ADENOSINE-DEAMINASE ISOENZYMES IN TYPHOID-FEVER

The activity of serum adenosine deaminase and its isoenzymes (ADA1 and ADA2) was measured in the sera of 55 patients with clinically diagnos ed typhoid fever, 46 of whom were seropositive for Salmonella typhi in fection. At presentation 95% of the serologically positive patients ha d increased serum adenosine deaminase activity, The increase in activi ty was greater than that of other frequently measured enzymes. Isoenzy me ADA2 accounted for 84% of the activity, indicating a monocyte/macro phage origin. Results show that in patients with typhoid fever, serum adenosine deaminase, particularly its isoenzyme ADA2, may be regarded as a marker for monocyte/macrophage activation acid could be valuable in diagnosis.