CD52 and multiple sclerosis: Alemtuzumab treatment (monoclonal antibody targeting CD52 found on several immune cells including B lymphocytes) ten years prior to admission may have contributed to his immunocompromised state as a pooled-safety analysis discovered continued elevated risk of infection six years after alemtuzumab infusion in a cohort of multiple sclerosis patients, though highest infection risk was in the first two years post-treatment [12].