Airway responsiveness to inhaled aspirin is influenced by airway hyperresponsiveness in asthmatic patients

Mechanisms of hypersensitivity reactions induced by drugs

Adverse drug reactions include drug hypersensitivity reactions (DHRs), which can be immunologically mediated or non-immunologically mediated. The high number of DHRs unconfirmed and/or self-reported is a frequent problem in daily clinical practice, with considerable impact on future prescription choices and patient health. It is important to distinguish between hypersensitivity and non-hypersensitivity reactions by adopting a structured diagnostic approach to confirm or discard the suspected drug, not only to avoid life-threatening reactions, but also to reduce the frequent over-diagnosis of DHRs. (www.actabiomedica.it)

Pharmacodynamics, Pharmacokinetics, and Antiviral Activity of BAY 81-8781, a Novel NF-κB Inhibiting Anti-influenza Drug

Influenza is a respiratory disease that causes annual epidemics. Antiviral treatment options targeting the virus exist, but their efficiency is limited and influenza virus strains easily develop resistance. Thus, new treatment strategies are urgently needed. In the present study, we investigated the anti-influenza virus properties of D,L-lysine acetylsalicylate ⋅ glycine (BAY 81-8781; LASAG) that is approved as Aspirin i.v. for intravenous application. Instead of targeting the virus directly BAY 81-8781 inhibits the activation of the NF-κB pathway, which is required for efficient influenza virus propagation. Using highly pathogenic avian influenza virus strains we could demonstrate that BAY 81-8781 was able to control influenza virus infection in vitro. In the mouse infection model, inhalation of BAY 81-8781 resulted in reduced lung virus titers and protection of mice from lethal infection. Pharmacological studies demonstrated that the oral route of administration was not suitable to reach the sufficient concentrations of BAY 81-8781 for a successful antiviral effect in the lung. BAY 81-8781 treatment of mice infected with influenza virus started as late as 48 h after infection was still effective in protecting 50% of the animals from death. In summary, the data represent a successful proof of the novel innovative antiviral concept of targeting a host cell signaling pathway that is required for viral propagation instead of viral structures.

Classification of Drug Hypersensitivity into Allergic, p-i, and Pseudo-Allergic Forms

Drug hypersensitivity reactions (DHR) are clinically and functionally heterogeneous. Different subclassifications based on timing of symptom appearance or type of immune mechanism have been proposed. Here, we show that the mode of action of drugs leading to immune/inflammatory cell stimulation is a further decisive factor in understanding and managing DHR. Three mechanisms can be delineated: (a) some drugs have or gain the ability to bind covalently to proteins, form new antigens, and thus elicit immune reactions to hapten-carrier complexes (allergic/immune reaction); (b) a substantial part of immune-mediated DHR is due to a typical off-target activity of drugs on immune receptors like HLA and TCR (pharmacological interaction with immune receptors, p-i reactions); such p-i reactions are linked to severe DHR; and (c) symptoms of DHR can also appear if the drug stimulates or inhibits receptors or enzymes of inflammatory cells (pseudo-allergy). These three distinct ways of stimulations of immune or inflammatory cells differ substantially in clinical manifestations, time of appearance, dose dependence, predictability, and cross-reactivity, and thus need to be differentiated.

[Aspirin hypersensitivity: characteristics and diagnostic approach]

INTRODUCTION

In routine medical practice, the diagnosis of aspirin hypersensitivity (AH) remains difficult. No clinical feature or biomarker is available to reliably confirm this diagnosis and oral provocation tests (OPT) are rarely performed.

AIM

To compare asthmatics with and without AH.

METHOD

The clinical characteristics of 21 asthmatics with and 24 without AH respectively were determined. AH was defined by a positive OPT. A full blood count was done before and 24 hours after the OPT.

RESULTS

The medical history was associated with a weak sensitivity (52%) and a good specificity (96%) for assessing the diagnosis of AH. There was a higher prevalence of AH in women, and a higher frequency of allergic rhinitis in AH, but no characteristic was useful to facilitate the diagnosis of AH in asthmatic patients. Our results demonstrate higher values of platelets in AH patients. Following OPT, in AH patients only, a decrease in blood eosinophils and an increase in neutrophils was observed.

CONCLUSIONS

These results confirm that the diagnosis of AH is challenging, with the history having only weak sensitivity. The observation that fluctuations in eosinophils and neutrophils occur following OPT in AH patients only warrants further investigations and suggests a rapid pro-inflammatory role for aspirin.

Low-dose CT measurements of airway dimensions and emphysema associated with airflow limitation in heavy smokers: a cross sectional study

Background

Increased airway wall thickness (AWT) and parenchymal lung destruction both contribute to airflow limitation. Advances in computed tomography (CT) post-processing imaging allow to quantify these features. The aim of this Dutch population study is to assess the relationships between AWT, lung function, emphysema and respiratory symptoms.

Methods

AWT and emphysema were assessed by low-dose CT in 500 male heavy smokers, randomly selected from a lung cancer screening population. AWT was measured in each lung lobe in cross-sectionally reformatted images with an automated imaging program at locations with an internal diameter of 3.5 mm, and validated in smaller cohorts of patients. The 15^th percentile method (Perc15) was used to assess the severity of emphysema. Information about respiratory symptoms and smoking behavior was collected by questionnaires and lung function by spirometry.

Results

Median AWT in airways with an internal diameter of 3.5 mm (AWT_3.5) was 0.57 (0.44 - 0.74) mm. Median AWT in subjects without symptoms was 0.52 (0.41-0.66) and in those with dyspnea and/or wheezing 0.65 (0.52-0.81) mm (p<0.001). In the multivariate analysis only AWT_3.5 and emphysema independently explained 31.1%and 9.5%of the variance in FEV₁%predicted, respectively, after adjustment for smoking behavior.

Conclusions

Post processing standardization of airway wall measurements provides a reliable and useful method to assess airway wall thickness. Increased airway wall thickness contributes more to airflow limitation than emphysema in a smoking male population even after adjustment for smoking behavior.