Similarities and differences in lectin cytochemistry of laryngeal and tracheal epithelium and subepithelial seromucous glands in cases of sudden infant death and controls

Background-It has been speculated that non-specific defence mechanisms of t he epithelium and subepithelial seromucous glands play a role in the larynx and lungs in cases of sudden infant death. Methods-The larynx and trachea from five children who had died of sudden in fant death (SID) syndrome and five control cases of comparable age were com pared for the presence of lectin binding sites (12 different lectins tested ). Results-The secretory product of mucin producing cells contained carbohydra tes including galactose and sialic acids. Binding sites for fucose and N-ac etylgalactosamine were only present in some of the specimens and distributi on revealed no correlation between cases of SID and controls. Epithelial ce lls and serous cells of seromucous glands contained binding sites for siali c acid in cases of SID and controls. Moreover, binding sites for mannose we re detected in these cells but were only present in SID cases. The differen ce between the SID and control groups as to the presence/expression of conc anavalin A was highly significant. Conclusions-It is suggested that mucus hypersecretion in SID occurs in resp onse to bacterial toxins or viral infection and is not specific. The differ ent binding sites for mannose in cases of SID and controls could indicate d ifferences in the production of antimicrobial peptides. A disturbed express ion pattern of antimicrobial peptides in children who later succumb to SID could be responsible for an imbalance of the local microflora with a higher density of microorganisms on the mucosa. Further studies are required to e lucidate the pattern of expression of antimicrobial peptides in subsequent SID victims.