RT Journal Article SR Electronic T1 Allogeneic BK Virus-Specific T-Cell Treatment in 2 Patients With Progressive Multifocal Leukoencephalopathy JF Neurology - Neuroimmunology Neuroinflammation JO Neurol Neuroimmunol Neuroinflamm FD Lippincott Williams & Wilkins SP e1020 DO 10.1212/NXI.0000000000001020 VO 8 IS 4 A1 Franziska Hopfner A1 Nora Möhn A1 Britta Eiz-Vesper A1 Britta Maecker-Kolhoff A1 Jens Gottlieb A1 Rainer Blasczyk A1 Nima Mahmoudi A1 Kaweh Pars A1 Ortwin Adams A1 Martin Stangel A1 Mike P. Wattjes A1 Günter Höglinger A1 Thomas Skripuletz YR 2021 UL http://nn.neurology.org/content/8/4/e1020.abstract AB Objective Progressive multifocal leukoencephalopathy (PML) is a devastating demyelinating opportunistic infection of the brain caused by the ubiquitously distributed JC polyomavirus. There are no established treatment options to stop or slow down disease progression. In 2018, a case series of 3 patients suggested the efficacy of allogeneic BK virus-specific T-cell (BKV-CTL) transplantation.Methods Two patients, a bilaterally lung transplanted patient on continuous immunosuppressive medication since 17 years and a patient with dermatomyositis treated with glucocorticosteroids, developed definite PML according to AAN diagnostic criteria. We transplanted both patients with allogeneic BKV-CTL from partially human leukocyte antigen (HLA) compatible donors. Donor T cells had directly been produced from leukapheresis by the CliniMACS IFN-γ cytokine capture system. In contrast to the previous series, we identified suitable donors by HLA typing in a preexamined registry and administered 1 log level less cells.Results Both patients' symptoms improved significantly within weeks. During the follow-up, a decrease in viral load in the CSF and a regression of the brain MRI changes occurred. The transfer seemed to induce endogenous BK and JC virus-specific T cells in the host.Conclusions We demonstrate that this optimized allogeneic BKV-CTL treatment paradigm represents a promising, innovative therapeutic option for PML and should be investigated in larger, controlled clinical trials.Classification of Evidence This study provides Class IV evidence that for patients with PML, allogeneic transplant of BKV-CTL improved symptoms, reduced MRI changes, and decreased viral load.BKV-CTL=BK virus-specific T-cell; HLA=human leukocyte antigen; PML=progressive multifocal leukoencephalopathy; JCPyV=JC polyomavirus; JCVAI=anti-JC virus antibody index