Original contribution Histopathologic, immunohistochemical, and polymerase chain reaction assays in the study of cases with fatal sporadic myocarditis Jeannette Guarner MD a , Julu Bhatnagar PhD a, * , Wun-Ju Shieh MD, PhD a , Kurt B. Nolte MD b , Dennis Klein MD b , Michelle S. Gookin BS c , Silvia Pen ˜ aranda BS c , M. Steven Oberste PhD c , Tara Jones MA, HTL (ASCP) a , Chalanda Smith BS a , Mark A. Pallansch PhD c , Sherif R. Zaki MD, PhD a a Infectious Disease Pathology Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA b Office of the Medical Investigator, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA c Polio and Picornavirus Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA Received 9 January 2007; revised 9 February 2007; accepted 16 February 2007 Summary Paraffin tissue blocks from 27 cases with sporadic myocarditis were collected during a 12-year period at a single medical examiner’s office. Blocks were studied by using histopathology; immunohistochemistry for viruses (adenovirus, enterovirus, influenza A and B, and human herpes types 4 and 5), bacteria (Neisseria menigitidis , Ehlichia sp, spotted fever group Rickettsia ) and parasites (Toxoplasma gondii and Trypanosoma cruzi ); and polymerase chain reaction (PCR)/RT-PCR for adenovirus and enterovirus. We identified enterovirus in 5 (18.5%) cases and Sarcocystis in a 36-year- old woman who had focal inflammation and myocyte necrosis. Immunohistochemical evidence of enteroviruses was found in the myocytes of 2 patients less than 6 months old who had diffuse mononuclear myocardial inflammation, interstitial pneumonitis; one also had encephalitis. In these 2 patients, the presence of enterovirus was confirmed by RT-PCR targeting the 5V nontranslated region and was serotyped as coxsackievirus B2 by sequencing the VP1 capsid region. In another 3 cases (ages 12, 47, and 54), enterovirus was detected by the 5V nontranslated region region; VP1 sequencing identified these as echoviruses 6, 13, and 7, respectively. Accurately identifying an infectious agent is the foundation for clinical and public health interventions. Despite using multiple diagnostic methods, an organism could only be detected in a small proportion of sporadic myocarditis cases. D 2007 Published by Elsevier Inc. 1. Introduction Postmortem studies have shown that myocarditis is a major cause of sudden, unexpected death in children and adults less than 40 years of age [1,2]. Outbreaks of myocarditis usually occur in young children, but sporadic 0046-8177/$ – see front matter D 2007 Published by Elsevier Inc. doi:10.1016/j.humpath.2007.02.012 * Corresponding author. Infectious Disease Pathology Activity, Centers for Disease Control and Prevention, Mailstop G32, 1600 Clifton Rd, NE, Atlanta, GA 30333. E-mail address: jbhatnagar@cdc.gov (J. Bhatnagar). Keywords: Myocarditis; Immunohistochemistry; Polymerase chain reaction; Enteroviruses; Sarcocystis Human Pathology (2007) 38, 1412 – 1419 www.elsevier.com/locate/humpath