Background: Airflow limitation in bronchial asthma is recurrent and produced by a variety of changes in the airway as bronchoconstriction, airway edema, hyper responsiveness, remodeling and cellular inflammation. Plasma β-thrombomodulin and platelet factor-4, common markers of platelet activation in vivo, have been reported to be elevated in symptomatic asthmatic patients' platelets express more P-selectin on their surface in asthmatic patients. The mean platelet volume, a common measure of platelet size, could be used as an indicator of activated platelets.
Objectives: To measure mean platelet volume in asthmatic patients to assess its use as a biomarker for asthma exacerbation.
Patients and Methods: This was a case control study involved 50 asthmatic patients during both stable and exacerbation, in addition to 50 age and sex matched healthy subjects as a control group. Measurements of platelet count, mean platelet volume (MPV), C reactive protein (CRP) and spiro metric indices were performed for all participants.
Results: Mean platelet volume (MPV) was significantly lower in exacerbation phase compared to both stable and control Group (p < .01), while it non significantly decreased in stable phase compared to control group. During acute exacerbation, the MPV /fl was positively correlated with FEV1%, FEV1/FVC ratio, VC%, FVC%, HB level, while it was negatively correlated with age, WBC, CRP, neutrophil percentage. Moreover, they were positively correlated with each other.  During stable asthma phase, the MPV /fl was positively correlated with FEV1%, FEV1/FVC ratio, VC%, FVC%, HB level, while it was negatively correlated with age, WBC, CRP, neutrophil percentage. Moreover, they were positively correlated with each other.
Conclusion: MPV was altered in exacerbation phase compared with stable phase and control group. Measurement of the MPV is a valuable indicator of asthma severity/activity and appears as a useful screening test for asthma exacerbation.