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Background: Accurate assessment of the somatic mutational status of clonal immunoglobulin variable region (IgV) genes is relevant in elucidating tumour cell origin in B-cell lymphoma; virgin B cells bear unmutated IgV genes, while germinal centre and postfollicular B cells carry mutated IgV genes. Furthermore, biases in the IgV repertoire and distribution pattern of somatic mutations indicate a possible antigen role in the pathogenesis of B-cell malignancies., Objectives: This work investigates the cellular origin and antigenic selection in primary cutaneous B-cell lymphoma (PCBCL)., Methods: We analysed the nucleotide sequence of clonal IgV heavy-chain gene (IgVH) rearrangements in 51 cases of PCBCL (25 follicle centre, 19 marginal zone and seven diffuse large B-cell lymphoma, leg-type) and compared IgVH sequences with their closest germline segment in the GenBank database. Molecular data were then correlated with histopathological features., Results: We showed that all but one of the 51 IgVH sequences analysed exhibited extensive somatic hypermutations. The detected mutation rate ranged from 1.6% to 21%, with a median rate of 9.8% and was independent of PCBCL histotype. Calculation of antigen-selection pressure showed that 39% of the mutated IgVH genes displayed a number of replacement mutations and silent mutations in a pattern consistent with antigenic selection. Furthermore, two segments, VH1-69 (12%) and VH4-59 (14%), were preferentially used in our case series., Conclusions: Data indicate that neoplastic B cells of PBCBL have experienced germinal centre reaction and also suggest that the involvement of IgVH genes is not entirely random in PCBCL and that common antigen epitopes could be pathologically relevant in cutaneous lymphomagenesis.

Background: In Alport syndrome (AS) impaired production and/or assembly of col IV alpha-chain isoforms results in abnormal structure of glomerular basement membrane (GBM), haematuria and, frequently, progressive renal disease. We investigated the relationship between col IV alpha-chains expression and morphology of GBM, as a possible key to the better understanding of the pathogenesis of renal disease in AS., Methods: GBM distribution of col IV alpha1-, alpha3-, and alpha5-chain was investigated by immunohistochemistry in 32 patients (21 males and 11 females, mean age at biopsy of 11.5 years) with ultrastructural findings suggestive of AS. Ten patients had a proven COL4A5 mutation. Based on the severity of ultrastructural findings, the biopsies were grouped in three (I-III) electron microscopy (EM) classes. Significant EM changes of GBM (thinning, thickening, splitting, basket weaving of the lamina densa) were singularly evaluated using a semiquantitative scale (0-3)., Results: Col IV alpha1-chain was demonstrated in GBM of all patients. Three patterns of staining for col IValpha3- and alpha5-chains were observed: positive, negative, and alpha3(IV)-positive/alpha5(IV)-negative. By chi(2)-test, EM class III lesions and complete loss of alpha3(IV)- and alpha5(IV)-antigen were significantly more frequent (P<0.05 and P<0.01) in male patients, but no significant relation was observed between EM classes and immunohistochemical patterns. GBM alterations did not correlate with staining for alpha5(IV)-chain. Intensity of alpha3(IV)-chain staining, however, had a negative correlation (P<0.05) with the severity of GBM basket weaving., Conclusions: Our results suggest that the alpha3(IV)-chain-containing col IV-network plays a fundamental role in structural and, possibly, functional organization of GBM. Absence of alpha3(IV)-chain in GBM could indicate a more severe renal disease in AS.

Background: Transforming growth factor-beta (TGF-beta) is a multipotent cytokine involved in the turnover of the extracellular matrix. Signal transduction of TGF-beta is regulated via at least five different surface receptors; most of the effects, however, are mediated through the interaction of receptors type I and II (RI and RII). We investigated the glomerular expression of TGF-beta and its receptors RI and RII in human glomerulonephritis., Methods: Indirect immunofluorescence using monoclonal and polyclonal antibodies against TGF-beta isoforms (1,2,3 and 2,3), TGF beta-RI and TGF beta-RII has been carried out on 30 consecutive renal biopsies (5 FSGS, 11 IgAN, 4 MCGN, 6 SLE, 2 RPGN) and on normal kidney tissue., Results: Glomerular immunoreactivity for TGF-beta isoforms correlated with the severity of proliferative lesions: immunofluorescent signal was absent or trace-like in normal kidneys, FSGS, and IgAN with mild mesangial cellularity, and was highest in IgAN with severe mesangial proliferation, MPGN, RPGN, and SLE. Glomerular positivity for TGF-beta-RI and -RII was detectable in SLE and RPGN; a low signal was present also in MPGN. Other types of glomerulonephritis, including focal extracapillary proliferations, and glomeruli of normal kidneys were always negative., Conclusions: Our data show that TGF-beta expression is a good indicator of the severity of proliferative glomerular lesions in most, if not all cases and that RI-RII expression occurs at levels detectable with indirect immunofluorescence in limited number of glomerulonephritides, mostly associated with systemic diseases. A complex interaction between TGF-beta and its ligand may represent a critical factor conditioning the tissue response to immunological injury.

The colony stimulating factor 1 (CSF-1) regulates osteoclastogenesis and bone resorption. Mutations in the CSF-1 gene cause an osteopetrosis characterized by the absence of osteoclasts. Mature osteoclasts respond to CSF-1 with inhibition of bone resorption and an increment of cell spreading. Herein we demonstrate that CSF-1-induced osteoclast spreading depends on the substrate the osteoclast interacts with and requires integrity of the vitronectin receptor and of the c-src proto-oncogene. Rabbit osteoclasts were allowed to attach to glass, serum, osteopontin, and bone substrates, and were treated with 10 ng/ml human recombinant CSF-1 for 4 h. In osteoclasts plated on glass, the cytokine induced 70% inhibition of bone resorption and 1.8-fold stimulation of cell spreading, without changes in podosome expression and microfilament array. In contrast, CSF-1 induced a 2.5-fold increase of osteoclasts showing filopodia, and a 9.5-fold increase of osteoclasts presenting lamellipodia, indicating that membrane motility was required for cell spreading. Osteoclasts plated on serum substrates showed a 50% reduction of spontaneous spreading. However, in this circumstance, CSF-1 still stimulated an increase of osteoclast area. In osteoclasts cultured on osteopontin substrate or on bone slices, an inhibition of CSF-1-induced osteoclast spreading was observed. To establish involvement of the vitronectin receptor and c-src proto-oncogene, cells were treated with the alpha vbeta3 integrin neutralizing antibody, LM609, or c-src antisense oligonucleotides, which reduced CSF-1-induced osteoclast spreading by 57% and 60%, respectively. The results demonstrate that CSF-1-induced osteoclast spreading requires both the vitronectin receptor and the c-src proto-oncogene and that this action is modulated by the adhesion substrata.

We report a patient with a widespread papular disorder characterized by extensive clear cell hyperplasia of the secretory portion of the eccrine units. A 46-year-old woman had a long history of diffuse papules which gave the skin a 'goose-flesh' appearance. She had severe diabetes. Histological examination of a papule showed marked clear cell hyperplasia that involved the secretory duct of all eccrine units present in the specimen sparing the secretory coil. The clear cells were periodic acid-Schiff (PAS) positive and Alcian blue negative. Ultrastructural study confirmed that the clear cells contained abundant intracytoplasmatic glycogen. We suggest that the diabetic condition may be important in promoting the accumulation of glycogen in the eccrine ducts. Our patient represents a peculiar disorder of the eccrine units that, on the basis of clinicopathological features, we have termed papular clear cell hyperplasia of the eccrine duct.

Before the advent of direct molecular gene analysis the diagnosis of Alport syndrome was operationally based on three of the four classical clinical criteria. Recently, mutations have been identified in the COL4A5 gene, which is involved in X-linked Alport syndrome. Here we describe two de-novo mutations in two unrelated children, a male and a female, both with early onset of the nephropathy, but with only one of the diagnostic criteria, i.e. electron-microscopy alterations. Because of the significant estimated proportion of de-novo mutations this diagnosis should be considered in children with early signs of nephropathy, even without a suggestive family history or clinical picture (ocular or audiologic abnormalities). In the future the diagnosis of Alport syndrome will probably be made on the basis of both clinical findings and molecular analysis. Now Alport syndrome is clearly underdiagnosed.

Clear cell chondrosarcoma is a recently recognized tumor of the bone. It has a low-grade malignant potential and characteristic histologic appearance. A case studied by light and electron microscopy showed considerable resemblance to chondroblastoma, but in addition, there were clusters of cells with clear cytoplasm containing glycogen and representing areas of well-differentiated chondrosarcoma. Electron microscopy demonstrated chondroid cells in various stages of differentiation from immature chondroblasts to mature chondrocytes.