Unexpected high multiple sclerosis activity after switching from fingolimod to alemtuzumab

Unexpected high disease activity (UHDA) after Fingolimod withdrawal has recently become a controversial concern for physicians. Here, we report the case of a patient with severe exacerbation of MS after switching from Fingolimod to Alemtuzumab treatment. This UHDA despite profound lymphopenia raised the question of the management of sequential use of biotherapies such as Fingolimod and Alemtuzumab in MS.