Treatment of progressive multifocal leukoencephalopathy with interleukin 7.

IMPORTANCE: No reliable treatment options are known for progressive multifocal leukoencephalopathy with underlying immunodeficiency. We describe successful compassionate use of recombinant human interleukin 7 in a patient with idiopathic CD4+ T-cell lymphocytopenia. OBSERVATIONS: After the diagnoses of progressive multifocal leukoencephalopathy and idiopathic CD4+ T-cell lymphocytopenia were established, a 61-year-old man was treated with recombinant human interleukin 7 on November 1, 2012. Except for an episode of epilepsia partialis continua on January 16, 2013, a gradual clinical improvement was observed until March. Abnormalities shown on magnetic resonance imaging regressed; JC virus DNA in plasma, likely originating from the brain based on sequencing data, cleared; and increases in peripheral CD4+ T cells and JC virus intrathecal antibodies were observed. One year after treatment, the CD4+ T-cell count returned to baseline and the clinical improvement waned, possibly due to the patient's complex epilepsy. On the latest evaluation on January 14, 2014, the patient's condition was unchanged, with no signs of ongoing central nervous system infection. CONCLUSIONS AND RELEVANCE: The present case argues strongly for proof of the treatment concept. However, deeper insight into the JC virus and its pathogenesis and the immune response during central nervous system infection as well as further clinical studies are needed before recombinant human interleukin 7 can be recommended for the treatment of other cases of immunodeficiency and progressive multifocal leukoencephalopathy.