lipid constituents such as essential FA sampled from circulating plasma.

Robust interferon-α and IL-12 responses by dendritic cells are related to efficient CD4+ T-cell recovery in HIV patients on ART.

Amongst HIV patients with successful virological responses to antiretroviral therapy (ART), poor CD4(+) T-cell recovery is associated with low nadir CD4(+) T-cell counts and persistent immune activation. These factors might be influenced by dendritic cell (DC) function. Interferon-α-producing plasmacytoid DC and IL-12-producing myeloid DC were quantified by flow cytometry after stimulation with agonists to TLR7/8 (CL075) or TLR9 (CpG-ODN). These were compared between patients who achieved CD4(+) T-cell counts above or below 200 cells/µL after 6 months on ART (High vs. Low groups). High Group patients had more DC producing interferon-α or IL-12 at Weeks 6 and 12 on ART than Low Group patients. The frequencies of cytokine-producing DC at Week 12 were directly correlated with CD4(+) T-cell counts at baseline and at Week 12. Patients with good recovery of CD4(+) T-cells had robust TLR-mediated interferon-α responses by plasmacytoid DC and IL-12 responses by myeloid DC during early ART (1-3 months).

Immunological markers of lung disease due to non-tuberculous mycobacteria.

Lung disease due to non-tuberculous mycobacteria (NTM) is a poorly understood condition that is difficult to treat. Treatment remains problematic as few tools are available to help clinicians monitor disease progression or predict treatment outcome. In this study, plasma levels of several inflammatory molecules and the frequency of circulating T cell subsets were measured in patients with NTM lung disease and known treatment status, and compared with their adult offspring and with unrelated healthy controls. Plasma levels of the chemokine CXCL10 and IL-18 were assessed for associations with treatment efficacy. CXCL10 was higher in patients than adult offspring (p< 0.001) and unrelated controls (p< 0.001). Plasma CXCL10 was also lower in patients who responded well to therapy or who controlled their infection without requiring therapy, when compared to patients who did not respond to therapy (p=0.03). Frequencies of activated (HLA-DR(+)) CD4(+) T cells were higher in patients than adult offspring (p<0.001) and unrelated controls (p<0.05), with the highest frequencies in individuals who had completed at least 6 months of treatment. Frequencies of activated (CD38(+)) CD8(+) T cells in most treatment responders were similar to unrelated controls. Low plasma levels of CXCL10 may reflect successful control of NTM lung disease with or without therapy. Compared with responders, patients who responded poorly to treatment generally had higher plasma levels of CXCL10 and IL-18, and higher frequencies of activated CD8(+) T cells.

Could natural killer cells compensate for impaired CD4+ T-cell responses to CMV in HIV patients responding to antiretroviral therapy?

We evaluated NK cell subsets and functions in previously immunodeficient HIV patients responding to ART. Cytokine receptor mRNA was quantitated in purified CD56+ cells. Data were correlated with CD4+ T-cell counts and IFNgamma responses to CMV. NK cell IFNgamma responses to K562 cells and proportions of CD56lo NK cells were correlated in patients (p < 0.001) and both were lower than in controls (p < 0.001 and p = 0.008, respectively), so all patients had poor NK cell function. Proportions of CD56hi NK cells correlated inversely with current CD4+ T-cell counts (p = 0.006) and perforin expression in CD56hi NK cells was higher in patients than controls (p < 0.05). Hence increased proportions and cytolytic function of CD56hi NK cells may partially compensate for CD4+ T-cell deficiency. NK cell IFNgamma responses correlated inversely with expression of IL-10 and IL-12 receptor mRNA. Expression of these transcripts is reduced by exposure to the cytokines, which may reflect immune activation in immunodeficient patients.