Use of lectins in the study of histogenesis of renal cysts

Two peroxidase-labeled lectins, from Tetragonolobus lotus and from peanut (Arachis hypogaea), were used in the study of five cases of polycystic kidney of different types. The two lectins bind with high selectivity of proximal tubules and collecting ducts, respectively. It was found that in infantile polycystic kidneys the cyst walls consistently stained with peanut lectin but not with Tetragonolobus lectin, confirming their origin from collecting ducts only. In adult polycystic kidneys there was mixture of two types of cysts: one positive for peanut, the other positive for Tetragonolobus. The two lectins were, however, mutually exclusive. Moreover, some cysts did not stain for either lectin. The findings suggest that in this type of disease a cyst can originate from any portion of the nephron. The data are also consistent with reports in the literature which used microdissection techniques or chemical analysis of the cyst content. The use of lectins will probably be useful in investigating other types of cystic kidneys, such as dysplastic kidneys and experimental models. The technique is relatively easy to use, but must be applied under strictly controlled conditions, especially when using surgical or postmortem material.