THE ANAPHYLAXIS HYPOTHESIS OF SUDDEN-INFANT-DEATH-SYNDROME (SIDS) - MAST-CELL DEGRANULATION IN COT DEATH REVEALED BY ELEVATED CONCENTRATIONS OF TRYPTASE IN SERUM

A series of cases of sudden unexpected post-neonatal deaths from two c entres in the UK have been investigated for evidence of mast cell acti vation using the biochemical markers tryptase and 9 alpha,11 beta-PGF( 2). Tryptase was selected as a possible marker because it is a compone nt of mast cell secretory granules and, unlike histamine, it is not re leased from basophils. The prostaglandin 9 alpha,11 beta-PGF(2) is an initial and pharmacologically active metabolite of PGD(2), the major m ast cell-derived cyclo-oxygenase product. This prostaglandin was chose n to serve as a marker of newly generated mediator release. In the stu dy, unexplained infant deaths were associated with a higher concentrat ion of tryptase in serum compared with cases of unexpected, but subseq uently explained death. However, 9 alpha,11 beta-PGF(2) was found to b e an unsuitable post mortem marker in this situation. These results pr ovide direct evidence that mast cell degranulation, possibly as a resu lt of anaphylaxis, may be occurring around the time of death in some c ases of cot death.