PRETREATMENT WITH METHYLPREDNISOLONE IN CORONARY-ARTERY BYPASS-GRAFTING INFLUENCES THE LEVELS OF HISTAMINE AND TRYPTASE IN SERUM BUT NOT INBRONCHOALVEOLAR LAVAGE FLUID

1. The presence of histamine and tryptase in serum during and after co ronary artery bypass grafting may be an indication of the induction of inflammation. 2. One group of patients received no glucocorticoids an d a second group received methylprednisolone before extracorporeal cir culation. In the steroid group no effects were seen on the basal level s of histamine (2.84 +/- 0.12 ng/ml) and tryptase (0.50 +/- 0.05 ng/ml ) during and after surgery. In the other group two peak levels of hist amine were observed: one at 10 min after starting extracorporeal circu lation (4.19 +/- 1.79 ng/ml) and another at 4 h after surgery (8.26 +/ - 4.85 ng/ml). In this group tryptase was only elevated during the per iod of extracorporeal circulation (1.54 +/- 0.16 ng/ml). 3. There were no differences between the two groups in complement activation. C3a l evels rose to 170 +/- 8% and 180 +/- 10% of the initial value in the s teroid and non-steroid group, respectively. 4. It was concluded that d uring surgery mast cells were activated, but since tryptase levels dec reased in the post-operative period, the second increase in the histam ine level can be explained by activation of basophils or by an unknown mechanism for the release of histamine but not tryptase by mast cells . 5. In the bronchoalveolar lavage fluid the levels of histamine and t ryptase showed no differences between the two groups of patients, but histamine was enhanced compared with normal levels.