The present disclosure relates to anti-CD200 antibodies (e.g., variant anti- CD200 antibodies having decreased or no effector function) and to biomarkers for use in a variety of diagnostic and therapeutic methods, e.g., determining whether a human has been administered one or more of the antibodies at a dose sufficient to induce a desired immunomodulatory effect in the human and/or selecting an appropriate dosing schedule for a patient.
