Progressive multifocal leukoencephalopathy treated with interleukin-7

Abstract Background Progressive multifocal leukoencephalopathy (PML) is a rare devastating brain infection caused by the JC polyomavirus (JCPyV) in patients with impaired cellular immune responses. In the absence of effective anti-viral therapy, it is unclear if the use of interleukin-7 (IL-7) could enhance cellular immune responses required to survive PML. Case report A 78-year-old woman who had been treated with corticosteroids for pulmonary sarcoidosis 25 years earlier developed PML associated with severe idiopathic T-cell lymphopenia characterized by expression of programmed cell death-1 (PD-1) receptors on circulating CD4+ and CD8+ T-cells. The patient was diagnosed 12 weeks after her initial symptoms, and treatment with mirtazapine was started immediately. The disease progressed, however, and treatment with IL-7 was initiated 17 weeks after initial symptomatology begun. Results At week 21, clinical improvement was observed and despite persistent JCPyV positive cerebrospinal fluid until week 36, the patient continued to improve remarkably, both clinically and radiologically, along with increasing peripheral lymphocytes and declining PD-1 expression. Treatment was well tolerated without late complications. More than one year after treatment (week 71) the patient cared for herself, and had no signs of PML recurrence, relapse of sarcoidosis, or cancer. A mild increase, however, in serum angiotensin-converting enzyme and plasma soluble interleukin-2 receptor was observed. Conclusion Faced with PML and lymphopenia, in the absence of conventional therapies to reverse the underlying immunodeficiency, IL-7 therapy may be helpful in combatting the JC polyomavirus.