PULMONARY EOSINOPHILIA IN SUDDEN-INFANT-DEATH-SYNDROME

A recent immunohistochemical study found increased numbers of eosinoph ils, but no mast cells, in the pulmonary parenchyma of infants who die d of sudden infant death syndrome (SIDS). The present study tested the hypothesis that this pulmonary eosinophilia could be IgE-mediated. Hi stomorphometry was used to compare the numbers of eosinophils, mast ce lls, and IgG-, IgA-, IgM- and IgE-expressing lymphoid cells in the lun gs of two groups of infants. Twenty-eight subjects aged less than 1 ye ar were selected from post-mortem records of infant deaths between 198 9 and 1992. Fourteen were cases of SIDS and these infants were matched for age and gender to 14 controls who died of other non-pulmonary con ditions. Immunohistochemical stains were used and positive cells were counted on six peribronchial and six subpleural fields. The numbers of eosinophils in both peribronchial and subpleural regions were signifi cantly higher in SIDS compared with controls (P=0.0071 and P=0.041, re spectively). The numbers of IgA-expressing lymphoid cells were also si gnificantly increased in SIDS cases (P=0.042). There were no differenc es in IgG, IgM or IgE expression or in mast cell numbers. These result s confirmed that pulmonary eosinophils are increased in SIDS, but not through an IgE-mediated pathway.