This can then become manifest once CD4+ T‐cell help is repopulated to levels that can facilitate autoantibody production and so account for a relative delay in the development of autoimmunity relative to the B‐cell repopulation kinetics.11, 12, 13 As people taking alemtuzumab require regular monthly blood sampling as part of their care package, monitoring the development of antigen‐specific (such as thyroid or, more easily, alemtuzumab‐specific) B‐cell and T‐cell function may provide a useful model system to study the development of human autoimmunity. The gene discussed is CD4; the disease is thyroiditis.