Increased lymphocyte adenosine deaminase in typhoid fever.

Adenosine deaminase in the peripheral lymphocytes (L-ADA) was determined in 27 patients with typhoid fever and in 15 normal controls. Increased values of enzymatic activity were found in the typhoid fever patients compared with the controls. The increase was prolonged and not correlated to treatment. L-ADA levels could be related to the immune response.