SARS-CoV-2 Vaccine-Elicited Immunity after B Cell Depletion in Multiple Sclerosis

Area of Science:

• Immunology
• Vaccinology
• Neuroimmunology

Background:

• B cell deficiency poses challenges for understanding vaccine responses, particularly for SARS-CoV-2 mRNA vaccines.
• Assessing vaccine immunity in immunocompromised populations like those with multiple sclerosis (MS) is clinically significant.

Purpose of the Study:

• To evaluate serological and cellular immune responses to SARS-CoV-2 mRNA vaccination in different cohorts.
• To compare responses between healthy individuals (pre-exposed or boosted) and MS patients undergoing B cell depletion therapy (MS-αCD20).

Main Methods:

• Comparative analysis of humoral (antibody) and cellular (T cell) responses post-vaccination.
• Evaluation of vaccine-elicited immune profiles in healthy controls and MS-αCD20 patients receiving mRNA homologous boosting.

Main Results:

• Pre-exposure to SARS-CoV-2 boosted humoral and CD4 T cell responses in healthy individuals.
• Novavax homologous boosting yielded superior serological responses compared to mRNA boosting.
• MS-αCD20 patients exhibited intact IgA mucosal responses and enhanced CD8 T cell responses to mRNA boosting, with expanded effector but not memory T cells.

Conclusions:

• B cell depletion in MS patients leads to an enhanced, albeit effector-focused, CD8 T cell response to mRNA vaccination.
• The findings suggest a regulatory interplay between B cells and CD8 T cell responses to vaccines.
• This highlights potential implications for vaccine strategies in B cell-deficient populations.