Epstein-Barr virus-specific T cell therapy for progressive multiple sclerosis

Abstract

Background: Increasing evidence indicates a role for EBV in the pathogenesis of multiple sclerosis (MS). EBV-infected autoreactive B cells might accumulate in the CNS because of defective cytotoxic CD8+ T cell immunity. We sought to determine the feasibility and safety of treating progressive MS patients with autologous EBV-specific T cell therapy.

Methods: An open-label phase I trial was designed to treat 5 patients with secondary progressive MS and 5 patients with primary progressive MS with 4 escalating doses of in vitro-expanded autologous EBV-specific T cells targeting EBV nuclear antigen 1, latent membrane protein 1 (LMP1), and LMP2A. Following adoptive immunotherapy, we monitored the patients for safety and clinical responses.

Results: Of the 13 recruited participants, 10 received the full course of T cell therapy. There were no serious adverse events. Seven patients showed improvement, with 6 experiencing both symptomatic and objective neurological improvement, together with a reduction in fatigue, improved quality of life, and, in 3 patients, reduced intrathecal IgG production. All 6 patients receiving T cells with strong EBV reactivity showed clinical improvement, whereas only 1 of the 4 patients receiving T cells with weak EBV reactivity showed improvement (P = 0.033, Fisher's exact test).

Conclusion: EBV-specific adoptive T cell therapy was well tolerated. Clinical improvement following treatment was associated with the potency of EBV-specific reactivity of the administered T cells. Further clinical trials are warranted to determine the efficacy of EBV-specific T cell therapy in MS.

Trial registration: Australian New Zealand Clinical Trials Registry, ACTRN12615000422527.

Funding: MS Queensland, MS Research Australia, Perpetual Trustee Company Ltd., and donations from private individuals who wish to remain anonymous.

Keywords: Autoimmune diseases; Clinical Trials; Neuroscience; T cells.

Figure 1. CONSORT diagram showing enrollment of participants, adoptive immunotherapy, and clinical follow-up.

Figure 2. Expansion of EBV-specific T cells from MS patients.

PBMCs (ex vivo) or T cells stimulated with AdE1-LMPpoly (T cell therapy) were assessed for the intracellular production of IFN-γ following recall with a peptide pool of CD8⁺ T cell epitopes encoded by EBNA1, LMP1, and LMP2A. Data represent the proportions of CD8⁺ T lymphocytes producing IFN-γ.

Figure 3. Fatigue score and cognitive function after T cell therapy.

(A) Fatigue Severity Scale (FSS) (ref. 22) score at week 1, immediately before the first T cell infusion, and at week 27 (n = 10). A total score of 36 (indicated by dotted horizontal line in B) or more suggests that a person is suffering from fatigue. The maximum score is 63 and the minimum score is 9. Horizontal bars indicate the medians and interquartile range. P = 0.0547, Wilcoxon matched-pairs signed-rank test. (B) FSS score over time in each of the treated patients. Vertical arrows indicate successive T cell infusions of 5 × 10⁶, 1 × 10⁷, 1.5 × 10⁷, and 2 × 10⁷ cells. Red lines indicate patients showing no symptomatic improvement (participants 2, 6, and 8) and green lines indicate patients showing symptomatic improvement (participants 1, 3, 4, 5, 9, 12, and 13). The participant showing the greatest reduction in fatigue (participant 5) received T cells with the highest degree of EBV reactivity (45.45% of CD8⁺ T cells). (C) Standardized change in scores (means with standard deviations indicated by horizontal bars) (n = 10) for the individual components of the comprehensive neuropsychological test battery (week 27 minus venesection visit) after T cell therapy. For each component, standardization was performed by dividing the change in test score from week 1 to week 27 by the standard deviation of the week 1 group mean. For example, a score of 1 indicates that the week 27 score is 1 standard deviation higher than the week 1 score. The obtained Z-scores for 4 variables were inverted (CTIP Reaction Time variables and BDI) to ensure consistency in the direction of change across all plots so that positive Z-scores indicate improved performance and negative Z-scores indicate decreased performance. COWAT, Controlled Oral Word Association Test; JOLO, Judgement of Line Orientation; CVLT-TL, California Verbal Learning Test – Total Learning; CVLT-DR, California Verbal Learning Test – Delayed Recall; BVMT-TL, Brief Visual Memory Test – Total Learning; BVMT-DR, Brief Visual Memory Test – Delayed Recall; SDMT, Symbol Digit Modalities Test; PASAT, Paced Auditory Serial Addition Test; DKEFS-CS, Delis–Kaplan Executive Function System – Correct Sorts; DKEFS-DS, Delis–Kaplan Executive Function System – Description Score; RT, Reaction Time; BDI, Beck Depression Inventory – Fast Screen.

Figure 4. CSF IgG analysis before and after treatment in participant 9.

CSF before and after the first course of autologous EBV-specific T cell therapy in participant 9 in 2013 (via the Special Access Scheme) and after retreatment in 2017 in the current trial. (A) CSF IgG index, with dotted horizontal line indicating upper limit of normal range. (B) Intrathecal IgG production [IgG(loc)] was calculated by the formula of Reiber and Felgenhauer (31). Vertical lines indicate successive T cell infusions of 5 × 10⁶, 1 × 10⁷, 1.5 × 10⁷, and 2 × 10⁷ cells, commencing in January 2013 and again in April 2017.

Figure 5. Relationship between EBV-specific CD8⁺ T cell reactivity of T cell product and clinical response to T cell therapy.

(A) Relationship between clinical response and the frequency of LMP/EBNA1-specific CD8⁺ T cells in the T cell product. Participants were grouped into those receiving T cell therapy with >5% of CD8⁺ T cells expressing a given individual cytokine (CD107a, IFN-γ, TNF-α, or IL-2) after recall with a peptide pool of CD8⁺ T cell epitopes encoded by EBNA1, LMP1, and LMP2A (strong reactivity) and those receiving T cell therapy with <5% reactivity (weak reactivity). A clinical response to T cell therapy was defined as clinical improvement at week 27 (the last clinical assessment in the study) compared with week 1 (immediately prior to the first T cell infusion). IL-2 expression was not assessed in the cells for participant 12. P values were calculated with Fisher’s exact test; n = 10 for CD107a, IFN-γ, and TNF-α; n = 9 for IL-2. (B) Proportion of LMP/EBNA1-specific CD8⁺ T cells expressing all the different combinations of the 4 cytokines (CD107a, IFN-γ, TNF-α, and IL-2) in the participants showing clinical improvement (Responder) compared with the participants not showing clinical improvement (Non-responder). This analysis was not able to be performed on the cells for participant 1 (n = 9). There was a higher proportion of EBV-specific polyfunctional T cells (expressing CD107a, IFN-γ, TNF-α, and IL-2) in the CD8⁺ T cells within the therapy administered to participants showing clinical improvement than in the therapy administered to participants not showing clinical improvement (P < 0.0001, multiple 2-tailed t test with the Holm-Sidak correction for multiple comparisons). Horizontal bars represent the mean and standard error of the mean.