[Serum adenosine deaminase (ADA) activity in patients with active pulmonary tuberculosis]

To clarify the immunological aspect of tuberculosis, we investigated serum adenosine deaminase (ADA) activity, T and B cell percentile in total peripheral mononuclear cells, peripheral T cell subpopulation and their relationship with other inflammatory parameters in 20 patients with active pulmonary tuberculosis. Serum ADA activity showed abnormal high level in all patients in nontreated phase with significant regression after three months treatment by anti-tuberculous drugs (P less than 0.05). In addition, significant positive correlation was observed between serum ADA activity and erythrocyte sedimentation rate at 1 hour (r = 0.56). Concerning about peripheral T cell subpopulation studied by two colour flow cytometry with FITC-conjugated anti-CD4 and phycoerythrin-conjugated anti-HLA-DR antibody, there was positive correlation between CD4(-) HLA-DR(+) T cell and serum ADA activity (r = 0.59) without any abnormal frequency of each T cell subpopulation. Additionally, after the treatment of pulmonary tuberculosis, significant increase of T cell percentile in total peripheral mononuclear cells were observed (P less than 0.005). In conclusion, these results may suggest serum ADA activity could be a parameter of activity of pulmonary tuberculosis and reflect the function of activated suppressor/cytotoxic T cell.