PROLIFERATION OF DENDRITIC CELLS IN THE BRONCHIOLES OF SUDDEN-INFANT-DEATH-SYNDROME VICTIMS

Sudden Infant Death Syndrome (SIDS) victims have significantly thicken ed bronchiolar walls with increased mononuclear cells in the adventiti a. An immunohistochemical study was performed on 25 SIDS and 18 aged-m atched control infants to characterize these cells. The panel of antib odies included alpha-1-antitrypsin, lysozyme, actin, vimentin, Leu MI, NSE, S-100, Leu 6, bombesin, serotonin, anti-substance P, vasoactive intestinal peptide, MAC 387, and Factor XIIIa. The bronchiolar cells s tained with S-100 antibody and demonstrated slender processes similar to dendritic cells, such as Langerhans' cells, and interdigitating ret iculum cells, present in normal tissues as well as in certain tumors a nd inflammatory diseases. Manual counting of the S-100 positive cells and fibers revealed both of these to be significantly increased in SID S infants as compared to age-matched control infants. Morphologically, the bronchiolar dendritic cells closely resembled Langerhans' cells a nd therefore may have similar immunologic functions, such as antigen p resentation and viral and neoantigen immunosurveillance. We hypothesiz e that the proliferation of these dendritic cells in SIDS victims is a result of exposure to environmental antigens, resulting in a thickeni ng of the bronchiolar walls, narrowing of the lumen, and reduction in airflow, thus causing a chronic or persistent hypoxia.