A young man, after a non penetrating chest trauma, developed recurrent episodes of fever, chest pain, pleural and pericardial effusion, without laboratory evidence of viral infections, or positivity for conventional autoimmunity markers. A clearcut positivity for more specific cardiac autoantibodies, against Beta 1 adrenoceptors (AB1AA), was found (at all dilutions from 1:20 to 1:160). A full dosage of Prednisone rapidly relieved all symptoms, whereas antibiotic therapy had been previously uneffective. At a follow-up control after three months, the patient was healed and AB1AA were positive only at dilutions 1:20 and 1:40. As silent viral myocarditis was apparently ruled out by serological negativity for viral infections, it is possible that autoimmunity could have played a primary pathogenetic role for the development of pericarditis in this patient. Further work is needed to ascertain whether or not AB1AA detection could be a specific marker of cardiac autoimmunity phenomena.