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Notes: CD 3 antigen expression was studied in a series of 98 T-cell lymphomas, using polyclonal antibodies which recognize this molecule in routinely processed, paraffin-embedded, tissue. We identified 40 cases in which CD3 was present on only a proportion of the neoplastic cells. This phenomenon of heterogeneous CD3 expression was commonest in pleomorphic T-cell lymphomas (22/42 cases) and in CD30 (Ki-1)-positive lymphomas (5/11 cases), and was less frequently observed in mycosis fungoides (4/18 cases) and not seen in T-cell lymphoblastic lymphoma (0/9 cases). CD3 expression was often related to cell morphology, with CD3 antigen being present on the smaller neoplastic cells but absent from the larger ones. The diagnostic significance of these observations is that, on occasion, it may be possible to diagnose a lymphoma as being of T-cell origin in paraffin sections by demonstrating a minor subpopulation of CD3-positive neoplastic cells.

Notes: Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, lysozyme (LYS)), Langerhans cells (CD1a), follicular dendritic cells (FDC: CD21, CD35) and S100 protein. This analysis revealed that 57 cases (93%) fit into four major immunophenotypic groups (one histiocytic and three dendritic cell types) utilizing six markers: CD68, LYS, CD1a, S100, CD21, and CD35. The four (7%) unclassified cases were further classifiable into the above four groups using additional morphological and ultrastructural features. The four groups then included: (i) histiocytic sarcoma (n=18) with the following phenotype: CD68 (100%), LYS (94%), CD1a (0%), S100 (33%), CD21/35 (0%). The median age was 46 years. Presentation was predominantly extranodal (72%) with high mortality (58% dead of disease (DOD)). Three had systemic involvement consistent with `malignant histiocytosis'; (ii) Langerhans cell tumour (LCT) (n=26) which expressed: CD68 (96%), LYS (42%), CD1a (100%), S100 (100%), CD21/35 (0%). There were two morphological variants: cytologically typical (n=17) designated LCT; and cytologically malignant (n=9) designated Langerhans cell sarcoma (LCS). The LCS were often not easily recognized morphologically as LC-derived, but were diagnosed based on CD1a staining. LCT and LCS differed in median age (33 versus 41 years), male:female ratio (3.7:1 versus 1:2), and death rate (31% versus 50% DOD). Four LCT patients had systemic involvement typical of Letterer–Siwe disease; (iii) follicular dendritic cell tumour/sarcoma (FDCT) (n=13) which expressed: CD68 (54%), LYS (8%), CD1a (0%), S100 (16%), FDC markers CD21/35 (100%), EMA (40%). These patients were adults (median age 65 years) with predominantly localized nodal disease (75%) and low mortality (9% DOD); (iv) interdigitating dendritic cell tumour/sarcoma (IDCT) (n=4) which expressed: CD68 (50%), LYS (25%), CD1a (0%), S100 (100%), CD21/35 (0%). The patients were adults (median 71 years) with localized nodal disease (75%) without mortality (0% DOD). In conclusion, definitive immunophenotypic classification of histiocytic and accessory cell neoplasms into four categories was possible in 93% of the cases using six antigens detected in paraffin-embedded sections. Exceptional cases (7%) were resolvable when added morphological and ultrastructural features were considered. We propose a classification combining immunophenotype and morphology with five categories, including Langerhans cell sarcoma. This simplified scheme is practical for everyday diagnostic use and should provide a framework for additional investigation of these unusual neoplasms.

Notes: [Auszug] Lymphocytes that are responsible for regional (tissue-specific) immunity home from the blood to the intestines, inflamed skin or other sites through a multistep process involving recognition of vascular endothelial cells and extravasation. Chemoattractant cytokine molecules known as chemokines ...

Notes: Abstract Background: Ninety percent of low-grade follicular lymphomas (FLs) carry the t(14;18) translocation. This event juxtaposes the bcl-2 oncogene to the immunoglobulin (Ig) heavy-chain gene and leads to bcl-2 gene over expression. Morphologic transformation of FL to high-grade lymphoma is associated with multiple secondary chromosomal abnormalities of the neoplastic cells. Design: To analyze whether additional structural alterations of the translocated bcl-2 gene are associated with morphologic transformation of FL, we PCR-amplified, cloned, and sequenced the major breakpoint region(MBR) and the open reading frames (ORF) of the translocated bcl-2 oncogene in six paired samples of FL and subsequent diffuse large-cell lymphoma(DLL). Results: In five cases, FL and DLL cells were clonally related, as suggested by the identical MBR sequences, but in one case they were different. PCR single-strand conformation polymorphism (SSCP) and sequence analyses were performed for identification of structural alterations of thebcl-2 gene in the OFR region corresponding to the 239 amino acid p26-bcl-2aprotein. In three of the six patients, a total of 11 point mutations of the ORF were detected in the DLL cells. Four of them, at positions 29, 46, 59,and 106, yielded amino acid replacements. Conclusions: These findings demonstrate that FL and DLL cells may be clonally related or unrelated. They also show that transformation of FL cell scan be associated with somatic point mutations of the bcl-2 oncogene ORF sequence resulting in alteration of the p26-bcl-2a gene product.

Notes: Abstract Background: Ninety percent of low-grade follicular lymphomas (FLs) carrythe t(14;18) translocation. This event juxtaposes the bcl-2 oncogene to theimmunoglobulin (Ig) heavy-chain gene and leads to bcl-2 gene overexpression.Morphologic transformation of FL to high-grade lymphoma is associated withmultiple secondary chromosomal abnormalities of the neoplastic cells. Design: To analyze whether additional structural alterations of thetranslocated bcl-2 gene are associated with morphologic transformation ofFL, we PCR-amplified, cloned, and sequenced the major breakpoint region(MBR) and the open reading frames (ORF) of the translocated bcl-2 oncogenein six paired samples of FL and subsequent diffuse large-cell lymphoma(DLL). Results: In five cases, FL and DLL cells were clonally related, assuggested by the identical MBR sequences, but in one case they weredifferent. PCR single-strand conformation polymorphism (SSCP) and sequenceanalyses were performed for identification of structural alterations of thebcl-2 gene in the OFR region corresponding to the 239 amino acid p26-bcl-2aprotein. In three of the six patients, a total of 11 point mutations of theORF were detected in the DLL cells. Four of them, at positions 29, 46, 59,and 106, yielded amino acid replacements. Conclusions: These findings demonstrate that FL and DLL cells may beclonally related or unrelated. They also show that transformation of FL cellscan be associated with somatic point mutations of the bcl-2 oncogene ORFsequence resulting in alteration of the p26-bcl-2a gene product.

Notes: Abstract Background: Castleman's disease or angiofollicular lymph node hyperplasia is a rare entity with a localized/unicentric or a generalized/multicentric presentation. Whilie surgery is curable for most localized presentations, there is limited information regarding the optimal management of the multicentric type. The latter type is associated with a poor prognoses and can be associated with the development of lymphoma and infections. Patients and methods: In this report we describe a case of multicentric Castleman's disease who failed steroids and chemotherapy and developed a follicular mixed lymphoma. He was treated with high-dose chemotherapy with autologous stem-cell support and remains disease at four years of follow-up. Conclusions: A long-term durable remission may be possible with high dose chemotherapy with stem-cell support. This treatment modality should be considered an option in the management of multicentric Castleman's disease.

Notes: Summary To determine whether lymphoid antigens and cellular morphology can be preserved after long-distance transport in buffer or cell culture medium, we stained cryostat sections prepared from human tonsil samples that had been kept at 4°C or 20°C for 24, 48 or 72 h. B-Cell antigens, T-cell antigens, and Ia antigens were well preserved after storage up to 72 h in buffer or medium at 4°C. Interstitial immunoglobulin (Ig) was decreased following all incubation procedures. We then investigated methods to diminish interstitial Ig in cryostat sections, since it would be inconvenient to keep 2–3 mm tissue slices in buffer or medium prior to freezing and subsequent Ig staining. Cryostat sections were air dried or briefly fixed in acetone prior to washing in buffer or medium at 4°C, 20°C or 37°C for 1, 2 or 24 h. Then sections were air dried or washed prior to acetone fixation and immunostaining. A method for washing cryostat sections was developed which diminished interstitial Ig without compromising the quality of immunostaining or cellular detail. These methods are especially useful for studying samples of lymphoid tissue in which the presence of large quantities of interstitial Ig obscures the detection of monotypic Ig staining patterns.