Adenine arabinoside in the treatment of progressive multifocal leukoencephalopathy: use of virus-containing cells in the urine to assess response to therapy.

Two patients with biopsy-proved progressive multifocal leukoencephalopathy (PML) were treated with near-maximal doses of adenine arabinoside (Ara-A), 18.6 and 20 mg per kilogram of body weight per day for 14 days. In both patients, clinical progression of the disease was correlated with an increase in the size of low-density lesions seen by computerized tomography. One of the patients was observed to excrete abnormal epithelial cells into the urine. These cells contained papovaviruslike particles, and JC virus was cultured from the urine sediment. The relative number of these abnormal cells declined during Ara-A treatment. Both patients died shortly after the conclusion of therapy without a change in the progression of the central nervous system disease. Systemic administration of Ara-A did not offer significant clinical benefit in the treatment of these 2 advanced cases of PML.