Automated eosinophilia: a marker for asthma severity. Is it a gauge for anti-inflammatory therapy?

ABSTRACT

Current therapy of asthma is based on its clinical severity, which mainly depends on symptoms and peak flow rate, and not on any laboratory criterion. The objective of this study is to investigate the value of total peripheral eosinophil count in asthma assessment through its correlation with the clinical severity. One hundred and seventy eight asthmatics referred to asthma and pediatric clinics were reviewed for complete history and examination. Clinical severity was assessed using symptoms criteria based on the global strategy for asthma management and prevention. Total peripheral eosinophil count by Cell-Dyne 3500 automated counter[registered] and asthma severities were analyzed for any significant association. Asthmatics were aged between 6 months and 70 years [mean = 17.5 years] and males formed 52%. Severity groups are intermittent 22 [12%], mild-persistent 87 [49%], moderate-persistent 56 [31.5%] and severe-persistent 13 [7%]. Total peripheral eosinophil count ranged between 10 and 2470 cells/mm[3] [mean=546 +/- SD]. Eosinophilia [>450 cells/mm] was found in 53% of cases, more in the persistent type [60%]. In each clinical group, total peripheral eosinophil count and their means showed a very significant positive correlation with increased asthma severity [P<0.001] with a high linear trend [P<0.001]. Additionally, total peripheral eosinophil count correlates significantly with a history of other allergic illnesses [P<0.001]. This data supports the use of total peripheral eosinophil count as an accumulative objective marker for asthma severity. In asthmatics, eosinophilia suggests higher severity and/or other allergic illnesses. Optimally, in those, anti-inflammatory drugs would be required to control asthma