Developmental aspects A, B, H, Lewis, I, i and Pr antigens in human kidney

Abstract

Summary Blood group antigens are widely distributed in human tissues. Numerous studies were carried out on adult kidneys, the aim of this work being to compare the distribution of ABH, I, i, Lewis and Pr antigens in adult kidneys with that of three month embryos. In actual fact, at this stage of development, the same structures as those observed in the adult can be seen. The study was carried out by means of the indirect immunofluorescence technique. In the adult, ABH antigens were evidenced on the cells of the vascular endothelium and in the distal, and collecting tubules of secretor subjects only. Lewis antigen was absent in the vascular structures but present in the cells of the distal and collecting tubules of all the subjects with the same Le gene. A high marker heterogeneity was noted inside a same tubule. I and i antigens were observed in the membrane and cytoplasm of some cells from the thick part of the loop of Henle and in some distal and collecting tubule cells. Pr antigen was present in the glomerulus and the distal and collecting tubules. In the three month fetus, ABH and Pr antigens were observed in the same structures. I antigen was absent, whereas i antigen was present in the cells of the distal and collecting tubules. However, the expression of the Lewis specificities was virtually inexistent. Therefore, at the age of three months, when the development of the organs is finished, the embryonic tissues possess the same markers as the adult with the exception of I and Lewis antigens. The results observed in the kidneys of the 14 week fetuses were similar to those observed in the adults (8, 10). Nevertheless, the staining of the apical membrane of the cells appeared stronger than in the adults. Lewis antigens were not shown on the endothelial cells of all the vessels. These antigens were only present in the membrane and cytoplasm of distal and collecting tubules [5]. Whilst the Lewis enzyme was clearly demonstrated in the glomerulus from Lewis positive kidneys, Lewis antigen was not found in the glomerulus [5, 9]. Although A, B, and H antigens were present on some kidney structures of the three month fetuses, Lewis antigens were only found in a small quantity. I and i antigens were only studied on the adult kidneys. In a former study, Feizi [2], using the method of inhibiting precipitation, did not evidence I and i antigens in the kidney. Moreover, in a recent paper, using indirect immunofluorescent techniques, Lenhart et al. [4] showed I and i antigens in different structures of adult kidney. As regards localization, our results come close to those observed by Lenhart et al. [4]. I and i antigen were also found mainly in the cytoplasm and on the surface of the epithelium of distal tubules ; no I and i antigens were found in the glomerulus. The fetuses of three months were completely lacking in I antigen. Whilst i antigen was expressed, its strength seems almost identical to that found in the adult. In contrast to Lenhart et al. [4], Pr antigens were found in the collecting and distal tubules. Nevertheless, some anti-Pr gave a very slight staining of the tubule, whereas the glomerulus were distinctly positive. Thus the main difference between the adult and fetus kidneys was the absence of I and Lewis antigens on the epithelium of the distal and collecting tubules.