Suppression of immune responses is necessary to limit damage to host tissue during inflammation, but it can

Interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor regulate the survival, proliferation, and differentiation of hematopoietic lineages. Phosphatidylinositol 3-kinase (PI3K) has been implicated in the regulation of these processes. Here we investigate the molecular mechanism by which PI3K regulates cytokine-mediated proliferation and survival in the murine pre-B-cell line Ba/F3. IL-3 was found to repress the expression of the cyclin-dependent kinase inhibitor p27 KIP1 through activation of PI3K, and this occurs at the level of transcription. This transcriptional regulation occurs through modulation of the forkhead transcription factor FKHR-L1, and IL-3 inhibited FKHR-L1 activity in a PI3K-dependent manner. We have generated Ba/F3 cell lines expressing a tamoxifen-inducible active FKHR-L1 mutant [FKHR-L1(A3):ER*]. Tamoxifen-mediated activation of FKHR-L1(A3):ER* resulted in a striking increase in p27KIP1 promoter activity and mRNA and protein levels as well as induction of the apoptotic program. The level of p27 KIP1 appears to be critical in the regulation of cell survival since mere ectopic expression of p27 KIP1 was sufficient to induce Ba/F3 apoptosis. Moreover, cell survival was increased in cytokine-starved bone marrow-derived stem cells from p27 KIP1 null-mutant mice compared to that in cells from wild-type mice. Taken together, these observations indicate that inhibition of p27 KIP1 transcription through PI3K-induced FKHR-L1 phosphorylation provides a novel mechanism of regulating cytokine-mediated survival and proliferation.

ISRCTN63545820.

Objective To determine which clinical variables provide diagnostic information in recognising heart failure in primary care patients with stable chronic obstructive pulmonary disease (COPD) and whether easily available tests provide added diagnostic information. Design Cross sectional diagnostic study. Setting 51 primary care practices. Participants 1186 patients aged ≥ 65 years with COPD diagnosed by their general practitioner who did not have a diagnosis of heart failure confirmed by a cardiologist. Main outcome measures Independent diagnostic variables for concomitant heart failure in primary care patients with stable COPD. Results 405 patients (34% of eligible patients) underwent a systematic diagnostic investigation, which resulted in 83 (20.5%) receiving a new diagnosis of concomitant heart failure. Independent clinical variables for concomitant heart failure were a history of ischaemic heart disease, high body mass index, laterally displaced apex beat, and raised heart rate (area under the receiver operating characteristic curve (ROC area) 0.70, 95% confidence interval 0.64 to 0.76). Addition of measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) to the reduced "clinical model" had the largest added diagnostic value, with a significant increase of the ROC area to 0.77 (0.71 to 0.83), followed by electrocardiography (0.75, 0.69 to 0.81). C reactive protein and chest radiography had limited added value. A simplified diagnostic model consisting of the four independent clinical variables plus NT-proBNP and electrocardiography was developed. Conclusions A limited number of items easily available from history and physical examination, with addition of NT-proBNP and electrocardiography, can help general practitioners to identify concomitant heart failure in individual patients with stable COPD.

Chronic obstructive pulmonary disease (COPD) is characterised by a chronic inflammation in the pulmonary tissue. The disease is associated with a switch from a self-limiting inflammatory response, mainly initiated by smoke inhalation, to a chronic persistent inflammatory response after prolonged interaction with cigarette smoke. The extent of the inflammatory reaction is correlated with the severity of the disease.Chronic inflammation in the pulmonary tissue is also associated with systemic effects. These effects range from cytokine-induced priming of peripheral leukocytes, to muscle wasting induced by cytokines such as tumour necrosis factor-a. Despite a general consensus that chronic inflammation is a characteristic phenomenon of the disease, surprisingly little is known regarding the underlying pathogenetic mechanisms.A clear communication is present between the disease mechanisms in the pulmonary compartment and peripheral tissues, leading to the concept of COPD as a systemic inflammatory disease. This communication can be mediated by: 1) leakage of reactive oxygen species and stress-induced cytokines directly into the peripheral blood, 2) (pre)activation of peripheral blood leukocytes that can result in aberrant homing and activation of inflammatory cells in distant tissues, and 3) the liberation of proinflammatory mediators by leukocytes and/or stromal cells present in the pulmonary tissues during progression of the disease.The current authors hypothesise that the occurrence of a chronic inflammatory response after prolonged interaction of the pulmonary tissue with cigarette smoke causes aberrant homing of leukocytes to the tissue and delayed apoptosis. This leads to the autonomous characteristic of the inflammatory response in patients with chronic obstructive pulmonary disease. Eur Respir J 2003; 22: Suppl. 46, 5s-13s.