Biomedical subjects

E Dabelsteen

Publications and source records attributed to E Dabelsteen.

At least 37 records · Page 2Linked to original sources

PubMed1996

Histo-blood group antigens in human fetal thymus and in thymomas.

The glycosylation of epithelial cell surface antigens follows cellular differentiation, and changes in the pattern of expression are seen in various premalignant and malignant epithelial lesions. The distribution of type-2 chain ABH-carbohydrate structures (N-acetyl-lactosamine, H-type 2 chain, Le-y, Le-x and sialyl-Le-x) of the ABO-histo-blood group system was investigated in 19 normal fetal thymuses (gestational age 16 to 39 weeks) and in 19 thymomas in order to study possible tumor-associated changes in the glycosylation pattern. The material was investigated by immunochemical stainings of formalin-fixed paraffin-imbedded tissue using monoclonal antibodies with defined specificity. In fetal thymus the epithelial cells of the medulla and the Hassal's bodies strongly expressed elongated carbohydrate structures (Le-y, Le-x and sialyl-Le-x). In a few cases the cortical epithelial cells weakly expressed Le-x and sialyl-Le-x. Compared with fetal thymus 16 of the thymomas showed a total loss, or a very much reduced expression of elongated carbohydrate structures. Three thymomas, which histologically had been reclassified according to Kirchner & Müller-Hermelink (14) as high grade thymic carcinomas, revealed strong expression of Le-y, moderate expression of Le-x and weak expression of sialyl-Le-x. This is of interest as in other tumors Le-y is correlated with increased cell motility and with poor prognosis.

ABO Blood-Group System↗

PubMed1996

Topical retinoic acid changes the epidermal cell surface glycosylation pattern towards that of a mucosal epithelium.

Topical all-trans retinoic acid (RA) produces a number of epidermal changes which are indistinguishable from those observed following treatment with a local irritant, namely sodium lauryl sulphate (SLS). This observation has led to criticism that the efficacy of RA in disorders such as photoageing, is merely a result of irritancy. In stratified epithelia, the cellular differentiation process is characterized by a stepwise synthesis of cell surface carbohydrates, and each type of stratified epithelium has its own specific pattern of carbohydrate expression. Glycosyltransferases, which are responsible for carbohydrate synthesis, are influenced by retinoids. Thus, we investigated whether epidermal cell surface glycosylation is altered in skin treated with topical RA, and contrasted it with changes induced by topical SLS. Skin biopsies were obtained from seven normal volunteers who had been treated, on three separate areas of buttock skin, with single applications of 0.1% RA, 2% SLS, or vehicle creams, followed by 4-day occlusion. Biopsies were assessed immunohistologically using highly specific monoclonal antibodies to cell surface carbohydrates (types 1, 2 and 3 chain structures), previously demonstrated in the epidermis and in oral mucosal epithelium. Although type 1 chain structures were not demonstrated in any of the samples, the distribution of type 2 and 3 chain structures in RA-treated epidermis was altered towards that seen in a mucosal epithelium. T antigen, a mucin-type cell surface carbohydrate structure normally expressed throughout the epidermis, was only observed in the granular layer of RA-treated epidermis--a feature of mucosal epithelia. Ley, normally only seen in non-keratinized buccal epithelium, was strongly expressed in RA-treated epidermis. In contrast, the glycosylation pattern of the SLS-treated epidermis was not significantly different from that observed after vehicle treatment. Thus, RA treatment converts normal stratified epithelium towards the phenotype of mucosal epithelium with a decrease in T antigen and a concomitant increase in Ley. These changes are not observed following treatment with SLS and identify an important difference between RA effects and irritancy.

Adult↗

PubMed1995

Expression of blood group-related glycoconjugates in the junctional and other oral epithelia of rodents.

BACKGROUND: The junctional epithelium (JE) attaches the gingiva to the non-vital tooth surface and has other unusual properties which protect the underlying periodontal tissues. The JE differs from other gingival and oral epithelia in its unusual expression of cytokeratins typical of both stratifying and of simple epithelia, a phenotypic pattern possibly related to its specialized functions. METHODS: The patterns of differentiation of rodent gingival and other epithelia were examined using monoclonal antibodies against various glycoconjugates which are expressed on epithelial cell surfaces and provide an alternative marker system for regionally-differing patterns of cell maturation. RESULTS: Markers that are typical of basal cells in other stratifying epithelia were expressed by all cell strata of JE. JE lacked differentiation markers typical of other stratifying oral epithelial but showed suprabasal expression of markers typically expressed by simple epithelia and specialized epithelia, such as taste buds. CONCLUSIONS: The phenotype of rodent JE differs from that of other oral epithelia and the pattern of differentiation assessed by its expression of glycoconjugates parallels that for other phenotypic markers, such as cytokeratins. Differentiation of rodent JE is similar to that of human JE. The functional significance of these patterns of expression is not yet clear but the markers characterizing this unusual epithelium in rodents may be associated with its behavior in periodontal disease and of value to experimental studies of its development.

ABO Blood-Group System↗

PubMed1995

Is the carbohydrate sialosyl-Tn a marker for altered, non-malignant activity in squamous epithelium in the head and neck region?

Cell surface carbohydrates are involved in many cell functions such as cellular differentiation, adhesion, and invasion. A carbohydrate, sialosyl-Tn (STn), is expressed in many human carcinomas but generally not in normal epithelia. In the oral mucosa, however, STn has recently been observed on basal cells in some lesions with epithelial hyperplasia and dysplasia. The aim of this study was to carry out a systematic investigation of STn expression on epithelial basal cells in hyperplastic, 'borderline' malignant, and malignant head and neck lesions, to see if the expression of STn is associated specifically with hyperplastic conditions. Using the primary monoclonal antibody TKH2, normal controls did not reveal STn. STn was detected on probably post-mitotic basal cells in hyperplastic head and neck lesions and on basal cells adjacent to cancers, but not within the carcinomas. A Ki67 antibody reacted with basal cells in other locations. The most highly differentiated lesions, such as focal epithelial hyperplasia and verrucous hyperplasia, revealed a high percentage (86 per cent in both cases) of STn reactivity. The least-differentiated verrucous carcinomas (VCs) and keratoacanthomas (KAs) did not express STn, in contrast to the highly differentiated VCs and KAs. These findings indicate that STn-negative cases may have a greater malignant potential that the STn-positive cases. In conclusion, STn expressed on basal cells is possibly a marker for non-malignant conditions with altered basal cell activity and for highly differentiated verrucous carcinomas.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed1995

The Thomsen-Friedenreich (T) simple mucin-type carbohydrate antigen in salivary gland carcinomas.

The simple mucin-type T (Thomsen-Friedenreich) antigen is a marker of carcinomas, and has been related to aggressiveness of malignant tumours. We studied the expression of T, sialosyl-T, A and H blood group antigens in salivary gland carcinomas. The aim was to study whether the tumours, based on the expression of these structures, could be divided into new diagnostic groups that may later show prognostic significance. Formalin fixed paraffin-embedded tissue sections from 77 salivary gland carcinomas of different histological types were studied using immunohistology and monoclonal antibodies (MAbs). Fresh frozen tissue was examined in 30 of the cases. Frozen sections were superior to paraffin sections in demonstrating T and H antigens. Aberrant glycosylation with accumulation of T (in cytoplasm) and sialosyl-T antigens (in cytoplasm, membrane and mucin) was found in all tumour types except acinic cell carcinomas. In carcinomas in pleomorphic adenomas (CinPA) the effect of fixation was minimal and T antigen location was different. In carcinomas with myoepithelial cell (MEC) participation, the MECs had retained a normal glycosylation pattern. H antigen was expressed in all tumour types, except acinic cell carcinomas and CinPA. A antigen was expressed in all tumour types from blood group A patients, except in CinPA. The expression of T, sialosyl-T, H and A antigens in relation to differentiation grade varied with tumour type in poorly differentiated areas. High and moderate differentiated areas were always stained, whereas poorly differentiated areas in some tumour types expressed T and sialosyl-T antigens and others did not. The accumulation versus lack of expression of the investigated structures in poorly differentiated areas of the tumours may be of prognostic significance.

ABO Blood-Group System↗

PubMed1995

Simple mucin-type carbohydrates in normal and malignant human endometrium.

The simple mucin-type carbohydrate antigens, Tn, sialosyl-Tn, and T, are tumor-associated antigens of adenocarcinomas. We evaluated by immunohistochemistry the expression of Tn, sialosyl-Tn (s-Tn), T, and sialosyl-T (s-T) antigens in normal nonsecretory, early gestational, and malignant human endometrium in relation to genetic (ABO/Lewis blood-type) and hormonal factors. The blood group status had no influence on staining. Tn and s-Tn antigens were infrequently demonstrated in normal nonsecretory endometria but showed an increased expression in adenomatous hyperplasias and endometrial carcinomas, which was unrelated to estradiol (E2) levels, grade, and stage. The T disaccharide was demonstrated infrequently in both normal and malignant endometrium. Staining for T antigen showed an inverse correlation to serum E2 levels. In contrast, s-T antigen showed a pronounced but varied expression in normal and malignant endometrium, and the expression of s-T antigen was positively correlated with E2 levels in serum. Our findings suggest a hormonal influence on expression of simple mucin-type carbohydrates in human endometrium. However, the accumulation of Tn and s-Tn antigens in malignant endometrial cells seem to be unrelated to both genetic and hormonal factors. Because s-Tn is also expressed by secretory endometria, only Tn antigen can be considered a "tumor-associated" antigen of endometrial tissue.

Adenocarcinoma↗

PubMed1995

Observer variability in the histologic assessment of oral premalignant lesions.

Histopathologic examination of oral leukoplakias has a major impact on the assessment of prognosis and treatment planning. We investigated the extent of agreement in grading epithelial dysplasia between pathologists with the same or different educational backgrounds. Two general pathologists and two oral pathologists were each given 100 sections of oral leukoplakia to grade from no dysplasia to carcinoma in-situ. The interobserver agreement rates were in the range of 49% to 69%. The calculated kappa values were in the range of 27% to 45%, showing poor to moderate agreement between the pathologists. When comparing the kappa values between the two pairs of pathologists with the same education, these values did not diverge from the general level of kappa values, indicating that the interobserver variability was due to individual differences rather than to educational background.

Clinical Competence↗

PubMed1994

Expression of type-2 histo-blood group carbohydrate antigens (Le(x), Le(y), and H) in normal and malignant human endometrium.

Changes in expression of histo-blood group ABH and Lewis antigens are common alterations in carcinomas. Using immunohistochemistry, we have evaluated the expression of type-2 histo-blood group antigens in normal and malignant endometrial tissues in relation to genetic and hormonal factors. The Le(x), sialosyl-Le(x), and Le(y) antigens were inconstantly expressed in the normal endometrium. The expression was uninfluenced by the secretor status but was related to the ABO blood group status in Oestradiol (E2) stimulated endometria. Le(y) was expressed most frequently in proliferating endometria from blood group 0 individuals. Le(x) and Le(y) were maximally expressed in atrophic endometria, and Le(x) and Le(y) staining scores correlated inversely with serum levels of E2 in normal, non-secretory endometria. No correlation was found in adenomatous hyperplasias and endometrial carcinomas, which when compared with atrophic endometria, showed a loss of Le(x) and Le(y) and an increased H-carbohydrate expression at apical membranes. Carcinomas from non-secretors showed lower expression of Le(y) and H-antigens than carcinomas from secretors. Our findings suggest that the genetic and hormonal influence on glycosylation based on type-2 chain carbohydrates differ between normal and malignant endometrium. This difference is probably related to specific tumour-associated qualitative and quantitative changes in the fucosyltransferases.

ABO Blood-Group System↗

PubMed1994

Type-1 chain histo-blood group antigens (Le(a), monosialosyl-Le(a), disialosyl-Le(a), Le(b), and H) in normal and malignant human endometrium.

Type-1 chain histo-blood group antigens such as the Lewis (Le)a, monosialosyl-Le(a), Le(b) and H antigens show an increased expression in endometrial carcinomas. However, the possibility that these antigens are expressed under genetic or hormonal influence in endometrial carcinomas has not been considered. In the present study, the expression of type-1 chain carbohydrate antigens in normal and malignant endometrium was evaluated by immunohistochemistry and related to both genetic and hormonal factors. The glands of normal, non-secretory endometria expressed, in contrast with surface epithelial cells, Le(a), Le(b), disialosyl-Le(a), and H determinants infrequently. Adenomatous hyperplasias and endometrial carcinomas showed an increased expression of type-1 chain carbohydrates that was qualitatively influenced by the erythrocyte Lewis phenotype and the secretor status. Whereas Le(a+b-) non-secretors mainly accumulated Le(a) antigen, and only limited amounts of Le(b) antigen, Le(a-b+) secretors expressed H, Le(b) and Le(a) antigens. The expression of type-1 chain antigens showed no association with the serum-oestrogen level or to the hormone-receptor status. Thus the Lewis secretor status has a qualitative influence on the increased expression of type-1 chain antigens, which, however, seem to be unrelated to hormonal factors. Our findings suggest an increased activity of the Se-gene-defined or a closely related fucosyl-transferase in neoplastic endometrial epithelial cells.

ABO Blood-Group System↗

PubMed1994

T (Thomsen-Friedenreich) antigen and other simple mucin-type carbohydrate antigens in precursor lesions of gastric carcinoma.

In a previous report we suggested that T antigen appeared to be associated with gastric carcinoma. To verify this hypothesis and characterize the pattern of expression of simple-mucin type carbohydrate antigens (Tn,sialyl-Tn and T before and after neuraminidase) in normal gastric mucosa and precursor lesions of gastric carcinoma, we studied the mucosa adjacent to 100 cases of gastric carcinoma, gastric biopsies of 60 dyspeptic patients, eight adenomatous polyps and eight hyperplastic polyps. The expression of the antigens was more related to the cell type and underlying lesions than to the coexistence of carcinoma. The most distinctive findings concerned intestinal metaplasia, dysplasia and hyperplastic lesions. In intestinal metaplasia, Tn was found mostly in columnar cells and sialyl-Tn in goblet cells. T was more prevalent in incomplete intestinal metaplasia than in complete. A high prevalence of sialyl-Tn expression and cell membrane immunoreactivity for T antigen, similar to those previously found in gastric carcinomas, were observed in three adenomatous polyps, one hyperplastic polyp, five cases of adenomatous dysplasia in the neighbourhood of intestinal carcinomas and four cases of marked foveolar hyperplasia, three of which were from the mucosa adjacent to diffuse carcinomas. We conclude that adenomatous and hyperplastic lesions share with gastric carcinomas features of aberrant glycosylation, namely the cell membrane expression of T antigen.

Adenocarcinoma↗

PubMed1994

Simple mucin-type carbohydrate antigens in major salivary glands.

Simple mucin-type carbohydrate antigens Tn, sialosyl-Tn and T are often markers of neoplastic transformation and have very limited expression in normal tissues. We performed an immunohistological study of simple mucin-type carbohydrate antigens, including H and A variants, with well-defined monoclonal antibodies (MAb) on frozen and paraffin-embedded normal salivary gland tissue from 22 parotid, 14 submandibular, six sublingual, and 13 labial glands to elucidate the simple mucin-type glycosylation pattern in relation to cyto- and histodifferentiation. The investigated carbohydrate structures were predominantly observed in the cell cytoplasm, most often in the supranuclear area, suggesting localization to the Golgi region, whereas ductal contents were unstained. Mucous acinar cells expressed Tn, sialosyl-Tn, and H and A antigens, regardless of glandular location. Serous acinar cells, on the other hand, expressed A, H, and inconstantly sialosyl-T, Tn, and sialosyl-Tn antigens in major salivary glands, whereas serous cells of minor (labial) salivary glands expressed H exclusively, Tn and sialosyl-T antigens inconstantly, but never sialosyl-Tn and A antigens. The difference may be related to a more simple cytodifferentiation of serous cells of minor (labial) salivary glands as compared with major salivary glands. Duct cells in major salivary glands expressed A, H, and inconstantly T, sialosyl-T, and Tn antigens, whereas minor (labial) salivary glands ducts exclusively expressed H, T and sialosyl-T antigens, differences that may be related to dissimilarities in the duct system. Myoepithelial cells and basal cells exclusively expressed T and sialosyl-T antigens, which may prove useful in studies of salivary gland tumors, since these cells are known to play a key role in the histological characteristics of some salivary gland tumors. The results indicate a similar glycosylation pattern in the different major salivary glands, whereas minor (labial) salivary gland differ slightly in serous and duct cells. The limited and exclusive intracellular expression of the immature Tn, sialosyl-Tn, and T antigens indicates that these structures may be of value as markers of salivary gland tumors.

Antibodies, Monoclonal↗

PubMed1994

A comparison of the effect of epidermal growth factor, platelet-derived growth factor, and fibroblast growth factor on rat periodontal ligament fibroblast-like cells' DNA synthesis and morphology.

An enhanced formation of bone, dentin, and collagen fibers in periodontal wounds after application of polypeptide growth factors has recently been reported. However, the complex environment in vivo makes it impossible to determine the specific effects of growth factors on various cells involved in the wound-healing process. We have therefore investigated the mitogenic and morphogenic effects of recombinant epidermal growth factor (rEGF), natural platelet-derived growth factor (nPDGF), and natural fibroblast growth factor (nFGF) on periodontal ligament fibroblast-like cells. A cell line was established from rat PDL tissue. The cell line was characterized according to morphology, growth pattern, cytoskeletal proteins, and growth kinetics. The mitogenic effect of growth factors was assessed by incorporation of [3H]thymidine in the cellular DNA for 4 hours. Differences between groups of observations were assessed by the Student t-test. The morphogenic effects of growth factors were described with respect to growth pattern, cell orientation, and cell and nucleus form after a random photographic recording. The fibroblast-like cell type and the non-transformed phenotype of the cell line have been identified by the presence of parameters considered to be characteristic of a normal fibroblast-like cell line. The morphogenic analysis of both experimental and control cultures showed a monolayer of adherent cells with spindle or stellate morphology, a random alignment and round or elongated nuclei. Incorporation of [3H]-thymidine was increased in a dose-dependent manner by all growth factors. Maximal effect on the DNA synthesis was: rEGF, 131%; nPDGF, 274%; and nFGF, 182%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Oncofetal fibronectins in oral carcinomas: correlation of two different types.

Different isoforms of fibronectin are derived from a single gene by alternative processing of the primary RNA transcript or by posttranslational modifications. We have previously demonstrated that an oncofetal fibronectin (FN) isoform derived by O-glycosylation is highly associated with malignancy in breast and oral tumors. Another oncofetal FN isoform containing the ED-B sequence is derived by alternative splicing, and FN containing ED-B has been found to be a stromal marker of malignancies in various tissues. Here we report a comparative study by immunohistology of the distribution of the ED-B-containing isoform and the oncofetal FN isoform derived by O-glycosylation, in oral squamous cell carcinomas, premalignant lesions, and normal oral mucosa. A selective expression of the ED-B-containing isoform was demonstrated in close relation to the invading carcinoma (38/38), whereas there was virtually no staining in submucosa underlying premalignant lesions (1/11) and normal epithelium (0/5). The ED-B-containing FN showed close co-distribution and staining pattern with the oncofetal isoform derived by O-glycosylation. These results demonstrate that accumulation of FN adjacent to oral carcinomas includes both the ED-B-containing isoform and the isoform derived by O-glycosylation. Although both the change in primary structure and glycosylation of FN create conformational and immunologically detectable changes, the functional consequences in association with invasive carcinoma are poorly understood at present. Diagnostic implications especially of borderline lesions as well as evaluation of tumor aggressiveness may, however, be important.

Aged↗

PubMed1993

Biosynthetic basis of incompatible histo-blood group A antigen expression: anti-A transferase antibodies reactive with gastric cancer tissue of type O individuals.

The expression of incompatible A carbohydrate antigens in some adenocarcinomas may provide an explanation for the generally observed lower incidence of adenocarcinoma among types O and B versus type A individuals. The chemistry and genetic basis of incompatible A expression is largely unknown. Here, we have screened 31 cases of gastric tumors of phenotype O for the expression of blood group A gene-defined glycosyltransferase by immunohistology on frozen sections using newly developed monoclonal antibodies to the transferases. Three cases were positive, and transferase expression was confirmed by enzyme analysis of extracts from the specimens. Blood group A carbohydrate antigens were also identified immunohistologically in these three cases as well as in five other cases. Thin-layer chromatography immunostaining analysis of glycolipid extracts from the three cases did not confirm the chemical presence of A antigen. The ABO genotype of all patients was found to be OO, showing that all carried O alleles with a structural defect at nucleotide position 261 leading to a shift in the reading frame. The data suggest that incompatible A antigen expression is a result of transferase expression derived from the ABO genes.

ABO Blood-Group System↗

PubMed1993

Simple mucin-type Tn and sialosyl-Tn carbohydrate antigens in salivary gland carcinomas.

BACKGROUND: Neoplastic transformation is associated frequently with changes in the glycosylation process. Simple mucin-type glycosylation in cancer cells has been found to be characterized by incomplete synthesis with precursor accumulation, leading to the exposure of the structures Tn and sialosyl-Tn, which are normally cryptic in human cells and secretions, including saliva and salivary glands. METHODS: Paraffin sections from 50 salivary gland carcinomas of different histologic types were investigated with immunohistologic studies and a panel of monoclonal antibodies with well-defined specificity for Tn and sialosyl-Tn. RESULTS: Tn and sialosyl-Tn antigens were expressed in the cytoplasm of glandular differentiated cells; in the luminal membranes and mucinous content of the glandular differentiated areas in almost all mucoepidermoid carcinomas and adenocarcinomas; and in carcinoma in pleomorphic adenoma, when the malignant component was an adenocarcinoma. In contrast, acinic cell carcinomas and adenoid cystic carcinomas expressed only minimal amounts of Tn and sialosyl-Tn, and the staining was seen only in relation to the luminal membrane and mucin of a few glandular structures. CONCLUSIONS: Mucin-type Tn and sialosyl-Tn may be regarded as markers of a glandular differentiation pattern in salivary gland carcinomas. The cellular location of the antigen-antibody complex indicates that they are synthesized and secreted from the tumor cells into saliva or serum.

Adenocarcinoma↗

PubMed1993

[Carbohydrate antigens and cancer].

Studies of cancer are often based upon the idea that disease can be explained satisfactorily through insight into biochemistry and molecular biology, and that diseases follow regular patterns, so that, given full understanding of the biochemical environment, their course can theoretically be predicted. This has led to the hypothesis that cancer cells or their precursors may be defined by certain products described as tumor markers. The ideal marker is one that, when present, indicates that cancer will develop and, when absent, will exclude such a possibility. Research into tumor markers has become sweeter in recent years, in that aberrant glycosylation can be detected in most types of human cancers and in some premalignant lesions. Most studies have concentrated on changes seen in the structure of cell surface carbohydrates, although changes have also been found on secreted mucins, on stomal glycoprotein, and on serum glycolipids and glycoproteins. As the terminal part of these glycoconjugates is strongly immunogenic, changes here can easily be detected by antibodies selected on basis of their reactivity with biochemically well-characterized carbohydrates. Several studies have demonstrated that the expression of certain carbohydrates in specific tumors is related to tumor prognosis. Demonstration that carbohydrates are ligands for certain cell adhesion molecules is of special interest in this context as certain carbohydrates expressed in tumors bind to activated endothelial cells and clearly may be of importance for the formation of metastases.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed1993

Distribution of blood-group-related carbohydrate antigens on oral endothelial cells.

Recent studies indicate that carbohydrate structures are involved in various endothelial functions such as inflammatory processes, adhesion of metastatic cells to endothelium and endothelial differentiation. In this paper we report the endothelial expression of various blood-group-related carbohydrate structures in normal oral mucosa using 15 different monoclonal antibodies reacting with type 1, 2 or 3 carbohydrate chains. Twenty biopsies, including normal oral mucosa, from secretor individuals comprised nine blood group O, nine A, one B and one AB. Endothelial staining was compared with epithelial staining in the same biopsies. Five blood-group-related carbohydrate antigens were detected on endothelial cells. The H type 2 antigen, which is the precursor of A, B and AB antigens, has previously been believed to be a universal marker for endothelial cells. All blood group O individuals (n = 9) showed strong H antigen staining in the endothelium of most vessels. However, of blood group A, B and AB individuals (n = 11), four showed heterogenous H antigen staining. In addition, we found that six out of ten blood group A or AB individuals, who expressed A or A and B antigens on spinous squamous cells and glandular epithelium, showed either heterogenous or no staining for these structures on their endothelial cells. It is concluded that there are differences between the biosynthesis of blood-group-related carbohydrate antigens in oral endothelium and epithelium.

ABO Blood-Group System↗

PubMed1993

Mosaic differentiation of human villus enterocytes: patchy expression of blood group A antigen in A nonsecretors.

BACKGROUND: The authors have shown that a mosaicism of brush border antigens may occur spontaneously on enterocytes of small intestine in human adult-type hypolactasia. The present paper gives another example of spontaneously occurring mosaicism as indicated by the patchy expression of blood group antigens on villus enterocytes. METHODS: Thirty-five individuals were examined by immunomorphological techniques with antibodies against blood group antigens. RESULTS: In 4 of 16 A blood group individuals, the blood group antigens were expressed only in some villus enterocytes. The individuals with this mosaic pattern were all shown to be nonsecretors. The A antigen in the positive enterocytes of these individuals was only present as the ALe(b) structure, whereas ALe(y) and ALe(d) were also present in the secretors. The patches of positive enterocytes were randomly distributed along the villus wall. CONCLUSIONS: A nonsecretor individuals express the blood group antigens only in some villus enterocytes; this mosaicism does not arise from a heterogeneous population of stem cells within the crypts but rather reflects subtle differences in the pattern of differentiation between monoclonally derived epithelial cells on the villus.

ABO Blood-Group System↗