We report fatal disseminated intravascular coagulation caused by Mycoplasma
pneumoniae infection in a 7-year-old white boy. The diagnosis was based on
relevant clinical material, absence of any other infections, a 4-fold rise
in titer of complement fixation for M. pneumoniae and open lung biopsy fin
dings. We discuss the association between M. pneumoniae and autoimmune mech
anism.