ADENOSINE-DEAMINASE ACTIVITY IN THE ETIOLOGIC DIAGNOSIS OF COMMUNITY-ACQUIRED PNEUMONIA

A prospective study was undertaken to assess the usefulness of serum a denosine deaminase (ADA) activity in the aetiological diagnosis of 75 patients (mean age 58 years) with community-acquired pneumonia who req uired hospitalization. Measurements of ADA were also carried out in 35 healthy subjects (mean age 52 years). The serum ADA activity in patie nts with typical bacterial pneumonia (TBP) was 21 +/- 7 IU/l and in co ntrols 22 +/- 9 IU/l. In 43 patients with atypical pneumonia (AP), ADA levels (43 +/- 23 IU/) were significantly higher than in the previous ly related groups (p < 0.001). Analysis within the group of atypical p neumonia showed significant differences for infections caused by Coxie lla burnetii (61 +/- 19 IU/l, p < 0.001), Mycoplasma pneumoniae (44 +/ - 26 IU/l, p < 0.001) and Legionella pneumophila (39 +/- 15 IU/l, p < 0.05), as compared with patients with bacterial pneumonia and normal c ontrol subjects. We conclude that serum ADA in patients with community -acquired pneumonia requiring hospitalization mag provide useful addit ional diagnostic information on the aetiology of pulmonary infection.