Welcome @tobytink, The National Organization of Rare Disorders has some information on cold agglutinin disease that might be helpful - https://rarediseases.org/rare-diseases/cold-agglutinin-disease/. You might also find the following organizations websites helpful for more information.

--- Cold Agglutinin Disease Foundation: https://coldagglutinindisease.org/
--- The Autoimmune Association: https://autoimmune.org/

Have you found any treatments or therapies that help?