Increased erythrocyte adenosine deaminase activity in asthmatic children.

Erythrocyte adenosine deaminase (ADA) activity was measured in 19 newly-diagnosed and 20 hyposensitized asthmatic children, as well as 11 age-matched normal children. ADA activity was determined by adenosine catalyzed reactions. The results showed: 1) The mean value of ADA activity was 72.9 +/- 30.4 mumole/min/unit OD541 nm in newly-diagnosed asthmatics; 52.7 +/- 37.9 mumole/min/unit OD541 nm in hyposensitized patients and 39.5 +/- 26.7 mumole/min/unit OD541 nm in normal controls; 2) there was significant elevation in erythrocyte ADA activity in newly-diagnosed asthmatic patients as compared to normal controls (P less than 0.05), but there was no difference between newly-diagnosed and hyposensitized patients (P greater than 0.05), and between hyposensitized patients and normal controls (P greater than 0.2). The mechanism and possible clinical implication of increasing erythrocyte ADA activity in newly-diagnosed asthmatic patients are discussed.