Árpád Pusztai published the first peer-reviewed paper to find negative effects from GM food consumption in 1999. Pusztai fed rats potatoes transformed with the "Galanthus nivalis" agglutinin (GNA) gene from the "Galanthus" (snowdrop) plant, allowing the tuber to synthesise the GNA lectin protein. While some companies were considering growing GM crops expressing lectin, GNA was an unlikely candidate. Lectin is toxic, especially to gut epithelia. Pusztai reported significant differences in the thickness of the gut epithelium, but no differences in growth or immune system function.