Eosinophil abnormal numbers

The amino acid precursor for 5-HT, L-tryptophan, increases the biosynthesis 5-HT and, therefore, has been investigated for potential antidepressant properties, but with mixed results (Green and Costain, 1979). It was withdrawn in 1990, following a number of fatal cases of eosinophilia myalgia (a disorder characterised by severe muscle pain and abnormally high levels of one type of white blood cell, the eosinophil) in individuals principally using it as a natural hypnotic. 

Asthma is a common disease affecting approx 10% of the population in developed countries, and the prevalence and mortality are rising. The disease has characteristic symptoms, namely intermittent airway obstruction, airway hyperresponsiveness, and increased numbers of activated inflammatory cells and airway structural changes as a result of chronic airway inflammation. The primary underlying abnormality in bronchial asthma is thought to be the unique form of airway inflammation, including particularly eosinophils and mast cells, that gives rise to reversible airway obstruction and hyperresponsiveness. 

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