Transient stimulatory adenosine deaminase activity in peripheral lymphocyte lysates from a case of T-cell lymphoma

A fourteen-year old female presented with a mediastinal mass and pleural effusion. A diagnosis of a poorly differentiated lymphocytic lymphoma was made from a lymph node biopsy. Fluid from a pleural tap contained numerous lymphoblasts; 91.5% of these lymphoblasts had a thymus leukemic antigen. At presentation, although morphologically normal, no adenosine deaminase (ADA) activity could be demonstrated in her peripheral blood lymphocytes. Lysates of her lymphocytes mixed with lysates of lymphocytes with known ADA activity resulted in ADA activity that was greater than expected. With disappearance of tumor following the institution of therapy, ADA activity appeared in her lymphocytes and the above phenomenon disappeared.