CD40LG and systemic lupus erythematosus: IgG anti‐dsDNA antibodies have been found to be more closely associated with SLE disease activity and tissue damage than IgM antibodies.54 Indeed, some studies suggest that IgM anti‐DNA antibodies may be protective,55 whereas other isotypes may also play a role in disease.56, 57, 58 However, there are no systematic BCR sequencing studies in SLE that incorporate analysis of isotypes.