We measured tnast-cell tryptase in postmortem blood from 22 heroin addiets
dying suddenly after injection. In 32%, the eoncentration of tryptase was
elevated (slO |J.g/l), and the mean value of tryptase was significantly
different from a control group dying from knowti, nonimtnunologic eauses
(f <0.05). The increased tryptase concentrations indicate that death was
preceded by systemic tnast-cell degranulatioti. All victims of drug deaths had
morphine in tjlood, most below 0.2 |J,g/ml. In 71% of the victims of drugrelated
deaths with tryptase values slO |j,g/l, the intermediate degradation
product, 6-monoacetyl-tnorphine, was tiot found in blood, whereas this was
the case in only two vietitns with values below that cutoff point. This indicates
that those with high tryptase concentrations survived longer than those with
lower values. No correlation was found between the IgE levels and tryptase
in either group, supporting the hypothesis that tryptase release was not
mediated by an allergie reaetion. Tlie well-known property of opiates to
stitnulate unspecifically the liberation of histamine and other constituents of
mast-cell granules offers one explatiation of our observations. Tlie results
suggest that many heroin fatalities arc eaused by an anaphylactoid reaetion.