POSTMORTEM SERUM LEVELS OF TRYPTASE AND TOTAL AND SPECIFIC IGE IN FATAL ASTHMA

Sera were obtained postmortem from 55 subjects classified into three g roups; death due to asthma (FA, n = 21), asthmatic but death not due t o asthma (NFA, n = 24) and a nonasthmatic control group (NAC n = 10). A full autopsy was performed on all cases and a medical history, inclu ding details of allergies, was obtained by questionnaire from the next of kin. Grading of asthma severity by either questionnaire or autopsy was comparable (t(p) = 0.435, p > 0.05) and the mean pathology-grade was significantly higher for the FA group (3.375) compared to the NFA group (2.375), p < 0.05. Tryptase was elevated (>2.0 mu g/L) in 21/55 sera (38%) and there was no significant difference between the groups, ROC plots showed that tryptase levels did not discriminate between th e FA and NFA groups, even if specimens were collected within 24 hours after death. Total IgE was significantly elevated in the FA group (geo metric mean 140.3 kU/L) compared to the other two groups (NFA 30.2 kU/ L, NAC 9.4 kU/L), p = 0.05. Fatal asthmatics also had a greater positi vity (67%) to a screen for common inhalant allergens than did the othe r groups (NFA 30%, NAC 20%). Sera with a positive screen were tested a gainst a panel of IO common aero-allergens. Each sample was then assig ned a number (Nj and a score (S), dependent on either the number of al lergens positive (N) or the total sum of pluses for all allergens (S). Both the N and S values were higher for the FA group (N = 98, S = 264 ) than the NFA group (N = 52, S = 151) and NAC roup (N = 4, S = 8). Th e ratio (S/N) which gives an index (I) was 2.69, 2.90 and 2.00 respect ively. Tryptase was poorly correlated to the total IgE level (r = 0.03 6); however, mean values for N and S were significantly different (N 6 81, S 4.50, and N 19.25, S 11.5 p < 0.05) for sera with tryptase level s <2.0 or greater than or equal to 2.0 mu g/L, respectively. We conclu de that total and specific IgE may be useful predictors of asthma seve rity but that postmortem tryptase is not useful in the diagnosis of a fatal asthmatic attack.