Immunohistochemical techniques improve the diagnosis of myocarditis in cases of suspected sudden infant death syndrome (SIDS)

Immunohistochemical techniques have improved the diagnosis of myocarditis. In a post mortem study, eight specimens in each case of the formalin-fixed and paraffin-embedded hearts of 20 suspected cases of sudden infant death syndrome (SIDS) were investigated with traditional hematoxylin-eosin staining and immunohistochemical methods. The hematoxylin-eosin stained specimens were examined for myocarditis according to the Dallas criteria; only in one case was a myocarditis diagnosed. The subsequent definition of the major histocompatibility complex class II antigens (HLA-DP,DQ,DR and HLA-DR), known to be enhanced in cases of myocarditis, the quantification of leucocytes with leucocyte common antigen (LCA) and characterization and quantification of T-lymphocytes using a specific marker (CD-3) allowed the definite diagnosis of myocarditis in three additional cases, six cases were found with moderate changes and ten cases without signs of inflammation.