Leu-7 Positive Cells Research Articles

The distribution and number of Leu-7 (CD57) positive cells in lung tissue from patients with pulmonary fibrosis.

Leu-7 positive lymphocytes, including natural killer cells, play an important role in the immune system's surveillance function to prevent the development of cancer. The incidence of lung cancer is significantly high in patients with end-stage pulmonary fibrosis. We hypothesized that the number of Leu-7 positive cells may be decreased in areas of severe pulmonary fibrosis. To demonstrate this, Leu-7 positive cells were immunohistochemically stained in 41 lung specimens obtained from patients with idiopathic pulmonary fibrosis and pulmonary fibrosis associated with collagen vascular disorders. The number of Leu-7 positive cells was evaluated according to the pathological findings. In pathologically normal lung, Leu-7 positive cells were mostly found within the capillaries of the septa and rarely in the alveolar space or the stroma. The number of Leu-7 positive cells was 0.69 +/- 0.15 in areas of advanced fibrosis (n = 41), 2.39 +/- 0.60 in areas that had newly developeing fibrosis (n = 41), 1.14 +/- 0.57 in bronchiolitis obliterans organizing pneumonia (n = 9), and 1.35 +/- 0.87 in diffuse alveolar damage (DAD) (n = 11). The number of Leu-7 positive cells in areas of newly developing fibrosis (2.39 +/- 0.60) was significantly higher than that in areas of established fibrosis (0.69 +/- 0.15, P < 0.05). Our present study demonstrates a significant decrease in the number of Leu-7 positive cells in areas of advanced fibrosis. This evidence may partly explain the high incidence of lung cancer associated with pulmonary fibrosis.

Immunoelectron microscopic observations on Leu-7 positive cells in virus-related chronic liver diseases

We investigated the liver biopsies of 78 patients with hepatitis virus-related chronic liver diseases (B type; 14 patients, C type; 64 patients) by immunoelectron microscopy with the Leu-7 monoclonal antibody in order to determine the association of NK/K cells in virus-related chronic liver diseases. Most Leu-7 positive cells in the liver had the Pit cell morphology but a few Pit cells were Leu-7 negative. A few Leu-7 positive cells had neither Pit cell nor typical T cell morphology. No ultrastructural difference was observed in Leu-7 positive cells between hepatitis B virus- and hepatitis C virus-related chronic liver diseases. Regardless of virus type and hepatitis activity, the fine morphology of extravascular Leu-7 positive cells differed considerably from intravascular cells. Leu-7 positive cells were regularly seen in the cellular infiltrates but the ratio of Leu-7 positive cells/whole infiltrates was low. There was no correlation between the inflammatory activity of the disease and the level of Leu-7 positive cell infiltration. A virus aetiology (hepatitis-C or hepatitis-B) did not affect Leu-7 positive cell infiltration. We conclude that NK cells play only a small role in the pathogenesis of hepatitis B virus or hepatitis C virus-related hepatocytolysis, during the chronic stage.

Distribution of natural killer cells in periodontal diseases: an immunohistochemical study.

We studied the distribution and incidence of natural killer (NK) cells in gingiva affected with adult periodontitis (AP) and rapidly progressive periodontitis (RP) with immunohistochemical methods using antibodies Leu-7 and Leu-11b. The incidence of Leu-7 positive cells revealed no significant difference among mild AP, severe AP, and RP. On the other hand, Leu-11b positive cells were frequently found in severe AP and RP. The accumulation of NK cells reacting with Leu-11b in the infiltrated connective tissue was greater in severe forms of periodontal disease (severe AP and RP) than in mild AP. These results suggest that Leu-11b positive NK cells may play a role in the destruction of tissues in periodontal diseases.

Heterotransplantation of a human oligoastrocytoma into nude mice: difference in tumour growth between males and females.

A human oligodendroglial tumour cell line was established in the nude mouse from a mixed oligoastrocytoma. This cell line was identified by immunoperoxidase screening for glial fibrillary acid protein (GFAP) and Leu-7, by electron microscopy, by its growth behaviour, and by radioreceptor assays for oestrogen, progestogen and androgen. At the first heterotransplantation, the tumour grew in the female but not in the male mice. GFAP-positive cells were much less abundant than in the initial tumour, although Leu-7 positive cells were plentiful. Growth curves were biphasic, and the tumours contained both oestrogen and androgen receptors. After three successive heterotransplantations in female mice, GFAP-negative, Leu-7-positive tumours with the cytological features of an oligodendroglioma were obtained. In contrast to those of the first heterotransplantation, the growth curves showed a longer latency and a single growth phase. The tumours contained both progestogen and androgen receptors but lacked oestrogen receptor. The 5th heterotransplantation in male mice exhibited rapid growth, similar to the three previous heterotransplantations in the female mice. The growth observed solely in the female mice at the first heterotransplantation was thought to derive from the hormonal status of the host. The presence of hormone receptors in the tumours at the first heterotransplantation lent support to this idea. There was no further influence of the sex of the host on tumour growth once the oligodendroglial line was established. The establishment and the development of oligodendrocytes may result from differentiation of transitory cells intermediate between astrocytes and oligodendrocytes. The effect of host-sex on the development of oligodendrocytes points to a new facet of the differentiation of CNS glial cells.

Augmentation of cytotoxicity of tumor-infiltrating lymphocytes by biological response modifiers

Lymphocyte infiltration into a tumor has been regarded as an expression of host immunity against cancer, but tumor-infiltrating lymphocytes (TIL) have little or no cytotoxicity. This study examined two different approaches to augment this low cytotoxicity. Firstly, biological response modifiers (OK-432, PSK) were injected into gastric cancer intralesionally. Intralesional injection of OK-432 or PSK significantly augmented the cytotoxicity of TIL. By the injection of OK-432, the ratio of OKT8-, Leu7-positive cells were increased in the TIL subset. In the second approach, TIL of gastric or pulmonary cancer patients were cultured with interleukin-2 (IL-2) in vitro. Co-culturing with IL-2 augmented the low cytotoxicity of TIL, and broad-reactive lymphokine-activated killer (LAK) cells were generated from TIL.

Peri-operative immunotherapy with OK-432

Pre- and postoperative intradermal administration of OK-432 enhanced the SU-PS skin reaction in patients with gastric cancer, but failed to prevent a fall in the NK activity induced by the operation. The change in NK activity was not associated with a change in the proportion of Leu 7-positive cells, but was related to Leu 11a-positive cells. Intradermal injection of OK-432 increased the proportion of Leu 7-positive cells in the patients in whom they accounted for less than 20% of lymphocyte population. The case was the same with Leu 11a-positive cells. Intravenous injection of OK-432 tended to increase suppressor-inducer T cells (CD4+2HA+ cells), B cells and Leu 7-positive cells. Particularly, the proportions of OK-M1-positive cells and MHC class II antigen-positive cells increased in all patients. Immunotherapy with OK-432 given intravenously at a dose of 0.1 KE appeared to be safe because no side effects were essentially observed.

A STUDY OF NATURAL KILLER CELLS IN REGIONAL LYMPH NODE OF COLON CANCER PATIENTS

The role of natural killer (NK) cells in regional lymph nodes was immunohistochemically investigated in patients with colon cancer. NK cells were detected with monoclonal antibody Leu7. Five hundred and thirty lymph nodes were isolated from 62 colon cancers with lymph node metastasis and were examined. Number of Leu7 positive cells in lymph nodes was compared with various factors including liver metastasis, peritoneal dissemination, depth of tumors, staging, pathological diagnosis, with or without metastasis in each lymph node and prognosis.The following results were obtained.1. Number of NK cells in metastatic lymph nodes was significantly decreased. Especialy, cases with the number of less than 1000/cm2 had poor prognosis.2. Number of NK cells in metastatic lymph nodes from mucinous adenocarcinoma was significantly decreased compared with other histologic carcinoma.3. Number of NK cells in non-metastatic lymph nodes was significantly correlated with the staging and lymph node involvement.It was suggested that the advance of a cancer caused the oppression of immune response at regional lymph nodes as self-defence mechanism, which might contribute to a further advance of the cancer.

Lymphocyte subset analysis to predict progression to AIDS in a cohort of homosexual men in San Francisco

A group of 10 leukocyte and lymphocyte subsets were measured by simultaneous dual immunofluorescence and flow cytometry in a group of homosexual men from the San Francisco General cohort. Absolute numbers and percentages of lymphocytes were determined in 30 individuals who progressed to AIDS and 29 who did not over a 44-month period at annual intervals. At entry into the study, all subjects were asymptomatic, HIV seropositive, and had multiple changes in lymphocyte subsets compared to HIV-negative controls. In progressors, large changes occurred from the first visit to the last visit before progression in both absolute numbers and percentages of CD4 cells. The percentage of HLA-DR-bearing CD8 cells also increased. We utilized a proportional hazards model to assign a predictive value for progression to AIDS to lymphocyte subsets in both univariate and multivariate tests. Increased DR-positive CD8 cells, decreased CD4 cells, and increased CD8-positive, Leu 7-positive cells independently predicted progression to AIDS at P < 0.006 (relative hazard 5.8-4.0). In a multivariate model, the most useful tests were either increased numbers or percentages of DR-positive CD8 cells. These data suggest parsimonious approaches to following HIV-positive individuals and further support the possibility of autoreactive T cells in the pathogenesis of HIV-associated diseases.

Correlation of content of B cells and Leu7-positive cells with subtype and stage in lymphocyte predominance type Hodgkin's disease.

Cases of lymphocyte predominance type Hodgkin's disease were investigated using immunohistochemical methods and compared for morphological subtype and clinical stage. Cases of nodular paragranuloma showed a high, diffuse paragranuloma a moderate, and the mixed type a low, content of B cells. There was no significant correlation between B cell content and clinical stage. The number of Leu7+ cells was significantly increased in stage I of nodular paragranuloma. Hodgkin cells did not react with the CD15 antibody in most cases of paragranuloma but showed reactivity in the mixed type.

Effect of Acute Physical Exercise on Lymphocyte Subpopulations in Trained and Untrained Subjects

To clarify the difference in immunity between untrained subjects and well-trained athletes, the number of total leukocytes (WBC), lymphocytes, and neutrophils, percentages of various lymphocyte subpopulations (OKT3, OKT4, OKT8, Leu7, OKla1), and the levels of lymphocyte transformation response to phytohemagglutinin (PHA) were determined in five untrained male subjects and six male athletes before, immediately after, and 24 and 72 h after acute physical exercise at 60% of VO2max for 2 h. Exercise produced a significant rise in the number of WBC, lymphocytes, and neutrophils in both groups. Immediately after exercise, the percentage of OKT3 or OKT4 positive cells had significantly decreased in both groups, whereas that of OKT8 positive cells had markedly increased only in the athletes. Neither group showed any change in the percentage of OKla1 positive cells. In both groups, the response of lymphocytes to PHA immediately after exercise was significantly lower than before, 24 h and 72 h after exercise. The level of Leu7 positive cells rose remarkably immediately after exercise in the athletes, but not significantly in the untrained subjects. These results suggest that an increase in Leu7 positive cells provides added host defense capacity in trained athletes during periods of stress which impair T-lymphocyte function.

Changes in beta-adrenoceptors and leucocyte subpopulations after physical exercise in normal subjects.

Seven healthy volunteers were subjected to standardized bicycle ergometry. Before and at the end of exercise, leucocyte and lymphocyte subset distribution was assessed by immunofluorescence labelling with monoclonal antibodies and the cytofluorograf. Competition binding studies were performed on mononuclear leucocytes with a fixed amount of the radioligand 125I-(-)-cyanopindolol (125I-CYP) and increasing concentrations of the hydrophilic ligand (-)4-(3-tertiary-butylamino-2-hydroxypropoxy)-benzimidazol-2-one hydrochloride (CGP-12177). Total numbers of beta-adrenoceptors per cell and the receptor-ligand affinities were then derived by computer analysis. In separate experiments with blood obtained from resting subjects, beta-adrenoceptor numbers of lymphocyte subsets, which had been sorted by the fluorescence activated cell sorter, were determined by saturation binding of 125I-CYP. During exercise there was a twofold increase in total leucocyte numbers. The ratio between monocytes (4%) and lymphocytes (55%) remained constant, but the composition of lymphocyte subsets had changed. A twofold increase was observed for the lymphocyte population carrying the Leu-7 and the CD8 antigens or only the Leu-7 antigen, whereas the number of B cells and CD4 positive T cells increased only slightly. The lymphocyte phenotype changes appeared after 3 min, reached a maximum at the end of ergometry and had disappeared 30 min after exercise. Exercise led to a doubling of the number of beta-adrenoceptors in unseparated mononuclear leucocytes from 240 +/- 46 to 535 +/- 190 sites per cell (SD, n = 6). beta-Adrenoceptor numbers were higher on sorted Leu-7 positive cells (KD 14 +/- 6 pmol/l, Bmax 1174 +/- 233 sites/cell) and on CD8 positive cells (KD 145 +/- 79 pmol/l, Bmax 1577 +/- 670 sites/cell) than on monocytes (KD 39 +/- 31 pmol/l, 647 +/- 91 sites/cell). Very low specific 125I-CYP binding was found on Leu-7 and CD8 negative cells (less than 0.2 pmol/l). Before exercise the displacement curves with CGP-12177 fitted best a single site model, whereas after exercise 12% of the receptors were in a low affinity state for CGP-12177 indicating internalized receptors. (ABSTRACT TRUNCATED AT 250 WORDS)

Cellular infiltrates in human skeletal muscle: Exercise induced damage as a model for inflammatory muscle disease?

The type and distribution of mononuclear cell infiltrates in muscle biopsies taken from 9 subjects at differing times after exercise in which the muscle is stretched (eccentric exercise) has been characterized. The appearances are compared to those seen in muscle from patients with inflammatory muscle disease. After exercise infiltrating cells were seen in perivascular, perimysial and endomysial regions, the extent being greater in the later biopsies (9–14 days). The predominant cell type was the macrophage (46–100% of all infiltrating cells), the remainder were T lymphocytes with a predominance of the CD4 positive helper/inducer subset. Approximately one third of the T cells expressed DA2 (class 2) antigen indicating that they were activated. Very few B lymphocytes and no Leu7 positive cells were seen. There was evidence of class 1 expression on some of the damaged muscle fibres. The appearance of the experimentally damaged muscle in normal subjects was very similar to untreated polymyositis suggesting that a proportion of the infiltrating cells seen in this disease may be present as part of a natural response to damage rather than being its cause.

Immunophenotype of the lymphoid cell infiltrates in breast carcinomas of low oestrogen receptor content.

Several studies of breast tumour histology and oestrogen receptor (ER) contents report an inverse correlation between the density of the stromal lymphoid cell infiltrate and the presence or concentration of ER. Using monoclonal antibodies to lymphoid cell surface markers we have examined the immunophenotype of the infiltrating lymphoid cells and related this to the tumour ER content. There is a significant inverse correlation between the presence of Leu7-positive cells, which includes a subpopulation of natural killer (NK) cells, and tumour ER content; this is possibly superimposed on the dilutional effect of macrophages and other infiltrating cells.

Enhancement of immune reactivities of regional lymphnodes by oral administration of OK-432 in colon cancer patients

Effect of oral administration of OK-432 on the immune reactivities of regional lymphnode (RNLs) and peripheral blood lymphocytes (PBLs) in colon cancer patients were investigated. Twenty KE of OK-432 was given orally on 7 days prior to the operation, and peripheral blood and regional lymphnodes were collected at the time of operation. As for the immune reactivities of PBLs such as lymphocyte proliferative response to phytohemagglutinin (PHA), natural killer (NK) cell activity and Concanavalin A (Con-A) induced suppressor cell activity, there were no significant differences between patients with oral OK-432 (OK-432 (+) group) and those without OK-432 (OK-432 (-) group). NK cell activity of RLNs was significantly higher in OK-432 (+) group than in OK-432 (-) group. Furthermore, the decline of Con-A induced suppressor cell acivity was found in OK-432 (+) group. T cell subsets in regional lymphnode tissues were identified with the use of monoclonal antibodies and immuneperoxidase technique. Both of Leu-2 a and Leu-7 positive cells distributed more frequently in lymphnodes from OK-432 (+) group than in those from OK-432 (-) group. Thus, these results suggested that immune reactivities of regional lymphnodes were en-hanced by oral administration of OK-432 in colon cancer patients.

Enhancement of Circulating Immune Complexes in Episodic Cluster Headache

Abnormalities have already been reported in the phenotypic frequency of the major histocompatibility complex antigens and in the relative proportions of the leukocyte subsets in patients affected by episodic cluster headache (ECH). Circulating immune complexes (CIC) and leukocyte subsets have been studied in 19 patients affected by episodic cluster headache during and in the absence of periods of crisis. The presence of CIC was determined in another five patients outside periods of crisis. CIC were evaluated using two techniques based on different principles revealing different types of CIC: the solid phase Clq method, and the conglutinin radioimmune assay. Monoclonal antibodies have been used to phenotype total T, helper/suppressor, K and NK leukocyte subsets, and monocytes. The findings demonstrate an increased incidence of CIC in the 19 ECH patients followed with time (37%) with respect to control subjects (10%), and an increase in Leu7-positive cells (K and NK cells) and in LeuM3-positive cells (monocytes). Interestingly, when patients were grouped according to the presence of CIC, only CIC-positive patients showed the previously described abnormalities. This would suggest that the cell-mediated immune alterations present in these patients may interact with the presence of CIC.

Immunoelectron microscopic identification of human NK cells by FITC-conjugated anti-Leu-11a and biotinylated anti-leu-7 antibodies

Human natural killer (NK) cells have been reported to express various surface antigens. The majority and the most functionally potent NK cells are Leu-11a (NKP-15) positive cells. Only a small number of functional NK cells express Leu-7 (HNK-1) antigen. In the present study, we have established techniques for immunoelectron microscopic identification of NK cells by mouse monoclonal FITC-conjugated anti-Leu-11a and biotinylated anti-Leu-7 antibodies. Ficoll-Hypaque-isolated peripheral blood lymphocytes (PBL) were reacted with the specific antibodies before or after fixation in a 1% glutaraldehyde/1% paraformaldehyde fixative. Prefixation labeling of viable cells with the antibodies was carried out at 4°C or 37°C. Cells prelabeled with anti-Leu-11a antibody were reacted with secondary antibodies either before or after fixation. Anti-Leu-7 antibody was stained directly via an avidin-biotin-peroxidase (ABC) system, anti-Leu-11a antibody was stained indirectly by the ABC immunoperoxidase procedure via a biotinylated anti-mouse IgG secondary antibody or by a 10 nm or 40 nm colloidal gold-labeled anti-mouse IgG antibody. Results indicate that Leu-7 antigen could be localized by incubation with the specific antibody either before or after 20 min fixation; however, Leu-11a antigen was totally abrogated following the same fixation procedure. The Leu-11a antigen was well stained by the methods of prefixation labeling of cells with anti-Leu-11a antibody and incubation with a biotinylated secondary antibody and the ABC system after fixation. With respect to colloidal gold labeling, better results were obtained when cells were reacted with the gold-labeled antibodies immediately after incubation with anti-Leu-11a antibody but before fixation. Ultrastructurally both Leu-7 positive (+) and Leu-11a positive (+) cells shared common ultrastructural features associated with large granular lymphocytes. Using the above described techniques, we found approximately 2–5% Leu-7+ and 9–15% Leu-11a+ cells in the PBL of healthy donors. The overall results suggest that Leu-11a antigen is more sensitive to glutaraldehyde/paraformaldehyde fixation than Leu-7, since it can be localized only by prefixation labeling procedures; the ABC immunoperoxidase procedure is an ideal technique for labeling NK cells for light and electron microscopic enumeration; the immunogold method provides an adequate technique for labeling NK cells which are designated for ultracythochemical studies.

Identification of lymphocyte subsets and natural killer cells in head and neck cancers. An immunohistological study using monoclonal antibodies.

We investigated host-immune defenses against head and neck cancer cells by using various monoclonal antibodies with an immunoperoxidase technique to define lymphocyte subsets and natural killer (NK) cells. By so doing, we were able to identify lymphocyte subsets and NK cells in various head and neck cancers. We found that the majority of these cells infiltrate in or around nests of cancer cells and are stained with Leu-1 antibody. They include both Leu-2a and Leu-3a positive cells, which show equally intense levels of infiltration. Leu-7 positive cells were only scattered in the peripheral portion of the cancer nests in some cases. We also found a tendency for T-cells to infiltrate more intensely in poorly differentiated squamous cell carcinomas (SCC) than in moderately or well-differentiated SCC. Similarly, T-cells were more prevalent in maxillary carcinomas than in laryngeal carcinomas. These findings suggest the presence of a host-immune defense mechanism against cancer cells in patients with head and neck cancers.

Infiltration density of HNK1 positive cells in non-hodgkin's lymphomas depends on histologic subtype: an in situ morphometric analysis

Numbers and distribution of HNK-1 (Leu7) positive cells within 115 malignant Non-Hodgkin'slymphomas (NHL) were evaluated in situ by immunomorphometry. Results on the infiltration were related to histological and clinical parameters. A mean of 4.099 ± 350 HNK 1 + cells/μl tumor tissue was found, which was comparable to normal (reactive) lymphatic tissues (4.441 ± 1.235) and was about a quarter of the population density of T helper/inducer (TH) and T cytotoxic/suppressor (T s) lymphocytes together. The distribution of HNK 1 + cells within the tumors was diffuse except in nodular lymphomas of follicular center cell origin (centroblastic/centrocytic = cb/cc NHL). When evaluating the different histological subgroups, the highest number of HNK 1 + cells was found within the tumor areas of cb/cc, which contained about three times as many positive cells as the other NHL. High numbers were also found in the diffuse variant of cb/cc but not in centrocytic NHL. Different degrees of HNK 1 + cell densities were observed in lymphocytic lymphomas (4.426 ± 754), with high numbers in, about 30% of the patients. Splenic tissues of 6 hairy cell leukemias displayed lower numbers of HNK 1 + cells as compared with other low grade malignant NHL. In ≪large cell≫ NHL, the lymphoblastic subtype showed only sparse HNK 1 + cells (1.345 ± 386). The number was significantly reduced in comparison to all other NHL (p < 0.01) and markedly lower than in the other NHL of high malignancy (immunoblastic and centroblastic NHL, p < 0.02). The diminuation was not due to a simple dilution phenomenon in a rapidly proliferating tumor, as T H and T S infiltrates were comparable to other NHL. Correlating results with the clinical course (available in 58 patients), significantly higher numbers of HNK 1 + cells were found in NHL of low malignancy (p < 0.02), but patients with a favourable course did not differ from those with progressive disease (p > 0.5). Patients treated by cytotoxic drugs showed higher numbers of HNK 1 + cells than those before or without treatment (p < 0.02). Results on T H and T S cell numbers in comparison to HNK 1 + cells showed completely different patterns of infiltration.

Immunohistological identification of B cell differentiation in human tonsillar follicles by using monoclonal antibodies.

Using immunoperoxidase technique and various monoclonal antibodies, B1, B2, OKT9, OKT10 and Leu-7, we investigated B cell differentiation in the tonsillar follicle. Mantle zone was stained with B1 intensely and B2 faintly. In contrast, germinal center was stained with B1, OKT10 and OKT9, and more intensely with B2. In the intermediate part of the germinal center some large cells were stained with OKT10. With OKT9 antibody, most of cells in the lymphoepithelial symbiosis and some large dendritic cells considered to be tangible body macrophages or dendritic reticulum cells in the germinal center were intensely stained. Leu-7 positive cells were localized mainly in the intermediate part of the germinal center. Stages of B cell differentiation in the tonsillar follicle were discussed, considering these results.

Localization and characterization of T-cell subpopulations and natural killer cells (HNK 1+ cells) in the human tonsilla palatina

In the present study attention was focussed on several lymphoid subpopulations and specific stationary cells of the human tonsilla palatina. They were labeled at the light- and electron-microscopic levels by means of monoclonal antibodies to cell surface antigens. Cells resembling interdigitating cells (IDC-like cells) within the crypt epithelium and the interdigitating cells in the parafollicular T-cell region express the HLA-DR antigen. This fact suggests a relationship between these two populations of cells. Both cell types were frequently found in close contact to T-helper cells labeled with Anti-Leu 3a. This fact is discussed as a confirmation of earlier suggestions that the tonsillar crypt epithelium serves as T-cell region. Cytotoxic/suppressor-T cells (OKT8+) and Leu 7-positive cells do not appear to contact interdigitating cells. Anti-Leu 7 is a monoclonal antibody, that defines a differentiation antigen shown to be selectively expressed on human natural killer cells (NK-cells). With the use of the immuno-electron-microscopic labeling method it was possible to analyze the ultrastructure of this lymphoid subpopulation. Two morphologically distinguishable subtypes of Leu 7-positive cells populate different microenvironments: The Leu 7-positive large-granular lymphocyte was predominantly found in the crypt epithelium, while numerous Leu 7-positive cells located in the germinal centers had the appearance of small lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)