CD40LG and small cell lung carcinoma: Interestingly, the presence of preexisting neural antigen‐specific cells in those with or without disease may be consistent with the frequent detection of neurological autoantibodies, particularly of the IgM subclass, in healthy control subjects.18 Similarly, screening of patients without neurological symptoms who have tumors and paraneoplastic autoantibodies, for example, GABAB‐receptor antibodies and small cell lung carcinoma,19 may identify those with a potentially increased rate of irAEs.