There is controversy over the histogenesis of Kaposi's sarcoma (KS) from lymphatic or blood vessel endothelium. D2-40 is a novel monoclonal antibody to an Mr 40,000 O-linked sialoglycoprotein that reacts with a fixation-resistant epitope on lymphatic endothelium. We sought to establish the selectivity of D2-40 for lymphatic endothelium in normal tissues and compare its reactivity with the expression of the widely used vascular endothelial marker CD31 in a series of 62 formalin-fixed and paraffin-embedded vascular lesions including KS. In normal tissues, D2-40 stained the endothelium of lymphatic channels but not of blood vessels, including arteries and capillaries defined by reactivity with the blood vessel endothelial marker PAL-E. In our series of vascular lesions, D2-40 stained lymphangiomas (10/10), benign tumors of undisputed lymphatic origin, but not benign neoplasms or tumorlike lesions of blood vessel origin, including hemangiomas (0/10), glomus tumors (0/3), angiolipomas (0/2), pyogenic granulomas (0/2), vascular malformations (0/2), hemangiopericytoma (0/1), or hemangioendothelioma (0/1). D2-40 stained all cases of cutaneous KS (24/24) at all stages of progression, including patch, plaque, and nodular stages, supporting the concept that this disease originates from a cell type capable of undergoing lymphatic differentiation. D2-40 also stained three of seven angiosarcomas, indicating that a subset of these tumors can undergo at least partial differentiation along the lymphatic endothelial lineage and could be classified as lymphangiosarcomas. In comparison, CD31 was expressed in all benign and malignant vascular lesions, except for glomus tumors (0/3) and 5/10 lymphangiomas, in which staining was absent. We conclude that D2-40 is a new selective marker of lymphatic endothelium in normal tissues and vascular lesions and is valuable for studying benign and malignant vascular disorders in routinely processed tissue specimens.

M2A antigen is an oncofetal antigen associated with germ cell neoplasia, present in testis on fetal gonocytes and re-expressed on carcinoma in situ (CIS) and germ cell tumours. We developed a panel of monoclonal antibodies (mAb), M2A (IgG2a), D1-26 (IgG2b) and D2-40 (IgG1), to this antigen in order to characterize its structure and study its distribution among germ cell tumours. M2A antigen was purified by sequential lectin and antibody affinity chromatography and characterized as a monomeric M r 40 000 surface sialoglycoprotein, extensively glycosylated with O-linked carbohydrate structures, but devoid of N-linked sugars. Terminal sialic acid residues were required for reactivity with mAb M2A and D1-26, but not D2-40. Sections of 69 testicular germ cell tumours, fixed in formalin and embedded in paraffin, were stained with mAb D2-40 to examine the distribution of M2A antigen. Uniform membrane staining was observed in seminomas, and focal staining in 69% of embryonal carcinomas, 29% of teratomas and 25% of yolk sac tumours. CIS in the vicinity of all germ cell tumours also displayed uniform membrane staining. The characterization of M2A antigen, and the development of mAb which react with it in conventionally preserved archival specimens, provide important initiatives to study the origin and progression of germ cell neoplasia. © 1999 Cancer Research Campaign

To study the relationship between abnormal Sertoli cell differentiation and spermatogenic impairment, we examined the expression of Sertoli cell markers normally lost at puberty, cytokeratin 18 (CK18), anti-Müllerian hormone (AMH) and M2A antigen, in three children (aged 1-2 years), 50 adults (aged 19-45 years) with obstructive or non-obstructive azoospermia or oligozoospermia, and six patients (aged 1-18 years) with 5 alpha-reductase deficiency. There was CK18 and/or AMH expression, but never M2A antigen expression, associated with spermatogonial arrest or Sertoli cell-only (SCO) syndrome in infertile men. Loss of M2A antigen suggests the transition of Sertoli cells to an adult phenotype, while CK18 and/or AMH expression may be a manifestation of de-differentiation of Sertoli cells. In 5 alpha-reductase deficiency, there was a sequential loss of CK18, M2A antigen and AMH around puberty, associated with partial spermatogenesis. The persistence of immature Sertoli cells expressing M2A antigen was associated with prepubertal seminiferous cords and SCO syndrome. Therefore, 5 alpha-reductase deficiency may prevent the maturation of Sertoli cells, resulting in impairment of spermatogenesis, and loss of M2A antigen expression coincides with a critical step in the Sertoli cell maturation. High follicle stimulating hormone concentrations due to failure of normal Sertoli cell differentiation indicate a normal development pattern of the hypothalamic-pituitary-gonadal axis.

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We have identified and biochemically characterized an antigen, 8A3, which is expressed on activated T lymphoblasts and activated platelets. Monoclonal antibodies to 8A3 were raised against the primitive lymphoid/myeloid cell line KG1a and additionally bound to the erythroleukemia-derived cell line HEL, whilst exhibiting little or no reactivity with a panel of other hematopoietic cell lines. The 8A3 antigen was expressed on poorly differentiated T-cell leukemias and on phytohemagglutinin-activated T-cells maintained in interleukin-2 (7,000 sites/cell). This antigen, though not detected on resting platelets, was expressed on thrombin-activated platelets (2,000 sites/platelet). Antibodies to 8A3 identified polypeptides of Mr 170,000 and 150,000 in lysates of surface-iodinated KG1a cells, T lymphoblasts, and activated platelets under both reducing and nonreducing conditions. However, peptide mapping and susceptibily to glycosidases indicated that the 8A3 antigen was a monomeric glycoprotein of Mr 170,000 which contained two N-linked endoglycosidase H-sensitive glycans, and that the Mr 150,000 structure was derived from it by proteolytic degradation. The 8A3 antigen was not detectably phosphorylated in KG1a cells in vivo, nor did immune complexes containing it exhibit kinase activity in vitro. Structural and serologic characteristics of the 8A3 antigen indicate that it is different from other previously described leukocyte activation antigens including transferrin receptors, interleukin-2 receptors, members of the integrin family of adhesion molecules, or “restricted” members of the leukocyte-common antigen/CD45 cluster. Furthermore, the 8A3 antigen does not appear to be related to the other previously described activation-specific platelet molecule, GMP140/PADGEM. This antibody may be useful in monitoring T-cell activation status in some clinical situations and in characterizing clinically relevant activation-associated platelet membrane alterations.

Objective. To determine which measure of the salivary flow rate, stimulated or unstimulated, is most strongly associated with pathologic changes in minor salivary gland (MSG) biopsy specimens, and to explore the correlation of salivary flow with oral surface damage, disease duration, and symptom severity in patients with primary Sjögren's syndrome (SS).Methods. In all patients (n ‫؍‬ 32), a biopsy of the MSG was performed, and stimulated salivary flow was assessed. Beginning in 2002, unstimulated salivary flow was also assessed. Scores for the severity of symptoms, according to the decayed/missing/filled teeth (DMF) index, were recorded. Associations between measures of salivary flow and covariates characterizing pathology were examined.Results. A definite association between stimulated salivary flow and the MSG focus score, the grade of MSG fibrosis, the duration of dry mouth symptoms, and the DMF score was observed. In contrast, unstimulated salivary flow was not associated with fibrosis, atrophy, the DMF score, or the duration of dry mouth symptoms. In patients with primary SS, the DMF score was associated with pathologic changes in the MSG. Among patients with sicca, 57.9% had an abnormal unstimulated salivary flow rate (versus 82.4% of patients with primary SS), and 15.2% had an abnormal stimulated salivary flow rate (versus 61.8% of patients with primary SS). Among patients with sicca, neither stimulated salivary flow nor unstimulated salivary flow was associated with the degree of fibrosis or atrophy or with the DMF score.

Sclerosing angiomatoid nodular transformation (SANT) is a splenic lesion composed of angiomatoid/vascular nodules surrounded by hyalinized/sclerotic stroma, fibroblasts, myofibroblasts, and inflammatory cells. The endothelium within the nodules has a phenotype resembling splenic sinusoids, capillaries, and small veins. Martel et al. (Am J Surg Pathol 28:1268-1279, 2004) suggested that SANT may represent the final pathway of a variety of splenic lesions including inflammatory pseudotumors (IPTs). Epstein-Barr virus (EBV) has a role in the genesis of some splenic IPTs, but its presence in SANT has not been investigated. Six cases of SANT are reported. All were stained for CD31, CD34, CD8, CD68, smooth muscle actin, muscle-specific actin, and CD30 and were tested for EBV by in situ hybridization (EBER). All cases showed angiomatoid nodules with complex expression of CD31, CD34, and CD8, with focal CD68. Expression of CD30 by endothelial cells was also seen. One case had small diffuse areas lacking nodules resembling an IPT and was positive for EBV. The inflammatory cells and the normal spleen were negative for CD30 and EBER. In conclusion, SANT shows upregulation of CD30 with respect to normal spleen. The presence of EBV in the stromal cells of a case supports the notion that a subset of SANT may be related to IPT.

BACKGROUND: Fluorescence in situ hybridization (FISH) results from fine needle aspirates (FNA) of B‐cell non‐Hodgkin lymphomas (NHLs) were reviewed to 1) investigate the value added by using specific gene rearrangement probes to lymphoma diagnosis, prognosis, and subtyping; and 2) evaluate the prevalence of cytogenetic alterations other than specific translocations. METHODS: FISH results from assays performed on cytospin preparations from NHL FNAs over a 6‐year period (2003‐2009) were selected. Immunophenotyping, clinical data, and cytomorphologic data were reviewed according to the current World Health Organization (WHO) classification system. Hybridized probes, the purpose for the assay (subtyping or prognosis), and the cytogenetic abnormalities observed were retrieved from cytology reports. Data was categorized according to specific rearrangements and other chromosomal abnormalities. RESULTS: Successful results were obtained in 284 (95.3%) of 298 cases from 282 patients. Abnormalities were found in 216 (76%) cases and 68 (24%) did not show alteration. Among cases submitted for subtyping, 198 showed FISH‐positive results, and specific gene rearrangements were found in 122 (61.6%) cases as follows: follicular 82, mantle cell 21, marginal zone 3, “dual hit” 13, and Burkitt lymphoma 3. In 21 cases, abnormalities were useful for prognosis. Nonspecific alterations alone or in combination with translocations were found in 98 cases. CONCLUSIONS: FISH performed on cytospin preparations was useful for confirmation of specific subclasses of NHL and may also provide valuable prognostic information. Cytogenetic abnormalities other than specific translocations were frequently found and could provide supportive evidence for a definitive diagnosis of lymphoma in FNA. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.