Is influenza vaccination in asthma helpful?

PURPOSE OF REVIEW: Influenza infections are frequently involved in asthma exacerbations. During influenza epidemics substantial excess morbidity due to respiratory tract complications is reported in all age categories as well as excess mortality among the elderly. Vaccines are available for protection against influenza. Worldwide, vaccination is advised and considered a quality point for asthma care. However, the protective effect of influenza vaccination in patients with asthma is still disputed. In order to establish the current state of affairs we reviewed the recent literature on the protective effect of influenza vaccination and its usefulness in patients with asthma. RECENT FINDINGS: Several studies were found addressing influenza and the protective aspects of vaccination. They discussed the incidence, the adverse effects of vaccination, the coverage of influenza vaccination among patients with asthma and the effectiveness of the vaccine. SUMMARY: Influenza vaccination can safely be used in patients with asthma. Allegations that vaccination could provoke asthma exacerbations are convincingly invalidated by previous and recent research. Although patients with asthma are one of the major target groups for immunization, vaccine coverage in all age categories remains low. So far, no unequivocal beneficial effect of influenza vaccination in patients with asthma was found in observational and experimental studies in the sense of reduction of asthma exacerbations and other complications. Recent studies confirm these negative findings. More long-term randomized, placebo-controlled studies, focusing on influenza- proven illness in patients with asthma, are needed to address the question of how helpful influenza vaccination is in these patients.     

Are antihistamines useful in managing asthma?

There continues to be a great deal of interest in the anti-asthmatic role of antihistamines. Antihistamines have recently been shown to have anti-inflammatory properties that are more extensive than simply the blocking of histamine receptors. For example, new evidence suggests that the suppression of cell adhesion molecule expression occurs with these drugs. The anti-inflammatory and anti-asthmatic effects of antihistamines have been evaluated in patients with both allergic asthma and rhinitis, given the established association between allergic inflammation of the upper and lower airways, with evidence to suggest that antihistamines have clinically relevant anti-asthmatic properties. As well as conferring benefits in asthma symptom control and the measurement of lung function, studies assessing the effect of histamine receptor antagonists on bronchial hyperresponsiveness suggest that there is bronchoprotection during both methacholine and mannitol challenges. Recently, there has also been considerable interest in the effect of combining an antihistamine with a leukotriene receptor antagonist. This combination has an anti-asthmatic effect that is greater than that of either drug given alone and may be comparable to inhaled corticosteroid therapy.     

T helper type 1 cells in asthma: friend or foe?

A large body of research supports a pathogenic role for T helper 2 cells in asthma, although T helper 1 cell-type responses may also contribute. Using the principle of T helper cell cross-regulation, investigators have attempted to regulate the pathological effects of T helper 2 cells using regimens that may promote T helper 1 cell-type inflammation. In this review, we propose that the use of factors that promote T helper 1 cell differentiation and activation to treat asthma may be counterproductive, and that alternate regulatory approaches should be explored.     

Targeting interleukin-4 in asthma: lost in translation?

The first discovery that interleukin-4 (IL-4) is crucial in the development of allergic airway inflammation originates from the early 1990s. Whereas initial studies in experimental animal models provided the community with the optimistic view that targeting IL-4 would be the ultimate solution for treating asthma, the translation of these findings to the clinic has not been evident and has not yet fulfilled the expectations. Many technical challenges have been encountered in the attempts to modulate IL-4 expression or activity and in transferring knowledge of preclinical studies to clinical trials. Moreover, biological redundancies between IL-4 and IL-13 have compelled a simultaneous blockade of both cytokines. A number of phase I/II studies are now providing us with clinical evidence that targeting IL-4/IL-13 may provide some clinical benefit. However, the initial view that asthma is a purely Th2-mediated disease had to be revised. Currently, different asthma phenotypes have been described, implying that blocking specifically Th2 cytokines, such as IL-4, IL-5, and IL-13, should be targeted to only a specific subset of patients. Taking this into consideration, IL-4 (together with IL-13) deserves attention as subject of further investigations to treat asthma. In this review, we will address the role of IL-4 in asthma, describe IL-4 signaling, and give an overview of preclinical and clinical studies targeting the IL-4 Receptor pathway.     

Biomarker-driven care in asthma: are we there?

Clinical asthma management is limited by the lack of straightforward and clinically applicable techniques to assess control and appropriately adjust therapy. The availability of biomarkers associated with airway caliber, responsiveness, or inflammation has prompted interest in the application of these measures as surrogate asthma end points in clinical trials. Use of a biomarker as a surrogate outcome in practice is most appropriate in settings in which the effects of therapy on clinical disease, as experienced by patients, are fully captured by that biomarker. Recent studies suggest that although asthma therapies can alter various biomarkers, the relationship between these biomarker changes and important clinical outcomes is inconsistent. Because symptom-driven titration of therapy is feasible and effective, additional data demonstrating clinically important benefits of biomarker-driven care in asthma are needed to justify the logistic and economic burdens associated with clinical dissemination of these techniques.     

Therapeutic blockade of TNF in patients with SLE-promising or crazy?

TNF is an important mediator of inflammation, but is also involved in the control of autoimmunity. The latter has been demonstrated in a murine model of SLE (NZB/W) and by the occurrence of autoantibodies to nuclear antigens as well as occasional, transient lupus-like syndromes in patients under TNF blockade. In contrast, data on increased TNF levels in serum, kidney and skin samples of SLE patients as well as results in other mouse models of the disease point to an inflammatory role of TNF in SLE organ disease. Despite all due caution, given these two sides of the cytokine, TNF blockade has by now been employed for several years in single cases and open label studies; data on more than fifty patients have meanwhile been published, for the vast majority of which infliximab was employed. These clinical data have to be very cautiously interpreted, as always with data on single cases or open label trials. However, some consistent pieces of information emerge and may inform controlled clinical trials: (i) While antibodies to double-stranded DNA commonly showed transient increases, lupus flares have not been seen so far and thus apparently are at least not the rule; (ii) in contrast, increases in anti-phospholipid antibodies may be associated with vascular adverse events; (iii) bacterial infections, pneumonia and urinary tract infections in particular, have been observed; (iv) short term induction therapy appears relatively safe, while long-term TNF blockade may confer significant risks in SLE; (v) TNF blocker induction therapy may lead to long-term remission in patients with lupus nephritis, hemophagocytic syndrome, and interstitial lung disease; (vi) patients with lupus arthritis often respond to TNF-blockade but symptoms recur after cessation of therapy, necessitating longer term therapy, which is more risky than short term treatment.     

Autophagy in airway diseases: a new frontier in human asthma?

The study of autophagy (‘self‐eating’), a fundamental cell fate pathway involved in physiological and pathological subcellular processes, opens a new frontier in the continuous search for novel therapies for human asthma. Asthma is a complex syndrome with different disease phenotypes. Autophagy plays a central role in cell physiology, energy and metabolism, and cell survival. Autophagy's hallmark is the formation of double‐membrane autophagic autophagosomes, and this process is operational in airway epithelial and mesenchymal cells in asthma. Genetic associations between autophagy genes and asthma have been observed including single nucleotide polymorphisms in Atg5 which correlate with reduced lung function. Immune mechanisms important in asthma such as Th2 cells and eosinophils also manifest autophagy. Lastly, we address the role of autophagy in extracellular matrix deposition and fibrosis in asthmatic airways remodeling, a pathologic process still without effective therapy, and discuss potential pharmacologic inhibitors. We end by offering two opposing but plausible hypotheses as to how autophagy may be directly involved in airway fibrosis.