Serum adenosine deaminase levels in patients with psoriasis: a prospective case-control study.

Adenosine deaminase (ADA) activity is a nonspecific marker of T cell activation. T cell activation is thought to play an important role in the pathogenesis of psoriasis. Our purpose was to assess the significance of serum ADA activity in psoriasis and its relevance to disease activity. ADA activity was determined with an enzymatic method in 25 patients with psoriasis and in 15 healthy subjects. These measurements were repeated for 10 patients after either PUVA or cyclosporin A treatments. Disease activity was estimated by the PASI scoring system. Serum ADA level was significantly elevated in patients with psoriasis compared to healthy subjects (p<0.05). There was a significant decrease in the ADA levels after treatment compared to pretreatment values in the same patients (p<0.05). There was no correlation between ADA levels and PASI scores. These results support the evidence that T cell activation is involved in the pathogenesis of psoriasis and that ADA may be valuable in the assessment of disease activity in psoriasis.