We routinely check total immunoglobulins before each anti-CD20 dose in line with the Summary of Product Characteristics for ocrelizumab that suggests checking “the patient's immune status before dosing since severely immunocompromised patients (e.g., with lymphopenia, neutropenia, hypogammaglobulinemia) should not be treated.” Our own practice is to consider results of total serum IgG and IgM in the context of recent infection burden. Here, CD40LG is linked to infection.