Immunity 12 years after alemtuzumab in RA: CD5+ B-cell depletion, thymus-dependent T-cell reconstitution and normal vaccine responses

Objectives. Lymphocyte depleting therapies have been used to treat refractory autoimmune disease, including RA, but treatment may be associated with long-term lymphopenia. It is unclear whether delayed reconstitution preferentially affects lymphocyte subsets, how this modulates immune challenges and whether thymic function influences the outcome. These questions are now addressed in a detailed analysis of RA patients 12 years after alemtuzumab (anti-CD52) treatment. Methods. Blood was obtained from 20 RA patients 12 years after alemtuzumab treatment. Lymphocyte subsets were enumerated by flow cytometry. T-cell receptor excision circles (TRECs)/ml were determined to quantify thymic function, and serological responses to neoantigens and recall antigens were assessed. Results. RA patients remained lymphopenic 12 years after their first dose of alemtuzumab. CD5 + B cells, which may be associated with autoantibody production, were significantly reduced in alemtuzumab-treated