To clarify the pathogensis of bronchial asthma, eosinophil and basophil precursor cells in peripheral blood were investigated in 28 patients with bronchial asthma (20 atopic and 8 non-stopic asthmatics) and 6 healthy subjects using in vitro colong forming assay with methylcellulose culture medium. There was no significant difference between the mean count of Eo-type colony in bronchial asthmatics and that in healthy subjects, although cases with high colony were more common in the asthma group. The Eo-type colony count was significantly higher in atopic asthmatics than in either non-atopic astmatics or healthy subjects. In contrast, the colony count in non-atopic asthmatics was significantly lower than that in healthy subjects. A significant correlation was found between the Eo-type colony count and peripheral blood eosinophil count in atopic asthmatics, but there was no correlation between the conlony count and peripherad blood basophil count.
These finidings suggest that circulating eosinophil and basophil precuresor cells play an important role in the pathogenesis of atopic bronchial asthma.