TRIM21 and autoimmune thrombocytopenic purpura: Where patients did have additional autoimmune conditions, these were type 1 diabetes mellitus, systemic lupus erythematosus, celiac disease, alopecia, and immune thrombocytopenia. ANAs were present in 56% of pregnancies, anti‐smooth muscle antibodies in 52%, and Ro‐52 antibodies in 50% (not mutually exclusive).