Grain-free food isnt inherently better for dogs with autoimmune disease. The focus should be on identifying and avoiding specific allergens, whether they are grains or other ingredients.
Its important to work closely with your vet to choose the appropriate diet for your dog, but we have compiled a list of reviews of the best dog foods for autoimmune diseases and options...

While some dogs with autoimmune disease may benefit from a grain-free diet, others may not. Consult with your veterinarian to determine if grain-free is suitable based on your dogs specific condition and health needs.

Immune-Mediated Hemolytic Anemia in Dogs. By Elaine Moore. Autoimmune hemolytic anemia is one of the most common of the autoimmune disorders known to affect our canine friends; causes include bee stings, infections, and vaccines.

Immune-mediated hemolytic anemia is one of the most common manifestations of canine immune-mediated disease, yet treatment regimens remain nonstandardized and, in some cases, controversial.
Canine autoimmune hemolytic anemia: management challenges. Fulltext.Balch A, Mackin A. Canine immune-mediated hemolytic anemia: pathophysiology, clinical signs, and diagnosis. Compend Contin Educ Vet. 2007;29(4):217225.
Maltese saved from Auto Immune Hemolytic Anemia (AIHA).Note: Canine autoimmune hemolytic anemia (AIHA) is a disease characterized by increased destruction of red blood cells (erythrocytes) by the dog's own immune system.