Aggravating effects of Asian sand dust on lung eosinophilia in mice immunized beforehand by ovalbumin

Asian sand dust (ASD) event may result in a significant influence on an asthmatic patient. However, for obvious reasons, there is no experimental study in which asthmatic patients are exposed to ASD. This study was undertaken to clarify the effects of ASD on lung eosinophiliain mice immunized beforehand by ovalbumin (OVA). CD-1 mice were instilled intratracheally with OVA four times at 2-week intervals. Simultaneous intratracheal administration of OVA and ASD (OVA + ASD sim) at the last OVA treatment or intratracheal administration with ASD 1 day before (OVA + ASD pre) /after (OVA + ASD post) the last OVA treatment was performed to investigate the effects of OVA and ASD exposure timing. The three kinds of treatment (OVA + ASD pre; OVA + ASD sim; OVA + ASD post) aggravated allergic lung inflammation and proliferation of goblet cells in the airway epithelium in mice, as evidenced by the cellular profile of bronchoalveolar lavage fluid (BALF) and pathological examination. As an overall trend, these changes were paralleled with the expression of Th2-associated effecter molecules and eosinophil relevant cytokine chimokines in BALF as well as the production of OVA-specific IgG1 compared with OVA treatment alone. OVA + ASD sim aggravated lung eosinophilia remarkably compared with the other treatments. The order of the potency of the aggravation was OVA+ASD pre < OVA+ASD post <OVA+ASD sim. These results indicate that ASD has a potent effect in activating lung eosinopilia in mice immunized beforehand by OVA. The simultaneous exposure of asthmatic patients to ASD and its antigen may have serious consequences for such individuals.