Objective: The aim of this study was to consider sleep apnea in Prader-Willi syndrome (PWS) children depending on age at growth hormone (GH) therapy onset. Study Design: We analyzed longitudinally cardiorespiratory polygraphy of 62 PWS children (aged 0-2.5 years at baseline). Twenty-one children (Group A) started GH-therapy during and 41 children (Group B) after their first year of life. Data were acquired before, at 3 and 6 months, then 1.2, 2.2, and 3.2 years after GH onset. Outcomes were determined with the obstructive apnea hypopnea index (OAHI), central apnea index (CAI), oxygen desaturation index (ODI), and by measuring obstructive sleep apnea (OSA) and peripheral blood oxygen saturation (SpO 2). Results: We observed no significant differences in OAHI, CAI, ODI, and SpO 2 depending on treatment onset. At baseline, 5/21 patients (23.8%) in Group A versus 15/41 patients (36.6%) in Group B showed pathological sleep ap-nea (OAHI ≥1.5). Pathological OSA increased significantly in Group A during the first 3 months of therapy but dropped below baseline after 1 year in both groups. ODI changed during GH therapy in both groups (from 4.0 to 2.6 in Group A, and 3.6 to 1.6 in Group B; baseline to 3.2 years; p < 0.05). Conclusions: OSA in PWS children appears to develop independently of treatment onset. Treatment may therefore safely be initiated early but should be accompanied by regular sleep analysis.
Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are characterized by increased pulmonary and systemic inflammation and commonly caused by bacterial and/or viral infection. Little is known about the T-cell dysregulation in AECOPD that promotes these outcomes.CD39 is an ectonucleotidase able to hydrolyse adenosine triphosphate to create adenosine that may inhibit T-cell responses in patients with AECOPD. Here T-cell expression of CD39 measured by flow cytometry was higher in AECOPD patients than stable COPD patients or healthy controls. Higher expression of CD39 was associated with higher levels of plasma soluble tumor necrosis factor receptor but lower interferon-γ (IFNγ) levels in supernatants from staphylococcal enterotoxin-B stimulated peripheral blood mononuclear cells. This links increased expression of CD39 with systemic inflammation and impaired T-cell responses (e.g. IFNγ). The blockade of CD39 pathways may be a novel approach to the control of AECOPD, reducing the dependency on antibiotics.
Impaired T helper type 1 (Th1) function is implicated in the susceptibility of patients with chronic obstructive pulmonary disease (COPD) to respiratory infections, which are common causes of acute exacerbations of COPD (AECOPD). To understand the underlying mechanisms, we assessed regulatory T (Treg) cells and the expression of an inhibitory T-cell receptor, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4). Cryopreserved peripheral blood mononuclear cells (PBMC) from patients with AECOPD (n = 17), patients with stable COPD (sCOPD; n = 24) and age-matched healthy non-smoking controls (n = 26) were cultured for 24 hr with brefeldin-A or monensin to detect intracellular or surface CTLA-4 (respectively) by flow cytometry. T cells in PBMC from AECOPD (n = 9), sCOPD (n = 14) and controls (n = 12) were stimulated with anti-CD3 with and without anti-CTLA-4 blocking antibodies and cytokines were quantified by ELISA. Frequencies of circulating T cells expressing intracellular CTLA-4 were higher in sCOPD (P = 0·01), whereas patients with AECOPD had more T cells expressing surface CTLA-4 than healthy controls (P = 0·03). Increased frequencies of surface CTLA-4 CD4 T cells and CTLA-4 Treg cells paralleled increases in plasma soluble tumour necrosis factor receptor-1 levels (r = 0·32, P = 0·01 and r = 0·29, P = 0·02, respectively) in all subjects. Interferon-γ responses to anti-CD3 stimulation were inversely proportional to frequencies of CD4 T cells expressing intracellular CTLA-4 (r = -0·43, P = 0·01). Moreover, CTLA-4 blockade increased the induction of interferon-γ, tumour necrosis factor-α and interleukin-6 in PBMC stimulated with anti-CD3. Overall, chronic inflammation may expand sub-populations of T cells expressing CTLA-4 in COPD patients and therefore impair T-cell function. CTLA-4 blockade may restore Th1 function in patients with COPD and so aid the clearance of bacterial pathogens responsible for AECOPD.
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