Immunoanatomic distribution of blood group antigens in the human urinary tract. Influence of secretor status
Blood Group Antigens
Seven mouse monoclonal antibodies and the lectin from Ulex europaeus, detecting blood group specificities of the ABH and Lewis systems, have been used to define the immunoanatomic distribution of these antigenic structures within the human nephron and urothelium. The reagents employed recognize the following blood group related antigens: A (all variants), B, H, Lewisa (Lea), Lewisb (Leb), X (Lewisx), Y (Lewisy) and type 1 precursor chain. We have analyzed the presence of these antigens in histologically normal kidney and urothelium from 22 adults and 3 fetuses by the immunoperoxidase method. In addition, we simultaneously examined blood group and secretor status in 15 of the 22 adult individuals studied. Immunohistochemical analyses demonstrated that these antigenic systems are differentially expressed in cell types and domains of the human urinary tract. Major differences were observed in secretor as compared to nonsecretor individuals, mainly in the more pronounced expression of precursor, H, Leb, and Y antigens in secretors. In the kidney, all antigens, except X, showed enhanced expression in secretor individuals on epithelial cells of the collecting ducts and urothelium; X antigen was mainly present in the proximal tubules and portions of Henle's loop. The urothelium was particularly rich in blood group antigens and in some cases showed differential expression of Lea/X and Leb/Y on the various cell layers. Secretors could be divided into two groups based on the intensity and pattern of staining; it is suggested that this may be determined by homo- or heterozygosity at the Se locus. Nonsecretor individuals lacked expression of Leb and Y determinants, as well as H antigen, in the urothelium (three of four cases). Comparison of normal fetal and adult tissues suggest that the expression of some of these antigens is related to maturation stages of the human nephron. These studies confirm the importance of blood group antigens as normal differentiation antigens. These reagents have a wide range of applications including typing of blood group and secretory status in body fluids and tissues, studies of histogenesis and organogenesis, and analyses of neoplastic and non-neoplastic diseases.