OBJECTIVE

To investigate whether platelets are activated during an asthmatic attack and to detect the correlation between platelet activation and severity of bronchial asthma.

METHODS

Plasma concentration of thromboxane B2(TXB2) and 11-dehydro-TXB2(11-DH-TXB2) and P-selectin (CD 62P) on platelet surface were measured in 44 patients with asthma and in 18 normal individuals using ELISA and FCP. The serum ECP level and pulmonary function were also analysed.

RESULTS

The plasma level of 11-DH-TXB2 and TXB2 and the positive percentage of CD 62P on platelets were significantly increased in patients with acute asthma (n = 28) as compared with the control (n = 18, P < 0.01). The plasma concentration of 11-DH-TXB2 and TXB2 were decreased significanty after the control of asthma. The level of platelet activation was correlated with ECP (r = 0.785, P < 0.05), FEV1% (r = -0.867, P < 0.01) and PEF(r = -0.745, P < 0.05).

CONCLUSIONS

These results suggest that there is an abnormal platelet activation in asthmatics, which can reflect the severity of bronchial asthma to a certain extent, although its exact, mechanism is unknown. The platelets secret a wide range of biologically active substances capable of inducing or augmenting the airway inflammatory responses in asthma.