[A rare manifestation of Lyme disease]. / Seltene Manifestation einer Borreliose.

A 33-year-old man presented to the authors' general medical practice with a striking alteration to the left nipple. After extensive diagnostic investigation to identify in particular hemato-oncological diseases, a rare manifestation of an infection with Borrelia burgdorferi due to a tick bite was diagnosed. Antibiotic treatment with doxycycline over a period of 3 weeks led to complete restitution of the alteration.

Mistletoe lectin binds to multidrug resistance-associated protein MRP5.

BACKGROUND: Mistletoe lectins (MLs) are the active components of aqueous mistletoe extracts widely used in complementary cancer therapy, however, it is not clear if they bind to carbohydrate residues only or whether they interact with proteins as well. Protein-protein interactions do not seem unlikely as MLs act at very low molar concentrations usually observed with peptide-peptide interactions only and not seen with lectin-sugar interactions. MATERIALS AND METHODS: In order to detect protein-protein interactions a random peptide library was screened for the ability to bind to MLs. RESULTS: MLs bound to peptides showing homologies to multidrug resistance-associated protein 5 (MRP5). However, the MLs only slightly modified the MRP5 efflux pump, while periodate treatment to inhibit cell membrane binding via glycan completely abolished the ML-I binding sites in MRP5 overexpressing cells. CONCLUSION: The protein sequence is not important for ML-I binding, indicating that the biological activity of MLs can most likely be attributed to the sugar chains.

Sarcoma of follicular dendritic cells with features of sinus lining cells--a new subtype of reticulum cell sarcoma?

Dendritic cell neoplasms of the World Health Organization classification comprise Langerhans cell histiocytosis, Langerhans cell sarcoma, interdigitating dendritic cell sarcoma, follicular dendritic cell sarcoma, and dendritic cell sarcoma, not otherwise specified. Several studies based on immunohistochemical and ultrastructural analysis tried to further clarify the origin of these neoplasms which are thought to derive from mesenchymal or bone marrow precursors. Lymphatic vessel endothelium hyaluronan receptor-1 (LYVE-1) was recently described as a marker for lymphatic endothelium which is expressed on normal liver blood sinusoid lining cells, spleen endothelium, activated tissue macrophages, blood vessels in the lung, endothelial cells of lymphatic sinuses, and in fibroblastic reticular cells in lymph nodes. We present a case of LYVE-1-positive reticulum cell neoplasm in an axillary lymph node. To the best of our knowledge, there has been no report about LYVE-1 expression in histiocytic or dendritic cell neoplasms so far. Due to the assumed specificity of this antibody, we propose designation of this reticulum cell sarcoma as lymphatic sinus lining cell sarcoma which might finally represent another subtype of reticulum cell sarcomas.

Bone marrow infiltration pattern in B-cell chronic lymphocytic leukemia is related to immunoglobulin heavy-chain variable region mutation status and expression of 70-kd zeta-associated protein (ZAP-70).

B-cell chronic lymphocytic leukemia (B-CLL) consists of at least 2 subtypes with either somatically mutated or unmutated immunoglobulin heavy-chain variable region (IgVH) genes. A prognostic significance of the infiltration pattern in bone marrow trephine biopsy has been described before. The combined pattern analysis and detection of 70-kd zeta-associated protein (ZAP-70) expression in formalin-fixed, paraffin-embedded bone marrow trephines has not been investigated so far. To evaluate the relationship between ZAP-70 expression, mutation status, and the infiltration pattern in B-CLL, we analyzed bone marrow trephine biopsies from B-CLL patients (n = 35). The expression of ZAP-70 was related to the infiltration type: in all samples with diffuse infiltration pattern, the leukemic cells showed ZAP-70 staining, whereas leukemic cells in a nodular infiltration pattern were negative. By contrast, the mixed-pattern type showed a variable ZAP-70 expression. Besides definitely negative or positive ZAP-70 expression, a few samples showed a faint ZAP-70 staining, and the classification into the positive or negative group was difficult. In addition, the infiltration type was related to the mutation status in a subset of samples: mutation of the IgVH gene was restricted to the nondiffuse infiltration pattern and was not found in cases with diffuse infiltration of bone marrow. The expression of ZAP-70, detected by an immunohistochemical assay and also by real-time quantitative reverse transcriptase-polymerase chain reaction assigned 83% of the chronic lymphocytic leukemia cases to the suspected immunoglobulin mutation subtype. In 2 patients with ZAP-70 expression, a mutated IgVH status was found. These cases exhibited a mixed pattern of infiltration. We conclude that the pure nodular type of marrow infiltration in B-CLL is associated with IgH hypermutation and ZAP-70 negativity, whereas the predominantly diffuse type of infiltration reveals unmutated IgH genes with ZAP-70 overexpression. The mixed type of infiltration is displayed by mutated as well as unmutated cases with a varying pattern of ZAP-70 expression.

Hyaluronate and its receptors in bone marrow.

Cell-cell and cell-matrix interactions, which are mediated by cell adhesion molecules, play a fundamental role during many cellular processes including growth, differentiation, cell migration and cancer metastasis. One molecule playing a major role in these processes is the CD44 surface receptor, which is expressed in a wide range of cells including many cells of the hemopoietic system, where it mediates the interaction with its major ligand, hyaluronate. However, little is known about CD44 and hyaluronate in bone marrow and this was investigated immunohistochemically in trephine biopsies and in cultivated human bone marrow stromal cells. In biopsy specimens, patches of hyaluronate deposition were detected in the extracellular matrix (ECM). However, most of the areas of the ECM were devoid of hyaluronate. Single mast cells and lymphocytes scattered throughout the marrow were CD44 immunopositive. Marrow-derived stromal cells (MDSC) expanded in cell culture were immunopositive for CD44, hyaluronate synthase, and hyaluronate. Hence, a marked difference between CD44 immunolocalisation and hyaluronate deposition can be observed between in situ and under cell culture conditions. Since in normal marrow in situ the number of CD44 immunopositive cells was low, interactions of CD44 and hyaluronate would appear to not to play a major role in cell adhesion in the normal bone marrow.

Osteosclerosis in advanced chronic idiopathic myelofibrosis is associated with endothelial overexpression of osteoprotegerin.

Advanced chronic idiopathic myelofibrosis (IMF) with osteosclerosis and increase and thickening of bone trabeculae is typically contrasted by the absence or sparse presence of osteoclasts. Because osteoclast formation can be inhibited by osteoprotegerin (OPG) we investigated OPG expression in IMF with severe fibrosis and osteosclerosis, which expressed significantly higher (up to 71-fold) OPG mRNA levels when compared with prefibrotic cellular IMF and control cases. The receptor activator of nuclear factor kappaB ligand (RANKL), a positive regulator of osteoclast differentiation and putative antagonist of OPG was overexpressed by up to 34-fold exclusively in advanced IMF. Case-specific calculation of the RANKL/OPG ratio in advanced IMF showed a wide range without significant differences when compared with the prefibrotic IMF and non-neoplastic haematopoiesis. Immunohistochemical detection of OPG protein revealed strong labelling of endothelial cells within proliferating vessels in fibrotic IMF and heterogeneously labelled megakaryocytes, and fibroblasts. Osteosclerosis and impaired osteoclast function in IMF appears to be associated with upregulated endothelial OPG expression but concomitant reduction of the antagonist RANKL could not be demonstrated. We conclude that osteosclerosis in IMF is associated with increased endothelial OPG expression without concomitant RANKL downregulation.

Aberrant expression of transforming growth factor beta-1 (TGF beta-1) per se does not discriminate fibrotic from non-fibrotic chronic myeloproliferative disorders.

Transforming growth factor beta-1 (TGF beta-1) is a potent inducer of fibrosis and has been shown to be essential for the development of bone marrow fibrosis in an animal model of idiopathic myelofibrosis (IMF). IMF belongs to the Philadelphia chromosome negative chronic myeloproliferative disorders (Ph(-) CMPD). Megakaryocytes and platelets have been suggested as the major cellular source of TGF beta-1 in IMF. The osteoclastogenesis inhibitory factor osteoprotegerin (OPG) seems to be regulated by TGF beta-1 and substantial involvement of OPG expression in the process of osteosclerosis in IMF has recently been suggested. In order to determine TGF beta-1 expression in IMF and other Ph(-) CMPD, total bone marrow cells as well as laser-microdissected megakaryocytes were quantitatively analysed by real-time RT-PCR. OPG mRNA expression in fibrotic IMF was correlated with TGF beta-1 mRNA expression in a case-specific manner. Both OPG and TGF beta-1 were detected immunohistochemically in order to delineate cellular origin. When total bone marrow cells were investigated, TGF beta-1 mRNA expression was increased in some but not all cases of IMF (n = 21), with highest values in fibrotic cases. Unexpectedly, increased values were also observed in essential thrombocythaemia (ET, n = 11) when compared to non-neoplastic haematopoiesis (n = 38). Megakaryocytes isolated by laser microdissection displayed elevated TGF beta-1 mRNA levels in most of the CMPD samples with no significant differences discernible between fibrotic IMF, polycythaemia vera (PV) and ET. TGF beta-1 protein was predominantly expressed by the myeloid lineage in Ph(-) CMPD and non-neoplastic haematopoiesis, which, however, displayed lower expression. IMF cases with advanced fibrosis concomitantly overexpressed TGF beta-1 and OPG. Immunohistochemically, OPG expression was found in different stromal cells and a subfraction of megakaryocytes. In conclusion, enhanced TGF beta-1 expression occurs in megakaryocytes as well as myeloid cells in Ph(-) CMPD. TGF beta-1 may be necessary, but is not sufficient, to induce bone marrow fibrosis in IMF because non-fibrotic Ph(-) CMPD entities share this feature with IMF and cannot be discriminated from each other on the basis of TGF beta-1 expression.