Abstract: | Twenty patients with bronchial asthma, on long-term oral therapy with theophylline, demonstrated an increased number of suppressor T-cells and impaired graft vs host reaction. Ten asthmatics on other therapy, not including theophylline, as well as ten normal healthy controls, failed to show similar findings. Elimination of suppressor T-cells corrected the above immunological abnormalities in the theophylline-treated patients, while addition of serum from theophylline-treated asthmatic patients to lymphocytes from normal healthy controls, affected the graft vs host reaction of these lymphocytes. We conclude that theophylline induces quantitative as well as qualitative immunological alterations by increasing the number and activity of suppressor T-cells, which most probably secrete a serum factor, responsible for some of the abnormalities observed. |