Optimizing follicular dendritic cell isolation by discontinuous gradient centrifugation and use of the magnetic cell sorter (MACS).

Follicular dendritic cells (FDC) contribute minimally to the total cell population of lymphatic tissue. In order to obtain higher numbers of viable FDC with only a small fraction of contaminating cells the following procedure was developed. Subsequent to the usual mechanical and enzymatical digestion of human tonsils, single cells were layered on top of a discontinuous bovine albumin gradient and centrifuged at 8500 x g. The suspension collected from the 1.052-1.030 interphase contained an average of 10.5% FDC. Next, the preparation was subjected to a new step involving separation of FDC previously treated with biotin-labelled KiM4 monoclonal antibody, raised against FDC, and attached via biotin-streptavidin bonding to streptavidin-conjugated paramagnetic beads. Purification on a magnetic cell sorter (MACS) yielded 3.3-10.1 x 10(6) cells with an average FDC content of 78.4%. The viability and morphology of the resulting FDC population was examined using trypan blue staining or electron microscopy. This technique will permit in vitro studies and long term cultures with FDC isolated from human lymphatic tissue.

Proliferation of germinal center B lymphocytes in vitro by direct membrane contact with follicular dendritic cells.

In secondary lymphoid organs, follicular dendritic cells (FDC) are located within B cell follicles and germinal centers. Through their cytoplasmic extensions they come into contact with a large number of neighboring lymphocytes. Using an enzyme cocktail to digest human tonsils followed by ultracentrifugation on bovine serum albumin gradients, single cell suspensions were obtained. Immunocytochemistry revealed that 7% of the cells were FDC, 5% T cells, and 5% macrophages. The remaining population were B cells with greater than 95% being of the germinal center phenotype (i.e. CD19-positive, CD39/sIgD negative). After 24 h of culture up to 44% of the lymphocytes were found in clusters centered around FDC. At the start of the culture as well as 24 and 72 h later, between 31 and 55% of the B cells within FDC associated clusters were in late G1 to M phase of the cell cycle. In contrast, less than 10% of the B cells not in contact with FDC (i.e. outside the clusters) were in an activated state. Autoradiography revealed that after three days of incubation the rate of proliferation was 26.2 times higher for the lymphocytes involved in cluster formation as compared to those cells not associated with FDC. Furthermore, the number of viable B cells after a 72 h mitogen-free culture period was determined. By adding FDC to these preparations, 31.9% of the lymphocytes were rescued from dying. These data show that FDC provide a microenvironment which can maintain the viability, activation and proliferation of germinal center B cells in vitro.

Effect of small doses of iodine on thyroid function in patients with Hashimoto's thyroiditis residing in an area of mild iodine deficiency.

OBJECTIVE: Several studies have suggested that iodine may influence thyroid hormone status, and perhaps antibody production, in patients with autoimmune thyroid disease. To date, studies have been carried out using large amounts of iodine. Therefore, we evaluated the effect of small doses of iodine on thyroid function and thyroid antibody levels in euthyroid patients with Hashimoto's thyroiditis who were living in an area of mild dietary iodine deficiency. METHODS: Forty patients who tested positive for anti-thyroid (TPO) antibodies or with a moderate to severe hypoechogenic pattern on ultrasound received 250 microg potassium iodide daily for 4 months (range 2-13 months). An additional 43 patients positive for TPO antibodies or with hypoechogenicity on ultrasound served as a control group. All patients were TBII negative. RESULTS: Seven patients in the iodine-treated group developed subclinical hypothyroidism and one patient became hypothyroid. Three of the seven who were subclinically hypothyroid became euthyroid again when iodine treatment was stopped. One patient developed hyperthyroidism with a concomitant increase in TBII titre to 17 U/l, but after iodine withdrawal this patient became euthyroid again. Only one patient in the control group developed subclinical hypothyroidism during the same time period. All nine patients who developed thyroid dysfunction had reduced echogenicity on ultrasound. Four of the eight patients who developed subclinical hypothyroidism had TSH concentrations greater than 3 mU/l. In 32 patients in the iodine-treated group and 42 in the control group, no significant changes in thyroid function, antibody titres or thyroid volume were observed. CONCLUSIONS: Small amounts of supplementary iodine (250 microg) cause slight but significant changes in thyroid hormone function in predisposed individuals.

Follicular dendritic cells in non-Hodgkin's lymphomas.

Follicular dendritic cells (FDC) are restricted to the B-cell regions of secondary lymphoid tissue and to non-Hodgkin's lymphomas derived from the follicular center or the mantle zone. With their cytoplasmic ramifications they form a dense network which contains the B-lymphocytes. In situ, FDC are only detectable at the ultrastructural level or when stained with anti FDC-reagents. On the surface of their dendritic extensions they express transferrin receptors (CD71), the B-cell epitope CD20, class II antigens, the myelomonocytic molecule CD14, the glycoprotein gp50 (CD40), and several receptors for components of the complement system (CD11b, CD21, CD35). Subsequent to an antigen challenge, FDC trap and retain immune-complexes for a long period of time. In vitro FDC and neoplastic lymphocytes spontaneously form small cellular aggregates. This adhesion is mediated by the LFA-1-alpha/beta = ICAM-1, the VLA-4 = VCAM-1, and the ICAM-1 = C3bi- receptor ligand pathways on B-cells and on FDC, respectively. The loss of LFA-1- alpha/beta and ICAM-1 molecules may enable neoplastic lymphocytes to detach from FDC. The monoclonal B-cells now invade new compartments. In vitro, FDC have the capacity to activate resting B-cells and to save them from dying by apoptosis. Signals involved in this activation include cell-surface immunoglobulin and CD40. Immunocytochemistry and autoradiography with single cell suspensions of neoplastic B cells suggest that FDC also provide signals leading to the continued stimulation of lymphoma lymphocytes. During the early stage of HIV infection lymph nodes show an immense follicular hyperplasia, with a massive increase of the dendritic network of FDC. In the later stage of the disease, the continuous involution of the germinal centers is associated with a progressive destruction of FDC.

Neoadjuvant, hyperfractionated irradiation induces apoptosis and decreases proliferation in squamous cell cancer of the oral cavity.

Twenty-eight patients with squamous cell carcinoma of the oral cavity were treated with a total dose of 20 Gy. Tissue samples for immunohistochemistry were taken at the time of diagnostic biopsy and at surgery after radiotherapy (RX). For detection of proliferating cells, the immunoperoxidase reaction with Ki67 was performed. Apoptotic cells were detected by the TdT-mediated biotin dUTP nick end labeling (TUNEL) method. RX reduced proliferation in 27 patients, only in one case did the proliferation index (PI) increase. Delta PI (PI before RX PI following RX) amounted to 4.11% (SD=3.2%; P<0.0001). The apoptotic index (AI) increased significantly subsequent to neoadjuvant RX. Delta AI (AI after RX--AI before RX) measured 1.82% (SD=0.9; P<0.001). These data indicate that RX of patients suffering from squamous cell carcinoma of the oral cavity with a dosis of 20 Gy induces apoptosis and inhibits proliferation of tumor cells.

[Management of hematologic systemic diseases and rare tumor entities with manifestations in the oromaxillofacial area]. / Management hämatologischer Systemerkrankungen und seltener Tumorentitäten bei Manifestation im Mund-Kiefer-Gesichtsbereich.

Malignant lymphomas, hematological malignancies, sarcomas, occult head and neck primaries, Merkel cell carcinomas and malignant melanomas are among the tumors that are rarely seen in the head and neck region. Almost 20% of patients with acute leukemia initially present with symptoms of the oral cavity (ulcerations, gingival hypertrophy, etc.). If a malignant lymphoma is suspected, the lymph node should be removed in toto to ascertain diagnosis. Furthermore, in order to make sure that the immunohistological work-up or electron microscopic analysis is adequate, the pathologist should be informed prior to extirpation of the suspicious lymph node. The same diagnostic procedure is indicated for metastases from undifferentiated or small cell cancer of an unknown primary. Metastatic squamous cell or undifferentiated carcinoma to a solitary cervical lymph node from an unknown primary can be cured by multimodal therapy (extirpation, radical neck dissection and adjuvant radiation) in 30% of the cases. Following polychemotherapy, long-term survival may also be achieved in disseminated stages of undifferentiated carcinoma or poorly differentiated adenocarcinoma in an occult primary. When osteosarcoma of the jaw is suspected, core biopsy has to be planned carefully: in order to prevent tumor seeding, the needle track has to be excised during definitive surgery. Most authors propose (neo-)adjuvant chemotherapy (or chemoradiation) for head and neck osteosarcoma, especially when additional risk factors, i.e. a large primary or poorly differentiated sarcoma, are present. Patients with positive margins should receive adjuvant radiotherapy in soft tissue sarcoma. Local control of angiosarcoma is possible exclusively by radiation. Adjuvant radiation is also indicated in Merkel cell carcinoma. Because this tumor spreads in a "cascade" fashion, elective node dissection may also provide a chance for cure. Excision with wide margins is the principal therapeutic step in malignant melanoma. Due to the anatomic localization, adequate resection may not be possible in mucosal melanoma of the head and neck. When regional lymph nodes are involved, radical lymph node dissection and adjuvant radiation have to be added to the therapeutic concept. There is an emerging role for adjuvant interferon alpha in intermediate and high-risk melanoma.

Thrombopoietin serum concentration in patients with reactive and myeloproliferative thrombocytosis.

We wished to test whether thrombopoietin (TPO) is entirely regulated by receptor binding or if other factors may play a role in the mechanism of TPO regulation. Therefore, we analyzed the TPO serum levels in 43 patients with reactive (secondary) thrombocytosis and in 37 with myeloproliferative thrombocytosis. Thrombocytosis was defined as a platelet level greater than 440 x 10(9)/l. Forty-two patients (98%) with reactive thrombocytosis had high concentrations of IL-6 correlating with elevated C-reactive protein levels. Twenty-three patients (53%) in this group had TPO serum concentrations of more than 300 pg/ml (normal: below 300 pg/ml). Only nine patients (24%) with myeloproliferative thrombocytosis had TPO serum levels above normal range, whereas 28 patients (76%) had normal levels of TPO. No correlation between the TPO serum levels and the concentrations of IL-6 or EPO was established. The other investigated thrombopoietic cytokines (IL-3, IL-11, GM-CSF) were unmeasurable; therefore, a correlation could not be assessed. We conclude that TPO concentrations are not strictly inversely related to platelet count. TPO serum levels are elevated especially in a considerable percentage of patients with reactive thrombocytosis, arguing for the existence of additional mechanisms of TPO regulation.

[Recurrent gastroparesis following abdominal irradiation. Therapy with cisapride]. / Rezidivierende Gastroparese nach Abdomenbestrahlung. Therapie mit Cisaprid.

Following abdominal radiation a 16-year-old male patient developed nausea and vomiting secondary to gastric stasis, dilatation and impairment of antral motility. Symptoms improved after 2 months of treatment with a cholinergic agonist. Now, 7 years later, symptoms recurred. Cisapride, a newly developed agent which stimulates gastrointestinal motility probably evoked a prompt increase of antral motility and gastric emptying. We conclude that abdominal irradiation may cause gastrointestinal motility disturbances which may respond to medical therapy.

Helicobacter pylori induces apoptosis in mucosal lymphocytes in patients with gastritis.

BACKGROUND: Previous studies suggest that Helicobacter pylori (H. pylori) induces apoptosis and compensatory hyperproliferation in gastric epithelial cells possibly explaining the carcinogenic capacity of the bacteria. The aim of this study was to measure the effect of H. pylori on apoptosis of gastric lymphoid cells in view of the development of gastric lymphoma. METHODS: 16 H. pylori-positive and 19 H. pylori-negative individuals were enrolled. Single cell suspensions were prepared from antral biopsies and apoptosis was measured by staining with the TUNEL-assay and the fluorochrome Hoechst 33342. Lymphocyte subsets were simultaneously identified by immunocytochemistry. RESULTS: The apoptotic index of all gastric mucosal cells was significantly higher in H. pylori-positive mucosa compared to negative controls. Additionally, H. pylori-infected patients showed a significant increase in apoptosis of mucosal B-lymphocytes. Apoptosis of T cells and plasma cells was unaffected by H. pylori. CONCLUSION: H. pylori induces apoptosis in mucosal B cells which might be important in the development of gastritis and possibly B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT).

Chemotherapy with cisplatin and paclitaxel in patients with locally advanced, recurrent or metastatic oesophageal cancer.

Single-agent therapy with paclitaxel is effective against both squamous cell carcinoma and adenocarcinoma of the oesophagus. However, only limited data are available on the combination of paclitaxel with other cytotoxic drugs in this entity. Patients with unresectable stage III, recurrent or metastatic tumours were treated in a multicentre setting with paclitaxel 90 mg m(-2) given over 3 h intravenously, followed by cisplatin 50 mg m(-2). The courses were repeated every 14 days. Twenty patients with squamous cell carcinoma or adenocarcinoma of the oesophagus were evaluable for response. The overall remission rate was 40% (8/20), including 15% (3/20) clinically complete responses. Clinical benefit response, defined as relief of dysphagia and/or significant gain in weight, was achieved in 70% of the patients. Neutropenia of CTC grade 3 occurred only in 10% of the patients; no grade 4 neutropenia and no severe thrombocytopenia was encountered. CTC grade 4 neurotoxicity was seen in 5% of patients. Cisplatin/paclitaxel administered every 14 days, was effective in patients with poor prognosis oesophageal cancer and toxicity was acceptable.

Antigenic phenotyping of human follicular dendritic cells isolated from nonmalignant and malignant lymphatic tissue.

Follicular dendritic cells (FDC) are located within follicles of secondary lymphoid tissue and in lymph nodes of patients with germinal center cell-derived non-Hodgkin lymphomas. Reliable antigenic phenotyping of FDC within tissue sections has been difficult due to simultaneous labeling of the surrounding germinal center cells. Using an enzyme cocktail to digest human tonsils and cervical lymph nodes with subsequent fractionation by albumin gradient centrifugation, cell isolates containing up to 20% FDC were obtained. This preparation allowed the determination of antigenic phenotype on individual FDC. Molecules expressed by FDC were detected by an isotype-specific immunocytochemical double-labeling procedure, i.e. a monoclonal antibody (mAb) specific for FDC (KiM4 or DRC1) in conjunction with a mAb reactive against an additional antigenic determinant. Nonspecific binding of mAb to immunoglobulin Fc receptors located on FDC membranes was avoided by incubation of cells with human IgG aggregates prior to immunostaining. The results revealed that isolated FDC from these lymphoid tissues express transferrin receptors, the intercellular adhesion molecule 1, class II antigens, the B cell antigens CD20 and CD21, and the myelomonocytic properties CD11b and CD14. Immunoglobulin mu or gamma heavy chains and the B cell antigens CD23 and CD24 are detected on 50% of an isolated FDC population. These FDC are negative for the T helper cell antigen CD4, the B cell cell antigens CD19 and CD22, the immunolobulin alpha and delta chains and the S-100 protein. FDC isolated from lymph nodes of patients with low-grade malignant non-Hodgkin lymphoma, identified by DRC1 or KiM4 mAb, presented the same antigenic profile as seen on FDC from nonmalignant tissue. This suggests that FDC from lymphoma tissue isolated in this manner have the same properties as those found in normal tissue.

Diagnostic value of endoscopic ultrasonography-guided fine-needle aspiration cytology of mediastinal masses in patients with intrapulmonary lesions and nondiagnostic bronchoscopy.

Several procedures are available for the cytopathological diagnosis of mediastinal lesions. The purpose of this study was to evaluate the diagnostic value of endoscopic ultrasonography (EUS)-guided fine-needle aspiration (FNA) in patients with mediastinal mass lesions/lymph node enlargement. All patients had intrapulmonary lesions on chest X ray and/or CT scan, and inconclusive findings by endobronchial forceps biopsy and/or brush cytology. EUS-guided FNA was performed in 16 patients using a modified oblique forward-viewing gastroscope with an electronic multielement curved linear ultrasound transducer. After the region of interest was localized, a 22-gauge Vilmann-Hancke needle was introduced via the 2-mm biopsy channel. The cytological diagnosis of EUS-guided FNA was conclusive for cancer in 9 patients and in the other 7 patients the aspirated samples revealed a benign lesion. In 10 patients the final diagnosis was cancer, thus EUS-guided FNA was diagnostic for malignancy in all but 1 of the lesions (sensitivity 90.0%). In 1 patient epitheloid cell granuloma was detected by cytological examination of the FNA. Following tuberculostatic treatment the lesions disappeared completely on CT scan and EUS. The overall accuracy in this study amounted to 93.7%. From this and other studies discussed, it is assumed that the procedure is an accurate and safe technique to examine nodular lesions suggestive of metastatic lymph node involvement.

Enhancement in number and function of antigen-presenting cells in the lymphatic tissue of rats after in vivo administration of diphenylhydantoin (DPH).

We present a monoclonal IgG1 antibody, KiMy1R, which is specific for macrophages and their derivatives in the lymphatic tissue of the rat, and evaluate the distribution of subsets of mononuclear cells in popliteal and para-aortal lymph nodes of Wistar rats after injection of 50 mg DPH into the hindpads. Compared with resting lymphatic tissue and lymph nodes of animals treated with phenobarbital, DPH induced a significant increase (P less than 0.01) of the proportion of phagocytic cells. Furthermore, the soluble antigen alkaline phosphatase was traced after inoculation into the footpads of rats: in locoregional lymph nodes the percentage (mean 12.8/10(3] and the total number (mean 476 x 10(3) cells/lymph node) of cells with membrane-bound or intracytoplasmic alkaline phosphatase, as detected by a monoclonal anti-alkaline phosphatase antibody, were significantly higher (P less than 0.001) in animals pretreated with DPH than in rats pretreated with phenobarbital (mean 2.1/10(3); 31.2 x 10(3) cells/lymph node) and in untreated animals (mean 1.9/10(3); 4.1 x 10(3) cells/lymph node). If verified in humans, the effect of DPH in enhancing the number and function of macrophages and other antigen-presenting cells may exert favourable effects in patients with impairment of the mononuclear phagocytic system.

c-kit mutation and osteopetrosis-like osteopathy in a patient with systemic mast cell disease.

We describe the case of a 69-year-old man with systemic mastocytosis and severe osteopetrosis who carries a somatic activating mutation in the c-kit proto-oncogene. The patient initially presented with urticaria pigmentosa, progressing to systemic mast cell disease with severe anemia due to bone marrow involvement, chronic diarrhea, and hepatosplenomegaly. Direct sequencing using amplimers from reverse transcriptase-polymerase chain reactions (RT-PCR) from skin mast cell-derived RNA revealed a point mutation in the c-kit proto-oncogene at position 2468, introducing a new recognition site for the restriction endonuclease HinfI. Treatment with interferon-alpha 2a, prednisone, and erythropoietin was initiated. Subsequently, clinical symptoms improved significantly and hemoglobin levels are now stable at 13 g/dl.