Novel immunotherapies for immune-mediated haemolytic anaemia in dogs and people

•Novel immunotherapies aim to restore peripheral tolerance.•Restoration of tolerance may control autoimmune disease safely.•Monoclonal antibodies may be used to deplete autoreactive B cells.•Regulatory T cells may be infused to control autoimmune responses.

Therapy of autoimmune diseases in dogs and people currently relies on use of broad-spectrum immunosuppressive drugs, which are associated with unacceptable adverse effects in some patients. Detractions of such drugs are particularly apparent in people and animals with autoimmune haemolytic anaemia (AIHA), when high doses are often required and for prolonged periods. Greater understanding of the immune aberrations that occur in patients with AIHA has permitted development of several forms of novel immunotherapy, which are intended to re-establish tolerance of self-antigens rather than suppressing all parts of the immune system. Such therapies should be efficacious while still permitting normal responses to pathogens and inoculation.Immunotherapies of particular interest currently include monoclonal antibodies that produce selective depletion of the B cell compartment to decrease autoantibody production, administration of peptide antigens by subcutaneous or sublingual routes to establish tolerance, adoptive transfer of regulatory T cells (Tregs), and administration of low dose recombinant interleukin 2 to encourage proliferation and activation of Tregs. These therapies are in variable stages of development, with some being trialled in people and client-owned dogs, and others undergoing validation in experimental murine models. Continued development of these immunotherapies is likely to lead to the introduction of several novel products for the management of autoimmune disease in veterinary practice in the future.