[The effect of mistletoe lectins on the limulus amebocyte lysate test].

Former reports about too high and from batch to batch changing endotoxin contents in mistletoe preparations and phytopharmaceuticals for parenteral administration correlated with clinically observed side effects led to investigations of the endotoxin content of ABNOBA-viscum. For that purpose the endotoxin levels of the raw materials, the equipment and the production steps were observed by using the limulus amebocyte lysate (LAL) test. The mean value found in the preparation containing the highest available concentration (dilution level 2 containing 15 mg of plant extract from 20 mg of fresh mistletoe in 1 ml) came to 66.7 endotoxin units (EU) per ml, corresponding to about one fifth of the commonly accepted limit value of 350 EU/ml, the human pyrogenic dose. Depending on their dilution level, lower concentrated preparations led also to lower LAL test results. It could be proved that lectins contained in mistletoe preparations cause false positive LAL tests. Such results implicate false too high contents of endotoxin. Different lysates, i.e. Limusate, Pyrogel, Pyrogent, and Pyroquant showed approximately the same results. Microbiological and LAL test results indicate that only 10% of the total amount of the LAL test result was caused by endotoxins. So it is necessary to form a new estimation of the former results of determination of the endotoxin content of mistletoe preparations.