Equine Asthma Syndrome (EAS) is a common respiratory problem that affects horses of any age. In the severe EAS form (historically referred to as recurrent airway obstruction or RAO) the diagnosis, based mainly on history and clinical signs, it is definitively confirmed by the cytological examination of the bronchoalveolar lavage (BAL), also very useful in monitoring lower airway inflammation in response to environmental management and medication. Cytocentrifugated preparation is usually the staging method for the BAL cytological interpretation. To evaluate whether the BAL cytology in horses with severe EAS under different environmental conditions and before and after treatment can undergo significant changes, and at the same time to investigate whether in the cytological evaluation of the BAL there are interpretative differences between two methods of smear preparation of the collected fluid, a study was carried out on a series of BAL samples (n=48) collected in 8 withdrawals from 6 EAS-affected horses subjected to process exacerbation through environmental stimuli and then to pharmacological treatment. Each BAL fluid collected was equally divided into duplicate portions: one set up by cytocentrifugation and one by sediment from simple centrifugation. The cytological examination revealed any significant difference between the EAS-affected horses in all experimental phases (asymptomatic, early exacerbation phase, late exacerbation phase, and remission phase). Diagnostic interpretive comparison between the two BAL preparations then showed no significant differences in results, suggesting how they can be used indifferently in the evaluation of BAL under conditions of airway inflammation in the horse. Thus, the concentrated smear preparation appears to be an equally diagnostically useful method in conditions where there is no possibility of using an appropriate cytocentrifuge.

Murine herpesvirus-68 (MHV-68) productively infects the mouse lungs, exhibiting a complex pathology characteristic of both acute viral infections and chronic respiratory diseases. We sought to discover proteins differentially expressed in bronchoalveolar lavage (BAL) from mice infected with MHV-68. Mice were infected intranasally with MHV-68. After 9 days, as the lytic phase of infection resolved, differential BAL proteins were identified by 2D electrophoresis and mass spectrometry. Of 23 unique proteins, acute phase proteins, vitamin A transport, and oxidative stress response factors Pdx6 and EC-SOD (Sod3) were enriched. Correspondingly, iNOS2 was induced in lung tissue by 7 days post infection. Oxidative stress was partly a direct result of MHV-68 infection, as reactive oxygen species (ROS) were induced in cultured murine NIH3T3 fibroblasts and human lung A549 cells infected with MHV-68. Finally, mice were infected with a recombinant MHV-68 co-expressing inflammatory cytokine murine interleukin 6 (IL6) showed exacerbated oxidative stress and soluble type I collagen characteristic of tissue recovery. Thus, oxidative stress appears to be a salient feature of MHV-68 pathogenesis, in part caused by lytic replication of virus and IL6. Proteins and small molecules in lung oxidative stress networks therefore may provide new therapeutic targets to ameliorate respiratory virus infections.