Lymphocyte uroporphyrinogen synthase activity as a diagnostic test in lymphoproliferative disorders — preliminary results

Uroporphyrinogen synthase (EC 4.3.1.8) (UROS), an enzyme in the heme biosynthetic pathway, converts porphobilinogen to uroporphyrinogen. Lym­phocyte UROS (L-UROS) is an inducible enzyme [1] and its activity is increased in erythroleukemia cells [2]. Recent observations [3, 4] showed the presence of circulating malignant lymphocytes in the blood of patients with lymphoproliferative diseases (LPD) without apparent peripheral in­volvement.