Allogeneic BK Virus-Specific T Cells for Progressive Multifocal Leukoencephalopathy

Abstract

JC virus, the cause of progressive multifocal leukoencephalopathy (PML), and the BK virus are genetically similar and share sequence homology in immunogenic proteins. We treated three immunosuppressed patients with PML with ex vivo-expanded, partially HLA-matched, third-party-produced, cryopreserved BK virus-specific T cells. The immunosuppression in these patients was due to the conditioning regimen for cord-blood transplantation in one patient, a myeloproliferative neoplasm treated with ruxolitinib in another, and acquired immunodeficiency syndrome in the third. After T-cell infusion in two of the patients, alleviation of the clinical signs and imaging features of PML was seen and JC virus in the cerebrospinal fluid (CSF) cleared. The other patient had a reduction in JC viral load and stabilization of symptoms that persisted until her death 8 months after the first infusion. Two of the patients had immune reconstitution syndrome. Donor-derived T cells were detected in the CSF after infusion. (Funded by the M.D. Anderson Cancer Center Moon Shots Program and the National Institutes of Health; ClinicalTrials.gov number, NCT02479698 .).

Figure 1. MRI before and after Infusion of Virus-Specific T Cells.

The day numbers at the top of the panels are the days after the first infusion. Panels A and B are from Patient 1. Panel A shows axial T₂-weighted fluid-attenuated inversion-recovery (T₂-FLAIR) images with hyperintensity in both middle cerebellar peduncles extending toward the pons (yellow arrows) and involvement of the left cerebellum (red arrow). Images from day 21 to day 258 after virus-specific T-cell infusion show reduction in the size of the white-matter lesions and atrophic changes. The image from day 258 shows prominence of cerebellar sulci (red arrow) and increased size of fourth ventricle. Panel B shows axial T₁-weighted, gadolinium-enhanced images with faint punctate and patchy cerebellar enhancement present before treatment that resolved after infusion. Enhancement within the middle cerebellar peduncles is seen on both sides (yellow arrows), a finding consistent with inflammatory progressive multifocal leukoencephalopathy (PML). By day 21, the extent and degree of enhancement within the middle cerebellar peduncles had decreased. On follow-up studies, further regression of the enhancement and consequent onset of atrophic changes were seen. Panels C through F are from Patient 2. Panel C shows axial T₂-FLAIR images with a large left posterior parietal white-matter lesion and punctate, deep white-matter lesions before T-cell infusion (left) an increase in the extent of FLAIR hyperintensity on day 11 after infusion (right), the latter possibly representing enlargement of the lesion or vasogenic edema resulting from an inflammatory response. Panel D shows faint peripheral enhancement around the lesion on axial T₁-weighted imaging with gadolinium enhancement (arrows), suggestive of immune reconstitution inflammatory syndrome (IRIS). Panels E and F show axial T₂-FLAIR imaging and axial T₁-weighted imaging with gadolinium enhancement, respectively, of multifocal white-matter disease, including in the splenium and the periventricular white matter. There was progression of imaging findings from day 11 to day 39 with increased T₂-FLAIR hyperintensity and enhancement involving the splenium and the periventricular white matter (arrows), findings consistent with IRIS. Panels G through J are from Patient 3. Panel G shows axial T₂-FLAIR images of several T₂-hyperintense foci in the subcortical white matter of the right parietal lobe that increased in size as a result of IRIS after T-cell infusion on day 26 (arrows) and decreased in size as a result of decreased edema by day 119. Panel H shows axial T₁-weighted images with gadolinium contrast in which increased enhancement (arrows) associated with the T₂-hyperintense foci in the subcortical white matter was seen by day 26 and resolved by day 119. Panels I and J show progressive T₂-FLAIR hyperintensity within the pons, medulla, and cerebellar vermis that was present from diagnosis to the time of treatment. T₂-FLAIR axial images at the pontine level (Panel I) and at the medulla (Panel J) show decreasing T₂-FLAIR hyperintensity and atrophic changes within the brain stem by day 119.

Figure 2. Homing of Donor-Derived HLA-Bw6–Positive T Cells to the Cerebrospinal Fluid (CSF) after Infusion in Patient 1.

Panel A shows donor BK virus–specific CD4 and CD8 T cells in the peripheral blood (top graph) and CSF (bottom graph) on day 14 after infusion, detected by multiparameter flow cytometry. Donor-derived T cells are identified by flow cytometry as HLA-Bw6–positive (indicated by the blue dashed oval in the histograms on the left). Natural killer (NK) cells were included as HLA-Bw6–negative controls. The contour fluorescence-activated cell sorting (FACS) plots on the right reflect gating on HLA-Bw6–positive cells and show the CD4 and CD8 T-cell subset frequencies in the peripheral blood and in the CSF. Horizontal black bars (in plots on the left) and squares (in plots on the right) delineate the cell populations of interest according to the indicated surface marker expression, and the adjacent numbers are the relative frequencies of these populations. Panel B shows the course of JC virus DNA load (yellow line), measured by quantitative polymerase chain reaction, together with percentages of HLA-Bw6– positive donor CD4 (blue bar) and CD8 (red bar) T cells in the CSF at multiple time points after T-cell infusion, detected by multiparameter flow cytometry, with disappearance of the viral DNA in the CSF in response to therapy. Recipient T cells are HLA-Bw6–negative.