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.