[L-tryptophan and the eosinophilia-myalgia syndrome--consequences for artificial nutrition?]

Present knowledge on the possible cause of the tryptophan-induced eosinophilia-myalgia syndrome is discussed on the basis of a literature survey. The initially favored hypothesis of metabolites of a deranged tryptophan metabolism in some persons as cause of the syndrome has no plausibility for several reasons discussed in this paper. In the meantime trace backs of implicated tryptophan lots have led to one manufacturer who has changed his production procedure. The implicated lots contain a variety of impurities detectable by HPLC. Whether these impurities are the immediate cause of the syndrome or just markers remains to be established. An animal model suitable to clarify this question has recently been developed. Taking all these measures to identify and eliminate suspicious lots, there is no reason to withhold live saving artificial nutrition with tryptophan-containing preparations.