Contributions
Abstract: P659
Type: Poster
Abstract Category: Therapy - disease modifying - 26 Immunomodulation/Immunosuppression
Rationale: Ocrelizumab is a humanized, anti-CD20 specific, cytolytic antibody that depletes B cells, and is indicated for the treatment of relapsing and primary progressive forms of multiple sclerosis in the US. B cells modulate T cell activity through antigen presentation, cytokine production, and support secondary lymphoid organ structure. We hypothesize that global T cell activity may be altered in patients undergoing ocrelizumab therapy. The goal of these studies was to evaluate the effect of ocrelizumab treatment on peripheral blood T cell prevalence and/or function in a subset of relapsing MS patients treated with ocrelizumab and enrolled in the OPERA I study at the University of California, San Francisco (UCSF).
Methods: A novel mass cytometry (CyTOF) assay was developed to immunophenotype a diverse array of B and T cell subsets utilizing 41 separate markers, and used to compare PBMCs from patients before and after ocrelizumab or interferon beta-1a treatment. To test the ability of T cells to elicit polyfunctional cytokine responses, PBMCs before and after treatment were stimulated with phorbol myristate acetate (PMA) and ionomycin and stained for intra-cellular cytokine secretion. The study assessed longitudinal PBMC samples from 7 unique patients that included 1 baseline untreated and 3 other post treatment samples from each patient. The experiments and data analysis were conducted while blinded to the treatment assignment for each patient.
Results: Despite dramatic reduction of all B cell subsets in blood after ocrelizumab treatment, no significant modulation in the frequency of T cell subsets was observed. Permutation testing identified that immune subsets significantly differentiated by ocrelizumab were all CD19+ B cell subsets. Furthermore, an unsupervised t-distributed stochastic neighbor embedding (t-SNE) based visualization only revealed B cell depletion and modulation; however, overt changes in T cell populations were not apparent.
Conclusions: Our findings suggest that the peripheral blood T cell compartment remains largely unaltered in RMS patients treated with ocrelizumab. The treatment also did not appear to affect the ability of T cells in these patients to elicit a functional cytokine response to stimulation. These results may be relevant for safety purposes.
Disclosure: Supported by F. Hoffmann-La Roche Ltd./Genentech, Inc.
H.-C. von Buedingen is an employee of F. Hoffmann-La Roche Ltd.
Q. Shon Nguyen in an employee of Genentech, Inc.
C. Harp is an employee of, and receives compensation from of Genentech, Inc.
S. Toghi Eshghi is an employee of Genentech, Inc.
E. Eggers has nothing to disclose.
A. Herman is an employee of Genentech, Inc., and shareholder of F. Hoffmann-La Roche Ltd.
Abstract: P659
Type: Poster
Abstract Category: Therapy - disease modifying - 26 Immunomodulation/Immunosuppression
Rationale: Ocrelizumab is a humanized, anti-CD20 specific, cytolytic antibody that depletes B cells, and is indicated for the treatment of relapsing and primary progressive forms of multiple sclerosis in the US. B cells modulate T cell activity through antigen presentation, cytokine production, and support secondary lymphoid organ structure. We hypothesize that global T cell activity may be altered in patients undergoing ocrelizumab therapy. The goal of these studies was to evaluate the effect of ocrelizumab treatment on peripheral blood T cell prevalence and/or function in a subset of relapsing MS patients treated with ocrelizumab and enrolled in the OPERA I study at the University of California, San Francisco (UCSF).
Methods: A novel mass cytometry (CyTOF) assay was developed to immunophenotype a diverse array of B and T cell subsets utilizing 41 separate markers, and used to compare PBMCs from patients before and after ocrelizumab or interferon beta-1a treatment. To test the ability of T cells to elicit polyfunctional cytokine responses, PBMCs before and after treatment were stimulated with phorbol myristate acetate (PMA) and ionomycin and stained for intra-cellular cytokine secretion. The study assessed longitudinal PBMC samples from 7 unique patients that included 1 baseline untreated and 3 other post treatment samples from each patient. The experiments and data analysis were conducted while blinded to the treatment assignment for each patient.
Results: Despite dramatic reduction of all B cell subsets in blood after ocrelizumab treatment, no significant modulation in the frequency of T cell subsets was observed. Permutation testing identified that immune subsets significantly differentiated by ocrelizumab were all CD19+ B cell subsets. Furthermore, an unsupervised t-distributed stochastic neighbor embedding (t-SNE) based visualization only revealed B cell depletion and modulation; however, overt changes in T cell populations were not apparent.
Conclusions: Our findings suggest that the peripheral blood T cell compartment remains largely unaltered in RMS patients treated with ocrelizumab. The treatment also did not appear to affect the ability of T cells in these patients to elicit a functional cytokine response to stimulation. These results may be relevant for safety purposes.
Disclosure: Supported by F. Hoffmann-La Roche Ltd./Genentech, Inc.
H.-C. von Buedingen is an employee of F. Hoffmann-La Roche Ltd.
Q. Shon Nguyen in an employee of Genentech, Inc.
C. Harp is an employee of, and receives compensation from of Genentech, Inc.
S. Toghi Eshghi is an employee of Genentech, Inc.
E. Eggers has nothing to disclose.
A. Herman is an employee of Genentech, Inc., and shareholder of F. Hoffmann-La Roche Ltd.